Seed layers for metallic interconnects and products

• US 8,586,471 B2
• Filed: 01/17/2012
• Issued: 11/19/2013
• Est. Priority Date: 10/02/1999
• Status: Expired due to Fees

• Current Assignee: Uri Cohen
• Original Assignee: Uri Cohen
• Inventors: Cohen, Uri
• Primary Examiner(s): Ahmadi, Mohsen
• Application Number:
  US13/352,180
• Publication Number:
  US 20120126409A1
• Time in Patent Office: 672 Days
• Field of Search: 438/625, 438627-629, 438/637, 438641-643, 438/759, 257/E21.169, 257/E21.211, 257/E21.575, 257/E21.582, 257/E21.585
• US Class Current: 438/625
• 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 21/28556 by chemical means, e.g. CVD, LPCVD, PECVD, laser CVD H01L21/28518 - H01L21/28537 and H01L21/28568 take precedence
• 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
• CPC Class Codes: H01L 23/528 Geometry or layout of the interconnection structure H01L27/0207 takes precedence; algorithms G06F30/00
• CPC Class Codes: H01L 23/53209 based on metals, e.g. alloys, metal silicides H01L23/53285 takes precedence
• CPC Class Codes: H01L 23/53238 Additional layers associated with copper layers, e.g. adhesion, barrier, cladding layers
• CPC Class Codes: H01L 23/53252 Additional layers associated with noble-metal layers, e.g. adhesion, barrier, cladding layers
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

A method is disclosed for depositing multiple seed layers for metallic interconnects over a substrate, the substrate includes a patterned insulating layer which comprises an opening surrounded by a field, said opening has sidewalls and top corners, and the method including: depositing a continuous seed layer over the sidewalls, using a first set of deposition parameters; and depositing another seed layer over the substrate, including inside the opening and over a portion of said field, using a second set of deposition parameters, wherein: the second set of deposition parameters includes one deposition parameter which is different from any parameters in the first set, or whose value is different in the first and second sets; the continuous seed layer has a thickness in a range from about 20 Å to not more than 250 Å over the field; and the combined seed layers leave sufficient room for electroplating inside the opening.

Claims

1. A method for depositing two or more PVD seed layers for metallic interconnects over a substrate, the substrate includes a patterned insulating layer which comprises at least one opening surrounded by a field, said at least one opening has sidewalls, bottom, and top corners, and the method comprising:

depositing a continuous PVD seed layer in a single step over the sidewalls and bottom of the at least one opening, using a first set of deposition parameters; and

then

depositing another PVD seed layer directly on the continuous PVD seed layer using a second set of deposition parameters, wherein;

(i) the second set of deposition parameters includes at least one deposition parameter whose value is different in the first and second sets of deposition parameters;

(ii) said at least one deposition parameter is selected from a group of deposition parameters consisting of substrate bias voltage, duration of deposition, background pressure, plasma power density, sputtering gas pressure, sputtering gas flow rate, cathodic voltage, and cathodic power;

(iii) the continuous seed layer has a thickness in a range from about 20 Å

to not more than 250 Å

over the field;

(iv) the combined seed layers leave sufficient room for electroplating inside the at least one opening and (v) at least one of the seed layers comprises a material selected from a group consisting of Cu, Ag, and alloys comprising at least one of these metals.

2. The method of claim 1, wherein:

(i) the thickness of the another PVD seed layer is from 100 Å

to 3,000 Å

over the field, (ii) the combined thickness of the seed layers over the field enables uniform electroplating across the substrate, and (iii) said another PVD seed layer has no substantial overhangs sealing or pinching-off the top corners of the at least one opening.

3. The method of claim 1, wherein the thickness of the continuous PVD seed layer over the field is within a range from about 20 Å

to not more than 150 Å

.

4. The method of claim 1, wherein the thickness of the continuous PVD seed layer over the field is within a range from about 20 Å

to not more than 50 Å

.

5. The method of claim 1, wherein said at least one deposition parameter is selected from a group of deposition parameters consisting of substrate bias voltage, sputtering gas pressure, cathodic voltage, cathodic power, and plasma power density.

6. The method of claim 5, wherein said at least one deposition parameter is substrate bias voltage.

7. The method of claim 5, wherein said at least one deposition parameter is selected from a group of deposition parameters consisting of sputtering gas pressure and cathodic power.

8. The method of claim 5, wherein said continuous PVD seed layer and said another PVD seed layer are deposited in the same PVD chamber.

9. The method of claim 5, wherein said continuous PVD seed layer is deposited in one PVD chamber and said another PVD seed layer is deposited in another PVD chamber.

10. The method of claim 1, wherein the thickness of the continuous PVD seed layer over the field is within a range from about 20 Å

to not more than 200 Å

.

11. The method of claim 1, wherein the thickness of the continuous PVD seed layer over the field is within a range from about 20 Å

to not more than 100 Å

.

12. The method of claim 1, further comprising depositing one or more barrier layer prior to the deposition of the seed layers.

