Introduction

As vehicles have become more autonomous driving, the need for electronic devices, especially sensor devices, would be extremely important. Most sensor devices as MEMS are with a vacuum sealed chip. If gases get into the device (external leakage) or if outgassing remains inside the device, it causes degradation and reliability is significantly reduced. On the other hand, advanced semiconductor devices have achieved significant improvements through bonding technologies such as "wafer to wafer" and mounting technologies such as "chip let". However, outgassing between bonding or during assembly is a major concern as it affects the quality of the manufacturing process. To maintain the quality of such devices, it is necessary to measure residual or entrapped gases, in the seal or bonding area and between each layer. This presentation describes the technology for leak testing and mass gas analysis to ensure the reliability of sensor devices for automotive applications and bonding devices for semiconductors.

Achieving Ultra-micro leakage measurement using 0.2% BeCu technology

In the ultra-high vacuum (UHV) and Extremely-high vacuum (XHV) region of E-7 Pa or lower, when conducting residual gas analyses with a standard quadrupole residual gas analyzer, outgassing from the sensor tip ion source cannot be ignored, and it is difficult to perform high-precision gas analyses under such conditions. The most important element for solving this problem is a flange-integrated ion source in which radiant heat from the thermionic cathode filament cannot reach the other electrode. A thermionic cathode filament/grid is surrounded by a low-thermal-radiation, high-thermal-conductivity 0.2% beryllium-copper alloy (BeCu) as shown to the right in Fig 1. This is constructed such that heat generated from the filament does not flow to the quadrupole analyzer section and the secondary electron multiplier (EM). As a result, WATMASS outgassing decreases to approximately 1/10000 that in a conventional residual gas analyzer (stainless steel material), and high precision gas analyses in the XHV region can be performed. Utilizing this performance, we have developed a WATMASS GA System that can analyze sealing devices such as MEMS and other devices with non-destructive and destructive analysis with E-16Pa m3/s (He). Details would be announced on the day. References: 1) Fumio Watanabe, Investigation, and reduction of Spurious peaks caused by electron – stimulated desorption and outgassing by means of a grid heating method in a hot-cathode quadrupole residual gas analyzer. J. Vac. Sci. Technol. A20, 1222 (2002) 2) Fumio Watanabe: J. Vac. Sci. Technol. A22 (2004) 181 & 739. 3) Fumio Watanabe: J. Vac. Soc. Jpn, Vlo. 56, No. 6, 2013 4) Hajime Yoshida, Kenta Arai: AIST Ultra - Fine leak calibration unit