AVS 46th International Symposium
    Applied Surface Science Division Monday Sessions
       Session AS2-MoA

Paper AS2-MoA2
Sputter Deposition and Annealing of Ta, TaSi and Ta@sub 4@B Composite Films and Their Application in Next Generation Lithography Masks

Monday, October 25, 1999, 2:20 pm, Room 6A

Session: Applied Surface Science for Microelectronics
Presenter: K. Racette, IBM
Authors: K. Racette, IBM
C. Brooks, IBM
Correspondent: Click to Email
Ta and Ta composites with other elements have been developed by several researchers as low stress absorbers for x-ray mask technology. These thin films are often produced in small quantities by sputter deposition from targets of pure Ta with chips of the minor elements placed on the target to create the composites. For membrane-mask manufacturing it is important that absorber films have uniform composition, thickness and low stress to assure that image size and pattern placement errors are minimal. Since sputter deposited films containing Ta have highly compressive stress, several methods have been used to reduce the final stress, including careful control of sputtering conditions, deposition of layered films with different stresses, and thermal annealing. Much data has been reported on the effects of thermal annealing of Ta films but less information is available on multiple element films such as TaSi and Ta@sub 4@B. Reports have generally been developmental in nature and not discussed behavior of these films under longer term, higher volume manufacturing conditions. During the last several years IBM has been engaged in development and fabrication of refractory x-ray membrane-masks using TaSi and Ta@sub 4@B as absorber materials. Films were sputter deposited from hot isostatically pressed powder targets of Ta, Si, and B using an S-gun cluster deposition system. This paper will report on the deposition and annealing of these films and their application to membrane-mask fabrication in a manufacturing environment. The effects of deposition parameters such as dc power, argon gas flow (pressure) and substrate on film stress, composition and density will be dicsussed. The results of air and nitrogen annealing on thick and thin films of TaSi and Ta@sub 4@B will be presented. Absorber film quality data and its impact on image size, pattern placement and defect density of some fabricated x-ray masks will be presented.