13. A method for depositing two or more PVD seed layers for metallic interconnects over a substrate, the substrate includes a patterned insulating layer which comprises at least one opening surrounded by a field, said at least one opening has sidewalls, bottom, and top corners, and the method comprising:

depositing a first PVD seed layer over the substrate using a first set of deposition parameters; and

then

depositing a second PVD seed layer in a single step directly on the first PVD seed layer using a second set of deposition parameters, wherein;

(i) the second PVD seed layer is continuous over the sidewalls and bottom of the at least one opening;

(ii) the second set of deposition parameters includes at least one deposition parameter whose value is different in the first and second sets of deposition parameters;

(iii) said at least one deposition parameter is selected from a group of deposition parameters consisting of substrate bias voltage, duration of deposition, background pressure, plasma power density, sputtering gas pressure, sputtering gas flow rate, cathodic voltage, and cathodic power;

(iv) the continuous seed layer has a thickness in a range from about 20 Å

to not more than 250 Å

over the field;

(v) the combined seed layers leave sufficient room for electroplating inside the at least one opening; and

(vi) at least one of the seed lavers comprises a material selected from a group consisting of Cu, Ag, and alloys comprising at least one of these metals.

14. The method of claim 13, wherein:

(i) the thickness of the first PVD seed layer is from 100 Å

to 3,000 Å

over the field, (ii) the combined thickness of the seed layers over the field enables uniform electroplating across the substrate, and (iii) the first PVD seed layer has no substantial overhangs sealing or pinching-off the top corners of the at least one opening.

15. The method of claim 13, wherein the thickness of the second PVD seed layer over the field is within a range from about 20 Å

to not more than 200 Å

.

16. The method of claim 13, wherein the thickness of the second PVD seed layer over the field is within a range from about 20 Å

to not more than 100 Å

.

17. The method of claim 13, wherein the thickness of the second PVD seed layer over the field is within a range from about 20 Å

to not more than 150 Å

.

18. The method of claim 13, wherein the thickness of the second PVD seed layer over the field is within a range from about 20 Å

to not more than 50 Å

.

19. The method of claim 13, wherein said at least one deposition parameter is selected from a group of deposition parameters consisting of substrate bias voltage, sputtering gas pressure, cathodic voltage, cathodic power, and plasma power density.

20. The method of claim 19, wherein said first PVD seed layer and said second PVD seed layer are deposited in the same PVD chamber.

21. The method of claim 19, wherein said first PVD seed layer is deposited in one PVD chamber and said second PVD seed layer is deposited in another PVD chamber.

22. The method of claim 19, wherein said at least one deposition parameter is substrate bias voltage.

23. The method of claim 19, wherein said at least one deposition parameter is selected from a group of deposition parameters consisting of sputtering gas pressure and cathodic power.

24. The method of claim 13, further comprising depositing one or more barrier layers prior to the deposition of the seed layers.

25. A method for depositing two or more PVD seed layers for metallic interconnects over a substrate, the substrate includes a patterned insulating layer which comprises at least one opening surrounded by a field, said at least one opening has sidewalls, bottom, and top corners, and the method comprising:

depositing in the same chamber both conformal and non-conformal PVD seed layers utilizing;

(a) two distinct single steps, wherein the deposition parameters during the first single step are suitable for the deposition of a substantially conformal PVD seed layer, and the deposition parameters during the second single step are suitable for the deposition of a substantially non-conformal PVD seed layer, wherein at least one deposition parameter has different values during the deposition of the distinct single steps;

or (b) wherein at least one of the deposition parameter is varied (or ramped) continuously or gradually, thereby changing the nature of the PVD seed layer from substantially conformal to substantially non-conformal, or vice versa;

or (c) a combination of at least one distinct single step of depositing a substantially conformal PVD seed layer and at least one gradual variation (or ramping) of at least one deposition parameter towards a substantially non-conformal PVD seed layer, or vice versa;

wherein;

(i) said at least one deposition parameter is selected from a group of deposition parameters consisting of substrate bias voltage, duration of deposition, background pressure, plasma power density, sputtering gas pressure, sputtering gas flow rate, cathodic voltage, and cathodic power;

(ii) said substantially conformal PVD seed layer has a thickness in a range from about 20 Å

to not more than 250 Å

over the field;

(iii) the combined seed layers leave sufficient room for electroplating inside the at least one opening; and

(iv) at least one of the seed layers comprises a material selected from a group consisting of Cu, Ag, and alloys comprising at least one of these metals.

26. The method of claim 25, wherein said at least one deposition parameter is selected from a group of deposition parameters consisting of substrate bias voltage, sputtering gas pressure, cathodic voltage, cathodic power, and plasma power density.

27. The method of claim 26, wherein said at least one deposition parameter is substrate bias voltage.

28. The method of claim 25, wherein the thickness of the substantially conformal PVD seed layer over the field is within a range from about 20 Å

to not more than 150 Å

.