TWI863231B - Method of replacing periodic maintenance with plasma assisted process - Google Patents

Abstract

The invention is a method of replacing periodic maintenance with a plasma-assisted process. It performs a first atomic layer deposition on a substrate on a carrier to form a thin film on the substrate, and determines the thickness of an insulating film on the carrier is greater than a preset value. A second atomic layer deposition is performed on the carrier without the substrate, and a conductive film is formed on the insulating film of the carrier, so that the carrier has conductive properties. Then the substrate can be placed on the carrier, and the first atomic layer deposition is performed on the substrate on the carrier. Through the method described in the invention, the cycle of cleaning and maintaining the carrier can be greatly extended, and it is beneficial to improve the efficiency of equipment use.

Description

A method of replacing periodic maintenance with a plasma-assisted process

The present invention relates to a method of replacing periodic maintenance with a plasma-assisted process, which can significantly extend the cleaning and maintenance cycle of the carrier plate and is beneficial to improving the efficiency of equipment use.

With the continuous advancement of integrated circuit technology, electronic products are currently developing towards being thin, light, short, high-performance, highly reliable and intelligent. The miniaturization technology of transistors in electronic products is crucial. As the size of transistors decreases, the current transmission time and energy consumption can be reduced to achieve the purpose of fast computing and energy saving. In today's miniaturized transistors, some key films are almost only a few atoms thick, and the atomic layer deposition process is one of the main technologies for developing these micro structures.

The atomic layer deposition process is a technology that deposits substances layer by layer on the wafer surface in the form of single atoms. The main reactants of atomic layer deposition are two chemical substances, usually called precursors, and the two precursors are delivered to the reaction space in sequence.

In actual application, the first precursor is first delivered to the reaction space so that the first precursor is guided to the surface of the wafer. An inert gas is delivered to the reaction space, and the gas in the reaction space is extracted to remove the remaining first precursor in the reaction space. The second precursor is injected into the reaction space so that the second precursor reacts with the first precursor on the surface of the wafer to form a thin film. Then, an inert gas is injected into the reaction space to remove the remaining second precursor in the reaction space. The above steps are repeated to form a thin film on the wafer.

The present invention proposes a novel method of replacing periodic maintenance with a plasma-assisted process, which mainly performs a first atomic layer deposition on a substrate on a carrier to form a thin film on the substrate, and determines whether the thickness of an insulating film deposited on the surface of the carrier is greater than a preset value.

If the thickness of the insulating film deposited on the surface of the carrier is greater than a preset value, the substrate on the carrier is removed, and a second atomic layer deposition is performed on the surface of the carrier without the substrate, so as to form a conductive film on the insulating film of the carrier. Then the substrate can be placed on the carrier, and the first atomic layer deposition is performed on the substrate on the carrier. Through the method described in the present invention, the cycle of cleaning and maintaining the carrier can be greatly extended, and it is beneficial to improve the efficiency of equipment use.

In order to achieve the above-mentioned purpose, the present invention proposes a method of replacing periodic maintenance with a plasma-assisted process, comprising: performing a first atomic layer deposition on a substrate on a carrier to form a thin film on the substrate, wherein an insulating film is formed on the carrier during the first atomic layer deposition; determining that the thickness of the insulating film on the carrier is greater than a preset value; and performing a second atomic layer deposition on the carrier to form a conductive film on the insulating film on the carrier.

In at least one embodiment of the present invention, it includes: determining that the number of times the second atomic layer deposition is performed is greater than a threshold value; and cleaning the carrier to remove the insulating film and the conductive film on the carrier.

In at least one embodiment of the present invention, the carrier is located in a containing space of a chamber, including: sequentially transporting a first precursor and a second precursor to the containing space of the chamber, and performing the first atomic layer deposition on the substrate on the carrier.

In at least one embodiment of the present invention, it includes: sequentially transporting a third precursor and the second precursor to the containing space of the chamber, and performing the second atomic layer deposition on the carrier in the containing space.

In at least one embodiment of the present invention, the thickness of the insulating film is greater than that of the conductive film.

In at least one embodiment of the present invention, the method includes: taking the substrate on which the first atomic layer deposition is completed from the carrier plate, and then performing the second atomic layer deposition on the carrier plate.

In at least one embodiment of the present invention, it includes: after completing the second atomic layer deposition, placing the substrate on the carrier and performing the first atomic layer deposition.

