Ionized PVD with sequential deposition and etching

• US 20040188239A1
• Filed: 03/05/2004
• Published: 09/30/2004
• Est. Priority Date: 05/04/2001
• Status: Active Grant

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: Faquet, Jacques, Brcka, Jozef, Robison, Rodney Lee, Cerio, Frank, Gittleman, Bruce, Yasar, Tugrul
• Granted Patent: US 7,744,735 B2
• Time in Patent Office: Days
• US Class Current: 204/192.3
• CPC Class Codes: C23C 14/046 Coating cavities or hollow spaces, e.g. interior of tubes; Infiltration of porous substrates
• CPC Class Codes: C23C 14/345 using substrate bias
• CPC Class Codes: C23C 14/358 Inductive energy
• CPC Class Codes: H01J 37/321 the radio frequency energy being inductively coupled to the plasma
• CPC Class Codes: H01J 37/34 operating with cathodic sputtering H01J37/36 takes precedence ; methods of cathodic sputtering C23C14/34
• CPC Class Codes: H01L 21/2855 by physical means, e.g. sputtering, evaporation H01L21/28518 - H01L21/28537 and H01L21/28568 take precedence
• CPC Class Codes: H01L 21/32131 by physical means only
• CPC Class Codes: H01L 21/76843 formed in openings in a dielectric
• CPC Class Codes: H01L 21/76862 Bombardment with particles, e.g. treatment in noble gas plasmas; UV irradiation
• CPC Class Codes: H01L 21/76865 Selective removal of parts of the layer H01L21/76844 takes precedence
• CPC Class Codes: H01L 21/76873 for electroplating
• CPC Class Codes: H01L 21/76877 Filling of holes, grooves or trenches, e.g. vias, with conductive material

Abstract

An iPVD apparatus (20) is programmed to deposit material (10) onto semiconductor substrates (21) by cycling between deposition and etch modes within a vacuum chamber (30). Static magnetic fields are kept to a minimum during at least the etch modes, at least less than 150 Gauss, typically less than 50 Gauss, and preferably in the range of 0-10 Gauss. Static magnetic fields during deposition modes may be more than 150 Gauss, in the range of 0-50 Gauss, or preferably 20-30 Gauss, and may be the same as during etch modes or switched between a higher level during deposition modes and a lower level, including zero, during etch modes. Such switching may be by switching electromagnet current or by moving permanent magnets, by translation or rotation. Static magnetic fields are kept to a minimum during at least the etch modes, at least less than 150 Gauss, typically less than 50 Gauss, and preferably in the range of 1-10 Gauss. The modes may operate at different power and pressure parameters. Pressure of more than 50 mTorr are preferred for deposition in a thermalized plasma while pressure of less than a few mTorr is preferred for etching.

Claims

1. An ionized physical deposition process comprising:

sealing a substrate within a chamber of a processing apparatus, and performing an ionized physical vapor deposition process to deposit a conductive layer on surfaces of high aspect ratio submicron features on the substrate by operating the apparatus, without opening the chamber, in a deposition mode, followed by an etch mode, the modes being affected by controlling the apparatus to operate with static magnetic field parameters that are different during deposition modes than during etch modes.

2. The method of claim 1 further comprising:

inductively coupling a high density plasma into a space within the chamber to produce ions of coating material to be deposited onto the substrate during the deposition mode and to produce ions for etching the substrate during the etch mode, and

the modes being affected by controlling the apparatus to operate at power and pressure parameters that are different during deposition modes than during etch modes, the controlling including operating the apparatus at a first processing pressure in a deposition mode, then, without opening the chamber, lowering the pressure to operate the apparatus at a second processing pressure in an etch mode followed by another deposition mode.

3. The method of claim 2 for depositing coatings on semiconductors having sub-micron, high aspect ratio wherein the performing of the ionized physical deposition process comprises:

forming a high density plasma in the chamber and producing ions therewith for depositing material onto the substrate and for etching the substrate;

operating the apparatus in the deposition mode at a pressure of at least approximately 30 mTorr while sputtering material from a target into the high density plasma to ionize the material, and depositing the ionized material with a high degree of directionality substantially normal to and onto the substrate;

operating the apparatus in the etch mode at a pressure of less than approximately 10 mTorr and with a bias on the substrate having a magnitude of more than approximately 100 volts without sputtering substantial material from the target.

