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CN-122025502-A - Plasma mass spectrum monitoring system and monitoring method thereof

CN122025502ACN 122025502 ACN122025502 ACN 122025502ACN-122025502-A

Abstract

The application provides a plasma mass spectrum monitoring system and a monitoring method thereof, wherein the plasma mass spectrum monitoring system comprises a movable sampling module, a mass spectrum analysis module, an ionization module and a data processing module, wherein the movable sampling module comprises a driving unit, a sampling tube and a temperature control unit sleeved on the sampling tube, the sampling tube is used for extending into a process cavity to acquire plasma, the temperature control unit is used for adjusting the temperature of the sampling tube in real time, the mass spectrum analysis module is arranged on the driving unit and used for analyzing and detecting ionized ions to acquire initial mass spectrum signals, the ionization module is connected with the mass spectrum analysis module, one side wall of the ionization module is communicated with one end of the sampling tube and used for ionizing the plasma, and the data processing module is electrically connected with the mass spectrum analysis module and used for acquiring the initial mass spectrum signals and calculating to acquire final mass spectrum signals. The plasma mass spectrum monitoring system provided by the application can adjust the sampling position of the sampling tube according to the requirement, thereby realizing high-precision spatial resolution detection of plasma components.

Inventors

  • HUANG XIAO

Assignees

  • 上海车仪田科技有限公司

Dates

Publication Date
20260512
Application Date
20260403

Claims (12)

