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EP-4287237-B1 - SYSTEM AND METHODS FOR AUTOMATED PROCESSING OF MULTIPLE SAMPLES IN A BIB SYSTEM

EP4287237B1EP 4287237 B1EP4287237 B1EP 4287237B1EP-4287237-B1

Inventors

  • HROUZEK, MICHAL
  • NOVAK, LIBOR
  • NEELISETTY, KRISHNA KANTH
  • Wandrol, Petr

Dates

Publication Date
20260513
Application Date
20230516

Claims (12)

  1. A method for efficiently processing multiple samples (104) with a broad ion beam (BIB) system (102), the method comprising the steps of: Removing (506) an individual sample holder (116) containing a sample (104) from a storage location within the BIB system (102), wherein the BIB system (102) includes multiple sample holders (116) positioned in one or more storage locations; loading (508) the individual sample holder (116) onto a sample stage (112) configured to hold the sample holder (116) during polishing of the corresponding sample (104) held by the individual sample holder (116); causing (510) a BIB source (106) to emit a broad ion beam (108) towards the sample (104), wherein the broad ion beam (108) removes at least a portion of the sample (104) upon which it is incident; removing (512) the individual sample holder (116) from the sample stage (112) after the corresponding sample (104) has been processed; and loading the individual sample holder back (116) into the storage location.
  2. The method of claim 1, wherein the storage location is a storage cassette (120) for storing multiple samples (104) for broad ion beam polishing, the storage cassette (120) comprising: a housing at least partially defining an internal storage volume (122); a plurality of sample holder housings located within the internal storage volume (122), wherein each individual sample holder housing is configured to receive a sample holder (116) that includes a corresponding sample (104) for polishing in a BIB system (102); and wherein the storage cassette (120) is configured to be inserted into the BIB system (102), and each of the sample holder housings are further configured to allow its corresponding sample holder (116) to be removed from the cassette (120) when the cassette (120) is inserted into the BIB system (102) so that the corresponding sample can be polished by the BIB system (102).
  3. The method of claim 2, wherein the storage cassette (120) stores a plurality of sample holders (116) that each contain a corresponding sample (104).
  4. The method of claim 3, further comprising repeating the method steps recited in claim 1 for one or more additional samples holders (116) stored in the storage cassette (120).
  5. The method of claim 3, wherein the samples (104) in the sample holders (116) stored in the storage cassette (120) are pre-aligned such that they do not need to be further aligned within the BIB system (102) before being processed.
  6. The method of claim 1, further comprising the steps of: removing (506) another individual sample holder (116) containing another sample (104) from the storage location; loading (508) the another individual sample holders (116) onto the sample stage (112); causing (510) the BIB source (106) to emit another broad ion beam (108) towards the sample (104), wherein the another broad ion beam (108) removes at least a portion of the another sample (104) upon which it is incident; removing (512) the another individual sample holder (116) from the sample stage (112) after the corresponding another sample (104) has been processed; and loading the another individual sample holder (116) back into the storage location.
  7. The method of claim 1, wherein the method steps are at least partially automatically performed by the BIB system (102).
  8. The method of claim 7, wherein the time period is determined based on one or more sensors receiving information indicating that one of: the portion of the sample (104) has been removed; and a region of interest has been exposed.
  9. The method of claim 7, further comprising: accessing sample information associated with the sample (104); and determining the time period based on the sample information associated with the sample (104).
  10. The method of claim 9, further comprising: detecting an identifier on the sample holder, the identifier comprising an identification code, a scannable identifier image, and an RFID; and wherein the data file is accessed on an accessible memory based on the identifier.
  11. The method of claims 9 or 10, wherein the sample information includes a processing schedule for the sample (104), the processing schedule comprising one or more of: a BIB strength; a BIB milling time; a portion of the sample (104) to be removed with BIB; and a surface of interest.
  12. A storage cassette (120) for storing multiple samples (104) for broad ion beam (BIB) polishing, the storage cassette (120) comprising: a housing at least partially defining an internal storage volume (122); a plurality of sample holder housings located within the internal storage volume (122), wherein each individual sample holder housing is configured to receive a sample holder (116) that includes a corresponding sample (104) for polishing in a BIB system (102); and wherein the storage cassette (120) is configured to be inserted into the BIB system (102), and each of the sample holder housings are further configured to allow its corresponding sample holder (116) to be removed from the cassette (120) when the cassette (120) is inserted into the BIB system (102) so that the corresponding sample (104) can be polished by the BIB system (102).

