Reaction chamber design to minimize particle generation in chemical

Abstract

A method of controlling deposition quality of line-of-sight and target surfaces in a plasma-enhanced chemical vapor deposition apparatus. Adhesion and integrity of deposited film on the surfaces is improved by one or more of (1) avoiding differential thermal expansion of the film and the underlying surfaces, (2) controlling geometry of the surfaces to eliminate edges which generate stress in the deposited film, and (3) using material for the surfaces which provides strong adhesion of the deposited film. For instance, differential thermal expansion can be avoided by maintaining the surfaces at a substantially constant temperature such as ambient temperature. Apparatus for controlling deposition quality of line-of-sight and target surfaces in a plasma-enhanced chemical vapor deposition apparatus. The apparatus includes a plasma shield having a line-of-sight surface and a plasma target having a target surface. The line-of-sight surface defines a bore through the plasma shield and is located out of direct contact with a plasma stream, such as oxygen, which passes from a plasma chamber, through the bore, and into a reaction chamber. A semiconductor specimen is mounted on a support in the reaction chamber. The target surface surrounds the specimen. The line-of-sight and target surfaces are maintained at a substantially constant temperature by circulating a fluid medium through fluid passages in the plasma shield and plasma target. The plasma target can include a removable plate having the target surface on one side thereof. The plasma shield can include a removable gas ring for ejecting gas, such as SiH.sub.4, into the bore.