Method and apparatus for sputtering with a plasma lens

Patent metadata

Field	Value
Publication number	US-9455057-B2
Application number	US-201213645962-A
Country	US
Kind code	B2
Filing date	Oct 5, 2012
Priority date	Apr 14, 2010
Publication date	Sep 27, 2016
Grant date	Sep 27, 2016

Abstract

A plasma lens for enhancing the quality and rate of sputter deposition onto a substrate is described herein. The plasma lens serves to focus positively charged ions onto the substrate while deflecting negatively charged ions, while at the same time due to the line of sight positioning of the lens, allowing for free passage of neutrals from the target to the substrate. The lens itself is formed of a wound coil of multiple turns, inside of which are deposed spaced lens electrodes which are electrically paired to impress an E field overtop the B field generated by the coil, the potential applied to the electrodes increasing from end to end towards the center of the lens, where the applied voltage is set to a high potential at the center electrodes as to produce a potential minimum on the axis of the lens.

First claim

What is claim is:

1. An apparatus comprising:
a magnetron including a target holder configured to hold a target;
a support configured to hold a substrate upon which a layer containing material from the target is to be deposited, the support being positioned opposite the target; and
a plasma lens, the plasma lens being disposed between the magnetron and the support, the plasma lens defining a line of sight path from the target to the support, the plasma lens operable to disperse negatively charged particles away from a center of the plasma lens as the negatively charged particles pass through the plasma lens, and the plasma lens operable to focus positively charged particles to the center of the plasma lens as the positively charged particles pass though the plasma lens, the plasma lens comprising:
a lens coil including multiple turns, the lens coil disposed about the line of sight path at a position along the line of sight path, and
a plurality of lens electrodes disposed at the position along the line of sight path, each of the lens electrodes forming a perimeter around the line of sight path, lens electrodes of the plurality of lens electrodes forming pairs of lens electrodes.

2. The apparatus of claim 1 , further comprising:
a first power supply operable to apply power to the lens coil to generate a magnetic field that forms lines of equipotential.

3. The apparatus of claim 1 , further comprising:
a second power supply operable to apply potential to each of the pairs of lens electrodes.

4. The apparatus of claim 3 , wherein the second power supply is operable to apply a high potential to a center pair of lens electrodes, and wherein the second power supply is operable to apply a potential to other pairs of lens electrodes with the potential decreasing in directions moving along the line of sight path, away from the center pair of lens electrodes.

5. The apparatus of claim 1 , further comprising:
a heater associated with the support.

6. The apparatus of claim 1 , further comprising:
a shield disposed between the support and an end of the plasma lens proximate the support, wherein the shield is operable to block negatively charged particles which have traveled through the plasma lens from the target towards the support.

7. The plasma lens of claim 3 , wherein the second power supply comprises a plurality of power supplies.

8. The plasma lens of claim 3 , wherein the second power supply comprises a single power supply including a stiff voltage divider.

9. The apparatus of claim 1 , wherein the plasma lens has a cylindrical shape, and wherein the plasma lens has a substantially circular cross-section.

10. The apparatus of claim 1 , wherein the plasma lens has an elongated cross-section, wherein one dimension is substantially larger than a dimension substantially perpendicular to it, and wherein the plasma lens has a flat-elliptical cross-section or a rectangular cross-section.

11. The apparatus of claim 1 , further comprising:
a vacuum chamber, the vacuum chamber housing the magnetron, the support, and the plasma lens.

12. A method of depositing a film comprising:
providing an apparatus including:
a magnetron including a target holder configured to hold a target;
a support configured to hold a substrate upon which a layer containing material from the target is to be deposited, the substrate support being positioned opposite the target; and
a plasma lens, the plasma lens being disposed between the magnetron source and the support, the plasma lens defining a line of sight path from the target to the support, the plasma lens comprising:
a lens coil including multiple turns, the lens coil disposed about the line of sight path at a position along the line of sight path, and
a plurality of lens electrodes disposed at the position along the line of sight path, each of the lens electrodes forming a perimeter around the line of sight path, lens electrodes of the plurality of lens electrodes forming pairs of lens electrodes;

applying a potential to the target;
forming an ionized plasma with a sputtering gas; and
applying power to the plasma lens to disperse negatively charged particles away from a center of the plasma lens as the negatively charged particles pass through the plasma lens and to focus positively charged particles to the center of the plasma lens as the positively charged particles pass though the plasma lens.

13. The method of claim 12 , wherein the apparatus further comprises:
a first power supply operable to apply power to the lens coil to generate a magnetic field including lines of equipotential.

14. The method of claim 12 , wherein the target is cooled when depositing the layer.

15. The method of claim 12 , wherein the substrate is moved laterally when depositing the layer to sequentially expose different portions of the substrate to neutral atoms and the positively charged particles.

16. The method of claim 12 , wherein the layer being deposited is doped ZnO, wherein the target comprises doped Zn, wherein the sputtering gas comprises argon, and wherein oxygen is input to the apparatus with the argon.

17. The method of claim 12 , wherein the substrate is heated when depositing the layer.

18. The method of claim 12 , wherein the apparatus further comprises:
a second power supply operable to apply potential to the pairs of lens electrodes.

19. The method of claim 12 , wherein applying power to the plasma lens includes applying potential to the pairs of lens electrodes, including applying a high potential to a center pair of lens electrodes and applying a potential to other pairs of lens electrodes with the potential decreasing in directions moving along line of sight path, away from the center pair of lens electrodes.

20. The method of claim 12 , wherein the apparatus further comprises:
a vacuum chamber, the vacuum chamber housing the magnetron, the support, and the plasma lens.

Assignees

• Univ California

Inventors

• Anders Andre

Classifications

• H01J37/3408

  Planar magnetron sputtering · CPC title

• H01J37/32697

  Electrostatic control · CPC title

• G21K1/087 Primary

  by electrical means · CPC title

• H01J37/3467

  Pulsed operation, e.g. HIPIMS · CPC title