Oscillator Substrate Sacrifice Layer Homogeneity
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Solution Overview
Problem
Existing methods for producing oscillator substrates face challenges in obtaining a sacrifice layer with sufficient heat resistance and etching processability, as it is difficult to find a material that meets these requirements when different from the substrate material.
Innovation Solution
The method involves forming a sacrifice layer using the same material as the substrate, specifically silicon, which allows for improved heat resistance and etching processability, and includes forming etching protective films to prevent substrate etching during the removal of the sacrifice layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a sacrifice layer made of different material than the substrate is used, then etching processability is improved, but heat resistance deteriorates
Solution Approach 1:
The sacrifice layer is formed of the same material as the substrate (silicon), ensuring homogeneous properties that provide both heat resistance matching the substrate and etching processability through standardized silicon etching techniques. This homogeneity resolves the contradiction by allowing the sacrifice layer to exhibit both thermal stability and etchability characteristics of silicon material.
2Reliability
If a sacrifice layer made of the same material as the substrate is used, then heat resistance is improved, but etching processability deteriorates
Solution Approach 1:
The sacrifice layer is formed of the same material as the substrate (silicon), ensuring homogeneous properties that provide both heat resistance matching the substrate and etching processability through standardized silicon etching techniques. This homogeneity resolves the contradiction by allowing the sacrifice layer to exhibit both thermal stability and etchability characteristics of silicon material.
3Ease of manufacture
If different materials are used for substrate and sacrifice layer, then etching selectivity is improved, but process complexity deteriorates
Solution Approach 1:
The sacrifice layer is formed of the same material as the substrate (silicon), ensuring homogeneous properties that provide both heat resistance matching the substrate and etching processability through standardized silicon etching techniques. This homogeneity resolves the contradiction by allowing the sacrifice layer to exhibit both thermal stability and etchability characteristics of silicon material.
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 approach enables the formation of oscillation spaces with accurate dimensions and characteristics, ensuring desired oscillation properties while maintaining substrate integrity and improving productivity by using the same etching devices for both the substrate and sacrifice layer.
Implementation Method 1
forming an etching protective film over an internal wall surface of the sacrifice layer removing holes
Implementation Method 2
leading an etchant to the sacrifice layer through the first opening to remove the sacrifice layer by wet etching
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
Provided is method for producing an oscillator substrate in which an oscillating section (17a) of an oscillating membrane (17) facing an oscillation space (15) is configured to oscillate in a direction normal to the membrane surface of the oscillating membrane (17), including: forming a sacrifice layer within a region over a substrate (10) intended to become the oscillation space (15), sacrifice layer being formed of same material as the substrate (10); forming the oscillating membrane (17) over the sacrifice layer; forming a sacrifice layer removing hole (12) in the substrate (10) in a manner to lead to the sacrifice layer from a surface of the substrate (10) opposite to the sacrifice layer; forming an etching protective film (13) over an internal wall surface of the sacrifice layer removing hole (12); and removing the sacrifice layer by etching through the sacrifice layer removing hole (12) to form the oscillation space (15).