What is claimed is:
1. An endpointing arrangement for ascertaining an end of an etch process while etching through a target layer on a substrate in a plasma processing system, comprising:
an electrostatic chuck having a first pole and a second pole;
a first DC power supply coupled to said first pole and said second pole for supplying chucking voltages to said first pole and said second pole;
a first current monitoring circuit coupled between said first pole and said first DC power supply for monitoring a first current supplied to said first pole, said first current monitoring circuit outputting a first signal indicative of said first current;
a second current monitoring circuit coupled between said second pole and said first DC power supply for monitoring a second current supplied to said second pole, said second current monitoring circuit outputting a second signal indicative of said second current;
a differential amplifier arrangement coupled to said first current monitoring circuit and said second current monitoring circuit, said differential amplifier arrangement receives said first signal and said second signal as input and outputs a control signal;
a variable DC power supply coupled to said differential amplifier arrangement for receiving said control signal, said variable DC power supply being configured to output a compensation voltage for biasing said first DC power supply responsive to said control signal; and
an endpoint monitoring circuit coupled to said variable DC power supply, said endpoint monitoring circuit receives as an input said compensation voltage and includes circuitry for analyzing said compensation voltage for a pattern characteristic of said end of said etch process, said endpoint monitoring circuit further including circuitry for outputting an endpoint signal indicative of said end of said etch process upon ascertaining said pattern in said compensation voltage.
2. The endpointing arrangement of claim 1 wherein said compensation voltage biases said first DC power supply to maintain said first current and said second current substantially constant during said etch process.
3. A method for ascertaining an end of an etch process while etching through a target layer on a substrate in a plasma processing system, said plasma processing system including an electrostatic chuck having a first pole, a first DC power supply coupled to said first pole for supplying a chucking voltage to said first pole, a first current monitoring circuit coupled between said first pole and said first DC power supply for monitoring a first current supplied to said first pole, said first current monitoring circuit outputting a first signal indicative of said first current, and a variable DC power supply configured to output a compensation voltage for biasing said first DC power supply responsive to said first signal, thereby causing said chucking voltage to vary responsive to said compensation voltage, said method comprising:
coupling an endpoint monitoring circuit to said variable DC power supply, said endpoint monitoring circuit having an endpoint monitoring input and an endpoint monitoring output;
receiving at said endpoint monitoring input said compensation voltage;
analyzing, using said endpoint monitoring circuit, said compensation voltage for a pattern characteristic of said end of said etch process; and
outputting at said endpoint monitoring output an endpoint signal indicative of said end of said etch process upon ascertaining said pattern in said compensation voltage.
4. The method of claim 3 wherein said electrostatic chuck includes a second pole coupled to said first DC power supply, said plasma processing system includes a second current monitoring circuit coupled between said second pole and said first DC power supply for monitoring a second current supplied to said second pole, wherein said compensation voltage output by said variable DC power supply is responsive to both said first signal and a second signal output by said second current monitoring circuit, said second signal being indicative of said second current.
5. The method of claim 4 wherein said plasma processing system includes a differential amplifier arrangement coupled to said first current monitoring circuit and said second current monitoring circuit, said differential amplifier arrangement receives said first signal and said second signal as input and outputs a control signal to said variable DC supply to cause said compensation voltage output by said variable DC power supply to vary responsive to both said first signal and said second signal.
6. The method of claim 4 wherein said first signal and said second signal is employed by said variable DC power supply to maintain said first current and said second current substantially constant during said etch process.
7. The method of claim 4 wherein said endpoint monitoring circuit includes a general purpose microcomputer.
8. The method of claim 4 wherein said electrostatic chuck represents a Johnsen-Rahbek chuck.
9. The method of claim 4 wherein said substrate includes a conductive layer underlying said target layer.
10. The method of claim 4 wherein said substrate includes a dielectric layer underlying said target layer.
11. The method of claim 4 wherein said target layer represents a silicon dioxide-containing layer, said substrate further includes a dielectric layer underlying said target layer.
12. The method of claim 4 wherein said target layer represents a low dielectric constant layer, said substrate further includes a dielectric layer underlying said target layer.
13. An endpointing arrangement for ascertaining an end of an etch process while etching through a target layer on a substrate in a plasma processing system, comprising:
an electrostatic chuck having a first pole;
a first DC power supply coupled to said first pole for supplying a chucking voltage to said first pole;
a first current monitoring circuit coupled between said first pole and said first DC power supply for monitoring a first current supplied to said first pole, said first current monitoring circuit outputting a first signal indicative of said first current;
a variable DC power supply configured to output a compensation voltage for biasing said first DC power supply responsive to said first signal, thereby causing said chucking voltage to vary responsive to said compensation voltage;
an endpoint monitoring circuit coupled to said variable DC power supply, said endpoint monitoring circuit receives as an input said compensation voltage and includes circuitry for analyzing said compensation voltage for a pattern characteristic of said end of said etch process, said endpoint monitoring circuit further including circuitry for outputting an endpoint signal indicative of said end of said etch process upon ascertaining said pattern in said compensation voltage.
