Method and apparatus for spacer-optimization (S-O)

• US 7,939,450 B2
• Filed: 09/21/2007
• Issued: 05/10/2011
• Est. Priority Date: 09/21/2007
• Status: Expired due to Fees

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: Prager, Daniel J., Sundararajan, Radha, Chen, Lee, Yamashita, Asao, Funk, Merritt
• Primary Examiner(s): DEO, DUY VU NGUYEN
• Application Number:
  US11/859,507
• Publication Number:
  US 20090081815A1
• Time in Patent Office: 1,327 Days
• Field of Search: None
• US Class Current: 438/706
• CPC Class Codes: H01J 37/32091 the radio frequency energy being capacitively coupled to the plasma
• CPC Class Codes: H01J 37/32422 Arrangement for selecting ions or species in the plasma
• CPC Class Codes: H01L 21/31116 by dry-etching
• CPC Class Codes: H01L 22/12 for structural parameters, e.g. thickness, line width, refractive index, temperature, warp, bond strength, defects, optical inspection, electrical measurement of structural dimensions, metallurgic measurement of diffusions electrical measurement of diffusions H01L22/14
• CPC Class Codes: H01L 29/6656 using multiple spacer layers, e.g. multiple sidewall spacers
• CPC Class Codes: H01L 29/66575 where the source and drain or source and drain extensions are self-aligned to the sides of the gate H01L29/66606 takes precedence
• CPC Class Codes: H01L 29/78 with field effect produced by an insulated gate H01L29/7725, H01L29/775, H01L29/778 take precedence
• 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

The invention can provide a method of processing a substrate using S-O processing sequences and evaluation libraries that can include one or more optimized spacer creation and evaluation procedures.

Claims

1. A method of processing a substrate comprising:

performing a first S-O sequence using a first etching subsystem, a first Chemical Oxide Removal (COR) subsystem, a first transfer subsystem, and a first evaluation subsystem wherein a first oxygen-containing spacer layer is produced on a plurality of gate structures and on one or more evaluation features on a first set of substrates;

obtaining first evaluation data for a first evaluation substrate using the first evaluation subsystem, the first evaluation data including Integrated Metrology (IM) data for a first evaluation feature associated with a first gate structure, the first evaluation feature having the first oxygen-containing spacer layer thereon;

identifying the first set of substrates as first verified substrates when the first evaluation data is less than or equal to first threshold data; and

identifying the first set of substrates as first un-verified substrates and performing a first corrective action, when the first evaluation data is greater than the first threshold data.

2. The method of claim 1, further comprising:

obtaining second evaluation data for a second oxygen-containing spacer on a second evaluation substrate using the first evaluation subsystem;

identifying the first set of substrates as second verified substrates when the second evaluation data is less than or equal to second threshold data; and

identifying the first set of substrates as second un-verified substrates and performing a second corrective action when the second evaluation data is greater than the second threshold data.

3. The method of claim 1, further comprising:

performing a first partial-etch procedure using one or more etching chambers in the first etching subsystem, wherein a first portion of the first oxygen-containing spacer layer is removed from a first area on the first set of substrates and a carbon-containing layer is deposited on a vertical portion of each of the gate structures;

transferring the first set of substrates to one or more processing elements in the first COR subsystem; and

performing a first Chemical Oxide Removal (COR) procedure using a first chemical treatment module and a first thermal treatment module in the first COR subsystem, wherein a second portion of the first oxygen-containing spacer layer is removed from the first area on the first set of substrates, the deposited carbon-containing layer protecting the vertical portion of each of the gate structures during the COR procedure.

4. The method as claimed in claim 3, further comprising:

transferring a first substrate to a first etching chamber in the first etching subsystem using a transfer subsystem coupled to the first etching subsystem, wherein the transfer subsystem is configured to prevent an oxide layer from forming on the first substrate during the transferring;

operating a first radio frequency (RF) source in a first frequency range from approximately 0.1 MHz. to approximately 200 MHz and in a first power range from approximately 400 watts to approximately 600 watts during a first part of the first partial-etch procedure, wherein the first RF source is coupled to an upper electrode in the first etching chamber; and

operating a second RF source in a second frequency range from approximately 0.1 MHz. to approximately 200 MHz and in a second power range from approximately 50 watts to approximately 150 watts during a second part of the first partial-etch procedure, wherein the second RF source is coupled to the upper electrode in the first etching chamber.

