Wafer-Level Time-of-Flight Sensor Fabrication
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Solution Overview
Problem
Current methods for fabricating Time-of-Flight sensor devices are inefficient, requiring numerous processing steps and time-consuming assembly, which hinders the production of large quantities with high precision.
Innovation Solution
A method utilizing Nano Imprint Lithography and wafer-level molding to create a wafer-level package with integrated lenses, where a light emitter device and light detecting areas are encapsulated in separate volumes of transparent material, with an opaque material acting as an optical barrier, allowing for accurate time measurement without electronic signal reliance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional assembly methods are used for fabricating Time-of-Flight sensor devices, then each device can be assembled individually, but the production time is long and the number of processing steps is large
Solution Approach 1:
The patent merges multiple individual device assembly operations into a single wafer-level packaging process. Multiple sensor devices are fabricated and assembled simultaneously on a common wafer substrate, integrating lens attachment, light emitter mounting, and optical path configuration into one unified process step, thereby dramatically increasing productivity and reducing the total number of processing steps required.
Solution Approach 2:
The wafer is divided into multiple wafer portions, each containing a complete sensor device with its own light emitter, light detecting areas, and optical reference path. This segmentation allows parallel processing of multiple devices while maintaining the integrity of each individual sensor unit, enabling high-volume production without sacrificing device performance.
2Measurement precision
If electronic signals are used to start the timer, then the timing mechanism is simple, but the measurement precision is reduced
Solution Approach 1:
The patent introduces an optical reference path as an intermediary mechanism between the light emitter and the timer start trigger. Instead of using electronic signals, scattered light from the light emitter serves as the intermediary that directly triggers the timer start, providing a more precise and physically direct measurement reference that eliminates electronic signal delays and synchronization errors.
Solution Approach 2:
The patent replaces the electronic signal-based timer triggering mechanism with an optical-based triggering mechanism. The scattered light from the light emitter directly activates the timer, substituting electronic signal transmission with optical field interaction, thereby achieving higher measurement precision through a more fundamental physical reference.
3Measurement precision
If light detecting areas are not optically isolated, then the structure is simpler, but the first light detecting area receives reflected light causing measurement errors
Solution Approach 1:
The patent segments the optical detection space by dividing it into separate optical zones using an opaque material barrier. This segmentation creates distinct optical paths for the light emitter and the two light detecting areas, preventing optical crosstalk and ensuring that each detector receives only its intended signal, thereby maintaining measurement precision while managing optical isolation requirements.
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 approach reduces assembly costs and enables the production of high-precision Time-of-Flight sensor devices with reduced footprint, improved resolution in multiple directions, and enhanced accuracy by eliminating the need for electronic signal initiation, thus improving product performance and efficiency.
Implementation Method 1
The first light detecting area is disposed close to the light emitter device so that scattered light emitted from the light emitter device is received from the first light detecting area
Implementation Method 2
An opaque material is placed on the wafer portions in a space between the respective first and second volume of the light transparent material
Data Source
AI summary
A method for fabricating a plurality of Time-of-Flight sensor devices (1) comprises a step of providing a wafer (100) including a plurality of wafer portions (110) for a respective one of the Time-of-Flight sensor devices (1), wherein each of the wafer portions (110) includes a first light detecting area (10) and a second light detecting area (20) and a respective light emitter device (30). The respective light emitter device (30) and the respective first light detecting area (10) is encapsulated by a first volume (40) of a light transparent material (130), and the respective second light detecting area (20) is encapsulated by a second volume (50) of the light transparent material (130). Before singulation of the devices (1), an opaque material (60) is placed on the wafer portions (110) in a space (120) between the respective first and second volume (40, 50) of the light transparent material (130).