Seed layers for interconnects and methods and apparatus for their fabrication

• US 6,610,151 B1
• Filed: 05/03/2000
• Issued: 08/26/2003
• Est. Priority Date: 10/02/1999
• Status: Expired due to Term

• Current Assignee: Uri Cohen
• Original Assignee: Uri Cohen
• Inventors: Cohen, Uri
• Primary Examiner(s): Hassanzadeh, Parviz
• Application Number:
  US09/563,733
• Time in Patent Office: 1,210 Days
• Field of Search: 118/719, 118/715, 118/695, 118/697, 118/698, 156/345-2-3, 204/298.25, 204/298.02, 438/687
• US Class Current: 118/719
• CPC Class Codes: H01L 21/76843 formed in openings in a dielectric
• CPC Class Codes: H01L 21/76873 for electroplating
• CPC Class Codes: H01L 2221/1089 Stacks of seed layers

Abstract

An apparatus for depositing seed layers from a group of Cu, Ag or an alloy thereof on a substrate having narrow openings surrounded by a filed; the apparatus comprising a controller, said controller including instructions to deposit a conformal seed layer having a thickness of 50-500 Å oil the filed and to deposit a non-conformal seed layer having a thickness of 100-3000 Å on the filed and to stop depositing the seed layers prior to filling the narrow openings, such that the rermaining narrow openings are filled by electroplating. In accordance with the invention, substantially conformal and non-conformal seed layers me deposited in an apparatus where the conformal and non-conformal seed layer deposition steps can be carried out without breaking vacuum, or without exposing the wafer to the atmosphere between the deposition steps. In another embodiment of the invention, the apparatus comprises a chamber in which both conformal and non-conformal seed layers are deposited utilizing two or more distinct steps, wherein the deposition variables (or conditions) during the first step are suitable for the deposition of a substantially conformal (or a non-conformal) seed layer, and the deposition conditions during the second step are suitable for the deposition of a substantially non-conformal (or a conformal) seed layer.

Claims

1. An apparatus for depositing seed layers on a substrate, said substrate comprising narrow openings surrounded by a field, said apparatus comprising:

at least one conformal deposition chamber adapted to deposit a substantially conformal seed layer on the substrate;

at least one non-conformal deposition chamber adapted to deposit a substantially non-conformal seed layer on the substrate, wherein said seed layers comprise a material selected from a group consisting of Cu, Ag, or alloys comprising one or more of these metals; and

a controller which includes recipe information, said recipe information includes deposition sequence and process parameters for operation of the deposition chambers, wherein the controller, in response to the recipe information, causes the conformal deposition chamber to deposit said substantially conformal seed layer having a thickness of about 50 Å

to about 500 Å

on the field and causes the non-conformal deposition chamber to deposit said substantially non-conformal seed layer having a thickness of about 100 Å

to about 3,000 Å

on the field, said controller causes the stopping of the deposition of said substantially conformal seed layer and causes the stopping of the deposition of said substantially non-conformal seed layer prior to filling the openings, thereby leaving enough room for electroplating inside the narrow openings.

2. The apparatus of claim 1 wherein said at least one conformal deposition chamber comprises a CVD seed chamber and said at least one non-conformal deposition chamber comprises a PVD seed chamber.

3. The apparatus of claim 2 which further comprises a transfer chamber adapted to transfer the substrate from said CVD seed chamber to said PVD seed chamber, and vice versa, without exposing the substrate to atmosphere.

4. The apparatus of claim 3 which further comprises a transfer chamber adapted to transfer the substrate from said CVD seed chamber to said PVD seed chamber, and vice versa, without breaking vacuum.

5. The apparatus of claim 2 further comprising a barrier chamber adapted to deposit a barrier layer.

6. The apparatus of claim 5 wherein said barrier layer comprises a material selected from the group consisting of Ta, TaN_X, Cr, CrN_X, Ti, TiN_X, W, WN_X, and other alloys containing one or more of these materials.

7. The apparatus of claim 5 wherein said barrier chamber comprises a CVD deposition chamber.

8. The apparatus of claim 5 wherein said barrier chamber comprises a PVD deposition chamber.

9. The apparatus of claim 2 wherein the CVD seed chamber is further adapted to deposit a CVD barrier layer.

10. The apparatus of claim 2 wherein the PVD seed chamber is further adapted to deposit a PVD barrier layer.

11. The apparatus of claim 1 wherein said controller further includes operation software which inputs the recipe information into the controller from a computer readable memory comprising data structures for controlling the sequence, duration, and process parameters of the deposition chambers, said data structures cause the apparatus to transfer the substrate between the conformal deposition chamber and the non-conformal deposition chamber, or vice versa.