In at least one embodiment of the present invention, the default value is 1000 angstroms.

In at least one embodiment of the present invention, the thickness of the conductive film is greater than 300 angstroms.

In at least one embodiment of the present invention, a precursor used in the first atomic layer deposition is different from a precursor used in the second atomic layer deposition.

20: Sedimentation equipment

21: Cavity

22: Storage space

23: Sprinkler head

231: Hole

24: Substrate

25: Carrier plate

261: Insulation film

2611: The first insulating film

2613: Second insulating film

263: Conductive film

2631: The first conductive film

2633: Second conductive film

27:Transmission pipeline

271:RF coil

[Figure 1] is a flow chart of the steps of an embodiment of the method of replacing periodic maintenance with a plasma-assisted process according to the present invention.

[Figure 2] is a cross-sectional schematic diagram of an embodiment of a deposition device suitable for the method of replacing periodic maintenance with a plasma-assisted process as described in the present invention.

[Figure 3] is a cross-sectional schematic diagram of an embodiment of a carrier plate formed by replacing periodic maintenance with a plasma-assisted process as described in the present invention.

FIG1 is a flow chart of steps of an embodiment of the method of replacing periodic maintenance with a plasma-assisted process according to the present invention. FIG2 is a cross-sectional schematic diagram of an embodiment of a deposition device applicable to the method of replacing periodic maintenance with a plasma-assisted process according to the present invention. The deposition device 20 includes a chamber 21, a spray head 23 and a support plate 25, wherein the spray head 23 is connected to the chamber 21 and faces a receiving space 22 of the chamber 21, and the support plate 25 is located in the receiving space 22 of the chamber 21.

The spray head 23 is connected to a delivery pipeline 27, wherein the delivery pipeline 27 is used to deliver one or more precursors to the spray head 23. The spray head 23 includes a plurality of holes 231, and the precursors are delivered to the accommodating space 22 of the cavity 21 through the holes 231 of the spray head 23.

In one embodiment of the present invention, the delivery pipeline 27 may include an RF coil 271, for example, the RF coil 271 may be wound around the outside of the delivery pipeline 27. The precursor in the delivery pipeline 27 is affected by the magnetic field generated by the RF coil 271 to form plasma, so that the deposition device 20 becomes a plasma-assisted atomic layer deposition device. In addition, the RF coil 271 may be arranged around the cavity 21. In different embodiments, the deposition device 20 may not include the RF coil 271, and a remote plasma source may be connected to the delivery pipeline 27.

The carrier plate 25 is used to carry one or more substrates 24 and can be used to heat the substrates 24 placed on the carrier plate 25. The spray head 23 is located above the carrier plate 25, wherein the hole 231 of the spray head 23 faces the upper surface of the carrier plate 25 and the substrate 24.

During the deposition process, the precursor is transferred to the spray head 23 through the delivery pipeline 27, and then transferred to the support plate 25 and the substrate 24 disposed on the surface of the support plate 25 through the hole 231 on the spray head 23, so that the precursor contacts the support plate 25 and the substrate 24 to form a thin film on the surface of the substrate 24.

In actual application, the first precursor can be transported to the containing space 22 of the cavity 21 through the hole 231 on the spray head 23, wherein the first precursor will be deposited on the substrate 24. Then, the inert gas is injected into the containing space 22 of the cavity 21 through the hole 231 of the spray head 23 to remove the unreacted first precursor and byproducts in the containing space 22.

Then, the second precursor is transported to the containing space 22 of the chamber 21 through the hole 231 on the spray head 23, where the second precursor reacts with the first precursor on the surface of the substrate 24 to form a thin film. Then, the inert gas is injected into the containing space 22 of the chamber 21 through the hole 231 of the spray head 23 again to remove the unreacted second precursor and byproducts in the containing space 22.

By repeatedly performing the above-mentioned cycle, a thin film can be formed on the surface of the substrate 24, and the thickness of the thin film can be controlled by the number of cycles.

Generally speaking, the first precursor may be a volatile metal compound, and the second precursor may be a non-metal compound such as H2O, NH3 or O3. For example, the first precursor may be trimethylaluminum (TMA), and the second precursor may be NH3, and an aluminum nitride (AlN) film may be formed on the surface of the substrate 24.

