Seed layers for metallic interconnects

• US 9,673,090 B2
• Filed: 05/26/2009
• Issued: 06/06/2017
• 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): SMITH, BRADLEY
• Application Number:
  US12/471,571
• Publication Number:
  US 20090233440A1
• Time in Patent Office: 2,933 Days
• Field of Search: 438653, 438654, 438687
• 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

One embodiment of the present invention is a method for depositing two or more PVD seed layers for electroplating metallic interconnects over a substrate, the substrate including a patterned insulating layer which includes at least one opening surrounded by a field, the at least one opening having top corners, sidewalls, and bottom, the field and the at least one opening being ready for depositing one or more seed layers, and the method includes: (a) depositing by a PVD technique, in a PVD chamber, a continuous PVD seed layer over the sidewalls and bottom of the at least one opening, using a first set of deposition parameters; and (b) depositing by a PVD technique, in a PVD chamber, another PVD seed layer over the substrate, using a second set of deposition parameters, wherein (i) the second set of deposition parameters includes at least one deposition parameter which is different from any of the parameters in the first set of deposition parameters, or the second set of deposition parameters includes at least one deposition parameter whose value is different in the two sets of deposition parameters, (ii) at least one of the PVD seed layers includes a material selected from a group consisting of Cu, Ag, or alloys including one or more of these metals, (iii) the PVD seed layers have no substantial overhangs sealing or pinching-off the top corners of the at least one opening, (iv) the combined thickness of the seed layers over the field is sufficient to enable uniform electroplating across the substrate, and (v) the combined seed layers inside the at least one opening leave sufficient room for electroplating inside the at least one opening.

Claims

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

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

depositing by a PVD technique, in a PVD chamber, another PVD seed layer over the substrate, 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 two sets of deposition parameters, 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) the PVD seed layers have no substantial overhangs sealing or pinching-off the top corners of the at least one opening, (iii) at least one of the PVD seed layers comprises a material selected from a group consisting of Cu, Ag, or alloys comprising one or more of these metals, (iv) the combined thickness of the seed layers over the field is sufficient to enable uniform electroplating across the substrate, (v) the combined seed layers inside the at least one opening leave sufficient room for electroplating inside the at least one opening, and (vi) said continuous PVD seed layer and said another PVD seed layer are deposited in the same PVD chamber; and

depositing at least one additional seed layer over the PVD seed layers prior to electroplating.

2. A method for depositing two or more PVD seed layers for electroplating metallic interconnects over a substrate, the substrate including a patterned insulating layer which comprises at least one opening surrounded by a field, the at least one opening having top corners, sidewalls, and bottom, the field and the at least one opening being ready for depositing one or more seed layers, and the method comprising:

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

depositing by a PVD technique, in a PVD chamber, another PVD seed layer over the substrate, 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 two sets of deposition parameters, 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) the PVD seed layers have no substantial overhangs sealing or pinching-off the top corners of the at least one opening, (iii) at least one of the PVD seed layers comprises a material selected from a group consisting of Cu, Ag, or alloys comprising one or more of these metals, (iv) the combined thickness of the seed layers over the field is sufficient to enable uniform electroplating across the substrate, (v) the combined seed layers inside the at least one opening leave sufficient room for electroplating inside the at least one opening, and (vi) said continuous PVD seed layer and said another PVD seed layer are deposited in the same PVD chamber; and

depositing at least one additional seed layer prior to the deposition of the PVD seed layers.

3. A method for depositing two or more PVD seed layers for electroplating metallic interconnects over a substrate, the substrate including a patterned insulating layer which comprises at least one opening surrounded by a field, the at least one opening having top corners, sidewalls, and bottom, the field and the at least one opening being ready for depositing one or more seed layers, and the method comprising:

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

depositing by a PVD technique, in a PVD chamber, another PVD seed layer over the substrate, 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 two sets of deposition parameters, 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) the PVD seed layers have no substantial overhangs sealing or pinching-off the top corners of the at least one opening, (iii) at least one of the PVD seed layers comprises a material selected from a group consisting of Cu, Ag, or alloys comprising one or more of these metals, (iv) the combined thickness of the seed layers over the field is sufficient to enable uniform electroplating across the substrate, (v) the combined seed layers inside the at least one opening leave sufficient room for electroplating inside the at least one opening, (vi) said continuous PVD seed layer and said another PVD seed layer are deposited in the same PVD chamber, (vii) said another PVD seed layer is deposited over the substrate prior to the deposition of the continuous PVD seed layer, and (viii) wherein a thickness of the continuous PVD seed layer over the field is from about 50 Å

to no more than 400 Å

, and the another PVD seed layer has a thickness from about 100 Å

to about 3,000 Å

over the field.

4. A method for depositing two or more PVD seed layers for electroplating metallic interconnects over a substrate, the substrate including a patterned insulating layer which comprises at least one opening surrounded by a field, the at least one opening having top corners, sidewalls, and bottom, the field and the at least one opening being ready for depositing one or more seed layers, and the method comprising:

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

depositing by a PVD technique, in a PVD chamber, another PVD seed layer over the substrate, 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 two sets of deposition parameters, 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) the PVD seed layers have no substantial overhangs sealing or pinching-off the top corners of the at least one opening, (iii) at least one of the PVD seed layers comprises a material selected from a group consisting of Cu, Ag, or alloys comprising one or more of these metals, (iv) the combined thickness of the seed layers over the field is sufficient to enable uniform electroplating across the substrate, (v) the combined seed layers inside the at least one opening leave sufficient room for electroplating inside the at least one opening, (vi) said continuous PVD seed layer and said another PVD seed layer are deposited in the same PVD chamber, (vii) said continuous PVD seed layer is deposited over the sidewalls and bottom of the at least one opening prior to the deposition of said another PVD seed layer, and (viii) wherein a thickness of the continuous PVD seed layer over the field is from about 50 Å

to no more than 400 Å

, and the another PVD seed layer has a thickness from about 100 Å

to about 3,000 Å

over the field.