Zig-Zag Bellows Actuator Ribs for Dicing Stability

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Solution Overview

Problem

The manufacturing process of MEMS structures used as actuators in optical scanning devices faces challenges during dicing, where the bellows structure is prone to vibration and damage due to low rigidity and water flow, leading to potential damage during the dicing process.

Innovation Solution

The implementation of a zig-zag bellows structure with ribs formed on the second surfaces of the beams closer to the axis, which increases the weight of the vibrating mode and reduces resonant frequency, thereby preventing damage during dicing by reducing frequency variations and stabilizing the actuator's operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the bellows structure is formed using only the active layer of the SOI substrate, then the actuator achieves the required flexibility and deformation capability, but the bellows structure has low rigidity and is prone to vibration and damage during dicing

Engineering Contradiction:

Improveflexibility of bellows structureVSAvoidrigidity of bellows structure

Core Design Contradiction:

Adaptability or versatilityVSStrength

Solution Approach 1:

The bellows structure is segmented into multiple beam elements connected by turnaround parts, creating a zig-zag configuration that provides both flexibility for actuation and structural integrity. The segmentation allows the structure to deform controllably while maintaining overall rigidity during manufacturing processes like dicing.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the bellows structure have different properties: the beam sections provide rigidity and structural support, while the turnaround parts provide flexibility and enable deformation. This local differentiation of structural qualities allows the bellows to achieve both flexibility for actuation and sufficient rigidity to resist damage during dicing.

Inventive Principle:

Principle #3Local quality

2Adaptability or versatility

If the bellows structure is formed using only the active layer of the SOI substrate, then the actuator achieves the required flexibility, but the bellows structure is not fixed to the dicing tape and is suspended during dicing

Engineering Contradiction:

Improveflexibility of bellows structureVSAvoidstability of bellows structure during dicing

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The segmented bellows structure with multiple beams and turnaround parts creates a more stable configuration that can be reliably fixed to the dicing tape. The segmentation provides multiple attachment points and distributes stresses, improving reliability during the dicing process while maintaining the flexibility needed for actuator operation.

Inventive Principle:

Principle #1Segmentation

3Productivity

If the wafer is diced while the bellows structure is suspended, then the dicing process can be completed, but the low rigidity of the bellows structure causes it to be vibrated and damaged by water flow and vibration during dicing

Engineering Contradiction:

Improvecompletion of dicing processVSAvoiddamage resistance of bellows structure

Core Design Contradiction:

ProductivityVSStrength

Solution Approach 1:

The segmented zig-zag bellows structure provides inherent structural stability that reduces susceptibility to vibration and water flow damage during dicing. The multiple beams and connection points distribute mechanical stresses and reduce the amplitude of vibrations, protecting the structure from damage while allowing the dicing process to complete successfully.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The turnaround parts in the bellows structure are designed with specific geometric properties that provide local reinforcement and stress distribution. These localized structural features increase the overall damage resistance of the bellows structure during the dicing process while maintaining the flexibility required for actuator function.

Inventive Principle:

Principle #3Local quality

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 configuration effectively prevents the bellows from being damaged during dicing while maintaining the frequency characteristics of the actuator, ensuring stable operation within a specific frequency range and reducing the risk of abnormal vibrations.

Implementation Method 1

an actuator including a piezoelectric substance, an upper electrode formed on the upper surface of the piezoelectric substance, and a lower electrode formed on the lower surface of the piezoelectric substance

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentUS11635615B2Actuator, optical scanning device, and manufacturing methods

Publication Date: 2023.04.25 MITSUMI ELECTRIC CO LTD

AI summary

An actuator includes a first driving beam that is connected to an object to be driven and includes multiple first beams extending in a direction orthogonal to a first predetermined axis, ends of each adjacent pair of the first beams being connected to each other via one of first turnaround parts such that the first driving beam forms a zig-zag bellows structure as a whole; first driving sources formed on first surfaces of the first beams; and ribs formed on second surfaces of the first beams at positions that are closer to the first predetermined axis than the first turnaround parts. The first driving sources are configured to move the first driving beam and thereby rotate the object around the first predetermined axis.