Method and apparatus for sputter coating stepped wafers

An apparatus for depositing a uniform distribution of sputtered material upon differently facing increments of a substrate surface, said apparatus comprising:

• a target of sputtering material having a generally concave sputtering surface supported in spaced relationship with the surface of the substrate, said sputtering surface having at least two regions including a first and a second target region defined thereon, each said target region having different geometric parameters defining the geometric relationship of the region with the differently facing increments of the substrate surface;
• a controller operable for establishing separate sets of electrical parameters, one for each of said target regions, said sets of electrical parameters being so related to said geometric parameters as to cause the deposition of the sum of material sputtered from all of said regions to be of a desired distribution across the substrate surface;
• at least two individually activatable magnets including a first and a second electromagnet positioned to generate, when activated, at least two magnetic fields including a first and a second magnetic field respectively corresponding to said first and second target regions to cause the emission of sputtered material from each respective target region corresponding to an activated magnetic field when said target is energized;
• a timing circuit for activating one of said first and second electromagnets while the other is deactivated;
• and
• a power supply operable to energize said target, in synchronism with the activation of the electromagnets, in accordance with the electrical parameters established for the target region corresponding to the magnetic field generated by the activated electromagnet.

A magnetron sputter coating apparatus for depositing across the surfaces of substrates a desired distribution of sputtering material and for controlling said distribution as different regions of a sputtering target of said apparatus erode at difference rates, wherein said target has a sputtering surface facing toward said substrate, said sputtering surface having defined thereon first and second regions, and wherein said apparatus further comprises:

• a controller establishing separate electrical parameters for each of said regions, which parameters, if maintained, will result in the deposition of the sum of material sputtered from all of said regions of said target to be of said desired distribution across the substrate surfaces;
• a first and a second individually activatable electromagnet, each magnet being positioned so as to generate, when activated, a magnetic field corresponding to a respective one of said first and second target regions to cause the emission of sputtered material, and the erosion of said target, at the target region corresponding to an activated field, when said target is energized;
• a circuit for alternately activating said first and second electromagnets;
• a power supply operable to alternately energize said target in accordance with the electrical parameters established for each respective target region and in synchronism with the activation of the magnetic field corresponding to the respective target regions;
• a detector operable to measure a parameter associated with said target to determine changes in said operational electrical parameters associated with changes in the state of erosion of each of the respective adjacent target regions;
• and
• said controller being operable to revise, in synchronism with the activation of said magnetic fields, at least one of the established electrical parameters associated with at least one of said regions in accordance with the measurement by said detector.

A device for separately controlling the deposition of sputter coating material from different regions of a sputtering target of a magnetron sputtering apparatus, said device comprising:

• at least two separate magnets, including a first and a second magnet, for respectively generating a first plasma supporting magnetic field associated with a first one of said target regions and a second plasma supporting magnetic field associated with a second one of said target regions;
• means for activating said first magnet and for deactivating said second magnet, and all other magnets generating plasma supporting magnetic fields associated with regions of said target other than said first region which are electrically connected to said first region during at least a portion of the time during which said first magnet is activated;
• means for measuring an electrical parameter of said target during a time when said first magnet is activated and all other of said magnets are deactivated;
• and
• wherein said target has a sputtering surface which comprises sputtering material and said target regions are areas on said sputtering surface of said target having at least one boundary defined by the intersection of lines of the magnetic field generated by the respective magnet with said sputtering surface.

A target assembly for a magnetron sputtering apparatus, said target assembly comprising:

• an annular target formed of a single piece of sputtering material, said target having a sputtering surface bounded by an inner edge and an outer edge extending forwardly of said inner edge, said surface being smooth, continuous and concave along a radial cross section from said inner edge to said outer edge;
• at least two magnets positioned adjacent said target and including a first magnet operable to form an inner plasma confining magnetic field outside of the inner edge of said target and a second magnet for forming an outer plasma confining magnetic field inside of said outer edge of said target and outside of said inner field, said fields defining respective first and second concentric regions on said sputtering surface;
• and
• the thickness of said sputtering material underlying said outer region continuously increasing outwardly from said inner region to a thickness greater than that underlying said inner region.

