Silicon Watch Components With Local Wafer Thinning for Easier Release
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Solution Overview
Problem
Existing methods for manufacturing silicon watch components on SOI wafers are complex, lengthy, and expensive due to the need for additional microfabrication steps in a clean room for releasing components, which are structurally supported only by thin bonding bridges.
Innovation Solution
A method involving the formation of watch components in a single silicon wafer thicker than the maximum component thickness, with etching performed from the lower side to thin the wafer locally, allowing for simpler, faster, and less expensive component release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If SOI wafers are used with component release steps, then component manufacturing precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts and removes the support layer from the SOI wafer structure after component formation. By etching away the support layer and buried oxide layer, only the thin bonding bridges remain to hold components, eliminating the need for complex release steps while maintaining manufacturing precision
Solution Approach 2:
The support layer is removed in advance before subsequent manufacturing steps. This preliminary removal of the support layer simplifies later processing by eliminating the need for complex release operations, reducing both device complexity and manufacturing cost
2Manufacturing precision
If SOI wafers are used with component release steps, then component manufacturing precision is improved, but manufacturing time increases
Solution Approach 1:
The support layer and buried oxide layer are extracted and removed in a single etching operation performed before subsequent manufacturing steps. This eliminates the need for multiple complex release steps, reducing total manufacturing time while maintaining component precision
Solution Approach 2:
The removal of support structures is performed as a preliminary action before subsequent manufacturing steps. This upfront removal simplifies the overall process timeline by eliminating the need for time-consuming release operations later in the manufacturing sequence
3Ease of manufacture
If a thin single silicon layer is used without support, then manufacturing cost is reduced, but etching step becomes delicate and difficult to control
Solution Approach 1:
The wafer is thinned to the final component thickness in advance, before the etching steps that form the watch components. This preliminary thinning creates a more manageable substrate thickness that is easier to etch with precision, reducing etching control difficulty while maintaining cost advantages
Solution Approach 2:
The wafer thickness parameter is changed from the original thick state to a thinned state before component etching. This parameter change makes the subsequent etching process more controllable and less delicate, while still maintaining the cost benefits of using a single silicon layer without support structures
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
Facilitates microfabrication steps with a robust wafer, reducing complexity and cost while maintaining component integrity and enabling subsequent manufacturing processes on the entire external surface.
Implementation Method 1
forming the watch components by etching patterns in the silicon layer from the upper side of the wafer; etching the wafer from its lower side to thin the wafer
Data Source
Figure 1a~1d
Figure 1e~1h
Figure 1i~1k
AI summary
A method of manufacturing a plurality of silicon watch components (90) in a wafer is described.The method comprises the following steps: (a) providing a wafer (10, 110) having a lower side (10A, 110A) and an upper side (10B, 110B), the wafer (10, 110) comprising a single silicon layer (30, 130) without a support layer, the single layer (30, 130) having a thickness (e30, e130) greater than a maximum thickness (e90) of the watch components; (b) forming the watch components (90) by etching patterns in the silicon layer (30, 30', 130, 130') from the upper side (10B, 110B) of the wafer (10, 110); and (c) either before or after step (b), etching the wafer (10, 110) from its lower side (10A, 110A) to thin the wafer at least locally by forming at least one thinned zone (36, 38, 38', 136) in which the watch components (90) have been or will be formed, the at least one thinned zone (36, 38, 38', 136) having a thickness substantially equal to the maximum thickness (e90) of the watch components.