ANALYSIS METHOD AND SEMICONDUCTOR ETCHING APPARATUS

• US 20150083328A1
• Filed: 06/13/2014
• Published: 03/26/2015
• Est. Priority Date: 09/20/2013
• Status: Active Grant

• Current Assignee: Hitachi High-Tech Company Limited (Hitachi, Ltd.)
• Original Assignee: Hitachi High-Technologies Corporation (Hitachi, Ltd.)
• Inventors: ASAKURA, Ryoji, TAMAKI, Kenji, KAGOSHIMA, Akira, SHIRAISHI, Daisuke
• Granted Patent: US 10,262,842 B2
• Time in Patent Office: Days
• US Class Current: 156/345.24
• CPC Class Codes: B81C 2201/0132 Dry etching, i.e. plasma etching, barrel etching, reactive ion etching [RIE], sputter etching or ion milling
• CPC Class Codes: H01J 2237/334 Etching
• CPC Class Codes: H01J 37/32926 Software, data control or modelling
• CPC Class Codes: H01J 37/32972 Spectral analysis
• CPC Class Codes: H01J 37/3299 Feedback systems
• CPC Class Codes: H01L 21/31138 by dry-etching
• CPC Class Codes: H01L 21/67069 for drying etching

Abstract

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.

Claims

1. An analysis method of identifying a wavelength and a time of plasma light-emission data, said wavelength and said time of said plasma light-emission data being to be used for the adjustment of an etching processing condition in a semiconductor etching processing for applying said etching processing to a semiconductor wafer using said plasma,

said analysis method, comprising:

an acquisition step of acquiring said plasma light-emission data indicating light-emission intensities at a plurality of different wavelengths and times, said plasma light-emission data being measured under a plurality of different etching processing conditions, and being obtained at the time of said etching processing;

a first evaluation step of evaluating the relationship between changes in said etching processing conditions and changes in said light-emission intensities at said plurality of different wavelengths and times with respect to said wavelengths and times of said plasma light-emission data; and

an identification step of identifying said wavelength and said time of said plasma light-emission data based on the result of said first evaluation step, said wavelength and said time of said plasma light-emission data being to be used for said adjustment of said etching processing condition.

2. The analysis method according to claim 1, wherein,

at said first evaluation step, said relationship between said changes in said etching processing conditions and said changes in said light-emission intensities at said plurality of different wavelengths and times with respect to said wavelengths and times of said plasma light-emission data is evaluated using a prediction error or a correlation coefficient.

3. The analysis method according to claim 1, further comprising:

a second evaluation step of evaluating the relationship between said light-emission intensities at said plurality of different wavelengths and times of said plasma light-emission data, and the etching processing result, and wherein,

at said identification step, said wavelength and said time of said plasma light-emission data are identified from said result of said first evaluation step and the result of said second evaluation step, said wavelength and said time of said plasma light-emission data being to be used for said adjustment of said etching processing condition.

4. The analysis method according to claim 3, wherein,

at said second evaluation step, said relationship between said light-emission intensities at said plurality of different wavelengths and times of said plasma light-emission data, and said etching processing result is evaluated using a prediction error or a correlation coefficient.

5. The analysis method according to claim 4, wherein,

at said identification step, said wavelength and said time of said plasma light-emission data are identified so that a function becomes equal to its minimum value, said prediction error or said correlation coefficient at said first evaluation step and said prediction error or said correlation coefficient at said second evaluation step being used in said function.

6. The analysis method according to claim 4, wherein

said wavelength and said time of said plasma light-emission data are identified so that the sum total of said prediction error at said first evaluation step and a product becomes equal to its minimum value, said product being obtained by multiplying said prediction error at said second evaluation step by a coefficient, said coefficient indicating said relationship between said light-emission intensities at said plurality of different wavelengths and times of said plasma light-emission data, and said etching processing result.

7. An analysis method of calculating an adjustment value of said etching processing condition so that said adjustment value becomes equal to a target value of said etching processing result, said adjustment value being calculated using said relationship between said light-emission intensity of said plasma light-emission data at said wavelength and said time, and said etching processing result, said wavelength and said time being identified using said analysis method according to claim 1.

8. A semiconductor etching apparatus, comprising:

a plasma micromachining unit for applying an etching processing to a semiconductor wafer using plasma;

an optical emission spectroscopy for measuring light-emission of said plasma during said etching processing; and

an analysis unit including a memory unit and a calculation unit, wherein said memory unit memorizes said plasma light-emission data indicating light-emission intensities at a plurality of different wavelengths and times, said plasma light-emission data being measured under a plurality of different etching processing conditions, and being obtained at the time of said etching processing,

said calculation unit performing a calculation of

evaluating the relationship between changes in said etching processing conditions and changes in said light-emission intensities at said plurality of different wavelengths and times with respect to said wavelengths and times of said plasma light-emission data, and

identifying a wavelength and a time of said plasma light-emission data based on said evaluation result (i.e., first evaluation result), said wavelength and said time of said plasma light-emission data being to be used for the adjustment of said etching processing condition.

9. The semiconductor etching apparatus according to claim 8, wherein

said calculation unit evaluates said relationship between said changes in said etching processing conditions and said changes in said light-emission intensities at said plurality of different wavelengths and times with respect to said wavelengths and times of said plasma light-emission data, using a prediction error or a correlation coefficient.

10. The semiconductor etching apparatus according to claim 8, wherein

said calculation unit

evaluates the relationship between said light-emission intensities at said plurality of different wavelengths and times of said plasma light-emission data, and the etching processing result, and

identifies said wavelength and said time of said plasma light-emission data from said evaluation result (i.e., second evaluation result) and said first evaluation result, said wavelength and said time of said plasma light-emission data being to be used for said adjustment of said etching processing condition.

11. The semiconductor etching apparatus according to claim 10, wherein

said relationship between said light-emission intensities at said plurality of different wavelengths and times of said plasma light-emission data, and said etching processing result is evaluated using a prediction error or a correlation coefficient.

12. The semiconductor etching apparatus according to claim 11, wherein,

in said identification process, said wavelength and said time of said plasma light-emission data are identified so that a function becomes equal to its minimum value, said prediction error or said correlation coefficient of said first evaluation result and said prediction error or said correlation coefficient of said second evaluation result being used in said function.

13. The semiconductor etching apparatus according to claim 11, wherein

said wavelength and said time of said plasma light-emission data are identified so that the sum total of said prediction error of said first evaluation result and a product becomes equal to its minimum value, said product being obtained by multiplying said prediction error of said second evaluation result by a coefficient, said coefficient indicating said relationship between said light-emission intensities at said plurality of different wavelengths and times of said plasma light-emission data, and said etching processing result.

14. The semiconductor etching apparatus according to claim 8, wherein

said calculation unit calculates an adjustment value of said etching processing condition so that said adjustment value becomes equal to a target value of said etching processing result, said adjustment value being calculated using said relationship between said light-emission intensity of said plasma light-emission data having said identified wavelength and said identified time, and said etching processing result,

said plasma micromachining unit performing said micromachining under said etching processing condition based on said adjustment value.