Method and device for detecting end point of plasma treatment, method and device for manufacturing semiconductor device, and semiconductor device

• US 5,989,928 A
• Filed: 04/20/1998
• Issued: 11/23/1999
• Est. Priority Date: 10/20/1995
• Status: Expired due to Term

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Nakata, Toshihiko, Ninomiya, Takanori
• Primary Examiner(s): Powell, William
• Assistant Examiner(s): PEREZ RAMOS, VANESSA
• Application Number:
  US09/051,767
• Time in Patent Office: 582 Days
• Field of Search: 438/7, 438/8, 438/9, 156/345
• US Class Current: 438/7
• CPC Class Codes: B24B 37/013 Devices or means for detecting lapping completion
• CPC Class Codes: H01J 37/32935 Monitoring and controlling tubes by information coming from the object and/or discharge
• CPC Class Codes: H01J 37/32963 End-point detection
• CPC Class Codes: H01L 22/26 Acting in response to an ongoing measurement without interruption of processing, e.g. endpoint detection, in-situ thickness measurement endpoint detection arrangements in CMP apparatus B24B37/013, in discharge apparatus H01J37/32

Abstract

In order to detect the end point of a plasma process stably and at a high precision always without being affected by the fine delineation of a pattern to be processed and an external disturbance, it is constructed such that emission wavelength components 27 of species are taken out of a plasma emission 24 and only a frequency component synchronous with a high-frequency electric power for plasma excitation is extracted by a synchronous detection circuit 30 and so on. Thereby, the progressing status of etching is seized more accurately and a change in signal at an end point becomes clear. As a result, the precision of detection of the end point of a plasma process for a minute aperture pattern is improved.

Claims

1. A plasma process end point detecting method in which when an object to be processed is subjected to a process using a plasma, the emission intensity of species producing an emission therefrom at a specified wavelength in said plasma is detected and an end point of the plasma process is detected from a change in amplitude of periodic temporal variations of said emission intensity.

2. A plasma process end point detecting method according to claim 1, wherein the frequency of the periodic temporal variations of said emission intensity is integer times as high as the frequency of a high-frequency power supply for plasma excitation.

3. A plasma process end point detecting method according to claim 1, wherein said species includes a reaction product generated by said plasma process.

4. A plasma process end point detecting method according to claim 1, wherein said species includes a reactive gas used in said plasma process or a decomposition product.

5. A plasma process end point detecting method according to claim 1, wherein said specified wavelength is approximately 219 nm.

6. A plasma process end point detecting method according to claim 1, wherein said specified wavelength is approximately 260 nm.

7. A plasma process end point detecting method according to claim 1, wherein the emission intensity of said species is detected by an imaging optical system provided with a photo detector which has an imaging relation with said plasma.

8. A plasma process end point detecting apparatus comprising emission detecting means for detecting, when an object to be processed is subjected to a process using a plasma, the emission intensity of species which produces an emission therefrom at a specified wavelength in said plasma, amplitude detecting means for detecting the amplitude of periodic temporal variations of the detected emission intensity signal, and end point judging means for detecting an end point of said process from a change in said amplitude.

9. A plasma process end point detecting apparatus according to claim 8, wherein the frequency of the periodic temporal variations of said emission intensity signal is integer times as high as the frequency of a high-frequency power supply for plasma excitation.

10. A plasma process end point detecting apparatus according to claim 8, wherein said species includes a reaction product generated by said plasma process.

11. A plasma process end point detecting apparatus according to claim 8, wherein said species includes a reactive gas used in said plasma process or a decomposition product.

12. A plasma process end point detecting apparatus according to claim 8, wherein said specified wavelength is approximately 219 nm.

13. A plasma process end point detecting apparatus according to claim 8, wherein said specified wavelength is approximately 260 nm.

14. A plasma process end point detecting apparatus according to claim 8, wherein said emission detecting means includes an imaging optical system provided with a photo detector which has an imaging relation with said plasma.

15. A semiconductor device manufacturing method in which when a semiconductor substrate is subjected to a process using a plasma, the emission intensity of species producing an emission therefrom at a specified wavelength in said plasma is detected and the plasma process is completed by detecting an end point of said plasma process from a change in amplitude of periodic temporal variations of said emission intensity.

16. A semiconductor device manufacturing apparatus in which a semiconductor substrate is subjected to a process using a plasma, the apparatus comprising emission detecting means for detecting the emission intensity of species which produces an emission therefrom at a specified wavelength in said plasma, amplitude detecting means for detecting the amplitude of periodic temporal variations of the detected emission intensity signal, and end point judging means for detecting an end point of said process from a change in said amplitude.

17. A semiconductor device manufactured by subjecting a semiconductor substrate to a process using a plasma, the semiconductor device being manufactured by detecting the emission intensity of species which produces an emission therefrom at a specified wavelength in said plasma and detecting an end point of said plasma process from a change in amplitude of periodic temporal variations of said emission intensity, thereby completing said plasma process.