4. An ionized physical vapor deposition processing apparatus having a controller programmed to operate the apparatus according to the method of claim 3.

5. The method of claim 1 further comprising:

when changing from a deposition mode to an etch mode, changing bias power on the substrate to facilitate a net etching during the etch mode of deposited material from at least certain areas of the substrate by ions of gas from the plasma; and

when changing from an etch mode to a deposition mode, changing the bias power on the substrate to facilitate deposition.

6. The method of claim 1 wherein:

the etch mode is carried out by sputtering with ions from the plasma, under parameters that cause to occur, at least one of the effects selected from the group consisting essentially of;

at least partially removing deposited material that overhangs edges of the features on the substrate,

at least partially removing deposited material from the bottoms of the features, and

resputtering deposited material from the substrate onto sidewalls of the features.

7. The method of claim 1 further comprising:

switching DC power to a sputtering target between deposition and an etching modes.

8. The method of claim 1 further comprising:

forming a high density plasma in a space within the chamber to produce ions of coating material for deposit onto the substrate during deposition modes and to produce ions for etching the substrate during etch modes; and

positioning the substrate at one position relative to the space during deposition modes and repositioning the substrate at another position relative to the space during etch modes.

9. The method of claim 1 further comprising:

forming a high density plasma in a space within the chamber to produce ions of coating material for deposit onto the substrate during deposition modes and to produce ions for etching the substrate during etch modes; and

positioning the substrate relative to the space during deposition modes and repositioning the substrate closer to the space during etch modes.

10. The method of claim 1 further comprising:

forming a high density plasma in a space within the chamber by coupling RF energy into the space to produce ions of coating material for deposit onto the substrate during deposition modes and to produce ions for etching the substrate during etch modes; and

coupling of RF energy into the space at one power level during deposition modes and at a different power level during etch modes.

11. The method of claim 1 further comprising:

forming a high density plasma in a space within the chamber by coupling RF energy into the space to produce ions of coating material for deposit onto the substrate during deposition modes and to produce ions for etching the substrate during etch modes; and

coupling RF energy into the space at one power level during deposition modes and at a lower power level during etch modes.

12. An ionized physical vapor deposition processing apparatus having a controller programmed to operate the apparatus according to the method of claim 1.

13. An ionized physical vapor deposition process comprising:

providing in a chamber a cathode of electrically conductive coating material having a cathode surface;

forming, in a process volume in the chamber, a high density plasma having an ion metal fraction of at least 30%;

sealing a substrate within the chamber, and, without opening the chamber, with the cathode so provided, and with the high density plasma present in the process volume, performing an ionized physical vapor deposition process that includes;

a deposition mode to deposit a conductive layer on surfaces of high aspect ratio submicron features on the substrate, then

an etch mode, then

another deposition mode; and

static magnetic field strength in the process volume being less than 30 Gauss, at least during the etch mode.

14. The ionized physical vapor deposition process of claim 13 wherein:

the static magnetic field in the process volume is approximately zero.

15. The ionized physical vapor deposition process of claim 13 further comprising:

generating a static magnetic field near the cathode surface that is greater than zero and less than 150 Gauss.

16. The ionized physical vapor deposition process of claim 13 further comprising:

generating a static magnetic field near the cathode surface that is less than 30 Gauss.

17. The ionized physical vapor deposition process of claim 13 further comprising:

generating a static magnetic field near the cathode surface that is less than 10 Gauss.

18. The ionized physical vapor deposition process of claim 13 further comprising:

the static magnetic field near the cathode surface that is less than 150 Gauss during the deposition modes.

19. The ionized physical vapor deposition process of claim 13 further comprising:

the static magnetic field near the cathode surface that is in the range of 20 Gauss to 30 Gauss during the deposition modes.

