Liquid phase atomic layer deposition

Abstract

A processing system and method for depositing a film on a substrate by liquid phase ALD is disclosed in various embodiments. The method includes providing the substrate in a process chamber, spinning on the substrate a first reactant in a first liquid to form a self-limiting layer of the first reactant on the substrate, spinning on the substrate a second reactant in a second liquid, where the second reactant reacts with the self-limiting layer of the first reactant on the substrate to form a film on the substrate, and repeating the spinning steps at least once until the film has a desired thickness. Other embodiments of the invention further include rinsing the substrate to remove excess first and second reactants from the substrate, and heat-treating the substrate during and/or following the film deposition.

Claims

1. A method for processing a substrate, the method comprising: providing the substrate in a process chamber; spinning onto the substrate a first reactant in a first liquid to deposit a self-limiting layer of the first reactant on the substrate, wherein the first reactant includes trimethylaluminum, tris(bis(trimethylsilyl)amido)lanthanum, or tetrakis(dimethylamido)titanium; thereafter, spinning onto the substrate a second reactant in a second liquid, wherein the second reactant reacts with the deposited self-limiting layer of the first reactant on the substrate to form a deposited film on the substrate; and sequentially repeating the spinning steps at least once until the deposited film has a desired thickness.

2. The method of claim 1, further comprising heat-treating the substrate after one or more of the spinning steps.

3. The method of claim 1, further comprising heat-treating the substrate after the film has been deposited on the substrate with the desired thickness.

4. The method of claim 1, further comprising rinsing the substrate with a rinsing liquid after one or more of the spinning steps.

5. The method of claim 4, wherein the rinsing liquid contains octane or pyridine.

6. The method of claim 4, further comprising heat-treating the substrate after the rinsing step.

7. The method of claim 1, further comprising exposing the substrate to a reducing atmosphere after one or more of the spinning steps.

8. The method of claim 7, wherein the reducing atmosphere includes hydrogen, ammonia, or a combination thereof.

9. The method of claim 7, wherein the exposing the substrate to a reducing atmosphere further comprises heat-treating the substrate.

10. The method of claim 1, wherein the second reactant includes water, ethylene glycol, ethane-1,2-dithiol, or ammonia.

11. The method of claim 1, wherein the first liquid, the second liquid, or both the first and second liquids, contain octane or pyridine.

12. The method of claim 1, wherein the deposited self-limiting layer consists of the first reactant, a flow of the first liquid into the process chamber for spinning the first reactant onto the substrate is stopped before spinning the second reactant onto the substrate, and a flow of the second liquid into the process chamber for spinning the second reactant onto the substrate is stopped before sequentially repeating the spinning steps.

13. A method for processing a substrate, the method comprising: providing the substrate in a process chamber; spinning on the substrate a first reactant in a first liquid to form a self-limiting layer of the first reactant on the substrate; thereafter, spinning on the substrate a second reactant in a second liquid, wherein the second reactant reacts with the self-limiting layer of the first reactant on the substrate to form a film on the substrate; and sequentially repeating the spinning steps at least once until the film has a desired thickness, wherein the film contains Al.sub.2O.sub.3, Alucone, Thio-Alucone, La.sub.2O.sub.3, or TiN.

14. The method of claim 13, wherein the first reactant includes trimethylaluminum, tris(bis(trimethylsilyl)amido)lanthanum, or tetrakis(dimethylamido)titanium.

15. The method of claim 13, further comprising heat-treating the substrate after one or more of the spinning steps, or heat-treating the substrate after the film has been deposited on the substrate with the desired thickness.

16. A method for processing a substrate, the method comprising: providing the substrate in a process chamber; spinning on the substrate a first reactant in a first liquid to form a self-limiting layer of the first reactant on the substrate, the first reactant containing a metal element; rinsing the substrate to remove excess of the first reactant from the substrate; thereafter, spinning on the substrate a second reactant in a second liquid, wherein the second reactant reacts with the self-limiting layer of the first reactant on the substrate to form a film on the substrate; rinsing the substrate to remove excess of the second reactant from the substrate; and sequentially repeating the spinning and rinsing steps at least once until the film has a desired thickness, wherein the film contains Al.sub.2O.sub.3, Alucone, Thio-Alucone, La.sub.2O.sub.3, or TiN.