Description

BACKGROUND OF THE INVENTION Broad Ion Beam (BIB) polishing systems are used to prepare samples for investigation. Specifically, BIB polishing systems directing a high energy, unfocused or minimally focused beams of ions (e.g., Argon ions) at a sample, where the beam degrades and/or otherwise removes the portions of the sample upon which it is incident. Because the broad ion beam does not require focusing or requires minimal focusing, the BIB polishing systems do not have the optical column limitations of other sample preparation techniques (such as focused ion beam (FIB) milling), and thus BIB polishing systems can employ much higher primary energy beam currents. Due to the higher primary energy beam currents, BIB systems are able to more rapidly remove sample material to expose a region of interest that prior systems, enabling a faster sample preparation process. Unfortunately, while highly efficient at removing sample material, samples being processed need to be precisely aligned with special masks that are designed to block portions of the beam from being incident on regions of the sample that users do not desire to be removed. Because this alignment process takes time and requires precise skill, it causes a slowdown in the sample preparation workflow. Additionally, because the higher current broad ion beam removes sample material more rapidly, the rate of redeposition of the removed material onto the broad ion beam source also increases forcing users to more frequently remove the source for cleaning requiring system downtime. Because of these limitations to workflow efficiency, the majority of the current use of BIB polishing systems has been to academic and other non-commercial applications. Therefore, it is desired to have new BIB polishing systems that are able to efficiently and accurately process many samples in shorter periods of time. US 2016/024645 A1 discloses an ion beam sample preparation and coating apparatus and methods. In US 2016/024645 A1, a sample may be prepared in one or more ion beams and then a coating may be sputtered onto the prepared sample within the same apparatus. A vacuum transfer device may be used with the apparatus in order to transfer a sample into and out of the apparatus while in a controlled environment. Various methods to improve preparation and coating uniformity are disclosed in US 2016/024645 A1 including: rotating the sample retention stage; modulating the sample retention stage; variable tilt ion beam irradiating means, more than one ion beam irradiating means, coating thickness monitoring, selective shielding of the sample, and modulating the coating donor holder. JP WO20 2117 1492 A1 discloses a semiconductor analysis system provided with: a processing device which produces a thin film sample for observation by processing a semiconductor wafer; a transmission electron microscope device which obtains a transmission electron microscopic image of the thin film sample; and a high order control device which controls the processing device and the transmission electron microscope device. The high order control device performs an evaluation of the thin film sample on the basis of the transmission electron microscopic image, updates the acquisition conditions for a transmission electron microscopic image on the basis of the evaluation results of the thin film sample, and outputs the updated acquisition conditions to the transmission electron microscope device. SUMMARY OF THE INVENTION Systems and methods for efficiently processing multiple samples with a broad ion beam (BIB) system, are disclosed. An example method for efficiently processing multiple samples with a BIB system according to the present invention comprises removing an individual sample holder containing a sample from a storage location within the BIB system, wherein the BIB system includes multiple sample holders positioned in one or more storage locations, loading the individual sample holder onto a sample stage configured to hold the sample holder during polishing of the corresponding sample held by the individual sample holder, and causing a BIB source to emit a broad ion beam towards the sample, wherein the broad ion beam removes at least a portion of the sample upon which it is incident. Once a desired portion of the sample is removed, the sample holder is removed from the sample stage and loaded back into the storage location. This process can be repeated for multiple samples stored in the BIB system. In this way, if the samples are pre-aligned, the processing of multiple samples can be performed with little no user input or oversight. BRIEF DESCRIPTION OF THE DRAWINGS The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identify the figure in which the reference number first appears. The same reference numbers in different figures indicates similar or identical items. Figure 1 depicts a cross section of example