12. The apparatus of claim 1 wherein the thickness of said substantially conformal seed layer is in the range of about 100 Å

to about 300 Å

on the field and the thickness of said substantially non-conformal seed layer is in the range of about 500 Å

to about 1,800 Å

on the field.

13. The apparatus of claim 12 wherein said controller causes the deposition of said substantially conformal seed layer prior to the deposition of said substantially non-conformal seed layer.

14. The apparatus of claim 12 wherein said controller causes the deposition of said substantially non-conformal seed layer prior to the deposition of said substantially conformal seed layer.

15. The apparatus of claim 1 wherein said controller causes the deposition of said substantially conformal seed layer prior to the deposition of said substantially non-conformal seed layer.

16. The apparatus of claim 1 wherein said controller causes the deposition of said substantially non-conformal seed layer prior to the deposition of said substantially conformal seed layer.

17. The apparatus of claim 1 wherein the controller further includes operation software which inputs the recipe information into the controller from a computer readable memory comprising data structures for controlling the sequence, duration, and process parameters of the deposition chambers.

18. An apparatus for depositing seed layers on a substrate, said substrate comprising narrow openings surrounded by a field, said apparatus comprising:

a deposition chamber adapted to deposit both a substantially conformal seed layer on the substrate and a substantially non-conformal seed layer on the substrate, wherein said seed layers comprise a material selected from a group consisting of Cu, Ag, or alloys comprising one or more of these metals; and

a controller which includes recipe information, said recipe information includes deposition sequence and process parameters for operation of the deposition chamber, wherein the controller, in response to the recipe information, causes the deposition chamber to deposit said substantially conformal seed layer having a thickness of about 50 Å

to about 500 Å

on the field and causes the deposition chamber to deposit said substantially non-conformal seed layer having a thickness of about 100 Å

to about 3,000 Å

on the field, said controller causes the stopping of the deposition of said substantially conformal seed layer and causes the stopping of the deposition of said substantially non-conformal seed layer prior to filling the openings, thereby leaving enough room for electroplating inside the narrow openings.

19. The apparatus of claim 18 wherein the controller further includes operation software which inputs the recipe information into the controller from a computer readable memory comprising data structures for controlling the sequence, duration, and process parameters of said deposition chamber, said data structures cause the deposition chamber to deposit at least two seed layers, in at least two distinct steps in succession, wherein deposition parameters used in one of the distinct steps produce a substantially conformal seed layer and deposition parameters used in another distinct step produce a substantially non-conformal seed layer.

20. The apparatus of claim 19 wherein the controller causes at least one of the deposition parameters to be varied continuously or gradually, thereby changing gradually the nature of the depositing seed layer from a substantially conformal seed layer to a substantially non-conformal seed layer, or vice versa, inside the same deposition chamber.

21. The apparatus of claim 19 wherein the controller causes at least one of the deposition parameters to vary in a manner to provide a combination of at least one distinct step of depositing a substantially conformal or a non-conformal seed layer and at least one gradual variation of the at least one deposition parameter towards a substantially non-conformal or a conformal seed layer, respectively, or vice versa, inside the same deposition chamber.

22. The apparatus of claim 18 wherein said deposition chamber comprises a PVD chamber, and wherein said controller causes at least one deposition parameter selected from the group consisting of substrate bias, gas pressure, cathodic voltage, and power density to vary in a manner to deposit a substantially conformal seed layer on the substrate in one step and to deposit a substantially non-conformal seed layer on the substrate in another step.

23. The apparatus of claim 22 wherein said PVD chamber comprises an ion plating deposition chamber.

24. The apparatus of claim 22 wherein said PVD chamber comprises an ionized metal plasma (IMP) deposition chamber.

25. The apparatus of claim 22 wherein said at least one deposition parameter comprises substrate bias, and wherein the controller causes a higher (more negative) substrate bias during deposition of said substantially conformal seed layer and a lower (less negative) substrate bias during deposition of said substantially non-conformal seed layer.

