Mirror Device Manufacturing via Anisotropic Etching and Wet Cleaning
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Solution Overview
Problem
In the manufacturing of mirror devices, there is a concern that the movable portions may be damaged during the cleaning process due to the load of the cleaning liquid, and weakening the cleaning intensity may result in foreign substances remaining on the wafer.
Innovation Solution
A method involving a wafer with a support layer, a device layer, and an intermediate layer, where a slit is formed to allow the movable portion to move relative to the base portion, followed by wet cleaning using a cleaning liquid, and finally cutting out the parts to form the mirror device. The intermediate layer is removed using anisotropic etching to prevent foreign substances from being caught between the support and device layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If wet cleaning is performed on the wafer after the movable portion is released, then foreign substances can be removed from the wafer, but the movable portions may be damaged due to the load of the cleaning liquid
Solution Approach 1:
The intermediate layer is removed by anisotropic etching before the wet cleaning step, creating a protective configuration where the end surface of the intermediate layer is not recessed relative to the support and device layers. This preliminary structural preparation prevents foreign substance accumulation and reduces cleaning load on the movable portion, enabling effective cleaning without damage
2Reliability
If the intensity of cleaning using a cleaning liquid is weakened to curb damage to movable portions, then damage occurrence is reduced, but foreign substances may remain on the wafer
Solution Approach 1:
The intermediate layer is removed by anisotropic etching before cleaning to create a configuration that prevents foreign substance entrapment between layers. This preliminary action enables effective foreign substance removal during cleaning without requiring high-intensity cleaning that would damage the movable portion
Solution Approach 2:
The cleaning process utilizes cleaning liquid flow to remove foreign substances from the wafer surface. The hydraulic action of the cleaning liquid, combined with the pre-prepared layer configuration, enables effective cleaning at reduced intensity that does not damage the movable portion
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 method effectively reduces the risk of damage to the mirror device during cleaning while ensuring that foreign substances are reliably removed from the wafer, maintaining the structural integrity and cleanliness of the device.
Implementation Method 1
In the second step, a part of the intermediate layer is removed from the wafer by anisotropic etching
Implementation Method 2
a third step of performing wet cleaning for cleaning the wafer using a cleaning liquid after the second step
Data Source
AI summary
A method for manufacturing a mirror device, the method includes a first step of preparing a wafer having a support layer, a device layer, and an intermediate layer; a second step of forming a slit in the wafer such that the movable portion becomes movable with respect to the base portion by removing a part of each of the support layer, the device layer, and the intermediate layer from the wafer and forming a plurality of parts each corresponding to the structure in the wafer, after the first step; a third step of performing wet cleaning using a cleaning liquid after the second step; and a fourth step of cutting out each of the plurality of parts from the wafer after the third step. In the second step, a part of the intermediate layer is removed from the wafer by anisotropic etching.