Impedance matching with restricted capacitor switching
First Claim
1. An impedance matching network comprising:
- an input configured to operably couple to a radio frequency (RF) source;
an output configured to operably couple to a plasma chamber for manufacturing a semiconductor;
a variable capacitor comprising;
a plurality of capacitors operably coupled in parallel, the plurality of capacitors comprising;
coarse capacitors comprising (a) first coarse capacitors each having a substantially similar first coarse capacitance; and
(b) second coarse capacitors each having a substantially similar second coarse capacitance; and
fine capacitors having different capacitances that increase in value, wherein at least one of the fine capacitors has a capacitance greater than the first coarse capacitance;
a plurality of switches, wherein each switch of the plurality of switches is operably coupled in series with a corresponding capacitor of the plurality of capacitors and configured to switch in and out the corresponding capacitor;
wherein each capacitor of the plurality of capacitors provides a change to a total capacitance of the variable capacitor when the capacitor is switched in;
a control circuit operably coupled to the variable capacitor, the control circuit configured to (a) determine which of the coarse capacitors and the fine capacitors to have switched in to achieve an impedance match and (b) cause the determined coarse and fine capacitors to be switched in;
wherein the control circuit is further configured to cause a gradual increase in the total capacitance of the variable capacitor by;
switching in, in a predetermined order, each of the first coarse capacitors, followed by each of the second coarse capacitors; and
only switching in the fine capacitors whose capacitance is less than a capacitance of a next coarse capacitor of the coarse capacitors predetermined to be switched in next.
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Accused Products
Abstract
In one embodiment, an RF impedance matching network for a plasma chamber is disclosed. It includes a variable capacitor comprising a plurality of capacitors comprising first coarse capacitors each having a substantially similar first coarse capacitance, second coarse capacitors each having a substantially similar second coarse capacitance, and fine capacitors having different capacitances that increase in value. At least one of the fine capacitors has a capacitance greater than the first coarse capacitance. A control circuit is configured cause a gradual increase in the total capacitance of the variable capacitor by switching in, in a predetermined order, each of the first coarse capacitors, followed by each of the second coarse capacitors, only switching in the fine capacitors whose capacitance is less than a capacitance of a next coarse capacitor of the coarse capacitors predetermined to be switched in next.
195 Citations
21 Claims
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1. An impedance matching network comprising:
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an input configured to operably couple to a radio frequency (RF) source; an output configured to operably couple to a plasma chamber for manufacturing a semiconductor; a variable capacitor comprising; a plurality of capacitors operably coupled in parallel, the plurality of capacitors comprising; coarse capacitors comprising (a) first coarse capacitors each having a substantially similar first coarse capacitance; and
(b) second coarse capacitors each having a substantially similar second coarse capacitance; andfine capacitors having different capacitances that increase in value, wherein at least one of the fine capacitors has a capacitance greater than the first coarse capacitance; a plurality of switches, wherein each switch of the plurality of switches is operably coupled in series with a corresponding capacitor of the plurality of capacitors and configured to switch in and out the corresponding capacitor; wherein each capacitor of the plurality of capacitors provides a change to a total capacitance of the variable capacitor when the capacitor is switched in; a control circuit operably coupled to the variable capacitor, the control circuit configured to (a) determine which of the coarse capacitors and the fine capacitors to have switched in to achieve an impedance match and (b) cause the determined coarse and fine capacitors to be switched in; wherein the control circuit is further configured to cause a gradual increase in the total capacitance of the variable capacitor by; switching in, in a predetermined order, each of the first coarse capacitors, followed by each of the second coarse capacitors; and only switching in the fine capacitors whose capacitance is less than a capacitance of a next coarse capacitor of the coarse capacitors predetermined to be switched in next. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. 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 input configured to operably couple to an RF source; an output configured to operably couple to the plasma chamber for manufacturing a semiconductor; a variable capacitor comprising; a plurality of capacitors operably coupled in parallel, the plurality of capacitors comprising; coarse capacitors comprising (a) first coarse capacitors each having a substantially similar first coarse capacitance; and