17. The method of claim 16, further comprising heat-treating the substrate after one or more of the spinning steps.

18. The method of claim 16, further comprising heat-treating the substrate after the film has been deposited on the substrate with the desired thickness.

19. The method of claim 16, wherein the first reactant includes trimethylaluminum, tris(bis(trimethylsilyl)amido)lanthanum, or tetrakis(dimethylamido)titanium, and wherein the second reactant includes water, ethylene glycol, ethane-1,2-dithiol, or ammonia.

20. A method for processing a substrate, the method comprising: providing the substrate in a process chamber; spinning on the substrate a first reactant in a first liquid to form a self-limiting layer of the first reactant on the substrate; spinning on the substrate a second reactant in a second liquid, wherein the second reactant reacts with the self-limiting layer of the first reactant on the substrate to form a film on the substrate; repeating the spinning steps at least once until the film has a desired thickness; and optionally, rinsing the substrate with a rinsing liquid after one or more of the spinning steps, wherein one or any combination of the first liquid, the second liquid, or the rinsing liquid contain octane or pyridine, and wherein the film contains Al.sub.2O.sub.3, Alucone, Thio-Alucone, La.sub.2O.sub.3, or TiN, or wherein the first reactant includes trimethylaluminum, tris(bis(trimethylsilyl)amido)lanthanum, or tetrakis(dimethylamido)titanium.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the drawings:

(2) FIG. 1 is a process flow diagram for processing a substrate according to an embodiment of the invention;

(3) FIG. 2 is a process flow diagram for processing a substrate according to an embodiment of the invention; and

(4) FIG. 3 schematically shows a processing system for processing a substrate according to an embodiment of the invention.

DETAILED DESCRIPTION OF SEVERAL EMBODIMENTS

(5) Embodiments of the invention provide a processing system and method for depositing a film on a substrate by liquid phase ALD. In some examples, the film may be a high-k film.

(6) FIG. 1 is a process flow diagram 1 for processing a substrate according to an embodiment of the invention. In step 100, the method includes providing a substrate in a process chamber of a processing system. An exemplary processing system is schematically shown in FIG. 3. The processing system may be configured to process 200 mm substrates, 300 mm substrates, or larger-sized substrates. In fact, it is contemplated that the processing system may be configured to process substrates, wafers, or LCDs regardless of their size, as would be appreciated by those skilled in the art. Therefore, while aspects of embodiments of the invention will be described in connection with the processing of a semiconductor substrate, the invention is not limited solely thereto.

(7) In step 102, the method includes spinning on the substrate a first reactant in a first liquid. The first reactant may be an organic compound that contains one or more a metal elements from the Periodic Table of the Elements. Non-limiting examples of the first reactant include trimethylaluminum (TMA), tris(bis(trimethylsilyl)amido)lanthanum, and tetrakis(dimethylamido)titanium (TDMAT). The first liquid can be an organic compound that readily dissolves the first reactant and facilitates transport of the first reactant to the substrate in the process chamber. Non-limiting examples of the first liquid include octane and pyridine. Step 102 may be performed using a liquid delivery nozzle positioned above an upper surface of the rotating substrate. Upon coming in contact with the substrate, a self-limited layer of the first reactant or reaction products of the first reactants is formed on the substrate, and excess first reactant in the first liquid is spun off the substrate.

(8) In step 104, the method includes rinsing the substrate with a rinsing liquid. The substrate may be spinning during the rinsing and the rinsing can aid in removing excess first reactant and reaction by-products from the substrate. Non-limiting examples of the first liquid include octane and pyridine.

