The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 22, 2014
Filed:
Jun. 18, 2012
BO Wang, Beijing, CN;
Lichun Xu, Beijing, CN;
Ming Zhang, Beijing, CN;
Ruzhi Wang, Beijing, CN;
Xuemei Song, Beijing, CN;
Yudong Hou, Beijing, CN;
Mankang Zhu, Beijing, CN;
Jingbing Liu, Beijing, CN;
Hao Wang, Beijing, CN;
Hui Yan, Beijing, CN;
Bo Wang, Beijing, CN;
Lichun Xu, Beijing, CN;
Ming Zhang, Beijing, CN;
Ruzhi Wang, Beijing, CN;
Xuemei Song, Beijing, CN;
Yudong Hou, Beijing, CN;
Mankang Zhu, Beijing, CN;
Jingbing Liu, Beijing, CN;
Hao Wang, Beijing, CN;
Hui Yan, Beijing, CN;
Beijing University of Technology, Beijing, CN;
Abstract
A method for improving the uniformity of high-frequency discharge plasma by means of frequency modulation is disclosed. In a plasma discharge chamber, there is a pair of parallel electrodes. A high-frequency power supply is adopted to feed the electrodes. The frequency range of the electromagnetic field is 13.56 MHz˜160 MHz. Discharge gas is input to form plasma. The frequency of the fed-in high-frequency electromagnetic field is under automatic tuning control, and keeps changing cyclically without stop in the course of plasma discharge. The range of the frequency change may fall into either a portion of or the entire range of 13.56 MHz˜160 MHz and makes the locations with higher plasma density on the plane in parallel with the electrodes and in the plasma discharge space changed cyclically. In a time slot longer than one frequency change cycle, the average plasma density between the parallel electrodes is uniform.