四极质谱计测量高压力的一种方法

真空镀膜、半导体加工等真空工艺气氛的原位监测对产品质量至关重要。由于一般质谱计测量上限的限制,较高压力下的工艺气氛的气体分析只能通过取样的方法来实现。四极分析器中离子与分子间的碰撞散射是导致四极质谱计在高压力下测量非线性的主要原因。为此,以碰撞散射为基本假设,推导出四极质谱计测量分压力的普遍公式。提出了四极质谱计在较高压力测量的两步校准法,通过与全压力规的配合,解决了四极质谱计在较高压力非线性条件下测量的实用问题。实验结果表明:可将四极质谱计的测量上限从10~(-2)Pa左右提高一个多数量级。

A METHOD OF HIGH PRESSURE MEASUREMENT BY QUADRUPOLE MASS SPECTROMETER

The collision of ions trapped in quadrupole fields with ambient atoms or molecules has been investigated. Basic relation of partial pressure measurement with quadrupole mass spectrometer is given. With the basic relation, partial pressure measurement in a system operating at a pressure higher than the measurement upper limit of quadrupole mass spectrometer can be done. It has been shown that the partial pressure measurement upper limit with the method given in this paper can reach 0.1 Pa.