As shown in FIG3 , during the process of depositing a thin film on the surface of the substrate 24, a thin film will also be formed on the surface of the carrier 25. For example, the carrier 25 can be a titanium plate and has conductive properties. After the first atomic layer deposition is performed on multiple batches of substrates 24, the thickness of the film deposited on the carrier 25 will increase, and an insulating film 261, such as an aluminum nitride film, will be formed on the surface of the carrier 25, so that the carrier 25 gradually loses its conductive properties.

As a result, some important process parameters such as DC bias cannot be observed during plasma-assisted atomic layer deposition (PEALD). In addition, the insulating film 261 on the carrier 25 will also reduce the uniformity (U%) of the film deposited on the surface of the substrate 24.

Generally speaking, when the thickness of the insulating film 261 on the surface of the carrier plate 25 is too thick, the cavity 21 needs to be opened and the carrier plate 25 in the cavity 21 needs to be taken out for cleaning to remove the insulating film 261 deposited on the surface of the carrier plate 25. After the carrier plate 25 is cleaned, the carrier plate 25 can be put back into the containing space 22 of the cavity 21, and the film deposition can continue through the deposition equipment 20.

Through the above-mentioned step of cleaning the carrier 25, the insulating film 261 deposited on the surface of the carrier 25 can be effectively removed to avoid the problem of being unable to observe some process parameters and reducing the uniformity of the film on the surface of the substrate 24. However, removing the carrier 25 from the chamber 21 and cleaning it will undoubtedly increase the cost and delay the subsequent process. In addition, in the process of opening the chamber 21, external contaminants may also enter the accommodating space 22 of the chamber 21, thereby affecting the subsequent process.

To this end, the present invention proposes a method of replacing periodic maintenance with a plasma-assisted process, which can effectively extend the maintenance cycle of the carrier 25. As shown in FIG1 , at least one substrate 24 is placed on the carrier 25, a first atomic layer deposition is performed on the substrate 24 on the carrier 25, and a thin film is formed on the surface of the substrate 24, as shown in step 11. The first atomic layer deposition is generally a deposition step performed on the surface of the substrate 24, for example, the thin film formed on the surface of the substrate 24 can be aluminum nitride.

During the process of first atomic layer deposition on substrate 24, the precursor will also contact the surface of carrier 25 and form an insulating film 261 on carrier 25.

Determine whether the thickness of the insulating film 261 deposited on the carrier plate 25 is greater than a preset value, as shown in step 13. In actual application, the thickness of the insulating film 261 can be inferred through the magnitude of the induced voltage between the RF coil 271 and the carrier plate 25, and determine whether the thickness of the insulating film 261 is greater than the preset value. The setting of the preset value can be adjusted based on the experience of actually operating the deposition equipment 20 or the accumulated data, for example, the preset value can be 1000 angstroms.

In different embodiments, the number of cycles of the first atomic layer deposition can also be used to determine whether the thickness of the insulating film 261 deposited on the carrier 25 is greater than a preset value.

When the thickness of the insulating film 261 on the surface of the carrier plate 25 is greater than a preset value, a second atomic layer deposition can be performed on the carrier plate 25 to form a conductive film 263 on the surface of the insulating film 261 of the carrier plate 25, as shown in step 15.

The insulating film 261 formed by the first atomic layer deposition and the conductive film 263 formed by the second atomic layer deposition are made of different materials, and the precursor used in the first atomic layer deposition is also different from the precursor used in the second atomic layer deposition.

During the first atomic layer deposition process, the first precursor and the second precursor can be sequentially delivered to the containing space 22 of the chamber 21 through the spray head 23. During the second atomic layer deposition process, the third precursor and the second precursor can be sequentially delivered to the containing space 22 of the chamber 21 through the spray head 23.

In one embodiment of the present invention, the insulating film 261 may be aluminum nitride, and the conductive film 263 may be titanium nitride. In addition, the first precursor used in the first atomic layer deposition may be trimethylaluminum, and the second precursor is ammonia, and the third precursor used in the second atomic layer deposition is tetrakis(dimethylamino)titanium (TDMAT) or tetrakis(diethylamino)titanium (TDEAT), and the second precursor is ammonia.

In practical application, after the first atomic layer deposition is completed on the substrate 24 on the carrier 25, the substrate 24 that has completed the first atomic layer deposition is taken out from the carrier 25. Then, different precursors are transported to the accommodation space 22 of the chamber 21 through the hole 231 of the spray head 23, and the second atomic layer deposition is performed on the carrier 25 to form a conductive film 263 on the surface of the insulating film 261 of the carrier 25.

