Time Multiplexed Etching for Semiconductor Micro-Mechanical Structures
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Solution Overview
Problem
Existing semiconductor device manufacturing processes often damage micro-mechanical structures due to inadequate etching techniques, leading to performance issues and quality concerns.
Innovation Solution
A time multiplexed etching process is employed, combining pulsed and constant radio frequency bias signals with varying durations to control etching steps, resulting in a smooth undulation pattern on side surfaces that prevents damage to micro-mechanical structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional etching process is used, then the etching speed is fast, but the micro-mechanical structures are damaged due to sharp edges formation
Solution Approach 1:
The patent applies periodic pulsed radio frequency bias signals during the etching process, alternating between etching phases and pause phases. This periodic action allows controlled removal of material while preventing the formation of sharp edges that would damage micro-mechanical structures, thus maintaining both etching efficiency and structure integrity
Solution Approach 2:
The patent changes the radio frequency bias signal parameters by using pulsed signals with varying duty cycles and frequencies. This parameter modulation enables precise control over the etching rate and edge formation, allowing fast etching while protecting micro-mechanical structures from damage
2Reliability
If a slow etching process is used, then the micro-mechanical structures are not damaged, but the manufacturing productivity is reduced
Solution Approach 1:
By implementing periodic pulsed etching with optimized duty cycles, the process achieves high overall etching rates while the pause phases prevent damage accumulation. This allows maintaining manufacturing productivity while ensuring micro-mechanical structure integrity
Solution Approach 2:
The patent uses dynamically adjustable pulsed radio frequency bias signals where the pulse width, frequency, and duty cycle can be varied during the etching process. This dynamic control enables optimization of both etching speed and structure protection, achieving high productivity without compromising reliability
3Device complexity
If a constant radio frequency bias signal is applied, then the etching process is simple, but sharp edges are formed on side surfaces
Solution Approach 1:
The patent replaces constant radio frequency bias signals with periodic pulsed signals. This addition of temporal modulation to the etching process prevents sharp edge formation on side surfaces while maintaining reasonable process complexity through standardized pulse generation techniques
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 enhances the manufacturing process by avoiding sharp edges and ensuring the micro-mechanical structures are not damaged, thereby improving the quality and performance of semiconductor devices.
Implementation Method 1
performing a time multiplexed etching process
Implementation Method 2
applying a pulsed radio frequency bias signal to a chuck
Implementation Method 3
performing a time multiplexed etching process, wherein a last etching step of the time multiplexed etching process is of a first time duration; and after performing the time multiplexed etching process, performing an etching step of a second time duration
Data Source
AI summary
According to an embodiment of a semiconductor device, the semiconductor device includes a micro-mechanical structure and a semiconductor material arranged over the micro-mechanical structure. A side surface of the semiconductor material includes a first region and a second region. The first region has an undulation, and the second region is a peripheral region of the side surface and decreases towards the micro-mechanical structure.