5. The method as claimed in claim 3, further comprising:

transferring a first substrate to a first etching chamber in the first etching subsystem using a transfer subsystem coupled to the first etching subsystem, wherein the transfer subsystem is configured to prevent an oxide layer from forming on the first substrate during the transferring;

providing a first process gas into the first etching chamber during a first part of the first partial-etch procedure, wherein the first process gas includes C₄F₈ at a first flow rate between approximately 10 sccm and approximately 50 sccm; and

providing a second process gas into the first etching chamber during a second part of the first partial-etch procedure, wherein the second process gas includes Argon (Ar) at a second flow rate between approximately 700 sccm and approximately 900 sccm, wherein the first etching subsystem comprises a gas supply system configured to provide the first and second process gasses to the first etching chamber.

6. The method as claimed in claim 3, further comprising:

transferring a first substrate to a first etching chamber in the first etching subsystem using a transfer subsystem coupled to the first etching subsystem, wherein the transfer subsystem is configured to prevent an oxide layer from forming on the first substrate during the transferring;

process; and

controlling a first pressure in the first etching chamber between approximately 0.1 mTorr and approximately 100 Torr during a first part of the first partial-etch procedure, wherein the first etching subsystem comprises a pressure control system configured to control the first pressure in the first etching chamber.

7. The method as claimed in claim 3, further comprising:

transferring a first substrate to a first etching chamber in the first etching subsystem using a transfer subsystem coupled to the first etching subsystem, wherein the transfer subsystem is configured to prevent an oxide layer from forming on the first substrate during the transferring;

process; and

providing a dual backside pressure to the first substrate during a first part of the first partial-etch procedure, wherein the first etching subsystem comprises a dual backside gas system (226), and wherein a first backside pressure is between approximately 8 Torr and 12 Torr proximate a substrate center, and a second backside pressure is between approximately 20 Torr and 30 Torr proximate a substrate edge.

8. The method as claimed in claim 3, further comprising:

transferring a first substrate to a first etching chamber in the first etching subsystem using a transfer subsystem coupled to the first etching subsystem, wherein the transfer subsystem is configured to prevent an oxide layer from forming on the first substrate during the transferring;

process; and

controlling a temperature of the first substrate during a first part of the first partial-etch procedure, the temperature being between approximately 20 degrees C. and 30 degrees C., and wherein the first etching subsystem comprises a temperature control system configured to control the temperature.

9. The method as claimed in claim 3, further comprising:

transferring a first substrate to a first etching chamber in the first etching subsystem using a transfer subsystem coupled to the first etching subsystem, wherein the transfer subsystem is configured to prevent an oxide layer from forming on the first substrate during the transferring;

process; and

controlling a processing time for a first part of the first partial-etch procedure, the processing time being between approximately 30 seconds and approximately 60 seconds, and wherein the first etching subsystem comprises a controller configured to control the processing time.

10. The method as claimed in claim 3, further comprising:

transferring a first substrate to a first etching chamber in the first etching subsystem using a transfer subsystem coupled to the first etching subsystem, wherein the transfer subsystem is configured to prevent an oxide layer from forming on the first substrate during the transferring;

process; and

controlling a substrate holder temperature during a first part of the first partial-etch procedure, the substrate holder temperature being between approximately 0 degrees Celsius and 300 degrees Celsius, and wherein the first etching subsystem comprises a temperature control system (228) configured to control the substrate holder temperature.

11. The method as claimed in claim 3, further comprising:

transferring a first substrate to a first chemical treatment chamber in the first COR module using one or more transfer subsystems coupled to the first COR subsystem wherein the first transfer subsystem is configured to prevent an oxide layer from forming on the first substrate during the transferring;

controlling a first pressure in the first chemical treatment chamber between approximately 0.1 mTorr and approximately 100 Torr during a first part of the COR procedure, wherein a first chemical treatment module comprises a first pressure control system coupled to the first chemical treatment chamber;

transferring the first substrate to a first thermal treatment chamber in the first thermal treatment module using an internal transfer element configured to isolate the first substrate; and

controlling a second pressure in the first thermal treatment chamber between approximately 0.1 mTorr and approximately 100 Torr during a second part of the COR procedure, wherein the first thermal treatment module comprises a second pressure control system coupled to the first thermal treatment chamber.

