Conductive interconnect structures and formation methods using supercritical fluids

• US 8,008,192 B2
• Filed: 08/23/2010
• Issued: 08/30/2011
• Est. Priority Date: 06/28/2005
• Status: Active Grant

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Sulfridge, Marc
• Primary Examiner(s): Sarkar; Asok K
• Assistant Examiner(s): Slutsker; Julia
• Application Number:
  US12/861,100
• Publication Number:
  US 20100317190A1
• Time in Patent Office: 372 Days
• Field of Search: 438/637, 438/618, 257/621, 257/E21.464, 257/E23.145
• US Class Current: 438/637
• CPC Class Codes: H01L 21/288 from a liquid, e.g. electrolytic deposition
• CPC Class Codes: H01L 21/76898 formed through a semiconductor substrate
• CPC Class Codes: H01L 2224/0401 Bonding areas specifically adapted for bump connectors, e.g. under bump metallisation [UBM]
• CPC Class Codes: H01L 2224/05 of an individual bonding area
• CPC Class Codes: H01L 2224/13025 the bump connector being disposed on a via connection of the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/131 with a principal constituent of the material being a metal or a metalloid, e.g. boron [B], silicon [Si], germanium [Ge], arsenic [As], antimony [Sb], tellurium [Te] and polonium [Po], and alloys thereof
• CPC Class Codes: H01L 23/481 Internal lead connections, e.g. via connections, feedthrough structures
• CPC Class Codes: H01L 27/14601 Structural or functional details thereof
• CPC Class Codes: H01L 27/14627 Microlenses
• CPC Class Codes: H01L 27/14636 Interconnect structures
• CPC Class Codes: H01L 27/14683 Processes or apparatus peculiar to the manufacture or treatment of these devices or parts thereof not peculiar thereto H01L21/00
• CPC Class Codes: H01L 2924/014 Solder alloys

Abstract

Conductive interconnect structures and formation methods using supercritical fluids are disclosed. A method in accordance with one embodiment of the invention includes forming a via in a substrate, with the via having a width and a length generally transverse to the width, and with a length being approximately 100 microns or more. The method can further include disposing a conductive material in the via while the via is exposed to a supercritical fluid. For example, copper can be disposed in the via by introducing a copper-containing precursor into the supercritical fluid and precipitating the copper from the supercritical fluid. Interconnect structures can be formed using this technique in a single generally continuous process, and can produce conductive structures having a generally uniform grain structure across the width of the via.

Claims

1. A method for processing a substrate having a bond site at a first surface and a second surface opposite the first surface, comprising:

forming a via in the substrate, the via having an opening proximate to the bond site of the substrate, a bottom portion in the substrate, and a sidewall between the opening and the bottom portion;

contacting the sidewall of the via with a precursor of a conductive material in a supercritical fluid;

depositing the conductive material on the sidewall of the via while the via is exposed to the precursor in the supercritical fluid, the conductive material being generally conformal to the sidewall of the via;

forming a vent hole in the substrate with the conformal conductive material on the sidewall of the via, the vent hole extending from the bottom portion of the via to the second surface of the substrate; and

filling the via with a fill material adjacent to the conformal conductive material after forming the vent hole.

2. The method of claim 1 wherein:

the fill material has a first end proximate to the first surface and a second end proximate the bottom portion of the via;

the method further includes removing material from the second surface of the substrate until the second end of the fill material is exposed; and

attaching a solder ball to the exposed second end of the fill material, the solder ball being in electrical communication with the bond site of the substrate via the fill material in the via.

3. The method of claim 1 wherein depositing the conductive material includes performing a reduction reaction of the precursor in the supercritical fluid.

4. The method of claim 1 wherein the precursor is a metal-containing precursor, and wherein depositing the conductive material includes combining the metal-containing precursor with a supercritical carbon dioxide solvent.

5. The method of claim 1 wherein depositing the conductive material includes disposing a first conductive material on the sidewall of the via, and wherein the method further comprises disposing a second conductive material in the via adjacent to the first conductive material.

