Stacked Sensor Die Assembly for Redundant Measurement Alignment
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Solution Overview
Problem
Existing sensor devices with redundant substrates require a larger footprint and are complicated to assemble, with misaligned sensors leading to inconsistent measurement results, particularly in automotive applications.
Innovation Solution
A sensor device with two stacked semiconductor dies, each with a sensor structure, where one die is rotated and shifted relative to the other such that their sensor locations align orthogonally, allowing for easy electrical connection and consistent measurement at the same location without the need for spacers or interposers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two substrates are placed side by side to provide redundant sensor measurements, then measurement redundancy is achieved, but package footprint increases
Solution Approach 1:
The patent transitions from a planar side-by-side substrate arrangement to a three-dimensional stacked configuration. The first and second substrates are positioned at different vertical levels (first level and second level), allowing redundant sensor measurements to be achieved without increasing the horizontal package footprint. This dimensional change enables compact integration while maintaining measurement redundancy.
2Area of stationary object
If substrates are stacked on top of each other to decrease footprint, then package footprint is reduced, but sensor alignment precision deteriorates
Solution Approach 1:
The patent introduces asymmetric positioning of sensor structures on the stacked substrates. The first sensor structure and second sensor structure are deliberately positioned at different horizontal locations on their respective substrates. By rotating one substrate relative to the other, the sensor structures are aligned vertically despite their asymmetric initial positions, achieving precise alignment without requiring high manufacturing precision in the stacking process.
Solution Approach 2:
The patent performs preliminary rotation of one substrate relative to the other before final stacking. This preliminary action pre-aligns the sensor structures so that when the substrates are stacked, the sensors are already in vertical alignment. This approach transfers the alignment requirement from the stacking process to the substrate preparation stage, where rotation can be more easily controlled.
3Measurement precision
If substrates are stacked with rotation and shift to align sensors, then measurement consistency improves, but device complexity increases
Solution Approach 1:
The patent uses asymmetric sensor positioning combined with substrate rotation to achieve alignment. Instead of requiring precise centralized positioning, the asymmetric configuration allows sensors to be aligned by rotating one substrate to a specific angle relative to the other. This simplifies the stacking configuration by replacing precision positioning requirements with a rotational alignment approach.
Data Source
Figure 1~2
Figure 3~4(b)
Figure 5(a)~6(b)
AI summary
A sensor device (1) comprising: a lead frame (9); a first/second semiconductor die (2a) having a first/second sensor structure (4a, 14a) at a first/second sensor location (L1, L2), and a plurality of first/second bond pads (7a, 7b) electrically connected to the lead frame (9); the semiconductor dies having a square or rectangular shape with a geometric center (6a); the sensor locations (L1, L2) are offset from the geometrical centers; the second die (2b) is stacked on top of the first die (2a), and is rotated by a non-zero angle and optionally also offset or shifted (DX, DY) with respect to the first die (2a), such that a perpendicular projection of the first and second sensor location (L1, L2) coincide.