Polycrystalline silicon sputtering target
View Patent ↗Provided is a polycrystalline silicon target produced by a melting method. In the polycrystalline silicon sputtering target, the average amount of nitride or carbide grains having a size of 100 μm or more for samples of 100×100 mm taken from an arbitrary plane of the target is less than three. Also provided is a method of producing a polycrystalline silicon sputtering target. The method is characterized in that a silicon ingot is produced by melting silicon as a raw material with an electron beam and pouring the molten silicon into a crucible heated at 90° C. or more, and the resulting ingot is machined into a target. The present invention has focused on polycrystalline silicon produced by a melting method, and an object of the present invention is to provide a polycrystalline silicon sputtering target having high quality by reducing the presence of silicon nitride and silicon carbide and to provide a polycrystalline silicon sputtering target having a high bending strength by devising the production process.
1. A polycrystalline silicon sputtering target produced by a melting method, wherein an average amount of nitride or carbide grains having a size of 100 μm or more for samples of 100×100 mm taken from an arbitrary plane of the polycrystalline silicon sputtering target is less than three, and the polycrystalline silicon sputtering target has a bending strength of 50 MPa or more and a purity, excluding gas components, of 6N or more.
2. A polycrystalline silicon sputtering target produced by a melting method, wherein an average amount of nitride or carbide grains having a size of 20 μm or more for samples of 100×100 mm taken from an arbitrary plane of the polycrystalline silicon sputtering target is less than three, and the polycrystalline silicon sputtering target has a bending strength of 50 MPa or more and a purity, excluding gas components, of 6N or more.
3. The polycrystalline silicon sputtering target according to claim 2 , wherein the bending strength of the target is 100 MPa or more.
4. A method of producing a polycrystalline silicon sputtering target, comprising the steps of:
producing a silicon ingot by melting silicon as a raw material with an electron beam and pouring the molten silicon into a crucible heated at 90° C. or more; and
machining the silicon ingot into a polycrystalline silicon sputtering target;
wherein an average amount of nitride or carbide grains having a size of 100 μm or more for samples of 100×100 mm taken from an arbitrary plane of the polycrystalline silicon sputtering target is less than three, and the polycrystalline silicon sputtering target has a bending strength of 50 MPa or more and a purity, excluding gas components, of 6N or more.
5. The method of producing a polycrystalline silicon sputtering target according to claim 4 , wherein the crucible used during said producing step is a copper or copper alloy crucible or a molybdenum crucible.
6. The method of producing a silicon target according to claim 5 , wherein a medium used for heating the crucible is water, oil, indium, or tin.
7. The method of producing a polycrystalline silicon sputtering target according to claim 6 , wherein the target has a bending strength of 100 MPa or more.
8. The method of producing a silicon target according to claim 4 , wherein a medium used for heating the crucible is water, oil, indium, or tin.
9. A method of producing a polycrystalline silicon sputtering target, comprising the steps of:
producing a silicon ingot by melting silicon as a raw material with an electron beam and pouring the molten silicon into a crucible heated at 90° C. or more; and
machining the silicon ingot into a polycrystalline silicon sputtering target;
wherein an average amount of nitride or carbide grains having a size of 20 μm or more for samples of 100×100 mm taken from an arbitrary plane of the polycrystalline silicon sputtering target is less than three, and the polycrystalline silicon sputtering target has a bending strength of 50 MPa or more and a purity, excluding gas components, of 6N or more.
10. The method of producing a polycrystalline silicon sputtering target according to claim 4 , wherein the target has a bending strength of 100 MPa or more.
11. The polycrystalline silicon sputtering target according to claim 1 , wherein the bending strength of the target is 100 MPa or more.