Process for producing a target formed of a sintering-resistant material of a high-melting point metal alloy, silicide, carbide, nitride or boride
A target is formed of a sintering-resistant material of high-melting point metal alloy, high-melting point metal silicide, high-melting point metal carbide, high-melting point metal nitride or high-melting point metal boride comprising a structure in which a material formed of a sintering-resistant material of high-melting point metal alloy, high-melting point metal silicide, high-melting point metal carbide, high-melting point metal nitride or high-melting point metal boride and a high-melting point metal plate other than the target are bonded. A production method of such a target is provided. Further the generation of cracks during the target production and high power sputtering, and the reaction of the target raw material with the die during hot pressing can be inhibited effectively, and the warpage of the target can be reduced.
1. A production method of a composite sputtering target comprising a sputtering target and a backing plate, the sputtering target formed of a sintered body formed of a powder of a sinter-resistant material of an alloy of high-melting point metals or a silicide, carbide, nitride or boride of one high-melting point metal, and the production method comprising the steps of:
placing a first plate in a graphite die, the first plate having a thickness of 2 to 6 mm and being made of a high-melting point metal different from the sinter-resistant material of the sputtering target;
placing powder of the sinter-resistant material in the graphite die on the first plate, thereby forming a layer of powder on the first plate within the graphite die;
placing a second plate on the layer of the powder of the sinter-resistant material in the graphite die, the second plate having a thickness of 2 to 6 mm and being made of a high-melting point metal different from the sinter-resistant material of the sputtering target to obtain a threefold layered structure consisting of the first plate, the layer of powder, and the second plate;
subjecting the threefold layered structure to heating and pressing to sinter the powder and to diffusion-bond the sintered powder to the first and second plates, the threefold layered structure thereby being converted to a sintered composite body;
removing the sintered composite body from the graphite die and bonding the first plate of the sintered composite body to a surface of the backing plate via an insert material made of aluminum or an alloy containing aluminum as a main component thereof, the backing plate being funned of copper or a copper alloy; and
machining the sintered composite body bonded to the backing plate to eliminate the second plate of the sintered composite body to form the composite sputtering target;
wherein the high melting point metals for making the sinter-resistant material for the sputtering target or for making the first and second plates are characterized in having a melting point of about 1700° C. or higher.
2. The production method according to claim 1 , wherein the first plate is made of tantalum, niobium, vanadium, titanium or molybdenum, or an alloy comprising one of tantalum, niobium, vanadium, titanium and molybdenum as a main component of the alloy.
3. The production method according to claim 2 , wherein the first plate is subject to diffusion bonding at a temperature of 1000 to 2000° C.
4. A production method of a composite sputtering target comprising a sputtering target and a backing plate, the sputtering target formed of a sintered body formed of a powder of a sinter-resistant material of an alloy of high-melting point metals or a silicide, carbide, nitride or boride of one high-melting point metal, and the production method comprising the steps of:
placing a first plate in a graphite die, the first plate having a thickness of 2 to 6 mm and being made of a high-melting point metal different from the sinter-resistant material of the sputtering target;
placing powder of the sinter-resistant material in the graphite die on the first plate, thereby forming a layer of powder on the first plate within the graphite die;
placing a second plate on the layer of the powder of the sinter-resistant material in the graphite die, the second plate having a thickness of 2 to 6 mm and being made of a high-melting point metal different from the sinter-resistant material of the sputtering target to obtain a threefold layered structure consisting of the first plate, the layer of powder, and the second plate;
subjecting the threefold layered structure to heating and pressing to sinter the powder and to diffusion-bond the sintered powder to the first and second plates, the threefold layered structure thereby being converted to a sintered composite body;
removing the sintered composite body from the graphite die and bonding the first plate of the sintered composite body to a surface of the backing plate via an insert material made of aluminum or an alloy containing aluminum as a main component thereof at a temperature of 150 to 350° C., the backing plate being formed of copper or a copper alloy; and
machining the sintered composite body bonded to the backing plate to eliminate the second plate of the sintered composite body to form the composite sputtering target;
wherein the high melting point metals for making the sinter-resistant material for the sputtering target or for making the first and second plates are characterized in having a melting point of about 1700° C. or higher.
5. The production method according to claim 4 , wherein the insert material has a thickness of 1 to 4 mm.
6. The production method according to claim 1 , wherein the insert material has a thickness of 1 to 4 mm.
7. The production method according to claim 1 , wherein the first plate is subject to diffusion bonding at a temperature of 1000 to 2000° C.