Mirror Wafer Cleaning Layout With Circulation Holes

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Solution Overview

Problem

The manufacturing method for mirror devices using a cleaning liquid after releasing the movable portion can cause damage to the movable portions and leave foreign substances, and reducing the cleaning intensity to prevent damage may result in residue.

Innovation Solution

A method involving etching to form slits and circulation holes in the wafer, allowing for wet cleaning with reduced load on movable portions, and including steps for protective film and patterning member removal to ensure thorough cleaning without damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the wafer is cleaned using a cleaning liquid after the movable portion is released, then foreign substances can be removed, but the movable portions may be damaged due to the load of the cleaning liquid

Engineering Contradiction:
Improvecleaning qualityVSAvoidmovable portion integrity
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent divides the cleaning process into two distinct stages: (1) cleaning before releasing the movable portion, when the wafer structure is intact and can withstand cleaning liquid load, and (2) cleaning after releasing the movable portion, when circulation holes are formed to reduce cleaning liquid load on the movable portions. This segmentation allows each cleaning stage to be optimized for its specific requirements without compromising the movable portions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary cleaning actions before the movable portion is released, when the wafer still has structural support. This preliminary cleaning removes foreign substances while the wafer structure can bear the cleaning liquid load, preventing damage to the movable portions that would occur if cleaning were performed after release.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 3:

The patent utilizes hydraulic principles by forming circulation holes that allow cleaning liquid to flow through the wafer structure. This circulation system reduces the hydrostatic pressure and load on the movable portions during post-release cleaning, enabling effective foreign substance removal without damaging the delicate movable structures.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Reliability

If the intensity of cleaning using a cleaning liquid is weakened to prevent damage to movable portions, then damage occurrence is reduced, but foreign substances may remain in the wafer

Engineering Contradiction:
Improvemovable portion integrityVSAvoidcleaning quality
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The cleaning process is segmented into intensive cleaning before release (when structural support exists) and gentle cleaning after release (through circulation holes). This segmentation allows the use of strong cleaning methods when safe, and gentle methods when necessary, achieving both thorough cleaning and movable portion protection.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent ensures continuous cleaning action by performing cleaning both before and after the movable portion release. The cleaning liquid flows continuously through the circulation holes after release, maintaining cleaning effectiveness while reducing load on the movable portions through the designed flow path.

Inventive Principle:
Principle #20Continuity of useful action

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

The method effectively reduces damage to mirror devices and removes foreign substances by circulating cleaning liquid through circulation holes, ensuring thorough cleaning while maintaining structural integrity.

Implementation Method 1

a third step of performing wet cleaning for cleaning the wafer using a cleaning liquid after the second step

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Data Source

PatentEP4471487B1Method of manufacturing mirror device
Publication Date: 2026.03.04 HAMAMATSU PHOTONICS KK
  • EP4471487B1 patent drawingFigure 1
  • EP4471487B1 patent drawingFigure 2
  • EP4471487B1 patent drawingFigure 3

AI summary

The present application relates to an optical scanning device comprising a base portion, a movable portion supported on the base portion, a coupling portion coupled to the movable portion such that the movable portion becomes movable with respect to the base portion and a mirror layer provided to the movable portion, wherein a first penetration region exhibiting a ring shape and extending along an outer edge of the movable portion, a plurality of second penetration regions positioned on a side outward from the first penetration region, and connection portions straddling parts of the first penetration region overlapping the second penetration regions therebetween are formed in the movable portion, and wherein a width of a part on an outward side of the second penetration regions in the movable portion is larger than a width of a part between the first penetration region and the second penetration regions in the movable portion.