Micromirror Wafer Separation Using Oxide-Guided Single-Step Etching
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Solution Overview
Problem
Existing methods for producing micromirror devices are complex and require multiple steps, including wet etching and singulation of mirror plates, which can be inefficient and cumbersome.
Innovation Solution
A simplified method involving the application of a silicon oxide layer on a silicon wafer, followed by precise etching using a mask to create separation regions, allowing for the simultaneous formation of micromirror devices with mirror plates and reinforcing structures in a single step, utilizing DRIE or ion beam etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a silicon oxide wafer is used with wet etching and separate singulation steps, then micromirror devices can be produced, but the production process becomes complex and inefficient
Solution Approach 1:
The patent combines the separation of mirror plates and the singulation of individual micromirror devices into a single etching step. By structuring the silicon oxide layer with first and second separation regions that are spatially separated along a separation plane, the etching process simultaneously creates both separations, eliminating the need for separate wet etching and singulation steps described in prior art.
Solution Approach 2:
The silicon oxide layer is segmented into distinct first and second separation regions with different etching characteristics. The first separation region has a first etching speed and the second separation region has a second etching speed, allowing selective and controlled separation of mirror plates and singulation of devices in one process step.
2Manufacturing precision
If multiple separate method steps are used for wafer separation and mirror plate singulation, then precise separation can be achieved, but production time increases
Solution Approach 1:
Multiple separation functions are merged into a single etching operation. The etching method simultaneously performs wafer separation along the first separation plane and mirror plate singulation along the second separation plane, achieving precise separation for both operations in one step rather than requiring sequential processing.
Solution Approach 2:
The silicon oxide layer is pre-structured with first and second separation regions having different etching speeds before the actual etching process. This preliminary structuring enables the etching method to automatically achieve precise separation without requiring multiple adjustment steps or separate operations.
3Productivity
If the silicon oxide layer is completely removed, then mirror plates can be separated, but material coherence is lost and additional structural support is needed
Solution Approach 1:
The silicon oxide layer is selectively removed only in specific separation regions rather than being completely removed. The first separation region is etched through to separate mirror plates, while the second separation region maintains residual silicon oxide to provide structural support and prevent excessive thinning of the wafer.
Solution Approach 2:
The silicon oxide layer serves dual purposes: it is discarded (removed) in the first separation region to enable mirror plate separation, while it is recovered (retained) in the second separation region to maintain structural integrity and provide mechanical support during and after the separation process.
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
Enables efficient and streamlined production of micromirror devices with mirror plates and reinforcing structures, enhancing mobility and stability while reducing complexity and material coherence, thus improving production efficiency.
Implementation Method 1
a silicon oxide layer is thermally applied to at least the front side of the silicon wafer
Implementation Method 2
utilizing DRIE or ion beam etching
Implementation Method 3
utilizing DRIE or ion beam etching
Data Source
AI summary
A method for producing a first and second micromirror device. A silicon oxide layer is applied to at least the front side of a silicon wafer. The silicon oxide layer is removed so that a first and second separation region of the silicon oxide layer are generated, which are arranged spatially separated from each other along a separation plane. A silicon layer is applied to the front side of the silicon wafer and to the silicon oxide layer. An etching mask is applied to the rear side of the silicon wafer, the etching mask having a first opening along the separation plane of the first and second separation region. The silicon layer and the silicon wafer are removed, according to the etching mask on the rear side of the silicon wafer and according to the silicon oxide layer of the first and second separation region.