  1. 1. A plasma mass spectrometry monitoring system, comprising: The movable sampling module comprises a driving unit, a sampling tube and a temperature control unit sleeved on the sampling tube, wherein the sampling tube is used for extending into a process cavity to obtain plasma, the temperature control unit comprises a controller, a temperature control tube, heating elements and a temperature sensor, the temperature control tube is sleeved on the sampling tube, a plurality of heating elements are arranged on the temperature control tube and used for independently adjusting the temperature on the temperature control tube, the temperature sensor is used for detecting the temperature in the sampling tube, the controller is electrically connected with the heating elements and the temperature sensor, and the controller is used for controlling and adjusting the heating temperature of each heating element in real time so that the temperature signal detected by the temperature sensor and the set target temperature error are within +/-1 ℃; The mass spectrum analysis module is arranged on the driving unit and used for analyzing and detecting ionized ions to obtain an initial mass spectrum signal; The ionization module is connected with the mass spectrometry module, and one side wall of the ionization module is communicated with one end of the sampling tube and is used for ionizing plasma; The data processing module is electrically connected with the mass spectrum analysis module and is used for acquiring the initial mass spectrum signal and calculating to obtain a final mass spectrum signal; And the driving unit drives the mass spectrometry module, the ionization module and the sampling tube to move so that the sampling tube stretches into a specific position in the process cavity.
  2. 2. The plasma mass spectrometry monitoring system of claim 1, wherein the sampling tube comprises a ceramic tube and a protective tube; The side wall of the ceramic tube, which is close to one end of the ceramic tube, is provided with a sampling hole, and the other end of the ceramic tube is communicated with the ionization module; the temperature control unit is sleeved on the ceramic tube and covers the outer wall of the ceramic tube; the protection pipe is sleeved on the temperature control unit.
  3. 3. The plasma mass spectrometry monitoring system of claim 2, wherein a thermal insulation material is filled between the temperature control unit and the protection tube, and/or, The sampling tube is in sealing connection with the process cavity through a flexible sealing sleeve.
  4. 4. The plasma mass spectrum monitoring system according to claim 2, wherein the temperature control tube is sleeved on the ceramic tube, the temperature control tube is divided into a plurality of temperature control sections along the axial direction of the temperature control tube in turn, and each temperature control section is provided with a mounting groove and a cooling flow passage; the temperature sensor is arranged in the mounting groove and is used for detecting the temperature in the ceramic tube; The heating elements are attached to the inner side wall of the temperature control tube, and the heating elements in each temperature control section independently control the temperature; the controller is also used for controlling the cooling liquid to be conveyed to the cooling flow channel so as to regulate the temperature of the ceramic tube in real time.
  5. 5. The plasma mass spectrometry monitoring system of claim 4, wherein the controller comprises an acquisition unit and a gradient temperature control unit; the acquisition unit is electrically connected with the temperature sensor and is used for acquiring temperature signals detected by the temperature sensor; the gradient temperature control unit is electrically connected with the acquisition unit and is used for setting the target temperature, the target temperature comprises a target axial temperature gradient, and the gradient temperature control unit controls the power of the heating element in each temperature control section so that the error between a temperature signal detected by the temperature sensor and the set target axial temperature gradient is within +/-1 ℃.
  6. 6. The plasma mass spectrometry monitoring system of claim 5, wherein the controller further comprises a compensation unit; The compensation unit is electrically connected with the acquisition unit and the data processing module, the compensation unit calculates a transmission efficiency correction factor eta i by acquiring the temperature signal and parameters of process gas in the process chamber, and the data processing module carries out trimming compensation on the initial mass spectrum signal according to the transmission efficiency correction factor eta i so as to obtain the final mass spectrum signal I i,corrected ; η i satisfies the following calculation formula: η i =exp ; Wherein L is the tube length of the sampling tube, v is the air flow speed in the process chamber, k ads,i is the adsorption rate constant of the plasma component i, and θ is the effective adsorption site coverage rate; i i,corrected satisfies the following calculation formula: I i,corrected =I i,raw /η i ; Wherein I i,raw is the initial mass spectrum signal.
  7. 7. The plasma mass spectrometry monitoring system of claim 1, wherein the ionization module comprises an ionization chamber and a dual mode adjustable ionization source; the ionization cavity is communicated with the sampling module; the dual-mode adjustable ionization source is arranged in the ionization cavity and comprises an electron bombardment ionization unit and a dielectric barrier discharge ionization unit, and the electron bombardment ionization unit and the dielectric barrier discharge ionization unit can be independently started or all started to realize three ionization working modes.
  8. 8. The plasma mass spectrometry monitoring system of claim 7, further comprising a vacuum pump; A baffle plate is arranged in the ionization cavity, the baffle plate divides the ionization cavity into a first cavity and a second cavity, a limiting hole is formed in the baffle plate, the limiting hole conducts the first cavity and the second cavity, and an air inlet hole and a suction hole are formed in the side wall of the first cavity; The dielectric barrier discharge ionization unit is arranged in the first chamber and communicated with the sampling tube; the air inlet is used for communicating with the air supply unit; The vacuum pump is communicated with the suction hole; The electron bombardment ionization unit is arranged in the second chamber.
  9. 9. The plasma mass spectrometry monitoring system of claim 7, wherein the mass spectrometry module comprises a mass spectrometry chamber, an ion optics system, a mass analyzer, a detection unit, and a vacuum system; The mass spectrometry cavity is communicated with the ionization cavity; the ion optical system is arranged on one side wall of the mass spectrum analysis cavity and extends into the ionization cavity to focus and inject an ion beam into the mass analyzer; The mass analyzer is arranged in the mass spectrum analysis cavity and is close to the ion optical system and used for analyzing an ion beam; The detection unit is arranged in the mass spectrum analysis cavity and is close to the mass analyzer and used for detecting ions; the vacuum system is connected with the mass spectrometry cavity and used for adjusting the vacuum environment in the mass spectrometry cavity.
  10. 10. A method of plasma mass spectrometry monitoring employing the plasma mass spectrometry monitoring system of any of claims 1 to 9, the method comprising: s100, controlling a movable sampling module to enable a sampling tube to extend into a preset position in a process cavity and to be used for acquiring plasma at a specific position in the process cavity; S200, setting a target axial temperature gradient on a temperature control unit, and controlling the temperature control unit to adjust the temperature in the sampling tube in real time; s300, starting an ionization module for ionizing plasma; S400, starting a mass spectrum analysis module so that the interior of the mass spectrum analysis module is in a vacuum environment, and analyzing and detecting ionized ions to obtain an initial mass spectrum signal; S500, a data processing module acquires the initial mass spectrum signal and calculates to obtain a final mass spectrum signal; And S600, sampling and analyzing plasmas at different positions in the process chamber by adopting the steps S100-S500 to acquire the spatial distribution information of the plasmas.
  11. 11. The method of claim 10, wherein the setting a target axial temperature gradient on the temperature control unit and controlling the temperature control unit to adjust the temperature in the sampling tube in real time comprises: Dividing a temperature control pipe in the temperature control unit into a plurality of temperature control sections in sequence; The temperature on each temperature control section is controlled based on the set target axial temperature gradient, so that the temperature in the sampling tube is distributed in a gradient way between 180 ℃ and 80 ℃; The temperature control unit is used for adjusting the temperature on the temperature control section in real time so that the error between the actual temperature in the sampling tube and the set target temperature is within +/-1 ℃.
  12. 12. The method of claim 10, wherein the initiating an ionization module for ionizing a plasma comprises: The ionization module has three ionization modes of operation: closing an electron bombardment ionization unit in the ionization module, and opening a dielectric barrier discharge ionization unit in the ionization module; Opening the electron bombardment ionization unit and closing the dielectric barrier discharge ionization unit; The dielectric barrier discharge ionization unit is started first, and then the electron bombardment ionization unit is started.

