Sensor Array Transfer Assembly for Fine-Pitch Tactile Sensing
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Solution Overview
Problem
Conventional methods for transferring and integrating sensor arrays face challenges, particularly with small devices where vacuum chucks struggle to overcome adhesion, and existing sensor arrays lack the sensitivity and precision required for human-scale tactile sensing applications.
Innovation Solution
A method involving the use of donor substrates with suspended sensors and tethers, allowing transfer to receiving substrates using vacuum chucks, and integration of sensor packages with IC dies for signal conditioning, which includes piezoelectric or capacitive sensing materials and AFE/ADC circuitry to enhance sensitivity and reduce latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If vacuum chucks are used to hold individual diced sensors, then transfer capability is enabled, but adhesion forces prevent successful transfer of small sensors
Solution Approach 1:
The invention segments the sensor array into individual diced sensors that can be independently transferred. Each sensor is separated from the wafer and held by a vacuum chuck during transfer, allowing selective placement on the substrate without transferring the entire wafer.
Solution Approach 2:
The vacuum chuck acts as an intermediary tool between the sensor wafer and the substrate. It provides a controlled vacuum environment to hold sensors during transfer, mediating the interaction between the sensor array and the target substrate to enable precise placement.
2Area of stationary object
If sensor arrays are arranged in geometric configurations to cover wide areas, then sensing coverage is improved, but manufacturing complexity increases
Solution Approach 1:
The large sensor array is divided into multiple individual sensor elements that can be independently manufactured on a wafer. These segmented sensors are then transferred and arranged in the desired geometric configuration on the substrate, simplifying the manufacturing of each individual sensor while achieving complex overall patterns.
Solution Approach 2:
The invention transitions from two-dimensional wafer processing to three-dimensional assembly. Sensors are first fabricated on a planar wafer, then lifted and positioned in three-dimensional space on the substrate, allowing flexible geometric arrangements that would be difficult to achieve through conventional planar manufacturing.
3Measurement precision
If piezoelectric or capacitive sensing materials are integrated with IC dies, then sensitivity and signal processing are improved, but integration complexity increases
Solution Approach 1:
The invention merges the sensor die containing piezoelectric or capacitive materials with the IC die in a stacked configuration. The sensor die is positioned on top of the IC die, combining the sensing function with signal processing circuitry in a single integrated package, thereby improving sensitivity while managing complexity through modular integration.
Solution Approach 2:
The sensor die is nested within the IC die structure, with the sensor element positioned on the top surface of the IC die. This nested arrangement allows the sensing materials to be integrated within the existing IC package footprint, reducing overall device complexity while maintaining high sensitivity.
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
Enables high-density sensor arrays to be transferred efficiently, reducing costs and achieving fine pitch, highly sensitive sensors capable of replicating human tactile sensing with reduced latency and signal loss.
Implementation Method 1
piezoelectric sensors can utilize the piezoelectric effect to detect changes in pressure, acceleration, temperature, or strain by converting such detections to an electrical charge
Implementation Method 2
capacitive sensors can utilize capacitive sensing to detect an object in proximity that may be conductive or may have a dielectric constant that is different from air
Implementation Method 3
conventional pick and place tools use a vacuum chuck to hold individual devices that are diced from a wafer
Data Source
AI summary
Sensor assemblies, sensor array transfer sequences, and methods of assembly are described. The sensors can include sensor dies as well as sensor packages including stacked sensor dies and IC dies.