System for providing variable capacitance
First Claim
1. A radio frequency (RF) impedance matching network comprising:
- an RF input configured to operably couple to an RF source;
an RF output configured to operably couple to a plasma chamber having a variable impedance;
electronically variable capacitors (EVCs) each comprising discrete capacitors operably coupled in parallel, the discrete capacitors comprising;
fine capacitors each having a capacitance value substantially similar to a fine capacitance value; and
coarse capacitors each having a capacitance value substantially similar to a coarse capacitance value, the coarse capacitance value being greater than the fine capacitance value;
wherein each EVC has a variable total capacitance that is increased when the discrete capacitors are switched in and decreased when the discrete capacitors are switched out; and
a control circuit operably coupled to the EVCs, the control circuit configured to determine the variable impedance of the plasma chamber;
the control circuit further configured to;
determine, based on the determined variable impedance, a total number of coarse capacitors of the coarse capacitors to have switched in;
determine, based on the determined variable impedance, a total number of fine capacitors of the fine capacitors to have switched in; and
cause an impedance match by causing the total number of coarse capacitors and the total number of fine capacitors to be switched in;
wherein the increase of the variable total capacitance of each EVC is achieved by switching in more of the coarse capacitors or more of the fine capacitors than are already switched in without switching out a coarse capacitor that is already switched in.
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Accused Products
Abstract
In one embodiment, a radio frequency (RF) impedance matching network includes electronically variable capacitors (EVCs), each EVC including discrete capacitors operably coupled in parallel. The discrete capacitors include fine capacitors each having a capacitance value substantially similar to a fine capacitance value, and coarse capacitors each having a capacitance value substantially similar to a coarse capacitance value. The increase of the variable total capacitance of each EVC is achieved by switching in more of the coarse capacitors or more of the fine capacitors than are already switched in without switching out a coarse capacitor that is already switched in.
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Citations
21 Claims
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1. A radio frequency (RF) impedance matching network comprising:
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an RF input configured to operably couple to an RF source; an RF output configured to operably couple to a plasma chamber having a variable impedance; electronically variable capacitors (EVCs) each comprising discrete capacitors operably coupled in parallel, the discrete capacitors comprising; fine capacitors each having a capacitance value substantially similar to a fine capacitance value; and coarse capacitors each having a capacitance value substantially similar to a coarse capacitance value, the coarse capacitance value being greater than the fine capacitance value; wherein each EVC has a variable total capacitance that is increased when the discrete capacitors are switched in and decreased when the discrete capacitors are switched out; and a control circuit operably coupled to the EVCs, the control circuit configured to determine the variable impedance of the plasma chamber; the control circuit further configured to; determine, based on the determined variable impedance, a total number of coarse capacitors of the coarse capacitors to have switched in; determine, based on the determined variable impedance, a total number of fine capacitors of the fine capacitors to have switched in; and cause an impedance match by causing the total number of coarse capacitors and the total number of fine capacitors to be switched in; wherein the increase of the variable total capacitance of each EVC is achieved by switching in more of the coarse capacitors or more of the fine capacitors than are already switched in without switching out a coarse capacitor that is already switched in. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of controlling an impedance matching network, the method comprising:
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providing an RF impedance matching network comprising; an RF input configured to operably couple to an RF source; an RF output configured to operably couple to a plasma chamber having a variable impedance; electronically variable capacitors (EVCs) each comprising discrete capacitors operably coupled in parallel, the discrete capacitors comprising; fine capacitors each having a capacitance value substantially similar to a fine capacitance value; and coarse capacitors each having a capacitance value substantially similar to a coarse capacitance value, the coarse capacitance value being greater than the fine capacitance value; wherein each EVC has a variable total capacitance that is increased when the discrete capacitors are switched in and decreased when the discrete capacitors are switched out; a control circuit operably coupled to the EVCs; by the control circuit, determining the variable impedance of the plasma chamber; by the control circuit, determining, based on the determined variable impedance, a total number of coarse capacitors of the coarse capacitors to have switched in; by the control circuit, determining, based on the determined variable impedance, a total number of fine capacitors of the fine capacitors to have switched in; and by the control circuit, causing an impedance match by causing the total number of coarse capacitors and the total number of fine capacitors to be switched in; wherein the increase of the variable total capacitance of the each EVC is achieved by switching in more of the coarse capacitors or more of the fine capacitors than are already switched in without switching out a coarse capacitor that is already switched in. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
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20. A method of fabricating a semiconductor, the method comprising:
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placing a substrate in a plasma chamber configured to deposit a material layer onto the substrate or etch a material layer from the substrate; and energizing plasma within the plasma chamber by coupling RF power from an RF source into the plasma chamber to perform a deposition or etching, and while energizing the plasma; providing an RF matching network between the plasma chamber and the RF source, the RF matching network comprising; an RF input configured to operably couple to an RF source; an RF output configured to operably couple to a plasma chamber having a variable impedance; electronically variable capacitors (EVCs) each comprising discrete capacitors operably coupled in parallel, the discrete capacitors comprising; fine capacitors each having a capacitance value substantially similar to a fine capacitance value; and coarse capacitors each having a capacitance value substantially similar to a coarse capacitance value, the coarse capacitance value being greater than the fine capacitance value; wherein each EVC has a variable total capacitance that is increased when the discrete capacitors are switched in and decreased when the discrete capacitors are switched out; a control circuit operably coupled to the EVCs; by the control circuit, determining the variable impedance of the plasma chamber; by the control circuit, determining, based on the determined variable impedance, a total number of coarse capacitors of the coarse capacitors to have switched in; by the control circuit, determining, based on the determined variable impedance, a total number of fine capacitors of the fine capacitors to have switched in; and by the control circuit, causing an impedance match by causing the total number of coarse capacitors and the total number of fine capacitors to be switched in; wherein the increase of the variable total capacitance of the each EVC is achieved by switching in more of the coarse capacitors or more of the fine capacitors than are already switched in without switching out a coarse capacitor that is already switched in.
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21. A semiconductor processing tool comprising:
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a plasma chamber configured to deposit a material onto a substrate or etch a material from the substrate; and an impedance matching circuit operably coupled to the plasma chamber, matching circuit comprising; an RF input configured to be operably coupled to an RF source; an RF output operably coupled to the plasma chamber, the plasma chamber having a variable impedance; electronically variable capacitors (EVCs) each comprising discrete capacitors operably coupled in parallel, the discrete capacitors comprising; fine capacitors each having a capacitance value substantially similar to a fine capacitance value; and coarse capacitors each having a capacitance value substantially similar to a coarse capacitance value, the coarse capacitance value being greater than the fine capacitance value; wherein each EVC has a variable total capacitance that is increased when the discrete capacitors are switched in and decreased when the discrete capacitors are switched out; and a control circuit operably coupled to the EVCs, the control circuit configured to determine the variable impedance of the plasma chamber; the control circuit further configured to; determine, based on the determined variable impedance, a total number of coarse capacitors of the coarse capacitors to have switched in; determine, based on the determined variable impedance, a total number of fine capacitors of the fine capacitors to have switched in; and cause an impedance match by causing the total number of coarse capacitors and the total number of fine capacitors to be switched in; wherein the increase of the variable total capacitance of each EVC is achieved by switching in more of the coarse capacitors or more of the fine capacitors than are already switched in without switching out a coarse capacitor that is already switched in.
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Specification