Measuring Ion Angle Distribution in Plasma Processes Using a MEMS Sensor

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This patent describes a method for accurately determining the angular distribution of ions (Ion Angular Distribution Function, IADF) impacting a substrate during plasma processes. The system uses a MEMS-based sensor with a tiltable, perforated plate and an ion detector. By tilting the plate and measuring ion current at different angles, the system can iteratively calculate the real angular distribution of ions hitting a surface.

Use CasesContent extracted from patent full text and abstract with AI.

• Characterization and optimization of plasma etching and deposition processes in semiconductor manufacturing
• Quality control and process monitoring in microelectronics fabrication
• Fundamental research on ion-surface interactions in plasma physics
• Development and calibration of plasma processing equipment

BenefitsContent extracted from patent full text and abstract with AI.

• Enables precise measurement and understanding of ion impact angles during plasma processing
• Improves control over surface treatment outcomes in semiconductor manufacturing
• Facilitates optimization of plasma processes for better yields and device performance
• Allows iterative and automated adjustment for accurate, real-time data collection
• Provides a robust method compatible with compact, integrated MEMS devices

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Patent Abstract

The invention relates to a method for determining an ion angular distribution function in plasma processes at a substrate surface, comprising a computing unit and an associated sensor with a microelectromechanical system (MEMS) and an ion detector arranged below it or integrated into the MEMS, wherein the MEMS has a deflectable plate with a perforation through which ions pass through to the ion detector. The plate is harmonically deflected to a tilt angle by means of at least one actuator, wherein the plate selects the ions based on their ion incidence angle perpendicular to the surface of the plate and by means of the ion detector detects an ion current strength as a function of the ion incidence angle and an amplitude of the tilt angle of the plate and transmits it to the computing unit, and wherein the computing unit iteratively determines a simulated ion current strength from an assumed or previously determined ion angular distribution function (IADF) in the form of an IADF parameter and an incidence angle-dependent transfer function that takes into account the geometric conditions of the perforations in the form of a filter effect, wherein a comparison of a deviation between the measured ion current strength at the ion detector and the simulated ion current strength of the computing unit is performed, and wherein after the comparison of the measured ion current strength and the calculated ion current strength an adjustment of the IADF parameter for a renewed simulation is performed or the iteration is terminated when a specified deviation or a minimum of the deviation is fallen below.