ETCHING DEVICE AND ETCHING METHOD

Abstract

An etching device and an etching method. The etching device includes an etching chamber and a chuck located therein for clamping a substrate to be etched, a plasma generating device surrounding the etching chamber in an area and a gas nozzle distribution device for introducing etching gas, which is situated above the chuck in such a way that an etching gas stream is directed essentially perpendicular to a surface of the substrate to be etched. A moving mechanism may be used to change the distance between the gas nozzle distribution device and the chuck as a function of the etching mode.

Claims

1. An etching device, comprising: an etching chamber and a chuck located therein to clamp a substrate to be etched; a plasma generating device surrounding the etching chamber in an area; and a gas nozzle distribution device to introduce etching gas, the gas nozzle distribution device being situated above the chuck in such a way that an etching gas stream is directed perpendicular to a surface of the substrate to be etched; wherein the gas nozzle distribution device is movable with respect to the surface of the substrate to be etched in such a way that, in a plasma etching mode, the gas nozzle distribution device is situated at such a first distance from the surface that the etching gas stream passes through the area surrounded by the plasma generating device, and that, in a non-plasma etching mode, the gas nozzle distribution device is situated at such a second, smaller distance from the surface that the etching gas stream does not pass through the area surrounded by the plasma generating device.

2. An etching device, comprising: an etching chamber and a chuck located therein to clamp a substrate to be etched; a plasma generating device surrounding the etching chamber in an area; and a gas nozzle distribution device to introduce etching gas, the gas nozzle distribution device being situated above the chuck in such a way that an etching gas stream is directed perpendicular to a surface of the substrate to be etched; wherein the chuck is movable with respect to the first gas nozzle distribution device in such a way that, in a plasma etching mode, the chuck is situated at such a first distance from the surface that the etching gas stream passes through the area surrounded by the plasma generating device, and that, in a non-plasma etching mode, the chuck is situated at such a second, smaller distance from the surface that the etching gas stream passes through the area surrounded by the plasma generating device.

3. An etching device, comprising: an etching chamber and a chuck located therein to clamp a substrate to be etched; a plasma generating device surrounding the etching chamber in an area; a first gas nozzle distribution device to introduce etching gas, the first gas nozzle distribution device being situated above the chuck in such a way that an exiting etching gas stream is directed perpendicular to a surface of the substrate to be etched, wherein the first gas nozzle distribution device is situated at such a first distance from the surface that the etching gas stream passes through the area surrounded by the plasma generating device; and a second gas nozzle distribution device to introduce etching gas, the second gas nozzle distribution device being situated above the chuck in such a way that an exiting etching gas stream is directed perpendicular to a surface of the substrate to be etched, wherein the second gas nozzle distribution device is movable in such a way that, in a plasma etching mode, the second gas nozzle distribution device is not situated above the surface and, in a non-plasma etching mode, the second gas nozzle distribution device is situated at a second, smaller distance from the surface.

4. The etching device as recited in claim 1, wherein an inner wall of the etching chamber is temperature-controllable.

5. The etching device as recited in claim 1, further comprising: a controllable gas supply device with the aid of which different etching gases may be fed to the etching chamber.

6. The etching device as recited in claim 5, wherein the etching gases may be pulsed or supplied continuously in the alternative.

7. The etching device as recited in claim 1, further comprising: a biasing device, where the chuck may be brought to a predetermined electrical potential with the aid of the biasing device.

8. The etching device as recited in claim 1, further comprising: a control unit with the aid of which the etching gas composition and the etching mode are controllable automatically.

9. The etching device as recited in claim 1, wherein the plasma generating device has a coil device surrounding the area.

10. The etching device as recited in claim 1, wherein the area forms a constriction of the etching chamber.

11. The etching device as recited in claim 2, wherein an inner wall of the etching chamber is temperature-controllable.

12. The etching device as recited in claim 2, further comprising: a controllable gas supply device with the aid of which different etching gases may be fed to the etching chamber.

13. The etching device as recited in claim 12, wherein the etching gases may be pulsed or supplied continuously in the alternative.

14. The etching device as recited in claim 2, further comprising: a biasing device, where the chuck may be brought to a predetermined electrical potential with the aid of the biasing device.

15. The etching device as recited in claim 2, further comprising: a control unit with the aid of which the etching gas composition and the etching mode are controllable automatically.