6. The method of claim 1 wherein depositing the conductive material includes:

exposing the via to the supercritical fluid;

introducing the precursor of the conductive material into the supercritical fluid;

reducing the precursor of the conductive material by introducing an additional chemical species, and/or elevating a temperature of the supercritical fluid; and

causing the conductive material to precipitate from the supercritical fluid.

7. The method of claim 1, further comprising removing an organic material from a surface of the sidewall of the via with the supercritical fluid before depositing the conductive material on the sidewall of the via.

8. The method of claim 1 wherein depositing the conductive material includes depositing the conductive material while the precursor of the conductive material has a generally uniform concentration gradient in the supercritical fluid along a length of the via.

9. The method of claim 1 wherein depositing the conductive material includes depositing the conductive material with a generally uniform grain structure.

10. A method for processing a substrate, comprising:

forming a via in a substrate, the via having an opening proximate to a bond site proximate a first surface of the substrate, a bottom portion in the substrate, and a sidewall between the opening and the bottom portion;

precipitating a conductive material from a precursor in a supercritical fluid onto the sidewall of the via, the conductive material being generally conformal to the sidewall of the via;

forming a vent hole in the substrate with the conformal conductive material on the sidewall of the via, the vent hole extending from the bottom portion of the via to a second surface of the substrate opposite the first surface; and

filling the via with a fill material adjacent to the conformal conductive material after forming the vent hole.

11. The method of claim 10 wherein precipitating a conductive material includes introducing the precursor of the conductive material into the supercritical fluid while the via is exposed to the supercritical fluid.

12. The method of claim 10 wherein precipitating a conductive material includes:

introducing the precursor into the supercritical fluid;

reducing the precursor by introducing an additional chemical species, and/or elevating a temperature of the supercritical fluid; and

causing the conductive material to precipitate from the supercritical fluid onto the sidewall of the via.

13. The method of claim 10 wherein precipitating the conductive material includes performing a reduction reaction of the precursor in the supercritical fluid.

14. The method of claim 10 wherein precipitating the conductive material includes combining the precursor containing a metal-containing constituent with a supercritical carbon dioxide solvent.

15. The method of claim 10 wherein precipitating the conductive material includes combining the precursor containing a metal-containing constituent with a supercritical non-polar solvent.

16. A method for processing a substrate, comprising:

forming a via in a substrate having a first surface and a second surface, the via having an opening proximate to the first surface of the substrate, a bottom portion in the substrate, and a sidewall generally transverse to a width of the opening;

introducing a precursor of a conductive material carried in a supercritical fluid to the sidewall of the via;

precipitating the conductive material from the precursor in the supercritical fluid onto the sidewall of the via, the precipitated conductive material being generally conformal to the sidewall of the via; and

after forming the conformal conductive material, forming a vent hole in the substrate extending from the bottom portion of the via to the second surface of the substrate.

17. The method of claim 16, further comprising filling the via with a fill material adjacent to the conformal conductive material after forming the vent hole.

18. The method of claim 16, further comprising maintaining a generally uniform concentration of the precursor in the supercritical fluid in the via as the conductive material is precipitated from the precursor.

19. The method of claim 16 wherein:

forming the via includes forming a via having a length of approximately 100 microns or more; and

the method further includes maintaining a generally uniform concentration of the precursor in the supercritical fluid along generally the entire length of the via as the conductive material is precipitated from the precursor.

20. The method of claim 16 wherein:

forming the via includes forming a via having a length of approximately 100 microns or more;

the method further includes maintaining a generally uniform concentration of the precursor in the supercritical fluid along generally the entire length of in the via as the conductive material is precipitated from the precursor;

introducing the precursor includes introducing a precursor containing at least one of nickel and copper;

precipitating the conductive material includes introducing hydrogen into the supercritical fluid and reducing the precursor of the conductive material with the introduced hydrogen.