12. The method as claimed in claim 3, further comprising:

transferring a first substrate to a first chemical treatment chamber in the first chemical treatment module using one or more transfer subsystems coupled to the first chemical treatment module wherein the first transfer subsystem is configured to prevent an oxide layer from forming on the first substrate during the transferring;

controlling a first temperature of a first temperature-controlled substrate holder between approximately 0 degrees Celsius and approximately 300 degrees Celsius during a first part of the COR procedure, the first chemical treatment chamber comprising the first temperature-controlled substrate holder configured to operate at the first temperature;

transferring the first substrate to a second temperature-controlled substrate holder in a first thermal treatment chamber using an internal transfer element configured to isolate the first substrate; and

operating the second temperature-controlled substrate holder at a second temperature between approximately 0°

C. and approximately 500°

Celsius during a second part of the COR procedure.

13. The method as claimed in claim 3, further comprising:

transferring a first substrate to a first chemical treatment chamber in the first chemical treatment module using one or more transfer subsystems coupled to the first chemical treatment module, wherein the first transfer subsystem is configured to prevent an oxide layer from forming on the first substrate during the transferring;

providing first process gasses into the first chemical treatment chamber during a first part of the first COR procedure, wherein the first process gasses include NH₃ at a first flow rate between approximately 10 sccm and approximately 50 sccm and Argon (Ar) at a second flow rate between approximately 10 sccm and approximately 50 sccm, wherein the first chemical treatment module comprises a first gas distribution system configured to provide the first process gasses into the first chemical treatment chamber, the first part lasting between approximately 30 seconds and approximately 500 seconds;

transferring the first substrate to a first thermal treatment chamber in the first thermal treatment module using an internal transfer element configured to isolate the first substrate; and

providing second process gasses into the first thermal treatment chamber during a second part of the first COR procedure, wherein the second process gasses include nitrogen (N₂) at a third flow rate between approximately 10 sccm and approximately 50 sccm, wherein the first thermal treatment module comprises a second gas distribution system configured to provide the second process gasses into the first thermal treatment chamber, the second part lasting between approximately 30 seconds and approximately 500 seconds.

14. A method of performing a Spacer-Optimization (S-O) procedure comprising:

obtaining first real-time S-O data for a first substrate from one or more subsystems in an Integrated-Processing System (IPS) comprising one or more etch subsystems, one or more Chemical Oxide Removal (COR) subsystems, one or more deposition subsystems, one or more evaluation subsystems, and a transfer subsystem, the transfer subsystem being coupled to the one or more etch subsystems, the or more COR subsystems, the one or more deposition subsystems, and the one or more evaluation subsystems, wherein the first substrate comprises a first set of gate structures and the first real-time S-O data comprises first measurement data for one or more spacer-related evaluation features on the first substrate;

depositing a first oxide spacer, wherein the first substrate is transferred to a first deposition subsystem in the IPS and a first Low Temperature Oxide (LTO) procedure is performed;

etching the first substrate, wherein the first substrate is transferred from the first deposition subsystem to a first etch subsystem in the IPS and a partial-etch procedure is performed;

obtaining first integrated metrology (IM) data for a first partially-etched substrate, wherein the first partially-etched substrate is transferred from the first etch subsystem to a first evaluation subsystem in the IPS and a partially-etched spacer layer is measured, wherein the first IM data comprises real-time data for a first partially-etched oxide spacer on the first substrate and includes real-time critical dimension (CD) data, real-time sidewall angle (SWA) data, real-time material data, real-time layer data, real-time optical data, or real-time structure data, or any combination thereof;

determining first feedback data and/or first feed forward data in real-time using the first real-time S-O data, the first IM data, or required product data, or any combination thereof;

performing additional processes using the first substrate and updating the partial-etch procedure using the first feedback data when the first feedback data is less than or equal to a first product limit; and

storing the first substrate and the data associated with the first substrate, when the first feedback data is greater than the first product limit.

