Apparatus and method for dynamic control of ion beam energy and angle

Patent metadata

Field	Value
Publication number	US-9336998-B2
Application number	US-201414274018-A
Country	US
Kind code	B2
Filing date	May 9, 2014
Priority date	May 9, 2014
Publication date	May 10, 2016
Grant date	May 10, 2016

Abstract

In one embodiment a method of etching a substrate includes directing a first ion beam to the substrate through an extraction plate of a processing apparatus using a first set of control settings of the processing apparatus. The method may further include detecting a signal from the substrate that indicates a change in material being etched by the first ion beam from a first material to a second material, adjusting control settings of the processing apparatus to a second set of control settings different from the first set of control settings based on the second material, and directing a second ion beam to the substrate through the extraction plate using the second set of control settings.

First claim

What is claimed is:

1. A method of etching a substrate, comprising:
directing a first ion beam to the substrate through an extraction plate of a processing apparatus using a first set of control settings of the processing apparatus;
detecting a signal from the substrate that indicates a change in material being etched by the first ion beam from a first material to a second material;
adjusting control settings of the processing apparatus to a second set of control settings different from the first set of control settings based on the second material; and
directing a second ion beam to the substrate through the extraction plate using the second set of control settings, wherein the adjusting the control settings to the second set of control settings comprises:
adjusting the control settings from the first set of control settings to a predetermined set of control settings associated with the second material;
performing metrology to measure at least one parameter of an ion beam directed through the extraction plate using the predetermined set of control settings, the measured at least one parameter comprising ion energy, ion beam current and ion angular distribution; and
adjusting the predetermined set of control settings to the second set of control settings based upon the measured at least one parameter of the ion beam.

2. The method of claim 1 , wherein the substrate comprises:
a layer stack comprising a plurality of layers on a substrate base; and
a mask comprising a plurality of mask features that is disposed on the layer stack before the directing the first ion beam.

3. The method of claim 2 , wherein the adjusting control settings comprises adjusting ion at least one control setting to adjust ion incidence angle between the first ion beam and second ion beam to account for differences in sputter etch characteristics of the first material and second material.

4. The method of claim 1 wherein the detecting the signal comprises receiving an optical emission spectroscopy (OES) signal generated by at least one element of the first material or second material.

5. The method of claim 4 , wherein the detecting the signal comprises detecting an OES signal from different positions that are adjacent the substrate.

6. The method of claim 1 , wherein the adjusting the control settings comprises adjusting at least one of: extraction voltage, RF power applied to a plasma chamber of the processing apparatus, separation between the substrate and the extraction plate, pressure of the plasma chamber, ion beam duty cycle for a pulsed ion beam, and scan speed applied to a substrate holder that holds the substrate.

7. The method of claim 1 wherein the adjusting the predetermined set of control settings comprises:
comparing the at least one parameter of the ion beam to a target ion beam profile for the second material; and
adjusting the control settings until the target ion beam profile is met.

8. The method of claim 1 , further comprising:
receiving an initial beam ion profile comprising at least one of: initial ion angle, initial ion energy, and initial ion current;
in response to the receiving the initial ion beam profile, generating a preliminary ion beam using a preliminary set of control settings;
performing metrology to measure the preliminary ion beam; and
adjusting the preliminary set of control settings until the preliminary ion beam matches the initial ion beam profile.

9. The method of claim 8 , wherein the adjusting the preliminary set of control settings comprises adjusting at least one of: extraction voltage, RF power applied to a plasma chamber of the processing apparatus, separation between the substrate and the extraction plate, pressure of the plasma chamber, duty cycle of a pulsed ion beam, and scan speed applied to a substrate holder that holds the substrate.

10. The method of claim 8 , wherein the initial ion beam profile further comprises a substrate rotation increment, initial substrate orientation angle and substrate temperature.

11. The method of claim 1 , wherein the substrate is a first substrate, the method further comprising:
associating the second set of control settings with the second material;
detecting a signal from a layer stack of a second substrate during etching of the second substrate that indicates a change in material from the first material to the second material; and
adjusting control settings of the processing apparatus to the second set of control settings.

12. The method of claim 1 , wherein the first ion beam has a first ion angular distribution and the second ion beam has a second ion angular distribution that is different from the first ion angular distribution.

13. A method of etching a device structure, comprising:
providing a substrate comprising a layer stack disposed on a substrate base, the layer stack having a multiplicity of layers that includes at least one metal layer, and a mask having plurality of mask features disposed on the layer stack;
directing a first ion beam to the layer stack through an extraction plate of a processing apparatus using a first set of control settings of the processing apparatus;
detecting an optical emission spectroscopy (OES) signal from the layer stack that indicates a change in material being etched in the layer stack from a first material to a second material;
adjusting control settings of the processing apparatus to a second set of control settings different from the first set of control settings based on the second material; and
directing a second ion beam to the layer stack through the extraction plate using the second set of control settings, wherein the adjusting the control settings to the second set of control settings comprises:
adjusting the control settings from the first set of control settings to a predetermined set of control settings associated with the second material;
performing metrology to measure at least one parameter of an ion beam directed through the extraction plate using the predetermined set of control settings, the measured at least one parameter comprising ion energy, ion beam current and ion angular distribution; and

adjusting the predetermined set of control settings to the second set of control settings based upon the measured at least one parameter of the ion beam.

14. The method of claim 13 , wherein the first ion beam has a first ion angular distribution and a first ion energy and the second ion beam has a second ion angular distribution and a second ion energy, wherein at least one of the first ion energy and first ion angular distribution differs from the second ion energy or second ion angular distribution, respectively.

15. The method of claim 13 , wherein the adjusting the control settings comprises adjusting at least one of: extraction voltage, RF power applied to a plasma chamber of the processing apparatus, separation between the substrate and the extraction plate, pressure of the plasma chamber, ion beam duty cycle for a pulsed ion beam, and scan speed applied to a substrate holder that holds the substrate.

16. A processing apparatus comprising:
a plasma source to generate a plasma in a plasma chamber;
an extraction plate disposed along a side of the plasma chamber, the extraction plate having an aperture configured to direct an ion beam to a substrate when a bias is applied between the plasma chamber and substrate;
a monitoring apparatus to measure at least one signal from the substrate;
at least one computer-readable storage medium comprising instructions that, when executed, cause the processing apparatus to:
identify a first signal from the sub

Assignees

• Varian Semiconductor Equipment

Inventors

• Godet Ludovic
• Distaso Daniel
• Munoz Nini
• Ma Tristan
• Liu Yu

Classifications

• H01J37/32146 Primary

  Amplitude modulation, includes pulsing · CPC title

• C23C14/54

  Controlling or regulating the coating process · CPC title

• H01J37/32422

  Arrangement for selecting ions or species in the plasma · CPC title

• H01J37/32972

  Spectral analysis · CPC title

• H01J37/3299

  Feedback systems · CPC title