Analysis method and semiconductor etching apparatus
There is provided a method of analyzing data obtained from an etching apparatus for micromachining a wafer using plasma. This method includes the following steps: acquiring the plasma light-emission data indicating light-emission intensities at a plurality of different wavelengths and times, the plasma light-emission data being measured under a plurality of different etching processing conditions, and being obtained at the time of the etching processing, evaluating the relationship between changes in the etching processing conditions and changes in the light-emission intensities at the plurality of different wavelengths and times with respect to the wavelengths and times of the plasma light-emission data, and identifying the wavelength and the time of the plasma light-emission data based on the evaluation result, the wavelength and the time being to be used for the adjustment of the etching processing condition.
1. A data analyzing apparatus for stabilizing a plasma processing result of a plasma processing apparatus by determining a suitable combination of a wavelength and time of a plasma light emission, the apparatus comprising:
a memory which stores data measured from an optical emission spectroscopy unit;
a calculation unit comprising a processor,
wherein the processor in the calculation unit is configured to calculate
a first value indicating a variation in a prediction result when an etching processing result is predicted from a light-emission intensity by using a relationship between the light-emission intensity at a wavelength of a plasma light emission and a time or a section of times that the plasma light emission is obtained and the etching processing result; and
a second value indicating a variation in the light-emission intensity when an etching processing condition is changed by using the relationship between a change of the etching processing condition and a change of the light-emission intensity at the wavelength of the plasma light emission and the time or the section of times that the plasma light emission is obtained; and
wherein the calculation unit is configured to specify a wavelength of a plasma light emission and a time or a section of times that the plasma light emission is obtained suitable for an adjustment of the etching processing condition based on the first value and the second value.
2. The data analyzing apparatus according to claim 1 , wherein
the first value is a prediction error or a correlation coefficient.
3. The data analyzing apparatus according to claim 1 , wherein
the second value is a prediction error or a correlation coefficient.
4. The data analyzing apparatus according to claim 2 , wherein
the second value is a prediction error or a correlation coefficient; and
the processor in the calculation unit is configured to specify the wavelength of the plasma light emission and the time or the section of times that the plasma light emission is obtained suitable for the adjustment of the etching processing condition so that a function using the prediction error or the correlation coefficient of the first value and the prediction error or the correlation coefficient of the second value becomes equal to its minimum value.
5. The data analyzing apparatus according to claim 2 , wherein
the second value is a prediction error or a correlation coefficient; and
the calculation unit specifies the wavelength of the plasma light emission and the time or the section of times that the plasma light emission is obtained suitable for the adjustment of the etching processing condition so that a sum total of the prediction error of the first value and a value multiplying the prediction value of the second value by a coefficient indicating a relationship between a change of the etching processing condition and a change of the light-emission intensity at the wavelength of the plasma light emission and the time or the section of times that the plasma light emission is obtained becomes equal to its minimum value.
6. The data analyzing apparatus according to claim 1 , wherein
the data analyzing apparatus is connected to a plasma processing apparatus performing an etching processing based on the etching processing condition;
the calculation unit is configured to calculate an adjustment value of the etching processing condition so that the etching processing result becomes a target value of the etching processing result by using the relationship between a light-emission intensity of a plasma light-emission data at the specified wavelength and the specified time or section of times and the etching processing result; and
the etching processing condition is adjusted based on the adjustment value calculated by the calculation unit.