A target for a magnetron sputtering apparatus, said target comprising:

• a single annular piece of sputtering material, said piece having a sputtering surface bounded by an inner edge, an outer edge extending forwardly of said inner edge, an inner sputtering region thereon proximate said inner edge and an outer sputtering region thereon between said inner region and said outer edge;
• said surface being smooth, continuous and concave across said regions along a radial cross section of said target;
• and
• the thickness of said sputtering material underlying said outer region continuously increasing outwardly from said inner region to a thickness greater than that underlying said inner region.

A method of depositing a desired distribution of sputtered material across the surface of a substrate and for controlling the deposition rate from different regions of a single-piece sputtering target which erode at different rates, said method comprising the steps of:

• providing a one piece sputtering target and defining a plurality of differently facing regions thereon, including a first region and a second region;
• establishing separate values for electrical parameters for each of said regions so as to cause the deposition of the sum of material sputtered from all of said regions to be of a desired distribution across the substrate surfaces;
• activating a first plasma supporting magnetic field adjacent said first target region so as to cause the emission of sputtered material, and the erosion of said target, in said first target region when said target is energized;
• energizing said target in accordance with the electrical parameter values established for said first target region while said first magnetic field is activated and other magnetic fields are deactivated;
• activating a second plasma supporting magnetic field adjacent said second target region so as to cause the emission of sputtered material, and the erosion of said target, in said second region when said target is energized;
• and
• energizing said target in accordance with the electrical parameter values established for said second target region while said second field is activated and other magnetic fields are deactivated.

A method for depositing a controlled distribution of sputtered material across the differently facing surfaces of substrates, said method comprising the steps of:

• providing a one-piece sputtering target and defining a plurality of differently facing regions on the sputtering surface of said sputtering target, said regions including a first region and a second region, said first and second sputtering surface regions facing different ones of said differently facing substrate surfaces;
• establishing separate electrical parameter values for each of said regions so as to cause the deposition of the sum of material sputtered from al of said regions to be of a desired distribution across the substrate surfaces;
• alternately activating first and second plasma supporting magnetic fields adjacent said first and second target regions to alternately cause the emission of sputtered material in the respective target region adjacent the activated field when said target is energized;
• and
• alternately energizing said target in accordance with the respective electrical parameter values established for each respective target region and in synchronism with the activation of the magnetic field adjacent the respective region.

A sputter coating method for separately controlling the deposition from different regions of a magnetron sputtering target, said method comprising the steps of:

• activating a first plasma supporting magnetic field associated with a first one of said target regions while deactivating all other plasma supporting magnetic fields associated with other regions of said target which are electrically connected to said first region;
• measuring a parameter related to the operation of said target in synchronism with the activation of said first magnetic field;
• activating a second plasma supporting magnetic field associated with a second on of said target regions while deactivating all other plasma supporting magnetic fields associated with all other regions of said target which are electrically connected to said first region;
• and
• measuring a parameter related to the operation of said target in synchronism with the activation of said second magnetic field

A method for obtaining a desired distribution of sputtered material deposited across the surface of a substrate, said method comprising the steps of:

• providing a target formed of a single piece of sputtering material having a sputtering surface in spaced relationship with the surface of the substrate, said target surface having a plurality of different regions thereon, each region having a different geometric relationship with the substrate surface so that material sputtered therefrom produces a different distribution across the substrate surface;
• establishing a plurality of sets of values for electrical parameters, each associated with a different one of said regions, said values and said geometric relationships being related in such a way as to cause the deposition of the sum of material sputtered from all of said regions to be of the desired distribution across the substrate surface;
• activating a plurality of magnetic fields, each adjacent a different one of said target regions, in accordance with parameter values associated with the respective region, to cause the emission of sputtered material from the respective target region when said target is energized;
• and
• energizing said target in synchronism with the activation of the magnetic fields and in accordance with parameter values associated with the respective target regions.