(b) second coarse capacitors each having a substantially similar second coarse capacitance; andfine capacitors having different capacitances that increase in value, wherein at least one of the fine capacitors has a capacitance greater than the first coarse capacitance; a plurality of switches, wherein each switch of the plurality of switches is operably coupled in series with a corresponding capacitor of the plurality of capacitors and configured to switch in and out the corresponding capacitor; wherein each capacitor of the plurality of capacitors provides a change to a total capacitance of the variable capacitor when the capacitor is switched in; a control circuit operably coupled to the variable capacitor, the control circuit configured to (a) determine which of the coarse capacitors and the fine capacitors to have switched in to achieve an impedance match and (b) cause the determined coarse and fine capacitors to be switched in; wherein the control circuit is further configured to cause a gradual increase in the total capacitance of the variable capacitor by; switching in, in a predetermined order, each of the first coarse capacitors, followed by each of the second coarse capacitors; and only switching in the fine capacitors whose capacitance is less than a capacitance of a next coarse capacitor of the coarse capacitors predetermined to be switched in next. - View Dependent Claims (9, 10, 11, 12, 13)
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14. A method of matching an impedance comprising:
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operably coupling an input of a matching network to an RF source; operably coupling an output of the matching network to a plasma chamber for manufacturing a semiconductor, the matching network comprising; a variable capacitor comprising; a plurality of capacitors operably coupled in parallel, the plurality of capacitors comprising; coarse capacitors comprising (a) first coarse capacitors each having a substantially similar first coarse capacitance; and
(b) second coarse capacitors each having a substantially similar second coarse capacitance; andfine capacitors having different capacitances that increase in value, wherein at least one of the fine capacitors has a capacitance greater than the first coarse capacitance; a plurality of switches, wherein each switch of the plurality of switches is operably coupled in series with a corresponding capacitor of the plurality of capacitors and configured to switch in and out the corresponding capacitor; wherein each capacitor of the plurality of capacitors provides a change to a total capacitance of the variable capacitor when the capacitor is switched in; and a control circuit; determining, by the control circuit, which of the coarse capacitors and the fine capacitors to have switched in to achieve an impedance match; and causing, by the control circuit, the determined coarse and fine capacitors to be switched in; wherein the control circuit is further configured to cause a gradual increase in the total capacitance of the variable capacitor by; switching in, in a predetermined order, each of the first coarse capacitors, followed by each of the second coarse capacitors; and only switching in the fine capacitors whose capacitance is less than a capacitance of a next coarse capacitor of the coarse capacitors predetermined to be switched in next. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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21. A method of manufacturing a semiconductor, the method comprising:
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operably coupling an input of a matching network to an RF source; operably coupling an output of the matching network to a plasma chamber, plasma chamber configured to deposit a material layer onto the substrate or etch a material layer from the substrate, the matching network comprising; a variable capacitor comprising; a plurality of capacitors operably coupled in parallel, the plurality of capacitors comprising; coarse capacitors comprising (a) first coarse capacitors each having a substantially similar first coarse capacitance; and
(b) second coarse capacitors each having a substantially similar second coarse capacitance; andfine capacitors having different capacitances that increase in value, wherein at least one of the fine capacitors has a capacitance greater than the first coarse capacitance; a plurality of switches, wherein each switch of the plurality of switches is operably coupled in series with a corresponding capacitor of the plurality of capacitors and configured to switch in and out the corresponding capacitor; wherein each capacitor of the plurality of capacitors provides a change to a total capacitance of the variable capacitor when the capacitor is switched in; and a control circuit; placing a substrate in the plasma chamber; energizing plasma within the plasma chamber by coupling RF power from the RF source into the plasma chamber to perform a deposition or etching; and determining, by the control circuit, which of the coarse capacitors and the fine capacitors to have switched in to achieve an impedance match; and causing, by the control circuit, the determined coarse and fine capacitors to be switched in; wherein the control circuit is further configured to cause a gradual increase in the total capacitance of the variable capacitor by; switching in, in a predetermined order, each of the first coarse capacitors, followed by each of the second coarse capacitors; and only switching in the fine capacitors whose capacitance is less than a capacitance of a next coarse capacitor of the coarse capacitors predetermined to be switched in next.
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Specification