CMUT Singulation Using Pre-Formed Trenches to Prevent Edge Damage
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Solution Overview
Problem
Mechanical singulation methods for micro-machined ultrasonic transducers (MUTs) often damage electrode pads due to vibrations during cutting, leading to reduced yield and quality of singulated MUTs.
Innovation Solution
The method involves forming trenches in advance on the device and electrode pad wafers, using a dry etching process, with the trenches being wider than the saw blade, allowing for precise cutting and minimizing damage during dicing, and forming protrusions on the edges of the singulated transducers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If mechanical singulation method is used to separate MUTs, then the MUTs can be singulated, but edges of the MUTs are damaged due to vibrations during cutting
Solution Approach 1:
Trenches are formed in advance at the cutting regions of the MUTs before the mechanical singulation process. This preliminary action creates a pre-defined cutting path that guides the saw blade, preventing vibrations from affecting the electrode pads and reducing edge damage during the actual cutting operation.
2Productivity
If mechanical cutting is performed on MUTs with cavities, then the MUTs can be separated, but vibrations cause the cut region to expand and damage electrode pads
Solution Approach 1:
Trenches are formed in advance at the cutting regions of the MUTs before the mechanical singulation process. This preliminary action creates a pre-defined cutting path that guides the saw blade, preventing vibrations from affecting the electrode pads and reducing edge damage during the actual cutting operation.
3Manufacturing precision
If trenches are formed wider than the saw blade, then cutting precision is improved and edge damage is reduced, but the manufacturing process becomes more complex
Solution Approach 1:
Trenches are formed in advance at the cutting regions of the MUTs before the mechanical singulation process. This preliminary action creates a pre-defined cutting path that guides the saw blade, preventing vibrations from affecting the electrode pads and reducing edge damage during the actual cutting operation.
Solution Approach 2:
The trenches act as an intermediary structure between the design layout and the final cut. They provide a physical guide that mediates the interaction between the saw blade and the MUT, ensuring precise cutting while protecting sensitive regions from vibration-induced damage.
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 edge damage and increases the yield of singulated capacitive micro-machined ultrasonic transducers by allowing for cleaner cuts and minimizing product failure rates.
Implementation Method 1
forming first trenches in regions of a device wafer, the device wafer including a plurality of the ultrasonic transducer structures thereon
Data Source
AI summary
A capacitive micro-machined ultrasonic transducer (CMUT) and a method of singulating the same. Singulating CMUTs may include forming first trenches in regions of a device wafer defining a plurality of ultrasonic transducer structures, the device wafer including a plurality of the ultrasonic transducer structures, forming an ultrasonic transducer wafer having a plurality of ultrasonic transducers by bonding an electrode pad wafer supplying electricity to the plurality of ultrasonic transducers and the device wafer, and dicing the ultrasonic transducer wafer to form the plurality of ultrasonic transducers by cutting the plurality of ultrasonic transducer structures on the first trench and the electrode pad wafer below the first trench.