14. The endpointing arrangement of claim 13 wherein said electrostatic chuck includes a second pole coupled to said first DC power supply, said endpointing arrangement further comprises:
a second current monitoring circuit coupled between said second pole and said first DC power supply for monitoring a second current supplied to said second pole, said second current monitoring circuit outputting a second signal indicative of said second current, wherein said compensation voltage output by said variable DC power supply is responsive to both said first signal and said second signal.
15. The endpointing arrangement of claim 14 wherein said compensation voltage output by said variable DC power supply is configured to keep said first current and said second current substantially equal but opposite in sign.
16. The endpointing arrangement of claim 14 wherein said compensation voltage output by said variable DC power supply is configured to keep said first current and said second current substantially constant throughout said etching irrespective whether magnitudes of said first current and said second current are equal.
17. The endpointing arrangement of claim 14 further comprising a differential amplifier arrangement coupled to said first current monitoring circuit and said second current monitoring circuit, said differential amplifier arrangement receives said first signal and said second signal as input and outputs a control signal to said variable DC supply to cause said compensation voltage output by said variable DC power supply to vary responsive to both said first signal and said second signal.
18. The endpointing arrangement of claim 14 wherein said endpoint monitoring circuit includes a general purpose microcomputer.
19. The endpointing arrangement of claim 14 wherein said electrostatic chuck represents a Johnsen-Rahbek chuck.
20. The endpointing arrangement of claim 14 wherein said substrate includes a conductive layer underlying said target layer.
21. The endpointing arrangement of claim 14 wherein said substrate includes a dielectric layer underlying said target layer.
22. The endpointing arrangement of claim 14 wherein said target layer represents a silicon dioxide-containing layer, said substrate further includes a dielectric layer underlying said target layer.
23. An endpointing arrangement for ascertaining an end of an etch process while etching through a target layer on a substrate in a plasma processing system, comprising:
an electrostatic chuck having a first pole;
a first DC power supply coupled to said first pole for supplying a chucking voltage to said first pole;
a first current monitoring circuit coupled between said first pole and said first DC power supply for monitoring a first current supplied to said first pole, said first current monitoring circuit outputting a first signal indicative of said first current;
an endpoint monitoring circuit coupled to said first current monitoring circuit, said endpoint monitoring circuit receives as a first input said first signal and includes circuitry for analyzing said first signal for a pattern characteristic of said end of said etch process, said endpoint monitoring circuit further including circuitry for outputting an endpoint signal indicative of said end of said etch process upon ascertaining said pattern in said first signal.
24. The endpointing arrangement of claim 23 wherein said electrostatic chuck includes a second pole coupled to said first DC power supply, said endpointing arrangement further comprises:
a second current monitoring circuit coupled between said second pole and said first DC power supply for monitoring a second current supplied to said second pole, said second current monitoring circuit outputting a second signal indicative of said second current, wherein said endpoint monitoring circuit receives as a second input said second signal, said endpoint signal being responsive to both said first signal and said second signal.
25. The endpointing arrangement of claim 23 wherein said electrostatic chuck represents a monopolar electrostatic chuck.
26. An endpointing arrangement for ascertaining an end of an etch process while etching through a target layer on a substrate in a plasma processing system, comprising:
an electrostatic chuck having a first pole and a second pole;
a first DC power supply coupled to said first pole and said second pole for supplying chucking voltages to said first pole and said second pole;
a first current monitoring circuit coupled between said first pole and said first DC power supply for monitoring a first current supplied to said first pole, said first current monitoring circuit outputting a first signal indicative of said first current;
a second current monitoring circuit coupled between said second pole and said first DC power supply for monitoring a second current supplied to said second pole, said second current monitoring circuit outputting a second signal indicative of said second current;
a differential amplifier arrangement coupled to said first current monitoring circuit and said second current monitoring circuit, said differential amplifier arrangement receives said first signal and said second signal as inputs and outputs a differential output signal responsive to both said first signal and said second signal;
an endpoint monitoring circuit coupled to said differential amplifier arrangement, said endpoint monitoring circuit receives as an input said differential output signal and includes circuitry for analyzing said differential output signal for a pattern characteristic of said end of said etch process, said endpoint monitoring circuit further including circuitry for outputting an endpoint signal indicative of said end of said etch process upon ascertaining said pattern in said differential output signal.
27. The endpointing arrangement of claim 26 wherein said electrostatic chuck represents a Johnsen-Rahbek chuck.
28. The endpointing arrangement of claim 26 wherein said substrate includes a conductive layer underlying said target layer.
29. The endpointing arrangement of claim 26 wherein said substrate includes a dielectric layer underlying said target layer.
