Development of new stage system for modern electron microscopes

Abstract

Analytical systems for high spatial resolution, such as transmission electron microscopes (TEM) and scanning transmission electron microscopes (STEM), are getting popular, since a target sample for modern science and industry is getting smaller. Thus, higher resolution and efficiency are required for modern microscope systems, along with further improved ease of use since a lot of functions are installed to a microscope and it makes its operations complicated. JEM‐F200 has been developed as an easy‐to‐use electron microscope for high resolution imaging and analysis for the requirements of those mentioned above. Among the components of the microscope, specimen system is one of the most important hardware to be developed because the all users must use the system frequently, and all users need to be careful for treating a sample. In this paper, we explain the features of a newly developed specimen system, which has three new features. The first element of the new stage system is a redesigned specimen drive mechanism, that is called as “Pico Stage Drive”. The specimen stage drive is fast and highly‐precise. The new ultra‐fast specimen drive enables the stage to move in approximately 7 seconds over a wide area of 2 mm diameter (highest speed: 0.3 mm / s). And the new ultrahigh‐precision drive allows a specimen (on the stage) to move in steps of sub‐nanometers (0.2 nm / step). The specimen stage can be driven with piezo device (0.05 nm / step) simultaneously. The second element of the new stage system is an auto insertion/extraction mechanism for specimen holder, which is called as “SPECPORTER”. Insertion or extraction of a specimen holder has been considered to be an operation where human error might occur, especially for novice users. To avoid the error, a new automated loading/extracting system for specimen holders, which needs no human operations, has been developed. With the SPECPORTER, the operator sets a specimen holder at a designated position and activates the SPECPORTER by simply clicking a switch, and then the holder is automatically inserted or extracted safely as shown in Figure 1. The operations of evacuation and opening a valve for sample holder are programmed and installed. The sample maintains its attitude to be horizontal during the procedure. If the SPECPORTER were applied to cooling holders, no liq. N 2 spilt is realized in the procedure of sample insertion. The system maintains the feature of JEOL double O‐ring holder, and therefore users can insert a old sample holder compatibly by manual loading and unloading. Furthermore, a conventionally‐used specimen holder can be modified so that the holder is inserted or extracted automatically using the SPECPORTR. The third element is a new clam shell, which covers a goniometer. The clam shell withstands pressure variation of the installation room to protect a sample. However, a few electrical feed through was prepared in old system. In the new system, more feed through are prepared for a variety of specimen holder (e.g. heating holder, see Figure 2). In conclusion, the new specimen system provides the easy, safe and smooth operation of samples, which gives a high throughput to users. Especially, the ultra fine specimen drive system enables accurate positioning of the sample with large travel (2 mm), which is requested by all kinds of target functions such as high resolution imaging and high resolution analysis.