Description

Plasma mass spectrum monitoring system and monitoring method thereof Technical Field The application relates to the technical field of ion body diagnosis and mass spectrometry, in particular to a plasma mass spectrometry monitoring system and a monitoring method thereof. Background In the field of semiconductor fabrication, particularly as the nodes of integrated circuit processes shrink, stringent requirements are placed on uniformity and repeatability of processes such as plasma etching, deposition, etc. The spatial distribution characteristics of the plasma components, including radial and axial concentration gradients, directly determine the process results on the wafer surface. For example, fluorocarbon plasma etches silicon dioxide (SiO 2) films, the difference in spatial distribution of reactive species such as CF +、CF2+、CF3+ plasma that participate in the reaction directly correlates to etch rate uniformity and sidewall profile conformality. If the spatial distribution of the plasma components cannot be accurately monitored, over etching or etching residues are easy to appear at the edge or the central area of the wafer, and the product yield is seriously reduced. In addition, in argon or other inert gas plasmas, the density distribution change of neutral plasma components caused by the gas heating effect also indirectly affects the electron temperature and energy distribution, thereby changing the stability of the process parameters, and therefore, the accurate representation of the change is also a key premise for optimizing a process window. Currently, detection techniques for plasma components rely mainly on two broad categories, optical diagnostics and mass spectrometry. The optical method such as laser-induced fluorescence technology can realize non-invasive measurement and has a certain space resolution capability, but the system is complex and high in cost, and is usually only aimed at specific excited state plasma components, and the Rayleigh scattering technology can be used for measuring the total particle number density, but can not distinguish different mass numbers, and has poor selectivity. Another widely used technique is conventional mass spectrometry, which generally collects a plasma sample through a sampling port fixed on the chamber wall, introduces the sample into an ionization chamber through a differential pumping system, and performs mass-to-charge ratio analysis on neutral particles and ions through electron bombardment ionization. However, the conventional fixed mass spectrometry technology has the significant drawbacks of insufficient spatial resolution when applied to monitoring of semiconductor mass production processes. Conventional mass spectrometry systems generally adopt a single-point fixed sampling port design, the sampling position is limited to the wall surface of a chamber or a specific position, local information near the sampling point can be obtained only, and plasma component concentration gradient information at different radial positions (such as the center to the edge of a wafer) or axial positions (such as the boundary of a plasma sheath to a body region) inside plasma can not be obtained under the premise of not damaging the structure of the chamber. Secondly, the lack of a compensation mechanism for the temperature drift of the sampling tube has poor long-term monitoring stability. In an actual plasma process environment, the sampling lines are often exposed to complex environments of temperature fluctuations, plasma radiant heat, and chemical reaction heat. In the traditional design, the temperature change of the sampling tube can cause the change of the adsorption/desorption coefficient of the tube wall to the active plasma component, and the drift of viscosity and conductance in the gas transportation process. These factors directly affect the representation and transmission efficiency of the sampled sample, which in turn leads to long-term drift of the mass spectrum signal. Due to the lack of an effective temperature compensation mechanism, the conventional system is difficult to meet the requirements of a semiconductor mass production line on continuous and stable operation of equipment and accurate control of process parameters, frequent calibration is often required, and the production efficiency is reduced. Disclosure of Invention The application aims to solve the technical problem of providing a plasma mass spectrum monitoring system and a monitoring method thereof, which have high-precision spatial resolution detection and high signal stability and improve the reliability of plasma component detection. To solve the above technical problem, in a first aspect, the present application provides a plasma mass spectrum monitoring system, including: The movable sampling module comprises a driving unit, a sampling tube and a temperature control unit sleeved on the sampling tube, wherein the sampling tube is used for extending into a process cavity t