Wafer-Level Sensor Packaging for Angular Alignment
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Solution Overview
Problem
Traditional semiconductor packaging methods face challenges in achieving precise angular alignment of sensors, leading to inaccuracies in measurements, and are costly due to the need for high-temperature processes and hermetic sealing, especially when packaging sensors and microelectronic devices of differing sizes.
Innovation Solution
A wafer-level packaging technique is employed, where sensors and microelectronic devices are packaged at the wafer level, allowing for high-throughput and precise placement, enabling accurate angular alignment and size reduction through the use of a composite sensor structure and mold material to match the footprint of controller dies, and incorporating conductive elements for improved electrical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional semiconductor packaging methods are used, then hermetic sealing and high-temperature processes are required, but packaging costs increase significantly
Solution Approach 1:
The patent changes the packaging parameters by eliminating hermetic sealing and high-temperature processes. Instead, it uses low-temperature die attach materials and standard packaging processes, transforming the packaging approach from high-reliability hermetic to cost-effective non-hermetic while maintaining sufficient performance for the application
Solution Approach 2:
The patent adopts non-hermetic packaging with standard die attach materials that are less expensive than hermetic sealing solutions. The package accepts reduced protection requirements in exchange for lower manufacturing costs, effectively trading some reliability for economic efficiency
2Manufacturing precision
If sensors and microelectronic devices of differing sizes are packaged using traditional methods, then precise angular alignment is difficult to achieve, but measurement accuracy decreases
Solution Approach 1:
The patent introduces an intermediary alignment structure consisting of alignment marks and fiducial features on the sensor die and package substrate. These intermediary elements mediate the alignment process, enabling precise angular positioning of differently-sized components through standardized marking and registration techniques
Solution Approach 2:
The patent performs preliminary alignment mark formation and fiducial feature creation during the sensor die fabrication process. By pre-establishing alignment references before packaging, the system enables accurate angular alignment during assembly without requiring complex real-time adjustment mechanisms
3Productivity
If wafer-level packaging is used for high-throughput production, then productivity increases, but handling sensors of differing sizes becomes more complex
Solution Approach 1:
The patent creates a universal package substrate design with standardized alignment marks, die attach areas, and sealing structures that can accommodate sensors of varying sizes. This multi-functional platform enables high-throughput wafer-level packaging of different sensor types without requiring separate handling procedures for each size variant
Solution Approach 2:
The patent segments the packaging process into standardized stages: wafer-level die attach, panel-level encapsulation, and individual package singulation. This segmentation allows high-throughput processing of multiple sensors simultaneously while managing size variations through modular process steps rather than complex integrated operations
Data Source
AI summary
A method (90) entails placing (124) sensor elements (122) in an array (126) arranged to correspond with locations of controller dies (24) in a controller wafer (94) and encapsulating (128) the array (126) in a mold material (74) to form a panel (130) of the sensor elements (122). The sensor elements (122) include bond pads (42) that are concealed by a material section (116, 118) of the sensor elements (122). The controller wafer (94) is bonded (134) to the panel (130) to form a stacked wafer structure (136). After bonding, methodology (90) entails forming (140) conductive elements (60) on the controller wafer (95), removing material sections (100) from the controller wafer (94) and removing the material sections (116, 118) from the sensor elements (122) to expose the bond pads (42), forming (148) electrical interconnects (56), applying (152) packaging material (64), and singulating to produce sensor packages (20, 76).