30. An endpointing arrangement for ascertaining an end of an etch process while etching through a target layer on a substrate in a plasma processing system, comprising:
an electrostatic chuck having a first pole and a second pole;
a first DC power supply coupled to said first pole and said second pole for supplying chucking voltages to said first pole and said second pole;
a first current path coupled in parallel with outputs of said first DC power supply;
a first current monitoring circuit coupled to a node in said first current path for monitoring a first current flowing to said node, said first current monitoring circuit outputting a first signal indicative of said first current; and
an endpoint monitoring circuit coupled to said first current monitoring circuit, said endpoint monitoring circuit receives as an input said first signal and includes circuitry for analyzing said first signal for a pattern characteristic of said end of said etch process, said endpoint monitoring circuit further including circuitry for outputting an endpoint signal indicative of said end of said etch process upon ascertaining said pattern in said first signal.
31. The endpointing arrangement of claim 30 wherein said first current monitoring circuit is coupled in series between said node and ground.
32. The endpointing arrangement of claim 30 further comprising a variable DC power supply, said first current monitoring circuit is coupled in series between said variable DC power supply and said node.
33. An endpointing arrangement for ascertaining an end of an etch process while etching through a target layer on a substrate in a plasma processing system, comprising:
an electrostatic chuck having a first pole;
a first DC power supply coupled to said first pole for supplying a chucking voltage to said first pole;
an endpoint monitoring circuit configured to receive a signal reflecting a potential of said substrate, said endpoint monitoring circuit including circuitry configured to analyze said signal reflecting said potential of said substrate for a pattern characteristic of said end of said etch process, said endpoint monitoring circuit further including circuitry for outputting an endpoint signal indicative of said end of said etch process upon ascertaining said signal reflecting said potential of said substrate.
34. The endpointing arrangement of claim 33 wherein said signal reflecting said potential of said substrate is obtained by a probe in contact with said substrate.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A communication system in which a mobile terminal apparatus and a base station apparatus communicate using a basic carrier and an extended carrier that is additionally allocated to the basic carrier, wherein:
the base station apparatus comprises:
a setting section that sets, in the extended carrier, a subframe of a first carrier type which can be received in each of a plurality of mobile terminal apparatuses of varying capabilities and a subframe of a second carrier type which can be received in part of the plurality of mobile terminal apparatuses; and
a transmission section that transmits the basic carrier and the extended carrier to the mobile terminal apparatus; and
the mobile terminal apparatus comprises:
a receiving section that receives the basic carrier and the extended carrier from the base station apparatus.
2. The communication system according to claim 1, wherein the setting section sets, in the basic carrier, the subframe of the first carrier type and the subframe of the second carrier type.
3. The communication system according to claim 1, wherein the setting section disallows allocating the subframe of the second carrier type, to a mobile terminal apparatus which can receive only the subframe of the first carrier type.
4. The communication system according to claim 1, wherein the base station apparatus further comprises a reporting section that reports a carrier type of each subframe.
5. The communication system according to claim 4, wherein the reporting section reports the carrier type of each subframe using bitmap information which indicates a subframe in which the mobile terminal apparatus is allowed to measure a reference signal.
6. A base station apparatus that communicates with a mobile terminal apparatus using a basic carrier and an extended carrier that is additionally allocated to the basic carrier, the base station apparatus comprising:
a setting section that sets, in the extended carrier, a subframe of a first carrier type which can be received in each of a plurality of mobile terminal apparatuses of varying capabilities and a subframe of a second carrier type which can be received in part of the plurality of mobile terminal apparatuses; and
a transmission section that transmits the basic carrier and the extended carrier to the mobile terminal apparatus.
7. A mobile terminal apparatus that communicates with a base station apparatus using a basic carrier and an extended carrier that is additionally allocated to the basic carrier, the mobile terminal apparatus comprising:
a receiving section that receives, from the base station apparatus, the extended carrier, in which a subframe of a first carrier type which can be received in each of a plurality of mobile terminal apparatuses of varying capabilities and a subframe of a second carrier type which can be received in part of the plurality of mobile terminal apparatuses, are set.
8. A communication method whereby a mobile terminal apparatus and a base station apparatus communicate using a basic carrier and an extended carrier that is additionally allocated to the basic carrier, the communication method comprising the steps of:
in the base station apparatus:
setting, in the extended carrier, a subframe of a first carrier type which can be received in each of a plurality of mobile terminal apparatuses of varying capabilities and a subframe of a second carrier type which can be received in part of the plurality of mobile terminal apparatuses; and
transmitting the basic carrier and the extended carrier to the mobile terminal apparatus; and
in the mobile terminal apparatus:
receiving the basic carrier and the extended carrier from the base station apparatus.
9. The communication system according to claim 2, wherein the setting section disallows allocating the subframe of the second carrier type, to a mobile terminal apparatus which can receive only the subframe of the first carrier type.