Multiple Plasma Ion Source for Inline SIMS Without Gas Switching
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Solution Overview
Problem
The challenge in semiconductor manufacturing is the damaging particle contamination caused by SIMS testing, which requires ex-situ testing and discarding the wafer, and the inefficiency of switching gases in inline SIMS tools, leading to prolonged downtime and reduced productivity.
Innovation Solution
A multiple ion source using a premixed gas mixture of oxygen and inert gases, such as argon, produces non-metallic ion species that can be selectively switched without gas changes, enabling inline SIMS processing compatible with fabrication flows, using a magnetic field to alter ion species and maintain a stable plasma.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If SIMS testing is performed using conventional single ion source with gas switching, then ion species can be changed for different measurements, but the process causes damaging particle contamination and requires wafer discarding
Solution Approach 1:
The patent combines multiple ion sources (oxygen ion source and inert gas ion source) into a single integrated SIMS system, allowing seamless switching between different ion species without physical gas changes. This merging enables versatile ion selection while maintaining a controlled environment that prevents particle contamination, solving the contradiction between adaptability and harmful factors.
Solution Approach 2:
The SIMS system is designed with multi-functionality to support both oxygen-based and inert gas-based ion sources within a single apparatus. This universal design allows the system to perform different measurement functions (negative ion detection with oxygen, positive ion detection with inert gases) without requiring separate equipment, thereby achieving ion species versatility while preventing contamination through controlled ion generation.
2Adaptability or versatility
If gas switching is performed in inline SIMS tools, then different ion species can be used for various measurements, but the gas switching process causes prolonged downtime and reduced productivity
Solution Approach 1:
By merging multiple ion sources into one system, the patent eliminates the need for physical gas switching operations. The integrated design allows electronic or software-controlled selection between oxygen and inert gas ion sources, enabling instant ion species changes without the downtime associated with conventional gas switching procedures, thus resolving the contradiction between versatility and productivity.
Solution Approach 2:
The system performs preliminary setup by having multiple ion sources pre-configured and ready within the same chamber. This preliminary preparation eliminates the need for time-consuming gas switching operations during actual measurements, as all required ion species are already available in the system, thereby reducing downtime and improving productivity while maintaining ion species adaptability.
3Object-affected harmful factors
If ex-situ SIMS testing is performed, then particle contamination is avoided, but the tested wafer must be discarded and cannot be reused in manufacturing flow
Solution Approach 1:
The patent employs an inert gas environment within the SIMS chamber to prevent particle contamination during testing. By using inert gases (such as nitrogen or noble gases) as the operating atmosphere, the system creates a controlled environment that minimizes contamination risks, allowing wafers to be tested without damage and subsequently reused in manufacturing, thus resolving the contradiction between avoiding contamination and maintaining wafer usability.
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 negative ion detection sensitivity, reduces downtime, and increases productivity by allowing seamless ion species switching, ensuring the substrate remains usable post-testing and maintaining high metrology data quality.
Implementation Method 1
injecting a premixed gas mixture of two or more gases into a plasma chamber configured to produce sputtering ions
Implementation Method 2
ejecting sputtering ions from the plasma chamber into a magnetic field, altering an intensity of the magnetic field to select a single species of ions
Implementation Method 3
directing the single species of ions towards a surface of the substrate, and detecting secondary ions sputtered from the surface of the substrate
Data Source
AI summary
Methods leverage premixed gas mixtures to perform a metrology process on a substrate using an inline secondary ion mass spectrometry (SIMS) process. The premixed gas mixture of two or more gases is injected into a plasma chamber that is configured to produce sputtering ions for the inline SIMS process. The two or more gases produce non-metallic ion species which are compatible with downstream substrate fabrication processes and allow further fabrication to be performed on the substrate after the inline SIMS process has completed. The sputtering ions are ejected from the plasma chamber into a magnetic field. The intensity of the magnetic field is altered to select a single species of ions. The single species of ions are directed towards a surface of the substrate and secondary ions sputtered from the surface of the substrate by the selected species of ions are detected and analyzed.