After the second atomic layer deposition is completed, the conductive film 263 deposited on the carrier 25 reaches a certain thickness, for example, the thickness of the conductive film 263 can be greater than 300 angstroms, which will make the carrier 25 have conductive properties. Then the substrate 24 can be placed on the carrier 25, and the first atomic layer deposition on the substrate 24 continues.

When performing the above method, there is no need to open the cavity 21, nor is there any need to remove the carrier plate 25 from the cavity 21, which can greatly reduce the time and cost spent on cleaning the carrier plate 25 and avoid possible contamination during the process of opening the cavity 21.

In one embodiment of the present invention, as shown in FIG3 , the thickness of the insulating film 261 formed on the carrier plate 25 may be greater than the thickness of the conductive film 263. For example, the insulating film 261 may be aluminum nitride with a thickness of 1000 angstroms, and the conductive film 263 may be titanium nitride with a thickness of 300 angstroms.

Through the method described in the present invention, steps 11 to 15 can be repeated to form an insulating film 261 and a conductive film 263 stacked alternately on the surface of the carrier 25. For example, a first insulating film 2611 is formed on the surface of the carrier 25, and a first conductive film 2631 is formed on the surface of the first insulating film 2611, a second insulating film 2613 is formed on the surface of the first conductive film 2631, and then a second conductive film 2633 is formed on the surface of the second insulating film 2613.

In addition, when the number of repetitions of steps 11 to 15 or the number of second atomic layer deposition is greater than a threshold value, for example, between ten and twenty times, it may be necessary to open the chamber 21, remove the carrier plate 25 from the chamber 21 for cleaning, and remove the insulating film 261 and the conductive film 263 on the surface of the carrier plate 25.

The above is only a preferred embodiment of the present invention and is not intended to limit the scope of implementation of the present invention. All equivalent changes and modifications made according to the shape, structure, features and spirit described in the patent application scope of the present invention should be included in the patent application scope of the present invention.

Claims (10)

A method for replacing periodic maintenance with a plasma-assisted process includes: performing a first atomic layer deposition on a substrate on a carrier to form a thin film on the substrate, wherein an insulating film is formed on the carrier during the first atomic layer deposition; determining that the thickness of the insulating film on the carrier is greater than a preset value; if the thickness of the insulating film deposited on the carrier is greater than the preset value, removing the substrate on the carrier; and performing a second atomic layer deposition on the carrier to form a conductive film on the insulating film on the carrier. The method of replacing periodic maintenance with a plasma-assisted process as described in claim 1 includes: determining that the number of times the second atomic layer deposition is performed is greater than a threshold value; and cleaning the carrier to remove the insulating film and the conductive film on the carrier. The method of replacing periodic maintenance with a plasma-assisted process as described in claim 1, wherein the carrier is located in a receiving space of a chamber, comprising: sequentially transporting a first precursor and a second precursor to the receiving space of the chamber, and performing the first atomic layer deposition on the substrate on the carrier. The method of replacing periodic maintenance with a plasma-assisted process as described in claim 3 includes: sequentially delivering a third precursor and the second precursor to the accommodation space of the chamber, and performing the second atomic layer deposition on the carrier in the accommodation space. A method of replacing periodic maintenance with a plasma-assisted process as described in claim 1, wherein the thickness of the insulating film is greater than that of the conductive film. The method of replacing periodic maintenance with a plasma-assisted process as described in claim 1 comprises: removing the substrate on which the first atomic layer deposition has been completed from the carrier, and then performing the second atomic layer deposition on the carrier. The method of replacing periodic maintenance with a plasma-assisted process as described in claim 6 comprises: after completing the second atomic layer deposition, placing the substrate on the carrier and performing the first atomic layer deposition. A method of replacing periodic maintenance with a plasma-assisted process as described in claim 1, wherein the default value is 1000 angstroms. A method of replacing periodic maintenance with a plasma-assisted process as described in claim 1, wherein the thickness of the conductive film is greater than 300 angstroms. A method of replacing periodic maintenance with a plasma-assisted process as described in claim 1, wherein a precursor used in the first atomic layer deposition is different from a precursor used in the second atomic layer deposition.

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