Method of forming metal blanks for sputtering targets
View Patent ↗The present invention relates to an improvement in the manufacture of metal blanks, discs, and sputtering targets by flattening only one of the two surfaces of a metal plate. The elimination of flattening the metal plate's second surface results in a significant cost reduction. The metal plate of the present invention preferably has a single-side flatness of 0.005 inches or less, which improves the reliability of the bond between the target blank and a backing plate. Preferred metals include, but are not limited to, tantalum, niobium, titanium, and alloys thereof. The present invention also relates to machining the first side of a metal plate, bonding the first side to a backing plate, and then optionally machining the second side of the metal plate.
1. A sputtering target comprising two essentially planar surfaces, wherein, prior to being attached to a backing plate, said sputtering target has a first surface having a flatness of about 0.005 inch or less, and wherein a second surface has a flatness of about 0.075 inch to about 0.025 inch.
2. The sputtering target of claim 1 , wherein said sputtering target comprises titanium, cobalt, aluminum, copper, tantalum, niobium, platinum, gold, silver, or alloys thereof.
3. The sputtering target of claim 1 , wherein said sputtering target is tantalum.
4. The sputtering target of claim 1 , wherein said sputtering target is niobium.
5. A sputtering target assembly having a metal target bonded to a backing plate produced by a method comprising the steps of:
(a) providing a metal sputter target which comprises a metal blank prepared by:
(1) supplying at least one planar metal plate having a first surface and a second surface, wherein said first and said second surfaces are essentially parallel; and
(2) flattening only said first surface of said metal plate whereby a metal blank is produced; and
(b) bonding said backing plate onto said metal blank
wherein, prior to being attached to said backing plate, said sputtering target has a first surface having a flatness of about 0.005 inch or less, and wherein a second surface has a flatness of about 0.075 inch to about 0.025 inch.