15. The method of claim 14, further comprising:

establishing first CD data and first sidewall angle data for a first gate structure;

determining a first multi-input multi-output (MIMO) model for predicting data for the first oxide spacer in a partially-etched layer on the first substrate using the first CD data and the first sidewall angle data for the first gate structure; and

establishing first predicted CD data and first predicted sidewall angle data for a first partially-etched oxide spacer layer using the first CD data, the first sidewall angle data, and the first MIMO model;

determining the first feedback data using the first measurement data, the first predicted CD data for the first partially-etched oxide spacer, and the first predicted sidewall angle data for the first partially-etched oxide spacer.

16. The method of claim 14, wherein the first set of gate structures include Negative Channel Field Effect Transistor (nFET) structures, Positive Channel Field Effect Transistor (PFET) structures, dual-gate structures, and tri-gate structures.

17. The method of claim 14, wherein a first set of S-O data comprises first spacer layer data, first gate oxide layer data, first undoped poly-Si layer data, first doped poly-Si layer data, first nitride cap layer data, first oxide layer data, or first bottom anti-reflective coating (BARC) layer data, or any combination thereof, and a second set of S-O data comprises second spacer layer data, second gate oxide layer data, second undoped poly-Si layer data, second nitride cap layer data, second oxide layer data, or second BARC layer data, or any combination thereof.

18. The method of claim 14, wherein the partial-etch procedure is performed using a chamber pressure between approximately 15 mTorr and approximately 25 mTorr, wherein a top electrode RF power level is between approximately 475 watts and approximately 525 watts, a bottom electrode RF power level is between approximately 90 watts and approximately 110 watts, a first flow rate for a first process gas is between approximately 10 sccm and approximately 30 sccm, a second flow rate for a second process gas is between approximately 700 sccm and approximately 900 sccm, a first backside pressure is between approximately 8 Torr and approximately 12 Torr proximate a center of the first substrate, a second backside pressure is between approximately 20 Torr and approximately 30 Torr proximate an edge of the first substrate, and a substrate holder temperature is between approximately 25 degrees C. and approximately 35 degrees C.

19. The method of claim 18, wherein the first process gas comprises C₄F₈ and the second process gas comprises Argon (Ar).

20. The method of claim 14, further comprising:

executing a COR process recipe, wherein exposed surfaces on the first substrate are chemically treating using a first process gas, and a solid reaction product is formed on at least one exposed surface of the first substrate, wherein the first process gas comprises Ar, HF and NH₃, and an Ar flow rate is between approximately 15 sccm and approximately 35 sccm, a HF flow rate is between approximately 40 sccm and approximately 60 sccm, and an NH₃, flow rate is between approximately 15 sccm and approximately 35 sccm, wherein a COR chamber top wall temperature is between approximately 30 degrees Celsius and approximately 70 degrees Celsius, a COR chamber side wall temperature is between approximately 30 degrees Celsius and approximately 70 degrees Celsius, a substrate holder temperature is between approximately 40 degrees Celsius and approximately 60 degrees Celsius, a COR chamber pressure is between approximately 5 mTorr and approximately 15 mTorr, and a COR process time is between approximately 100 seconds and approximately 140 seconds; and

executing a post heat treatment (PHT) process recipe, wherein the solid reaction product is evaporated using a second process gas, wherein the second process gas comprises N₂ and a N₂ flow rate is between approximately 800 sccm and approximately 1000 sccm, wherein a PHT chamber top wall temperature is between approximately 70 degrees Celsius and approximately 90 degrees Celsius, a PHT chamber side wall temperature is between approximately 70 degrees Celsius and approximately 90 degrees Celsius, a PHT substrate holder temperature is between approximately 120 degrees Celsius and approximately 180 degrees Celsius, a PHT chamber pressure is between approximately 650 mTorr and approximately 700 mTorr, and a PHT process time is between approximately 100 seconds and approximately 140 seconds.