Dry etching method and method for manufacturing semiconductor device
A dry etching method includes a process of, while continuously applying bias power using an ion species to a material to be processed including a first conductive member, a first insulating film provided on the first conductive member, a second conductive member provided on the first insulating film, and a second insulating film provided on the second conductive member, dry etching the second insulating film to expose the second conductive member. A time for which the bias power is continuously applied is set to 50 microseconds or less and a duty ratio of the bias power is set to 50% or less.
1. A dry etching method comprising:
a first process of, while applying bias power to a material to be processed including a first conductive member, a first insulating film provided on the first conductive member, a second conductive member provided on the first insulating film, and a second insulating film provided on the second conductive member, dry etching the second insulating film to expose the second conductive member by using an ion species generated by applying the bias power,
wherein the bias power is applied during a first period, a time for which is set to 50 microseconds or less,
wherein the bias power is applied during a second period such that a ratio of the first period to a time for the second period is set to 50% or less,
wherein the second conductive member is electrically insulated from the first conductive member,
wherein the bias power applied during the first period is a superimposed wave of first alternating-current power with a first frequency, second alternating-current power with a second frequency lower than the first frequency, and a pulse signal with a third frequency lower than the second frequency.
2. The dry etching method according to claim 1 , wherein the time for the second period is set to 50 microseconds or more.
3. The dry etching method according to claim 1 , wherein the second conductive member is not exposed at a surface of the material to be processed.
4. The dry etching method according to claim 1 , further comprising:
before the first process, a second process of, while applying bias power using an ion species, etching the second insulating film without exposing the second conductive member,
wherein the a duty ratio of the bias power of the second process is set to 100%.
5. The dry etching method according to claim 4 , wherein, in the second process, the bias power is continuously applied or is intermittently applied at a duty ratio higher than the ratio of the time for the first period to the time for the second period.
6. The dry etching method according to claim 4 , further comprising:
after the second process and before the first process, a third process of not applying bias power.
7. A method for manufacturing a semiconductor device, comprising:
a first process of, while applying bias power to a material to be processed including a first conductive member, a first insulating film provided on the first conductive member, a second conductive member provided on the first insulating film, and a second insulating film provided on the second conductive member, etching the second insulating film to expose the second conductive member by using an ion species generated by applying the bias power,
wherein the bias power is applied during a first period, a time for which is set to 50 microseconds or less,
wherein the bias power is applied during a second period such that a ratio of the time for the first period to a time for the second period is set to 50% or less,
wherein the second conductive member is electrically insulated from the first conductive member,
wherein the bias power applied during the first period is a superimposed wave of first alternating-current power with a first frequency, second alternating-current power with a second frequency lower than the first frequency, and a pulse signal with a third frequency lower than the second frequency.
8. The method for manufacturing a semiconductor device, according to claim 7 , further comprising:
a second process of forming the second insulating film by alternately stacking a silicon oxide layer and a silicon nitride layer in layers.
9. The method for manufacturing a semiconductor device, according to claim 7 , wherein the time for the second period is set to 50 microseconds or more.
10. The method for manufacturing a semiconductor device, according to claim 7 , wherein the second conductive member is not exposed at a surface of the material to be processed.
11. The method for manufacturing a semiconductor device, according to claim 7 , further comprising:
before the first process, a second process of, while applying bias power using an ion species, etching the second insulating film without exposing the second conductive member,
wherein the a duty ratio of the bias power of the second process is set to 100%.
12. The method for manufacturing a semiconductor device, according to claim 11 , wherein, in the second process, the bias power is continuously applied or is intermittently applied at a duty ratio higher than the ratio of the time for the first period to the time for the second period.
13. The method for manufacturing a semiconductor device, according to claim 11 , further comprising:
after the second process and before the first process, a third process without applying bias power.