Plasma etching device

• US 20030121609A1
• Filed: 11/26/2002
• Published: 07/03/2003
• Est. Priority Date: 11/26/1999
• Status: Active Grant

• Current Assignee: Tadahiro Ohmi, Tokyo Electron Limited
• Original Assignee: Tadahiro Ohmi, Tokyo Electron Limited
• Inventors: Ohmi, Tadahiro, Hirayama, Masaki, Hirayama, Yusuke, Takano, Haruyuki
• Granted Patent: US 8,114,245 B2
• Time in Patent Office: Days
• US Class Current: 156/345.47
• CPC Class Codes: H01J 37/32082 Radio frequency generated discharge H01J37/32357, H01J37/32366, H01J37/32394 and H01J37/32403 take precedence
• CPC Class Codes: H01J 37/32623 Mechanical discharge control means
• CPC Class Codes: H01J 37/3266 Magnetic control means

Abstract

A plasma etching device which has an auxiliary electrode enabling realization of a uniform plasma density of generated plasma on the surface of a base and which enables uniform etching with respect to the base without depending upon pressure and without rotating a magnetic field applying means. The plasma etching device has magnetic field applying means which has two parallel plate electrodes I and II and RF power applying means, with the base set on the electrode I, and which is horizontal and unidirectional with respect to the surface of the base where plasma etching is carried out. In this plasma etching device, an auxiliary electrode is provided at least on the upstream side of the base in a flow of electron current generated by the magnetic field applying means. The auxiliary electrode includes a local electrode arranged on the side facing the electrode II and means for adjusting impedance provided at a part of the local electrode to be electrically connected with the electrode I.

Claims

1. An etching device, having two parallel plate type electrodes electrode I and/or electrode II, and means for applying high frequency power connected to the electrode I and electrode II, with a base to be subject to etching processing using plasma being mounted on a surface of the electrode I opposite to the electrode II, and provided with means for applying a unidirectional magnetic field that is horizontal with respect to the surface of the base to be subjected to plasma etching, comprising an auxiliary electrode at least on an upstream side, with respect to the base, of a flow of electrons generated by the magnetic field applying means, the auxiliary electrode including a local electrode arranged on a side facing the electrode II and means for adjusting impedance provided at a part of the local electrode to be electrically connected with the electrode I.

4. The plasma etching device as disclosed in any one of claim 1 to claim 3, wherein the magnetic field applying means is a dipole ring magnet (DRM).

5. The plasma etching device as disclosed in claim 1 or claim 3, wherein the local electrode constituting the auxiliary magnet is a first local electrode formed of a conductive material provided only at an upstream side of a flow of electrons caused by the magnetic field applying means,

6. The plasma etching device as disclosed in of claim 1 or claim 3, wherein the local electrode constituting the auxiliary electrode is formed from a combination of a second local electrode formed of a conductive material provided at least at an upstream side of a flow of electrons caused by the magnetic field applying means, and a third local electrode formed of an insulating material provided at a portion other than the upstream side.

7. The plasma etching device as disclosed in claim 1 or claim 3, wherein the local electrode constituting the auxiliary electrode is formed from a combination of a fourth local electrode formed of a conductive material and being wide at least at an upstream side of a flow of electrons caused by the magnetic field applying means and being narrow at other than the upstream side, and a fifth local electrode formed of an insulating material provided outside a region where the fourth electrode is narrow, looking from the base side.

8. The plasma etching device as disclosed in claim 1 or claim 3, wherein the local electrode constituting the auxiliary electrode provided at least at an upstream side of a flow of electrons caused by the magnetic field applying means is of a size that covers the upstream side of the electron flow, observed from all positions of the base.

9. The plasma etching device as disclosed in claim 1 or claim 3, wherein the means for adjusting junction impedance has an uneven shape at a section of the local electrode to be electrically connected to the electrode I.

10. The plasma etching device as disclosed in claim 1 or claim 3, wherein the means for adjusting junction impedance has an uneven shape at a section of the electrode I to be electrically connected to the local electrode.

11. The plasma etching device as disclosed in claim 1 or claim 3, w-herein the means for adjusting junction impedance is provided between the local electrode and the electrode I, and is a single layer film of multi layer film formed of a material having a different dielectric constant from that of the local electrode and the electrode I.

12. The plasma etching device as disclosed in claim 1 or claim 3, wherein the means for adjusting junction impedance is a cavity provided inside the local electrode.

13. The plasma etching device as disclosed in claim 1 or claim 3, wherein the means for adjusting junction impedance is a cavity provided in the vicinity of a boundary between the local electrode and the electrode I.

14. The plasma etching device as disclosed in claim 12 or claim 13, wherein the inside of the cavity is either a vacuum, an inert gas, or a material having a different dielectric constant from that of the local electrode and the electrode I.

