Fine tuning highly resistive substrate resistivity and structures thereof

• US 8,679,863 B2
• Filed: 03/15/2012
• Issued: 03/25/2014
• Est. Priority Date: 03/15/2012
• Status: Active Grant

• Current Assignee: GlobalFoundries, Inc.
• Original Assignee: International Business Machines Corporation
• Inventors: Gambino, Jeffrey P., Liu, Derrick, Martin, Dale W., Pfeiffer, Gerd
• Primary Examiner(s): Nikmanesh, Seahvosh
• Assistant Examiner(s): Seven, Evren
• Application Number:
  US13/420,637
• Publication Number:
  US 20130244348A1
• Time in Patent Office: 740 Days
• Field of Search: 438/663, 438/3, 438/10
• US Class Current: 438/10
• CPC Class Codes: H01L 21/324 Thermal treatment for modifying the properties of semiconductor bodies, e.g. annealing, sintering H01L21/20 - H01L21/288 and H01L21/302 - H01L21/322 take precedence
• CPC Class Codes: H01L 22/14 for electrical parameters, e.g. resistance, deep-levels, CV, diffusions by electrical means
• CPC Class Codes: H01L 22/20 Sequence of activities consisting of a plurality of measurements, corrections, marking or sorting steps
• 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

Methods are provided for fine tuning substrate resistivity. The method includes measuring a resistivity of a substrate after an annealing process, and fine tuning a subsequent annealing process to achieve a target resistivity of the substrate. The fine tuning is based on the measured resistivity.

Claims

1. A method comprising:

performing back end of the line (BEOL) processes on a substrate;

measuring a first resistivity of the substrate after performing an annealing process of the BEOL processes;

continuing to perform the BEOL processes on the substrate after the measuring the first resistivity;

measuring a second resistivity of the substrate after performing a subsequent annealing process of the continued BEOL processes;

determining whether the second resistivity of the substrate is at a target resistivity; and

when the second resistivity is not at the target resistivity, fine tuning a final annealing process to achieve the target resistivity by extrapolating correlation data of historical substrates with known resistivities after annealing processes to a resistivity change between the first resistivity and the second resistivity.

2. The method of claim 1, wherein the measuring the first resistivity is provided after completion of an initial BEOL process comprising a metallization layer process.

3. The method of claim 2, wherein the fine tuning comprises adjusting the final annealing process of the substrate to a predetermined temperature and time to achieve the target resistivity.

4. The method of claim 3, wherein the correlation data further comprises oxygen concentrations at a known anneal temperature and time.

5. The method of claim 1, further comprising adjusting anneal rates for one or more metallization layer processes based on the target resistivity of the substrate and an amount of metallization layers required for a structure.

6. The method of claim 5, wherein the fine tuning comprises adjusting an annealing temperature after completion of a final metallization layer.

7. The method of claim 5, wherein the fine tuning comprises adjusting an annealing temperature based on the second resistivity of the substrate after any of the one or more of metallization layer processes.

8. The method of claim 7, wherein the fine tuning comprises providing the final annealing process at a predetermined temperature and time based on the correlation data.

9. The method of claim 8, wherein the correlation data further comprises oxygen concentrations at a known anneal temperature and time for several different resistances.

10. The method of claim 7, wherein the fine tuning comprises adjusting the annealing rates based on a measured resistivity of the substrate after each of the metallization layer processes.

11. A method comprising:

obtaining a initial resistivity of a substrate;

performing back end of the line (BEOL) processes on the substrate after obtaining the initial resistivity, wherein the performing the BEOL processes comprises depositing metallization layers on the substrate using annealing processes;

after a first metallization layer is deposited on the substrate, measuring a starting resistivity of the substrate;

after a second metallization layer is deposited on the substrate, measuring a subsequent resistivity of the substrate; and

adjusting a final anneal process of the substrate to a predetermined temperature and time to achieve a target resistivity by extrapolating correlation data of historical substrates with known resistivities after annealing processes to a resistivity change between the initial resistivity, the starting resistivity, and the subsequent resistivity.

12. The method of claim 11, further comprising obtaining a base line resistivity after the front end of the line processes are performed on the substrate.

13. The method of claim 11, wherein the starting resistivity is obtained after an initial BEOL processes on the substrate.

14. The method of claim 13, wherein the initial BEOL processes includes the deposition of the first metallization layer and a contact.

15. The method of claim 14, further comprising obtaining substrate resistivity measurements after each BEOL annealing process.

16. The method of claim 15, wherein the adjusting of the final anneal process is performed after a final metallization layer is deposited on the substrate.

17. The method of claim 15, wherein the extrapolated correlation data further comprises known anneal temperatures and times for the annealing processes of the metallization layers.

18. A method comprising:

determining a target resistivity of a substrate after a final annealing process;

determining how many metallization layers are required for a particular build structure on the substrate;

determining required anneal rates for each back end of the line (BEOL) process that is used for processing each of the determined metallization layers to obtain the target resistivity;

annealing each of the determined metallization layers using the determined anneal rates;

measuring the resistivity of the substrate after each annealing of the determined metallization layers or after annealing any combination of the determined metallization layers; and

adjusting the anneal rates after the annealing of each or any combination of the determined metallization layers to achieve the target resistivity,

wherein the required anneal rates and adjusted anneal rates are determined by extrapolating correlation data of historical substrates with known resistivities after annealing processes to a resistivity change between an initial resistivity of the substrate and the measured resistivity of the substrate.

19. The method of claim 18, further comprising obtaining a starting resistivity of the substrate after a first metallization layer process, wherein the adjusting is based on the initial resistivity, the measured resistivity, and the starting resistivity.

20. A method comprising:

providing a substrate having a first resistivity value;

forming structures upon the substrate through annealing processes;

obtain a base line resistivity value of the substrate after the annealing processes;

performing back end of the line (BEOL) processes on the substrate after the obtaining of the baseline resistivity, wherein the BEOL process comprise subsequent annealing processes that change the base line resistivity value of the substrate to a first resistivity value;

measuring the first resistivity value of the substrate after performing a first subsequent annealing process of the BEOL processes;

continuing to perform the BEOL processes on the substrate after the measuring the first resistivity value;

measuring a second resistivity value of the substrate after performing a second subsequent annealing process of the continued BEOL processes;

determining whether the second resistivity value of the substrate is at a target resistivity value; and

when the second resistivity value is not at the target resistivity, modifying a dopant concentration in the substrate to change the second resistivity value to the target resistivity value through BEOL annealing processes,

wherein the modifying is performed by extrapolating correlation data of historical substrates with known resistivities after annealing processes to a resistivity change between the first resistivity value, the base line resistivity value, the first resistivity value, and the second resistivity value.

21. The method of claim 20, wherein the modifying the dopant concentration comprises an oxygen content.

22. A computer program product comprising a computer usable tangible storage medium having readable program code embodied in the storage medium which can be read by a computer, the computer program product includes at least one component operable to:

receive a base line resistivity of a substrate;

measure a first resistivity of the substrate after a first annealing process of back end of line (BEOL) processes is performed on the substrate;

measure a second resistivity of the substrate after a second annealing process of BEOL processes is performed on the substrate;

determining whether the second resistivity of the substrate is at a target resistivity; and

when the second resistivity is not at the target resistivity, extrapolate a final anneal rate for the substrate to achieve the target resistivity of the substrate,

wherein the extrapolating is performed by extrapolating correlation data of historical substrates with known resistivities, anneal times, and temperatures after annealing processes to a resistivity change between the base line resistivity, the first resistivity, and the second resistivity.