16. The etching device as recited in claim 2, wherein the plasma generating device has a coil device surrounding the area.

17. The etching device as recited in claim 2, wherein the area forms a constriction of the etching chamber.

18. The etching device as recited in claim 3, wherein an inner wall of the etching chamber is temperature-controllable.

19. The etching device as recited in claim 3, further comprising: a controllable gas supply device with the aid of which different etching gases may be fed to the etching chamber.

20. The etching device as recited in claim 19, wherein the etching gases may be pulsed or supplied continuously in the alternative.

21. The etching device as recited in claim 3, further comprising: a biasing device, where the chuck may be brought to a predetermined electrical potential with the aid of the biasing device.

22. The etching device as recited in claim 3, further comprising: a control unit with the aid of which the etching gas composition and the etching mode are controllable automatically.

23. The etching device as recited in claim 3, wherein the plasma generating device has a coil device surrounding the area.

24. The etching device as recited in claim 3, wherein the area forms a constriction of the etching chamber.

25. The etching device as recited in claim 3, wherein an inner wall of the etching chamber is temperature-controllable.

26. The etching device as recited in claim 3, further comprising: a controllable gas supply device with the aid of which different etching gases may be fed to the etching chamber.

27. The etching device as recited in claim 26, wherein the etching gases may be pulsed or supplied continuously in the alternative.

28. The etching device as recited in claim 3, further comprising: a biasing device, where the chuck may be brought to a predetermined electrical potential with the aid of the biasing device.

29. The etching device as recited in claim 3, further comprising: a control unit with the aid of which the etching gas composition and the etching mode are controllable automatically.

30. The etching device as recited in claim 3, wherein the plasma generating device has a coil device surrounding the area.

31. The etching device as recited in claim 3, wherein the area forms a constriction of the etching chamber.

32. An etching method, comprising: clamping a substrate to be etched on a chuck located in an etching chamber, a plasma-generating device surrounding the etching chamber being provided in an area; introducing etching gas into the etching chamber with the aid of a gas nozzle distribution device, which is situated above the chuck in such a way that an etching gas stream is directed perpendicular to a surface of the substrate to be etched; and in a plasma etching mode, moving the gas nozzle distribution device in such a way with respect to the surface of the substrate to be etched that the gas nozzle distribution device is situated at such a first distance from the surface that the etching gas stream passes through the area of etching chamber surrounded by a plasma generating device; and in a non-plasma etching mode, moving the gas nozzle distribution device in such a way with respect to the surface of the substrate to be etched that the gas nozzle distribution device is situated at such a second, smaller distance from the surface that the etching gas stream does not pass through the area surrounded by the plasma generating device.

33. An etching method, comprising: clamping a substrate to be etched on a chuck located in an etching chamber, a plasma-generating device surrounding the etching chamber being provided in an area; introducing etching gas into the etching chamber with the aid of a gas nozzle distribution device, which is situated above the chuck in such a way that an etching gas stream is directed perpendicular to a surface of the substrate to be etched; in a plasma etching mode, moving the chuck with respect to the first gas nozzle distribution device in such a way that chuck is situated at such a first distance from the surface that the etching gas stream passes through the area surrounded by the plasma generating device; and in a non-plasma etching mode, moving the chuck with respect to the first gas nozzle distribution device in such a way that the chuck is situated at such a second, smaller distance from the surface that the etching gas stream passes through the area surrounded by the plasma generating device.

34. An etching method, comprising: clamping a substrate to be etched on a chuck located in an etching chamber, a plasma-generating device surrounding the etching chamber being provided in an area; introducing etching gas into the etching chamber with the aid of a first gas nozzle distribution device, which is situated above the chuck in such a way that an etching gas stream is directed perpendicular to a surface of the substrate to be etched, the first gas nozzle distribution device being situated at such a first distance from the surface that the etching gas stream passes through the area surrounded by the plasma generating device; and introducing etching gas into the etching chamber with the aid of a second gas nozzle distribution device, which is situated above the chuck in such a way that an exiting etching gas stream is directed perpendicular to a surface of the substrate to be etched; the second gas nozzle distribution device being moved in such a way that, in a plasma etching mode, the second gas nozzle is not situated above the surface and, in a non-plasma etching mode, the second gas nozzle is situated at a second, smaller distance from the surface.

35. The etching method as recited in claim 32, wherein a sacrificial layer etching process is carried out by alternating the plasma etching mode and the non-plasma etching mode.

