High purity tantalum sputtering target is widely used in the manufacturing of electronic information products, as a sputtering barrier layer, with high purity copper will gradually replace aluminum to become the metallized wiring material on silicon chips, to be more widely used. The grain size, microstructure uniformity and grain orientation distribution of high purity Ta sputtering target have important effects on sputtering performance. With the increase of the size of semiconductor silicon chip, the size of sputtering target is also developing to large size, in order to ensure the consistency of quality between the same target and different batches of large-size semiconductor sputtering target, so as to ensure the quality and yield of different batches of sputtering films. The control of microstructure uniformity and orientation distribution of target thickness direction and sputtering plane direction is more strict. The process of plastic deformation and heat treatment is the key to control the microstructure and orientation of sputtering target. The process includes homogenization heat treatment of ingot, circular/axial forging opening, annealing, cold rolling, recrystallization annealing, etc. Generally, the quality of the target material can be adjusted and controlled by annealing, cold rolling, recrystallization heat treatment and so on.
At present, the microstructure and orientation control of high-purity Ta sputtering target is the key technology in the processing of high-purity Ta sputtering target due to the lack of understanding of the microstructure evolution during plastic processing and heat treatment and the relationship with the processing technique. Therefore, how to control the uniformity of microstructure in the direction of thickness while ensuring the uniformity of microstructure and orientation control on the sputtering surface is an urgent problem to be solved in the field of semiconductor sputtering target processing.
The processing technique of high purity tantalum sputtering target can be used to roll the round blank of forged and blank tantalum sputtering target. During the rolling process, the rolling direction is rotated 135° every time and then rolled until rolling one week, and the arc thickness ratio of pass reduction is controlled at 2 ~ 3. In the processing of high purity tantalum sputtering target, the arc thickness ratio of pass drop can be controlled at 2.5.
