APPARATUS FOR FABRICATING A HIGH DIELECTRIC CONSTANT TRANSISTOR GATE USING A LOW ENERGY PLASMA SYSTEM

Abstract

The present invention generally provides methods and apparatuses that are adapted to form a high quality dielectric gate layer on a substrate. Embodiments contemplate a method wherein a metal plasma treatment process is used in lieu of a standard nitridization process to form a high dielectric constant layer on a substrate. Embodiments further contemplate an apparatus adapted to “implant” metal ions of relatively low energy in order to reduce ion bombardment damage to the gate dielectric layer, such as a silicon dioxide layer and to avoid incorporation of the metal atoms into the underlying silicon. In general, the process includes the steps of forming a high-k dielectric and then terminating the surface of the deposited high-k material to form a good interface between the gate electrode and the high-k dielectric material. Embodiments of the invention also provide a cluster tool that is adapted to form a high-k dielectric material, terminate the surface of the high-k dielectric material, perform any desirable post treatment steps, and form the polysilicon and/or metal gate layers.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.

FIG. 1A (prior art) is a schematic cross-sectional view of FET and can be produced in accordance with the present invention.

FIG. 1B (prior art) is a graph showing nitrogen concentration profiles, based on secondary ion mass spectroscopy data, for a conventional thermal nitridation process and for a conventional plasma nitridation process.

FIG. 2A is a process flow diagram illustrating a method for fabricating a gate dielectric of a field effect transistor in accordance with one embodiment of the present invention.

FIG. 2B is a process flow diagram illustrating a method for fabricating a gate dielectric of a field effect transistor in accordance with one embodiment of the present invention.

FIG. 2C is a process flow diagram illustrating a method for fabricating a gate dielectric of a field effect transistor in accordance with one embodiment of the present invention.

FIG. 2D is a process flow diagram illustrating a method for fabricating a gate dielectric of a field effect transistor in accordance with one embodiment of the present invention.

FIG. 2E is a process flow diagram illustrating a method for fabricating a gate dielectric of a field effect transistor in accordance with one embodiment of the present invention.

FIG. 2F is a process flow diagram illustrating a method for fabricating a gate dielectric of a field effect transistor in accordance with one embodiment of the present invention.

FIGS. 3A-3F illustrate a series of schematic cross-sectional views of a substrate upon which a gate structure is fabricated using the method of FIG. 2A.

FIG. 4A illustrates a schematic cross-sectional view of a plasma treatment chamber according to another embodiment of the invention.

FIG. 4B illustrates a schematic cross-sectional view of a plasma treatment chamber according to another embodiment of the invention.

FIG. 4C illustrates a schematic cross-sectional view of a plasma treatment chamber according to one embodiment of the invention.

FIG. 4D is a table of theoretical calculations that illustrate the various properties of a hafnium and lanthanum targets according to one embodiment of the invention.

FIG. 4E is a graph of self-bias voltage versus frequency for a capacitively coupled plasma processing chamber according to one embodiment of the invention.

FIG. 4F illustrates a schematic cross-sectional view of a plasma processing chamber according to one embodiment of the invention.

FIG. 4G illustrates a schematic cross-sectional view of a plasma processing chamber according to one embodiment of the invention.

FIG. 4H illustrates a schematic cross-sectional view of a plasma processing chamber according to one embodiment of the invention.

FIG. 5A illustrates the timing of the off-cycle of the pulsed RF/VHF excitation energy and pulsed DC voltage applied to a target according to another embodiment of the invention.

FIG. 5B illustrates the timing of the off-cycle of the pulsed RF/VHF excitation energy and pulsed DC voltage applied to a target according to another embodiment of the invention.

FIG. 5C illustrates the timing of the off-cycle of the pulsed DC voltage and continuous RF/VHF energy applied to a target according to another embodiment of the invention.

FIG. 6A is a process flow diagram illustrating a method 100 for fabricating a gate dielectric of a field effect transistor in accordance with one embodiment of the present invention.

FIGS. 6B-6G illustrate a series of schematic cross-sectional views of a substrate upon which a gate structure is fabricated using the method of FIG. 6A.

FIG. 7 illustrates an integrated processing system according to one embodiment of the invention.

Claims

1. An apparatus for forming a high-K dielectric layer, comprising: a transfer chamber having one or more walls that form a transferring region and a transfer robot positioned in the transferring region;a plasma nitride chamber coupled to the transfer chamber and configured to form a nitride on a surface of a substrate in a first processing region of the nitride chamber, wherein the plasma nitride chamber comprises: an RF source that is in electrical communication with the first processing region; anda nitrogen containing gas source in selective communication with the first processing region; anda first low energy plasma processing chamber coupled to the transfer chamber in transferable communication with the robot, wherein the first low energy plasma processing chamber comprises: one or more walls forming a second processing region;a target having a surface exposed to the second processing region, wherein the target comprises a first material;a first RF generator is adapted to supply energy to the second processing region at a first RF frequency; anda substrate support positioned in the second processing region.

2. The apparatus of claim 1, further comprising a polysilicon deposition chamber that is in transferable communication with transfer region and is configured to deposit a polysilicon layer on the surface of the substrate.

3. The apparatus of claim 1, further comprising an annealing chamber that is in transferable communication with transfer region and is configured to anneal the substrate at a temperature between about 800° C. and about 1100° C.

