Browse Prior Art Database

Original Publication Date: 2000-Mar-01
Included in the Prior Art Database: 2003-Jun-19

Publishing Venue



Disclosed is a protective vacuum-sealing method to provide an effective structure against plasma corrosion at an interface between a vacuum and the atmosphere. In conventional sealing method, O- ring is usually selected to fit the material to its purpose, and the sealing structure is a single O-ring structure as shown in Fig. 1. Viton is a name of a material made of fluoridated rubber and the most general material. Indeed the viton may be less expensive, general, and effective to seal a chamber from the atmosphere, however, the viton is a weak O-ring material against oxygen plasma or against oxygen/CF4 plasma. The viton surface can be easily attacked, decayed, and can be a dust generating source. Kalrez is a name of a material made of perfluore rubber, and a strong material against oxygen plasma or against oxygen/CF4 plasma, however, it is almost ten times as expensive as the viton and not very effective to seal a chamber. Our disclosed structure, which is less expensive and an effective method to protect O-ring surface from plasma corrosion while keeping the sealing ability, is shown in Fig. 2. The inner O-ring having a double-circled structure in Fig.2 is Teflon-covered viton O-ring. The Teflon covered viton O-ring has poor capability to seal a chamber, but it has much more resistance to the plasma than other material and less expensive. The vacuum is effectively kept by the outer O-ring, viton. The plasma cannot reach the outer O-ring and the surface of the outer viton O-ring does not rot away. Exchange timing of the O-rings using the structure shown in Fig. 1 can be extended 50 times as long as that of the viton O-rings using the single O-ring structure. 1 2