Plasma processing method and plasma processing apparatus
A plasma processing method apparatus for accurately estimating the amount of lateral etching and determining an end point based on the estimated amount of etching, including: a first step of irradiating the wafer with light; a second step of receiving light reflected from the wafer at a plurality of predetermined times during the plasma process on the wafer; a third step of performing signal processing on light amount data on each of a plurality of wavelengths of the light thus received; a fourth step of determining the amount of etching in the wafer during the plasma process by use of processed data subjected to the signal processing; and a fifth step of determining an end point of the plasma process based on the amount of etching.
1 . A plasma processing method for etching in a lateral direction one of a plurality of films arranged on a wafer located in a processing chamber using plasma generated therein, the plasma processing method comprising:
a first step of irradiating light with a light source onto a surface of the wafer;
a second step of receiving light reflected from the surface of the wafer at a plurality of predetermined times during the processing of the wafer;
a third step of performing signal processing on data indicating amounts of the light with a plurality of wavelengths, the data indicating the amounts of the light including vibration components in amplitudes vibrating in a wavelength direction of the plurality of wavelengths corresponding to an increase or a decrease of wavelengths or wavenumbers with a plurality of maximum values or minimum values, and the signal processing including a step of removing the vibration components vibrating in the wavelength direction in a range of frequencies of vibration which are larger than a predetermined value;
a fourth step of determining an amount of etching for at least one of the predetermined times during the processing of the wafer by using a result of the signal processing in the third step; and
a fifth step of determining an end point of the processing of the wafer based on the result of the determining of the amount of etching in the fourth step and stopping or changing a condition for the processing of the wafer.
2 . The plasma processing method according to claim 1 , wherein:
the signal processing includes a sixth step of converting the plurality of wavelengths into wavenumbers and performing interpolation and resampling on the light amount data such that the wavenumbers are aligned at equal intervals along an axis indicative of the plurality of wavenumbers.
3 . The plasma processing method according to claim 1 , wherein
in the fourth step, the amount of etching in the wafer is determined based on the data obtained through the signal processing on the data indicating the amount of light during the processing of the wafer by use of pattern data obtained in advance associated with a plurality of amounts of etching.
4 . The plasma processing method according to claim 1 , wherein
the wafer includes a multilayer film formed on the surface of the wafer, in which insulating films and target films for the processing of the wafer including metal are alternately laminated in an up-down direction; and
in the fourth step, the amount of lateral etching in the target films is detected.
5 . The plasma processing method according to claim 4 , wherein:
the insulating films are made of a substance containing silicon oxide; and
the target films each have a surface made of a substance configured to reflect light.
6 . A plasma processing method for etching a wafer located in a processing chamber using a plasma generated therein, the plasma processing method comprising:
a first step of irradiating light from a light source onto a surface of the wafer;
a second step of receiving light reflected from the surface of the wafer at a plurality of predetermined times during the processing of the wafer;
a third step of performing signal processing on data indicating amounts of the light with a plurality of wavelengths, the data indicating of the amount of the light including vibration components in amplitudes vibrating in a wavelength direction of the plurality of wavelengths corresponding to an increase or a decrease of wavelengths or wavenumbers with a plurality of maximum values or minimum values, and the signal processing including a step of removing the vibration components vibrating in the wavelength direction in a range of frequencies of vibration that are larger than a predetermined value, and the signal processing includes a step of detecting a lower envelope or an upper envelope of the vibration components in the data indicating the amount of the light;
a fourth step of determining an amount of etching for at least one of the predetermined times during the processing of the wafer by using a result of the signal processing in the third step; and
a fifth step of determining an end point of the processing of the wafer based on the result of the determining of the amount of etching in the forth step and stopping or changing a condition for the processing of the wafer.
7 . The plasma processing method according to claim 6 , wherein
in the fourth step, the amount of etching in the wafer is determined based on the data obtained through the signal processing on the data indicating the amount of light during the processing of the wafer by use of pattern data obtained in advance associated with a plurality of amounts of etching.
8 . The plasma processing method according to claim 6 , wherein
the wafer includes a multilayer film formed on the surface of the wafer, in which insulating films and target films for the processing of the wafer including metal are alternately laminated in an up-down direction; and
in the fourth step, the amount of lateral etching in the target films is detected.
9 . The plasma processing method according to claim 8 , wherein
the insulating films are made of a substance containing silicon oxide; and
the target films each have a surface made of a substance configured to reflect light.