4. The apparatus of claim 1, further comprising a processing chamber that is in transferable communication with transfer region and is configured to form a high-k dielectric layer on a surface of the substrate using a CVD or ALD deposition process.

5. The apparatus of claim 1, further comprising: a second low energy plasma processing chamber that is in transferable communication with the robot, wherein the second low energy plasma processing chamber comprises: one or more walls forming a third processing region;a second target having a surface exposed to the third processing region;a second RF generator that is configured to supply energy to the second processing region at a second RF frequency; anda substrate support positioned in the third processing region.

6. The apparatus of claim 1, wherein the target in the second low energy plasma processing chamber contains a metal selected from a group consisting of aluminum, lanthanum, and hafnium.

7. The apparatus of claim 1, wherein the target in the first low energy plasma processing chamber contains a metal selected from a group consisting of aluminum, lanthanum, and hafnium.

8. The apparatus of claim 1, wherein the first low energy plasma processing chamber further comprises a DC voltage source coupled to the target.

9. The apparatus of claim 8, further comprising: a computer-readable program containing instructions when executed by a controller, direct the operation of the first low energy plasma processing chamber to perform a method comprising: (i) pulsing RF energy delivered from the first RF generator; and(ii) pulsing the target with a DC voltage delivered from the DC voltage source.

10. The apparatus of claim 1, wherein the first RF frequency is between about 1 MHz and about 200 MHz.

11. The apparatus of claim 1, further comprising: a computer-readable program containing instructions when executed by a controller, comprising: directing the operation of the first low energy plasma processing chamber to perform a method comprising delivering RF energy from the first RF generator at a first RF frequency and a first RF power to a processing region so that the first material of the target can be disposed within a dielectric layer formed on a surface of a substrate; anddirecting the operation of the a plasma nitride chamber to perform a method comprising exposing the dielectric layer and the first material to an RF plasma comprising nitrogen.

12. An apparatus for forming a high-k dielectric layer, comprising: one or more walls forming a processing region;a target having a surface that is exposed to the processing region;a substrate support having at least one surface that is facing the processing region, wherein the substrate support is adapted to support a substrate having a dielectric layer formed on a surface of the substrate;a first generator that is in electrical communication with the target and is configured to maintain a capacitively coupled plasma in the processing region by delivering a first amount of energy at a frequency which is between about 1 MHz and about 200 MHz to the target, wherein the first generator is configured to create a bias on a surface of the target so that material can be sputtered therefrom; anda controller configured to control the frequency delivered by the first generator to the target.

13. The apparatus of claim 12, wherein the frequency is between about 30 MHz and about 60 MHz.

14. The apparatus of claim 12, wherein the first amount of energy is delivered at a first power that is between about 0.1 and about 1000 W.

15. The apparatus of claim 12, wherein the target further comprises at least one of hafnium, lanthanum, aluminum, titanium, zirconium, strontium, lead, yttrium, and barium.

16. The apparatus of claim 12, further comprising a second generator that is in electrical communication with the target and is configured to generate a capacitively coupled plasma in the processing region by delivering a second amount of energy at a second frequency to the target, wherein the first frequency is lower than the second frequency.

17. The apparatus of claim 16, further comprising a switch that is adapted to selectively couple the first or second generator to the target.

18. The apparatus of claim 16, wherein the second frequency is between about 27 MHz and about 100 MHz.

19. The apparatus of claim 16, further comprising a temperature controller capable of maintaining a temperature of the substrate support between about 20° C. and about 800° C.

20. The apparatus of claim 12, further comprising a second generator that is electrical communication with an electrode and the substrate support, wherein the second generator is adapted to provide a RF bias to a substrate positioned on the substrate support during processing.

21. The apparatus of claim 12, further comprising a grounded collimator positioned between the target and the substrate support.

22. An apparatus for forming a high-k dielectric layer, comprising: one or more walls forming a processing region;a target having a surface exposed to the processing region and in electrical communication with a DC power supply;a first coil in electrical communication with the processing region and a first generator, wherein the first coil and the first generator are configured to generate a plasma in the processing region adjacent to the surface of the target; anda substrate support positioned in the processing region.

23. The apparatus of claim 22, wherein the material from which the target is made contains an element selected from a group hafnium, lanthanum, aluminum, titanium, zirconium, strontium, lead, yttrium, and barium.

24. The apparatus of claim 22, further comprising a temperature controller capable of maintaining a temperature of the substrate support between about 20° C. and about 800° C.

25. The apparatus of claim 22, further comprising a second generator that is electrical communication with an electrode and the substrate support, wherein the second generator is configured to provide a RF bias to a substrate positioned on the substrate support during processing.

26. The apparatus of claim 22, further comprising a grounded collimator that positioned between the target and the substrate support.

27. The apparatus of claim 22, further comprising a second generator that is in electrical communication with the target, wherein the second generator is configured to maintain a capacitively coupled plasma in the processing region by delivering a first amount of energy at an RF frequency which is between about 1 MHz and about 200 MHz to the target and the second coil has a desired inductance.

28. The apparatus of claim 22, further comprising a second coil that is electrically coupled to first generator and the target, wherein the first generator is configured to form an inductively coupled plasma in the processing region using the first coil and a capacitively coupled plasma in the processing region using the second coil and the target by delivering a first amount of energy at an RF frequency.