36. The etching method as recited in claim 32, wherein a trench etching process is carried out by alternating the plasma etching mode and the non-plasma etching mode.

37. The etching method as recited in claim 33, wherein a sacrificial layer etching process is carried out by alternating the plasma etching mode and the non-plasma etching mode.

38. The etching method as recited in claim 33, wherein a trench etching process is carried out by alternating the plasma etching mode and the non-plasma etching mode.

39. The etching method as recited in claim 34, wherein a sacrificial layer etching process is carried out by alternating the plasma etching mode and the non-plasma etching mode.

40. The etching method as recited in claim 34, wherein a trench etching process is carried out by alternating the plasma etching mode and the non-plasma etching mode.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The present invention is explained in greater detail below based on the exemplary embodiments presented in the figures.

[0035] FIG. 1 shows a schematic cross-sectional representation for elucidating an etching device and a corresponding etching method according to a first specific embodiment of the present invention.

[0036] FIG. 2 shows a schematic cross-sectional representation for elucidating an etching device and a corresponding etching method according to a second specific embodiment of the present invention.

[0037] FIG. 3 shows a schematic cross-sectional representation for elucidating an etching device and a corresponding etching method according to a third specific embodiment of the present invention.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0038] Identical reference symbols and numerals in the figures denote identical elements or elements having an identical function.

[0039] FIG. 1 shows a schematic cross-sectional representation for elucidating an etching device and a corresponding etching method according to a first specific embodiment of the present invention.

[0040] In FIG. 1, reference numeral 1 denotes an etching chamber, within which a chuck C is situated, on which a substrate S having a surface OF is clamped. The clamping takes place, for example, with the aid of suction nozzles or a mechanical clamping device. A width of etching chamber 1 is advantageously only slightly greater than the diameter of chuck C in order to achieve a suitable etching gas density.

[0041] Connected to etching chamber 1 is a pump device P for producing a desired process pressure and for pumping off the etching gas, in particular when a change of the etching gas is required. With the aid of an electrical line L, chuck C is connected via a capacitor device C to a biasing device B, which on the other hand is connected to ground potential GND. Biasing device B is used for applying a desired electrical potential to chuck C if a sputtering defect is desired. The chuck is preferably temperature-controllable, for example, in the temperature range between 10 C. and 100 C.

[0042] An inner wall I of etching chamber 1 may also be temperature-controlled, for example, in the same temperature range between 10 C. and 100 C. In the upper area, etching chamber 1 has a constricted area 1a which is surrounded by a plasma generating device C, which includes a circular coil device, which is connected via an electrical line L and a capacitor device C and a radio frequency generating device RF, which is in turn connected to ground potential GND.

[0043] Reference numeral 10 denotes a gas nozzle distribution device which is situated on the upper end of constricted area 1a and through which etching gas may be introduced, which is supplied from a gas supply device G via a line device LG. Line device LG may also be temperature-controlled in the range between 10 C. and 100 C.

[0044] Gas supply device G is connected to multiple gas sources (not shown), from which the particularly required etching gases may be extracted. A control unit denoted by reference symbol ST provides for an automatic selection of the required gas source or etching gas sources and is also used for adjusting gas nozzle distribution device 10 as a function of a selected etching mode, which is described in greater detail below.

[0045] Gas nozzle distribution device 10 is situated above chuck C in such a way that an etching gas stream GS is directed essentially perpendicular to surface OF of substrate S to be etched.

[0046] It may be moved with respect to surface OF of the substrate to be etched by an actuator device (not shown) in such a way that it is situated in a plasma etching mode at such a first distance from surface OF that etching gas stream GS passes through constricted area 1a surrounded by plasma generating device C. The selected etching gas passing through is thus activated by plasma generating device C and then reaches surface OF of substrate S to be etched.

[0047] In a non-plasma etching mode, on the other hand, gas nozzle distribution device 10 is moved in the direction of surface OF of the substrate through constricted area 1a including surrounding plasma generating device C, so that it is located at a second, smaller distance from surface OF, which results in a better etching condition for isotropic etching, since the etching volume is reduced.

[0048] This movability is schematically indicated by a double arrow having reference symbol V.

[0049] Thus, appropriate programming of control unit ST may be used for configuring alternating plasma-free and plasma-assisted etching cycles using different etching gases.