(9) In step 106, the method includes spinning on the substrate a second reactant in a second liquid. The second reactant may be an oxidizing agent or a reducing agent. Non-limiting examples of the second reactant include water, ethylene glycol, ethane-1,2-dithiol, or ammonia. The second liquid may be the same as the first liquid. The second liquid can be an organic compound that readily dissolves the second reactant and facilitates transport of the second reactant to the substrate in the process chamber. Non-limiting examples of the second liquid include octane and pyridine. Step 106 may be performed using a liquid delivery nozzle positioned above an upper surface of the rotating substrate. Upon coming in contact with the substrate, the second reactant reacts with the self-limited layer of the first reactant or reaction products of the first reactants, and excess second reactant in the second liquid is spun off the substrate. Step 106 forms a film or a portion of a film that provides a suitable surface for repeating steps 102 and 106 at least once until the film has a desired thickness. This is shown by process arrow 110.

(10) In step 108, the method includes rinsing the substrate with a rinsing liquid. The substrate may be spinning during the rinsing and the rinsing can aid in removing second reactant and reaction by-products from the substrate. Non-limiting examples of the rinsing liquid include octane and pyridine.

(11) According to some embodiments of the invention, the substrate may be heat-treated after one or more of the spinning steps 102 and 106 and/or after one or more of the rinsing steps 104 and 108. The heat-treating may be performed by increasing the substrate temperature above the temperature of steps 102-108. According to one embodiment, the substrate may be heat-treated after several cycles of steps 102-104 and/or when the film has been deposited on the substrate with the desired thickness. The heat-treating may be carried out at a substrate temperature that is sufficiently high for curing the film.

(12) According to some embodiments of the invention, the substrate may be exposed to a reducing atmosphere after one or more of the spinning steps 102 and 106 and/or after one or more of the rinsing steps 104 and 108. The reducing atmosphere can contain hydrogen, ammonia, or a combination thereof. The exposure to the reducing atmosphere may be combined with the heat-treating described above. According to one embodiment, the substrate may be exposed to the reducing atmosphere after several cycles of steps 102-104 and/or when the film has been deposited on the substrate with the desired thickness.

(13) FIG. 2 is a process flow diagram 2 for processing a substrate according to an embodiment of the invention. The process flow diagram 2 is similar to the process flow diagram 1 of FIG. 1 but the steps 104 and 108 of rinsing the substrate with a rinsing liquid are omitted. The process flow diagram 2 includes, in step 200, providing the substrate in a process chamber, in step 202, spinning on the substrate a first reactant in a first liquid to form a self-limiting layer of the first reactant on the substrate, in step 204, spinning on the substrate a second reactant in a second liquid, where the second reactant reacts with the self-limiting layer of the first reactant on the substrate to form a film on the substrate, and in step 206, repeating the spinning steps at least once until the film has a desired thickness.

Example 1: Deposition of an Al2O3 Film

(14) The method includes, spinning on a substrate a solution of trimethylaluminum (TMA) reactant in octane liquid, rinsing the substrate with octane rinsing liquid, spinning on the substrate a solution of water reactant in pyridine liquid, and rinsing the substrate with octane rinsing solution. These steps may be performed a plurality of times (e.g., 10 times) under an inert atmosphere (e.g., Ar or N.sub.2). Thereafter, the Al.sub.2O.sub.3 film may be heat-treated in vacuum at 300 C. for 1 minute.

Example 2: Metalorganic FilmAlucone (Aluminum Alkoxide Polymer)

(15) The method includes, spinning on a substrate a solution of trimethylaluminum (TMA) reactant in octane liquid, rinsing the substrate with octane rinsing liquid, spinning on the substrate a solution of ethylene glycol reactant in octane liquid, and rinsing the substrate with octane rinsing solution. These steps may be performed a plurality of times (e.g., 10 times) under an inert atmosphere (e.g., Ar or N.sub.2). Thereafter, the alucone film may be heat-treated in vacuum.

