Pressure Sensor Support Body Trench Design for Thermomechanical Stress Reduction
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Solution Overview
Problem
Pressure measuring devices face challenges in reducing thermomechanical stresses on semiconductor pressure sensors due to differing thermal expansion coefficients between the sensor and its housing, leading to measurement inaccuracies and increased manufacturing complexity and cost.
Innovation Solution
A pressure measuring device design featuring a support body with trenches on its end face, where the first trench surrounds the joint surface with the pressure sensor, limiting the joint area and absorbing excess joining material, and a second trench on the carrier side to reduce thermomechanical coupling, allowing for a larger support body with a simpler shape that can be produced and mounted more easily.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the base area of the support body is reduced to minimize thermomechanical stresses on the pressure sensor, then measurement accuracy improves, but manufacturing precision and alignment difficulty worsen
Solution Approach 1:
The support body is segmented into two distinct functional zones: a large base area for stable mounting and alignment on the carrier, and a smaller joint area (defined by the trench) for bonding the pressure sensor. This segmentation allows each zone to optimize its function without compromising the other.
Solution Approach 2:
Different regions of the support body are given different properties: the base area has a larger surface for stable attachment to the carrier, while the joint area (within the trench) has a smaller surface for pressure sensor bonding. This local differentiation resolves the contradiction between needing a small joint area for accuracy and a large base area for manufacturability.
2Object-affected harmful factors
If the base area of the support body is significantly smaller than the pressure sensor area, then thermomechanical stresses are reduced, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The support body structure is segmented with a trench that creates distinct functional zones, separating the mounting function (large base) from the sensor bonding function (small joint area within trench). This segmentation achieves stress reduction without requiring an overall small support body.
Solution Approach 2:
The trench acts as an intermediary structure that mediates between the carrier and the pressure sensor. It provides a controlled joint area for sensor attachment while the larger base area provides stable support, thus reducing thermomechanical stresses without increasing overall device complexity.
3Ease of manufacture
If the support body is made larger and simpler in shape, then ease of manufacture improves, but the joint area with the pressure sensor increases, potentially increasing thermomechanical stresses
Solution Approach 1:
The support body is segmented by the trench into a large base area for easy manufacturing and mounting, and a smaller joint area (within the trench) for pressure sensor attachment. This allows the overall support body to be large and simple for ease of manufacture, while the segmented joint area remains small to minimize thermomechanical stresses.
Solution Approach 2:
The support body exhibits local quality differentiation: the overall structure is large and simple for ease of manufacture, but the local joint area (defined by the trench) is smaller and specifically configured to minimize thermomechanical stresses on the pressure sensor.
4Object-affected harmful factors
If a smaller base area is used for the support body, then thermomechanical coupling is reduced, but adhesive introduction and alignment become more difficult
Solution Approach 1:
The support body is segmented with a trench that creates a well-defined joint area. This segmentation provides a clear target for adhesive introduction and ensures proper alignment, making the bonding process easier despite the relatively small joint area.
Solution Approach 2:
The trench is pre-formed in the support body before the bonding process. This preliminary action creates a ready-made receptacle for the adhesive and pressure sensor, facilitating easier and more precise adhesive introduction and alignment without requiring real-time adjustment during assembly.
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 effectively reduces thermomechanical stresses on the pressure sensor, improves measurement accuracy, and simplifies and cost-reduces the manufacturing process by using a larger, easier-to-produce support body with a smaller joint area, while absorbing excess joining material and enhancing thermomechanical decoupling.
Implementation Method 1
the first trench has a width that is greater than or equal to a minimum width of 150 μm to 1 mm, and the first trench has a depth (that is greater than or equal to a minimum depth of 0.3 mm to 2 mm... excess joining material is received by the first trench
Implementation Method 2
a first joint which connects the supporting body to the pressure sensor and comprises a joining material
Implementation Method 3
a second joint which comprises a joining material and connects the supporting body to the carrier
Implementation Method 4
Housing and pressure sensor are therefore made of materials that have very different thermal expansion coefficients. Due to the mechanical connection between housing and pressure sensor required for sensor installation, thermomechanical stresses can therefore occur
Implementation Method 5
the first trench surrounds a joint surface of the support body (3) facing the pressure sensor... the joint surface of the support body and a base surface of the first joint are essentially the same size and actually smaller than a base surface of the pressure sensor facing the first joint
Data Source
Figure 1~3
Figure 4~6
Figure 7
AI summary
The invention relates to a pressure measuring device that can be cost-effectively produced and comprises a carrier (1), a support body (3) arranged on the carrier (1), a pressure sensor (5) arranged on the support body (3), a first join (17) containing a joining material and connecting the support body (3) to the pressure sensor (5), and a second join (19) containing a joining material and connecting the support body (3) to the carrier (1), wherein the pressure sensor is protected against thermomechanical tensions, wherein the support body (3) has a first groove (21) on the end side thereof facing the pressure sensor (5), which groove is designed in such a way that the first groove (21) externally completely surrounds a joining surface (23) of the support body (3) facing the pressure sensor (5), the joining surface (23) of the support body (3) and a base surface of the first join (17) are substantially the same size or purely smaller than a base surface of the pressure sensor (5) facing the first join (17), the first groove (21) has a width (b) that is greater than or equal to a minimum width of 150 μm to 1 mm, and the first groove (21) has a depth (t) that is greater than or equal to a minimum depth of 0.3 mm to 2 mm.