Semiconductor Pressure Sensor Lead Segmentation
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Solution Overview
Problem
Conventional semiconductor devices with semiconductor sensor chips for detecting pressure variations, such as sound pressure, face challenges in downsizing and stable mounting on printed-circuit boards due to unstable installation and the need for precise alignment of cover members for electromagnetic shielding.
Innovation Solution
A semiconductor device design where a semiconductor sensor chip with a diaphragm is mounted on a substrate with exposed chip connection leads and packaging leads, allowing for stable mounting on a printed-circuit board, and a cover member with electromagnetic shield terminals is used to form a hollow space embracing the sensor chip, ensuring easy electromagnetic shielding without requiring high precision in assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If outer leads are arranged only in one long side of a package to downsize the device, then the device size is reduced, but the installation stability on the printed-circuit board deteriorates
Solution Approach 1:
The lead arrangement is segmented into two distinct groups: chip connection leads arranged along one long side for electrical connection, and packaging leads arranged along the opposite long side for mechanical support and stability. This segmentation allows each group to fulfill its specific function optimally while maintaining a compact package size.
2Object-affected harmful factors
If the cover member is precisely aligned with connection terminals for electromagnetic shielding, then the shielding effectiveness is improved, but the assembly complexity and difficulty increase
Solution Approach 1:
The cover member is designed with an equipotential structure where the entire lower surface forms a uniform electromagnetic shield at the same potential level. This eliminates the need for precise point-to-point alignment with individual connection terminals, as the entire surface provides continuous shielding coverage, greatly simplifying the assembly process.
Solution Approach 2:
The cover member's lower surface automatically provides electromagnetic shielding coverage for all connection terminals and internal spaces through its inherent design, without requiring additional alignment features or complex positioning mechanisms. The shielding function is self-realized through the cover member's placement on the substrate.
3Measurement precision
If the diaphragm size is increased to improve detection sensitivity, then the detection sensitivity is improved, but the device size increases
Solution Approach 1:
The diaphragm is positioned in a three-dimensional internal space formed between the substrate and cover member, utilizing the vertical dimension for detection sensitivity while keeping the horizontal footprint compact. This allows a relatively large diaphragm area for sensitivity without proportionally increasing the overall device package size.
Solution Approach 2:
The diaphragm is nested within the hollow internal space created by the substrate and cover member, allowing the detection element to be contained within the package boundaries rather than extending the package footprint. The internal space efficiently accommodates the diaphragm structure.
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 design enables downsizing of semiconductor devices while maintaining detection sensitivity and effectively blocking electromagnetic noise, ensuring stable and accurate detection of pressure variations without the need for precise cover member alignment.
Implementation Method 1
a semiconductor sensor chip having a diaphragm for detecting pressure variations based on the displacement of the diaphragm
Implementation Method 2
Conductive layers are formed on the interior surfaces of the cover members so as to block electromagnetic noise, which is transmitted into the internal spaces via the opening holes, from being transmitted toward the semiconductor sensor chips by way of electromagnetic shields
Implementation Method 3
the bridge-resistance circuits detect the displacement (or deformation) of the diaphragms caused by sound pressure as variations of electric resistance
Data Source
AI summary
A semiconductor device is designed such that a semiconductor sensor chip having a diaphragm for detecting pressure variations based on the displacement thereof is fixed onto the upper surface of a substrate having a rectangular shape, which is covered with a cover member so as to form a hollow space embracing the semiconductor sensor chip between the substrate and the cover member. Herein, the substrate is sealed with a molded resin such that chip connection leads packaging leads are partially exposed externally of the molded resin; the chip connection leads are electrically connected to the semiconductor sensor chip and are disposed in line along one side of the semiconductor sensor chip; and the packaging leads are positioned opposite the chip connection leads by way of the semiconductor sensor chip. Thus, it is possible to downsize the semiconductor device without substantially changing the size of the semiconductor sensor chip.