20. The ionized physical vapor deposition process of claim 13 further comprising:

maintaining a static magnetic field near the cathode surface during the deposition modes in the range of 0 Gauss to 50 Gauss; and

maintaining the strength of the static magnetic field near the cathode surface during etch modes in the range of 0 Gauss to 10 Gauss.

21. The ionized physical vapor deposition process of claim 13 further comprising:

maintaining a static magnetic field near the cathode surface during the deposition modes at a deposition-mode level;

changing the strength of the static magnetic field near the cathode surface during processing of a single wafer between the deposition-mode level during deposition modes and a lower etch-mode level during etch modes.

22. The ionized physical vapor deposition process of claim 21 further comprising:

maintaining a static magnetic field near the cathode surface during the deposition modes in the range of 20 Gauss to 30 Gauss; and

maintaining the strength of the static magnetic field near the cathode surface during etch modes in the range of 0 Gauss to 10 Gauss.

23. The ionized physical vapor deposition process of claim 21 wherein:

the changing of the static magnetic field strength is achieved by moving magnets between the vicinity of the cathode during deposition modes to a distance of up to 100 mm during etch modes.

24. The ionized physical vapor deposition process of claim 21 wherein:

the changing of the static magnetic field strength is achieved by use of electromagnets behind the cathode.

25. The ionized physical vapor deposition process of claim 21 wherein:

the changing of the static magnetic field strength is achieved by rotating the magnets between a deposition-mode position in the vicinity of the cathode during deposition modes and an etch-mode position at an angle of 35 to 180 degrees relative to the deposition-mode position.

26. The ionized physical vapor deposition process of claim 13 wherein:

the static magnetic field is maintained at the same level during deposition modes as during etch modes.

27. The ionized physical vapor deposition process of claim 13 wherein:

the static magnetic field is maintained at a substantially zero level during deposition modes and during etch modes.

28. An ionized physical vapor deposition apparatus comprising:

a vacuum chamber therein and being operable to perform ionized physical vapor deposition on a substrate therein over a pressure range of from not more than approximately 1 mTorr to over 30 mTorr;

a sputtering target at one end of the chamber and a substrate support at the other end of the chamber;

an ICP source operable to inductively coupling RF energy into a plasma in a process volume within the chamber to form a high density plasma therein; and

a controller programmed to operate the apparatus sequentially, with a single substrate in the chamber and without opening the chamber;

in a deposition mode by sputtering material from a sputtering target into the plasma to ionize the material and depositing the material onto the substrate; and

in an etch mode, without a static magnetic field of more than 150 Gauss present in the process volume, to etch deposited material from substrate with ions from the plasma.

29. The ionized physical vapor deposition apparatus of claim 28 further comprising:

a magnet assembly behind the sputtering target; and

the controller being programmed to operate the apparatus to switch the static magnetic field in the chamber between a deposition-mode level during deposition modes and a lower etch-mode level during etch modes.

30. The ionized physical vapor deposition apparatus of claim 28 further comprising:

a magnet assembly behind the sputtering target; and

the controller being programmed to operate the apparatus to move the magnet assembly to switch the static magnetic field in the chamber between a deposition-mode level during deposition modes and a lower etch-mode level during etch modes.

31. The ionized physical vapor deposition apparatus of claim 28 further comprising:

a magnet assembly configured to produce a static magnetic field in process volume that is not more than 150 Gauss during both the deposition and etch modes.

32. The ionized physical vapor deposition apparatus of claim 28 further comprising:

a magnet assembly configured to produce a static magnetic field adjacent the surface of the sputtering target that is more than 200 Gauss, the assembly including magnet structure configured to block the static magnetic field to less than 150 Gauss in the process volume.

33. The ionized physical vapor deposition apparatus of claim 28 further comprising:

a magnetron magnet assembly adjacent the target; and

magnetic shunt structure positioned and configured to direct static magnetic field due to the magnetron magnet assembly from the process space.

34. The ionized physical vapor deposition apparatus of claim 28 further comprising:

a magnetron magnet assembly adjacent the target; and

switchable magnetic shunt structure positioned and configured to direct static magnetic field due to the magnetron magnet assembly from the process space, at least during the etch modes.