Study On The Fabrication And Properties Of Standard Leak Based On Anodic Aluminum Oxide

Standard leak is a ruler of vacuum metrology technology,and its performance directly affects the accuracy of vacuum measurement and vacuum leak detection results.At present,the commonly used physical standard leaks exist many problems,such as the shape and size of leak are not controllable,the leak rate is uncertain,the gas of the leak is in the complex transition flow regime.These drawbacks will make it impossible to calibrate leak detector and vacuum gauge accurately.To solve the existing problems of traditional standard leak,a new method,which combines anodic aluminum oxide(AAO)temple and mask coating technology,is proposed to prepare a new molecular flow standard leak in this paper.AAO is a kind of nanoscale porous material with the diameter of a hole under 100 nm,which is commonly used in micro-nano processing.We make a double coating processing to AAO by using mask coating technology,and the result of coating is observed by optical microscope.The experiment results show that by using different sizes of mask templates,we can prepare AAO with different effective area and tube number.Then we use the leak calibration device based on difference method,which was designed and assembled by myself,to measure the leak rate and conductance of the standard leak which was formed by AAO after mask coating technology.Helium,nitrogen,argon are chosen as experimental gas.The experiment results show that:(1)The conductance of standard leak is proportional to the effective area of AAO.(2)For a particular leak,the conductance has nothing to do with upstream pressure,which is less than 100 kPa,thus the gas flow in the leak is a complete free molecular flow.At the same time,the conductance is proportional to the reciprocal of the square root of the molecular mass.In this paper,we report a new method based on AAO to prepare a new kind of molecular flow standard leak.This method has a lot of advantages,such as low costs,simple experiment process,wide scope of upstream pressure.Meanwhile,we can control the conductance of the leak by using different sizes mask and we can predict the conductance for other gases when we just know the conductance of the leak for helium.