Semiconductor Laser Etching Rate Stabilization via Vacuum Pressure Control
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Solution Overview
Problem
The use of chlorine-based gases in etching semiconductor laser devices and optical directional couplers leads to variations in etch depth and characteristics due to changes in etching rate, even under optimal conditions, resulting in inconsistent performance across different wafers and requiring frequent maintenance to maintain process chamber uniformity.
Innovation Solution
A method involving the use of a vacuum chamber where the first substrate is etched with a chlorine-based gas, followed by evacuation to monitor and control the partial pressure of hydrogen chloride within a predetermined range, allowing the second substrate to be etched under controlled conditions without frequent exposure to atmosphere, thereby stabilizing the etching rate and reducing variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a chlorine-based gas is used for etching, then the etching process can be performed, but the etching rate changes greatly causing variations in etch depth
Solution Approach 1:
The patent changes the chemical environment parameter by introducing oxygen gas into the vacuum chamber after chlorine-based etching. This transforms the chemical state of the chamber from containing reactive chlorine species to containing oxygen, which prevents chloride formation during subsequent etching processes. The parameter change from chlorine atmosphere to oxygen atmosphere stabilizes the etching rate across multiple wafers.
Solution Approach 2:
The patent creates an inert-like environment by filling the vacuum chamber with oxygen gas after etching. This oxygen atmosphere acts as a protective environment that prevents the formation of volatile chlorides during subsequent etching operations, thereby maintaining consistent etching rates. The oxygen atmosphere serves as a stable chemical environment analogous to an inert atmosphere.
2Manufacturing precision
If frequent maintenance is performed to maintain process chamber uniformity, then etching rate consistency is improved, but production efficiency decreases
Solution Approach 1:
The patent performs a preliminary action by introducing oxygen gas into the vacuum chamber immediately after each etching process completes. This preliminary oxygen introduction prepares the chamber environment for the next etching operation, preventing chloride accumulation before it can affect subsequent etching rates. This proactive measure eliminates the need for frequent maintenance interruptions.
Solution Approach 2:
The patent enables continuous production by eliminating the need for frequent maintenance interruptions. The oxygen introduction step is integrated into the process flow between wafers, allowing the system to maintain consistent etching performance throughout extended production runs without stopping for chamber cleaning or maintenance activities.
3Object-generated harmful factors
If the process chamber is opened to atmosphere for cleaning, then chlorides can be removed, but time is lost and production efficiency is reduced
Solution Approach 1:
The patent converts the potentially harmful chloride byproducts of etching into a manageable situation by introducing oxygen gas. The oxygen reacts with or displaces chlorine species, preventing harmful chloride accumulation without requiring chamber opening. This transforms the harmful etching byproduct issue into a controlled chemical environment management problem that can be solved within the closed vacuum system.
Solution Approach 2:
The patent introduces oxygen gas as an intermediary substance that mediates between the etching process and the chamber environment. The oxygen acts as a buffer that prevents direct interaction between chlorine species and the chamber walls or subsequent substrates, eliminating the need for physical cleaning while maintaining chamber integrity.
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 reduces variations in the etching characteristics of semiconductor laser devices and optical directional couplers, improving production efficiency by minimizing the need for frequent maintenance and maintaining consistent etching rates across multiple substrate processes.
Implementation Method 1
a second step of evacuating the vacuum chamber while monitoring a partial pressure of hydrogen chloride in the vacuum chamber so as to obtain the partial pressure of the hydrogen chloride within a predetermined range
Implementation Method 2
a first step of etching the first substrate product with a chlorine-based gas in a vacuum chamber by using a dry etching method
Data Source
AI summary
A method of producing a semiconductor laser device includes the steps of preparing first and second substrate products each of which includes a substrate and a stacked semiconductor layer formed on the substrate, the first and second substrate products being different from each other; etching the first substrate product with a chlorine-based gas in a vacuum chamber by using a dry etching method; evacuating the vacuum chamber while monitoring the pressure of hydrogen chloride in the vacuum chamber so as to obtain a partial pressure of the hydrogen chloride within a predetermined range; after evacuating the vacuum chamber, introducing the second substrate product into the vacuum chamber while maintaining a vacuum state inside the vacuum chamber; and etching the second substrate product with a chlorine-based gas in the vacuum chamber by using the dry etching method.