Method of controlling the switched mode ion energy distribution system
First Claim
1. A method for providing a modified periodic voltage function to an electrical node, the electrical node configured for electrically-coupling to a substrate support of a plasma processing chamber, the method comprising:
- obtaining an effective capacitance value, C1, of the substrate support;
storing the effective capacitance value, C1, in a memory;
providing an ion current compensation, IC, to the electrical node;
providing a periodic voltage function to the electrical node, the periodic voltage function being modified by the ion current compensation, IC, to form the modified periodic voltage function;
providing the modified periodic voltage function to the electrical node, the modified periodic voltage function having pulses and a portion between the pulses;
accessing the memory to retrieve the effective capacitance value, C1;
determining a slope, dV0/dt, of the portion between the pulses of the modified periodic voltage function; and
controlling a DC current source to adjust a magnitude of the ion current compensation, IC, applied to the substrate support until
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Abstract
Systems, methods and apparatus for regulating ion energies in a plasma chamber and chucking a substrate to a substrate support are disclosed. An exemplary method includes placing a substrate in a plasma chamber, forming a plasma in the plasma chamber, controllably switching power to the substrate so as to apply a periodic voltage function (or a modified periodic voltage function) to the substrate, and modulating, over multiple cycles of the periodic voltage function, the periodic voltage function responsive to a defined distribution of energies of ions at the surface of the substrate so as to effectuate the defined distribution of ion energies on a time-averaged basis.
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Citations
20 Claims
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1. A method for providing a modified periodic voltage function to an electrical node, the electrical node configured for electrically-coupling to a substrate support of a plasma processing chamber, the method comprising:
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obtaining an effective capacitance value, C1, of the substrate support; storing the effective capacitance value, C1, in a memory; providing an ion current compensation, IC, to the electrical node; providing a periodic voltage function to the electrical node, the periodic voltage function being modified by the ion current compensation, IC, to form the modified periodic voltage function; providing the modified periodic voltage function to the electrical node, the modified periodic voltage function having pulses and a portion between the pulses; accessing the memory to retrieve the effective capacitance value, C1; determining a slope, dV0/dt, of the portion between the pulses of the modified periodic voltage function; and controlling a DC current source to adjust a magnitude of the ion current compensation, IC, applied to the substrate support until - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method comprising:
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applying a modified periodic voltage function to an electrical node, the modified periodic voltage function comprising a periodic voltage function modified by an ion current compensation, wherein the electrical node is configured for coupling to a substrate support coupled to a substrate in a plasma processing chamber; sampling at least one cycle of the modified periodic voltage function to generate voltage data points; estimating a value of a first ion energy for ions reaching a surface of the substrate, the estimating based on the voltage data points, and wherein the estimating is a function of ion current, and the ion current is a function of the ion current compensation; and adjusting the modified periodic voltage function until the first ion energy equals a defined ion energy; wherein the following equation is used in the estimating a value of the first ion energy; - View Dependent Claims (15, 16, 17, 18)
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19. A non-transitory, tangible computer readable storage medium, encoded with processor readable instructions to perform a method for identifying a defined ion current compensation, IC, the method comprising:
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sampling a modified periodic voltage function given the ion current compensation, IC, having a first value; sampling a modified periodic voltage function given the ion current compensation, IC, having a second value; accessing a memory to obtain an effective capacitance, C1, for the plasma processing chamber; determining a slope, dV0/dt, of the modified periodic voltage function based on the first and second sampling; and controlling a DC current source to adjust a magnitude of ion current compensation current, IC, applied to the substrate support until; - View Dependent Claims (20)
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Specification