Semiconductor Pressure Sensor With Overlapping Pads
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Solution Overview
Problem
Conventional semiconductor pressure sensors face challenges in reducing the total area and improving production yield, while also requiring multiple power supply units and lacking redundancy in pressure measurement.
Innovation Solution
A semiconductor pressure sensor design featuring five conductive connection pads forming a single or two full Wheatstone bridges, with overlapping pads to minimize area and four semiconductor resistance units that adjust resistance in response to external pressure, allowing for a single power supply and independent pressure measurement using two full Wheatstone bridges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If connection pads are arranged in parallel without overlapping, then electrical connection reliability is improved, but total area of the sensor increases
Solution Approach 1:
The connection pads are arranged in a parallel configuration along the longitudinal direction of the semiconductor chip rather than being distributed in a two-dimensional grid. This one-dimensional arrangement reduces the total area occupied by the pads while maintaining adequate spacing for reliable wire bonding along the length of the chip.
2Reliability
If multiple power supply units are used, then pressure measurement redundancy is improved, but device complexity increases
Solution Approach 1:
Two full Wheatstone bridge circuits share a common power supply unit and common connection pads. The first full bridge uses resistors R1-R4 with power supply pad P3, and the second full bridge uses resistors R5-R8 with the same power supply pad P3. This merging approach provides measurement redundancy through two independent bridge circuits while avoiding the complexity of separate power supply units for each bridge.
3Productivity
If connection pads are overlapped to reduce area, then production yield is improved, but wire bonding area is reduced
Solution Approach 1:
Connection pads are extended in the longitudinal direction of the chip to provide sufficient wire bonding area. The parallel arrangement along the length of the chip allows pads to be sufficiently long for reliable bonding while keeping the transverse width minimal, thus reducing total area without compromising bonding capability.
4Device complexity
If five connection pads are used for single full bridge, then power supply efficiency is improved, but measurement versatility is reduced
Solution Approach 1:
The five connection pads (P1-P5) serve dual functions: they constitute a complete full Wheatstone bridge circuit for pressure measurement, and simultaneously provide common power supply connections for multiple bridge circuits. P3 serves as a common power supply pad for both bridges, and P1/P2 or P4/P5 can serve as output pads depending on which bridge is active, enabling versatile measurement capabilities with minimal pads.
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 design simplifies manufacturing, reduces costs, enhances production yield, and improves pressure measurement accuracy by enabling comparison of two pressure values and providing redundancy in case of component failure.
Implementation Method 1
four semiconductor resistance units connecting a predetermined pair of the connection pads to each other among the connection pads and having resistance values varying in proportion to a variation of a length due to the external pressure
Implementation Method 2
The pressure sensor includes a Wheatstone bridge to which a voltage is applied, so that, when an external pressure is applied to the Wheatstone bridge, the resistance value of the semiconductor generated due to physical bending is measured to detect a degree of pressure
Data Source
AI summary
Provided is a semiconductor pressure sensor which includes: five connection pads having plate shapes and formed of conductive materials, respectively, and arranged in parallel with each other; and four semiconductor resistance units connecting a predetermined pair of the connection pads to each other among the connection pads and having resistance values varying in proportion to a variation of a length due to the external pressure, wherein the five connection pads include a power supply pad, a first output voltage pad, a first ground pad, a second output voltage pad, and a second ground pad.