Example 3: Metalorganic FilmThio-Alucone (Alucone-Like Film with Sulfur in the Place of Oxygen)

(16) The method includes, spinning on a substrate a solution of trimethylaluminum (TMA) reactant in octane liquid, rinsing the substrate with octane rinsing liquid, spinning on the substrate a solution of ethane-1,2-dithiol reactant in octane liquid, and rinsing the substrate with octane rinsing solution. These steps may be performed a plurality of times (e.g., 10 times) under an inert atmosphere (e.g., Ar or N.sub.2). Thereafter, the thio-alucone film may be heat-treated in vacuum.

Example 4: La2O3 Film

(17) The method includes, spinning on a substrate a solution of tris(bis(trimethylsilyl)amido)lanthanum reactant in octane liquid, rinsing the substrate with octane rinsing liquid, spinning on the substrate a solution of water reactant in pyridine liquid, and rinsing the substrate with octane rinsing solution. These steps may be performed a plurality of times (e.g., 10 times) under an inert atmosphere (e.g., Ar or N.sub.2). Thereafter, the La.sub.2O.sub.3 film may be heat-treated in vacuum at 300 C. for 1 minute, and the deposition process repeated until the La.sub.2O.sub.3 film has a desired thickness.

Example 5: Reduced Metal Nitride Film

(18) The method includes, spinning on a substrate a solution of tetrakis(dimethylamido)titanium (TDMAT) reactant in octane liquid, rinsing the substrate with octane rinsing liquid, spinning on the substrate a solution of ammonia reactant in pyridine liquid, and rinsing the substrate with octane rinsing solution. These steps may be performed a plurality of times (e.g., 5 times) under an inert atmosphere (e.g., Ar or N.sub.2). Thereafter, the film may be exposed to plasma-excited H.sub.2 gas and while heat-treated at 200 C. The deposition process may be repeated until the TiN film has a desired thickness.

(19) FIG. 3 schematically shows a processing system 300 for processing a substrate according to an embodiment of the invention. The processing system 300 may be a semi-closed spin-on deposition system similar to what the semiconductor industry currently employs for coating substrates (wafers) with photoresist layers. The semi-closed configuration allows fume control and minimizes exhaust volume. The processing system 300 contains a process chamber 310 that includes a substrate holder 312 for supporting, heating, and rotating (spinning) a substrate 302, a rotating means 318 (e.g., a motor), and a liquid delivery nozzle 314 configured for providing a processing liquid 316 to an upper surface of the substrate 302. Liquid supply systems 304, 306 and 308 supply different processing liquids to the liquid delivery nozzle 314. The different processing liquids can, for example, include a first reactant in a first liquid, a second reactant in a second liquid, and a rinsing liquid. According to other embodiments, the processing system 300 may include additional liquid delivery nozzles (not shown) for providing different liquids to the substrate. Exemplary rotating speeds can be between about 500 rpm and about 1500 rpm, for example 1000 rpm, during exposure of the upper surface of the substrate 302 to the processing liquid 316.

(20) The processing system 300 further includes a controller 320 that can be coupled to and control the process chamber 310, the liquid supply systems 304, 306 and 308, the liquid delivery nozzle 314, the rotating means 318, means for heating the substrate holder 312. The substrate 302 may be under an inert atmosphere during the film deposition. The processing system 300 may be configured to process 200 mm substrates, 300 mm substrates, or larger-sized substrates. The processing system 300 may be configured to process substrates, wafers, or LCDs regardless of their size, as would be appreciated by those skilled in the art. Therefore, while aspects of the invention will be described in connection with the processing of a semiconductor substrate, the invention is not limited solely thereto.

(21) A processing system and method for depositing a film on a substrate by liquid phase ALD have been disclosed in various embodiments. The foregoing description of the embodiments of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. This description and the claims following include terms that are used for descriptive purposes only and are not to be construed as limiting. Persons skilled in the relevant art can appreciate that many modifications and variations are possible in light of the above teaching. Persons skilled in the art will recognize various equivalent combinations and substitutions for various components shown in the Figures. It is therefore intended that the scope of the invention be limited not by this detailed description, but rather by the claims appended hereto.