Temporary Gimbal Anchors for Hidden Hinge MEMS Fabrication

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The manufacturing of multi-layer hidden-hinge MEMS mirrors is challenging due to the risk of damage from suspended structures like gimbals during fabrication, which can lead to interference, stiction, and failure of hinges, especially when the hinge layer forms an intermediate layer.

Innovation Solution

Introducing temporary anchors that secure suspended structures during fabrication to reduce their freedom of movement, thereby minimizing the risk of damage, and releasing them later in the process to maintain the device's functionality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the hinge layer is etched mid-way through the fabrication process to avoid challenges, then the manufacturing process becomes easier, but the suspended structures (gimbals) gain excessive freedom of movement which increases the risk of damage

Engineering Contradiction:

Improveease of etching hinge layerVSAvoidrisk of damage to suspended structures

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies preliminary action by temporarily anchoring the suspended structures (gimbals and platforms) to the substrate before completing the fabrication process. This preliminary anchoring prevents excessive movement and damage during subsequent fabrication steps, while allowing the hinge layer to be etched mid-way without compromising structural integrity. The temporary anchors are later removed to restore the intended freedom of movement.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses temporary anchors as intermediary structures that mediate between the need for structural support during fabrication and the need for freedom of movement in the final device. These anchors serve as a temporary supporting framework that protects suspended structures during manufacturing, then are removed to allow the device to function as designed.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If temporary anchors are introduced to secure suspended structures during fabrication, then the risk of damage is reduced, but the device complexity increases

Engineering Contradiction:

Improveintegrity of suspended structuresVSAvoidcomplexity of fabrication process

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies the discarding and recovering principle by introducing temporary anchors that are deliberately designed to be discarded after serving their protective function during fabrication. These anchors are removed in a controlled manner (through etching or mechanical release) to recover the intended freedom of movement of the suspended structures, thus adding minimal permanent complexity to the final device.

Inventive Principle:

Principle #34Discarding and recovering

Solution Approach 2:

The temporary anchors function as disposable structures that are inexpensive and short-lived, serving only during the fabrication process. They are designed to be easily added and removed without leaving traces in the final device, thus protecting the suspended structures while adding minimal complexity to the overall system.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Strength

If the outer platform is made elongate to provide sufficient support, then the structural strength is improved, but the platform may still be damaged after etching the gimbal layer due to excessive movement

Engineering Contradiction:

Improvestructural support of outer platformVSAvoiddamage risk during fabrication

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent applies preliminary action by temporarily anchoring the elongate outer platform to the substrate before completing the fabrication process. This preliminary anchoring compensates for the platform's elongate shape that would otherwise cause excessive movement and damage, allowing the platform to maintain its structural support function while preventing fabrication-related damage.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS9696540B2Hidden hinge MEMS with temporary gimbal anchor

Publication Date: 2017.07.04 WELLS FARGO BANK NA

AI summary

Micro-electro-mechanical system (MEMS) mirror devices and manufacturing methods thereof. The device comprising a hinge layer having orthogonal tilt and roll hinges connecting inner and outer platforms such that the inner platform has bi-directional rotation. An electrode layer connected beneath the hinge layer controls rotation of the platforms. A mirror layer above the hinge layer comprises a mirror connected to the inner platform via a pedestal and fixed membrane connected to the hinge layer but detached from the mirror. An anchor temporarily reduces movement of the outer platform during fabrication. In a fabrication state, the anchor anchors the outer platform to the mirror layer's fixed membrane. In a post-fabrication state, a gap releases the outer platform.