26. The apparatus of claim 22 wherein said at least one deposition parameter comprises gas pressure, and wherein the controller causes a higher gas pressure during deposition of said substantially conformal seed layer and a lower gas pressure during deposition of said substantially non-conformal seed layer.

27. The apparatus of claim 18 wherein the thickness of said substantially conformal seed layer is in the range of about 100 Å

to about 300 Å

on the field and the thickness of said substantially non-conformal seed layer is in the range of about 500 Å

to about 1,800 Å

on the field.

28. The apparatus of claim 27 wherein said controller causes the deposition of said substantially conformal seed layer prior to the deposition of said substantially non-conformal seed layer.

29. The apparatus of claim 27 wherein said controller causes the deposition of said substantially non-conformal seed layer prior to the deposition of said substantially conformal seed layer.

30. The apparatus of claim 27 wherein said deposition chamber comprises a PVD deposition chamber.

31. The apparatus of claim 27 wherein said deposition chamber comprises a CVD deposition chamber.

32. The apparatus of claim 18 wherein said controller causes the deposition of said substantially conformal seed layer prior to the deposition of said substantially non-conformal seed layer.

33. The apparatus of claim 18 wherein said controller causes the deposition of said substantially non-conformal seed layer prior to the deposition of said substantially conformal seed layer.

34. The apparatus of claim 18 wherein said deposition chamber comprises a PVD deposition chamber.

35. The apparatus of claim 18 wherein said deposition chamber comprises a CVD deposition chamber.

36. The apparatus of claim 18 wherein said deposition chamber comprises a CVD chamber, said controller causes at least one deposition parameter selected from the group consisting of substrate temperature, precursor or reacting gas partial pressure (or flow rate), and plasma power density (in PECVD) to vary in a manner to deposit a substantially conformal seed layer on the substrate in one step and to deposit a substantially non-conformal seed layer on the substrate in another step.

37. The apparatus of claim 36 wherein said at least one deposition parameter comprises substrate temperature, and wherein said controller causes a higher substrate temperature during deposition of the substantially non-conformal seed layer and a lower substrate temperature during deposition of the substantially conformal seed layer.

38. The apparatus of claim 36 wherein said at least one deposition parameter comprises precursor partial pressure (or flow rate), and wherein said controller causes a higher precursor partial pressure (or flow rate) during deposition of the substantially conformal seed layer and a lower precursor partial pressure (or flow rate) during deposition of the substantially non-conformal seed layer.

39. An apparatus for depositing seed layers on a substrate, said substrate comprising narrow openings surrounded by a field, said apparatus comprising:

at least one conformal deposition chamber adapted to deposit a substantially conformal seed layer on the substrate;

at least one non-conformal deposition chamber adapted to deposit a substantially non-conformal seed layer on the substrate, wherein said seed layers comprise a material selected from a group consisting of Cu, Ag, or alloys comprising one or more of these metals; and

means for controlling the deposition chambers, according to deposition sequence and process parameters, wherein said means for controlling causes the conformal deposition chamber to deposit said substantially conformal seed layer having a thickness of about 50 Å

to about 500 Å

on the field and causes the non-conformal deposition chamber to deposit said substantially non-conformal seed layer having a thickness of about 100 Å

to about 3,000 Å

on the field, said means for controlling causes the stopping of the deposition of said substantially conformal seed layer and causes the stopping of the deposition of said substantially non-conformal seed layer prior to filling the openings, thereby leaving enough room for electroplating inside the narrow openings.

40. An apparatus for depositing seed layers on a substrate, said substrate comprising narrow openings surrounded by a field, said apparatus comprising:

a deposition chamber adapted to deposit both a substantially conformal seed layer on the substrate and a substantially non-conformal seed layer on the substrate, wherein said seed layers comprise a material selected from a group consisting of Cu, Ag, or alloys comprising one or more of these metals; and

means for controlling the deposition chamber according to deposition sequence and process parameters, wherein said means for controlling causes the deposition chamber to deposit said substantially conformal seed layer having a thickness of about 50 Å

to about 500 Å

on the field and causes the deposition chamber to deposit said substantially non-conformal seed layer having a thickness of about 100 Å

to about 3,000 Å

on the field, said means for controlling causes the stopping of the deposition of said substantially conformal seed layer and causes the stopping of the deposition of said substantially non-conformal seed layer prior to filling the openings, thereby leaving enough room for electroplating inside the narrow openings.