15. The plasma etching device as disclosed in claim 1 or claim 3, wherein the means for adjusting junction impedance is a capacitor provided between the local electrode and the electrode I.

16. The plasma etching device as disclosed in claim 1 or claim 3, wherein the material constituting the local electrode is either Al, Cu, Si, Sic or glassy carbon.

17. The plasma etching device as disclosed in claim 1 or claim 3, wherein a surface of the local electrode to be exposed to plasma is either at the same height as a surface of the base, or higher than a surface of the base within a width of an ion sheath.

18. The plasma etching device as disclosed in claim 1 or claim 3, wherein a distance between the local electrode and a section of the electrode I on which the base is mounted is longer than a distance at which electrical shorting takes place, and shorter than a distance at which movement of electrons generated at eh local electrode no longer reaches the base.

23. The plasma etching device as disclosed in any one of claims 1 to 3, wherein a shower head comprising introduction pipes numerously arranged in a region of the electrode II that is electrically grounded is used a structure for introducing process gas within a space sandwiched between the electrode I and the electrode II.

2. A plasma etching device, having two parallel plate type electrodes electrode I and electrode II, and means for applying high frequency power connected to the electrode I and electrode II, with a base to be subject to etching processing using plasma being mounted on a surface of the electrode I opposite to the electrode II, the electrode II comprising a central portion electrically corrected to ground, and an outer portion connected to a high frequency power supply capable of being controlled independently of a high frequency power supply connected to the electrode I.

19. The plasma etching device as disclosed in claim 2 or claim 3, wherein an outer end of the base mounted on said electrode I is located either at the same position as the outer end of said electrode II or inside the outer end of said electrode II.

20. The plasma etching device as disclosed in claim 2 or claim 3, wherein a distance between the electrode II and the electrode I is a distance at which movement of electrons generated on the surfaces of each of the electrode I and the electrode II have an effect on one another.

21. The plasma etching device as disclosed in claim 2 or claim 3, wherein a distance between a central section and an outer section constituting the electrode II is longer than a distance at which electrical shorting occurs.

22. The plasma etching device as disclosed in claim 2 or claim 3, wherein an outer end of the base mounted on the electrode I is located within a range from an outer end to an inner end of an outer section constituting the electrode II.

24. The plasma etching device as disclosed in claim 2 or claim 3, wherein, when a base mounted on the electrode I is plasma etched by applying high frequency separately to the electrode I and the electrode II, a relationship between a frequency f1 of high frequency applied to electrode I and a frequency f2 of high frequency applied to electrode II is f1≦

f2.

3. An etching device, having two parallel plate type electrodes electrode I and electrode II, and means for applying high frequency power connected to the electrode I and electrode II, with a base to be subject to etching processing using plasma being mounted on a surface of the electrode I opposite to the electrode II, and provided with means for applying a unidirectional magnetic field that is horizontal with respect to the surface of the base to be subjected to plasma etching, comprising an auxiliary electrode at least on an upstream side, with respect to the base, of a flow of electrons generated by the magnetic field applying means, the auxiliary electrode including a local electrode arranged on a side facing the electrode II and means for adjusting impedance provided at a part of the local electrode to be electrically connected with the electrode I, and the electrode II comprising a central portion electrically connected to ground, and an outer portion connected to a high frequency power supply capable of being controlled independently of a high frequency power supply connected to the electrode I.

25. An etching device, having two parallel plate type electrodes electrode I and/or electrode II, and means for applying high frequency power connected to the electrode I and electrode II, with a base to be subject to etching processing using plasma being mounted on a surface of the electrode I opposite to the electrode II, and provided with means for applying a unidirectional magnetic field that is horizontal with respect to the surface of the base to be subjected to plasma etching, comprising an auxiliary electrode of a ring body provided at a peripheral section of the base, the auxiliary electrode including a local electrode arranged on a side facing the electrode II and means for adjusting impedance provided at a part of the local electrode to be electrically connected with the electrode I, and the impedance of the ring body at a section corresponding to an upstream side in an electron flow generated by the magnetic field applying means being lower than at other sections.

26. A plasma etching device, having two parallel plate type electrodes electrode I and electrode II, and means for applying high frequency power connected to the electrode I and electrode II, with a base to be subject to etching processing using plasma being mounted on a surface of the electrode I opposite to the electrode II, the electrode II comprising a central portion electrically connected to ground, and an ring body outer portion connected to a high frequency power supply capable of being controlled independently of a high frequency power supply connected to the electrode I, with the impedance of the ring body at a section corresponding to an upstream side in an electron flow generated by the magnetic field applying means being lower than at other sections.