[0050] For the plasma-free etching, for example, XeF.sub.2 (xenon difluoride) CIF (chlorine monofluoride), CIF.sub.3 (chlorine trifluoride), CIF.sub.5 (chlorine pentafluoride), BF.sub.3 (bromine trifluoride), BF.sub.5 (bromine pentafluoride), IF.sub.5 (iodine pentafluoride), IF.sub.5 (iodine heptafluoride) may be used as etching gases.

[0051] For a plasma-assisted etching, for example, F.sub.2 (fluorine gas), SF.sub.6 (sulfur hexafluoride), CF.sub.4 (carbon tetrafluoride), CHF.sub.3 (trifluoromethane) CH.sub.2F.sub.3 (trifluoromethanecation), C.sub.2F.sub.6 (hexafluoroethane), C.sub.3F.sub.8 (octafluoropropane) or NF.sub.3 (nitrogen trifluoride), etc., may be used. The above etching processes are in particular suitable for sacrificial layer etching.

[0052] An isotropic opening of buried natural SiO.sub.2 may be achieved, for example, by anhydrous HF gas, isopropanol, etc. Polymer passivation is, for example, possible with the aid of C.sub.4F.sub.8 (octafluorocyclobutane).

[0053] Ar (argon), N.sub.2 (nitrogen), O.sub.2 (oxygen), H.sub.2 (hydrogen), Cl.sub.2 (chlorine gas), Br.sub.2 (bromine gas), I.sub.2 (iodine gas), HCl (hydrogen chloride gas), HBr (hydrogen bromide gas), HI (hydrogen iodide gas) etc., are conceivable as additional etching gases.

[0054] It is advantageous that all etching processes are possible under continuous flux or pulsed flux.

[0055] Plasma generating device C above substrate S typically has a distance of 30 cm from surface OF.

[0056] Another possibility is a protective ring for the edge of substrate S (not shown) which is movable in the z-direction.

[0057] Furthermore, it is possible to implement an optical end point detection for all etching steps.

[0058] FIG. 2 shows a schematic cross-sectional representation for elucidating an etching device and a corresponding etching method according to a second specific embodiment of the present invention.

[0059] According to the second specific embodiment, in contrast to the above-described first specific embodiment, a first gas nozzle distribution device 10a and a second gas nozzle distribution device 10b are provided.

[0060] In contrast to the first specific embodiment, first gas nozzle distribution device 10a is provided stationarily above plasma generating device C.

[0061] Second gas nozzle distribution device 10b is provided in a lateral recess 1b of etching chamber 1 and has a movability V along the direction indicated by the double arrow, i.e., in the horizontal direction in the drawing. It is connected to a second gas supply device G via a line device LG.

[0062] In plasma-free etching, second gas nozzle distribution device 10b is located in recess 1b and is deactivated.

[0063] In plasma-assisted etching, on the other hand, first gas nozzle distribution device 10a is deactivated and second gas nozzle distribution device 10b is moved in the horizontal direction above surface OF of the substrate in such a way that an etching gas stream GS exiting it is directed essentially perpendicular to surface OF of substrate S to be etched.

[0064] In this second specific embodiment, an appropriately modified control unit ST provides for the etching gases to be provided by gas supply devices G, G and for the movability of second gas nozzle distribution device 10, so that this arrangement yields the same effect as in the first specific embodiment described above.

[0065] FIG. 3 shows a schematic cross-sectional representation for elucidating an etching device and a corresponding etching method according to a third specific embodiment of the present invention.

[0066] In the third specific embodiment, gas nozzle distribution device 10, which is situated above the plasma generating device, is also stationary; however, chuck C may be adjusted in direction of travel V in such a way that substrate S may be brought closer to gas nozzle distribution device 10 during a plasma-free etching process. Consequently, in this specific embodiment, the same effect as in the above-described first and second specific embodiments is also achievable, namely a reduction in the etching volume in plasma-free etching.

[0067] Although the present invention has been described based on preferred specific embodiments, it is not limited thereto, but is instead modifiable in a variety of ways.

[0068] In particular, it is possible to design both the gas nozzle distribution device and the chuck to be adjustable, in order, for example, to further reduce the etching volume during plasma-free etching.

[0069] The present invention is also not limited to the above-named etching gases, but is instead applicable in principle for arbitrary etching gases or passivation gases.

[0070] Furthermore, it is also possible to apply the present invention to an etching chamber, in which a plurality of substrates are to be etched simultaneously.