Patent Application
20230343562
The present disclosure relates to a method of protecting an apparatus from an etching material. In particular, the present disclosure relates to a method of protecting an apparatus comprising aluminum from an etching material comprising fluorine.
Additionally, the present disclosure relates to a method of forming an oxide film.
Elements such as a semiconductor element, a display element and the like comprise various types of layers such as a semiconductor layer, a metal layer, an oxide layer, a nitride layer and the like. Among the layers, the oxide layer is widely used for a semiconductor material, an erosion prevention layer and the like. In particular, a small-sized and high-integrated semiconductor element requires finer patterns. To embody finer patterns, a high-temperature oxide layer having high resistance against thermal deformation is required.
Additionally, an oxide film can be formed based on a deposition process, in an apparatus comprising various types of parts such as a chamber, a shower head, a heater and the like. After the deposition process is completed, a substrate on which the oxide layer is formed comes out of the chamber, and then a cleaning process is performed. In the cleaning process, the oxide layer formed on the inner surface of the chamber, the surface of the shower head, the surface of the heater and the like is removed with a cleaning agent comprising an etching material. However, the cleaning agent often reacts directly with components of the chamber, the shower head, the heater and the like, not stopping at the oxide layer. For example, in the case where a cleaning agent comprising nitrogen trifluoride (NF3) is used to perform the cleaning process, after the high-temperature oxide layer is formed, fluorine-based by-products can react with aluminum (Al) or aluminum alloy constituting the chamber, the heater and the like and generate aluminum fluoride (AlF3) powder. The generated aluminum fluoride can contaminate or damage the chamber, the heater and the like.
To solve the above problems, in the case of an apparatus performing a high-temperature oxidation process, a protective layer is ordinarily formed on the inner wall of the chamber or the surface of the heater.
As a patent document, KR Patent Publication No. 10-2004-0081150 (hereafter, patent document 1), which was published on Sep. 20, 2004, suggests heating a coating material that comprises at least one material selected from a group consisting of aluminum fluoride and magnesium fluoride, such that the coating material falls into a semi-liquid state, and depositing the heated coating material on the aluminum surface to form a protective layer.
However, the method of forming a protective layer in patent document 1 is hardly performed right before or right after processing such as a process of forming an oxide, and when the coating material separates, an apparatus needs to be disassembled, and a protective layer needs to be formed again in an additional place.
The objective of the present disclosure is to provide a method of protecting an apparatus from an etching material that can prevent the etching material from contaminating or damaging the apparatus during processing.
The objective of the present disclosure is to provide a method of forming an oxide film, such that contact of a fluorine-based etching material with the exposed surface of an apparatus comprising Al is suppressed during etching and cleaning processes.
A method of protecting an apparatus from an etching material, according to the present, disclosure comprises (a) forming a protective layer on an exposed surface of an apparatus; (b) forming a seasoning layer on the protective layer; (c) performing a deposition process comprising loading a wafer into the apparatus in which the protective layer and the seasoning layer are formed, depositing in the apparatus, and unloading the wafer from the apparatus; (d) removing a deposition film on the seasoning layer of the apparatus in the deposition process and the seasoning layer, with a first etching material; and (e) removing the protective layer, with a second etching material.
The seasoning layer is a layer that has a high etch rate with respect to the first etching material, and the protective layer is a layer that has a high etch rate with respect to a second etching material. According to the present disclosure, in the step (d), the protective layer having a low etch rate with respect to the first etching material may suppress contact of the first etching material with the exposed surface of the apparatus. Accordingly, the apparatus may be protected from the etching material.
The etch rate of the protective layer with respect to the first etching material may account for one fourth or less of the etch rate of the seasoning layer with respect to the first etching material. When the etch rate of the protective layer with respect to the first etching material accounts for one fourth or less of the etch rate of the seasoning layer with respect to the first etching material, a greater effect in the protection of the apparatus may be produced.
The protective layer may be a layer having compressive stress. The layer having compressive stress may have a low etch rate with respect to the first etching material, thereby producing a great effect in the protection of an apparatus.
The wafer processing in the step (c) may comprise forming an oxide film, and the seasoning layer may comprise an oxide. In the case where the wafer processing is forming an oxide film, the seasoning layer is formed with the same sort of the oxide film, such that the oxide film formed on the seasoning layer, and the seasoning layer are removed together, in one process, at a time of wafer processing.
The deposition process may be performed twice or greater. In the case where the protective layer and the seasoning layer remain based on the deposition process, the deposition process may also be performed to another wafer, and then an etching/cleaning process may proceed, thereby ensuring improvement in productivity. In another embodiment, the step of forming a seasoning layer to the step of removing the seasoning layer may be performed twice or greater.
A method of forming an oxide film according to the present disclosure comprises (a) forming a protective layer on an exposed surface of an apparatus comprising aluminum; (b) forming a seasoning layer on the protective layer; (c) performing a oxide film deposition process comprising loading a wafer into the apparatus in which the protective layer and the seasoning layer are formed, depositing in the apparatus, and unloading the wafer from the apparatus; (d) removing the oxide film formed on the seasoning layer of the apparatus in the deposition process and the seasoning layer, with a fluorine-based etching material; and (e) removing the protective layer, with a non-fluorine-based etching material.
In the above configuration, the protective layer having a low etch rate with respect to the fluorine-based etching material may suppress contact of the fluorine-based etching material with the exposed surface of the apparatus, even when cleaning is performed with fluorine-based etching material, thereby protecting the apparatus from the etching material.
The etch rate of the protective layer with respect to the fluorine-based etching material may account for one fourth or less of the etch rate of the seasoning layer with respect to the fluorine-based etching material.
The protective layer may be selected from an amorphous carbon layer, a boron-doped carbon layer, and a tungsten-doped carbon layer.
The protective layer may be a layer having compressive stress.
The seasoning layer may comprise an oxide.
The above-described step (c) may be performed twice or greater. In another example, the above-described steps (b), (c) and (d) may be performed twice or greater.
In a method of protecting an apparatus from an etching material according to the present disclosure, a coating layer, which has a low etch rate with respect to a specific etching material such as a fluorine-based etching material, is formed on the exposed surface of an apparatus such as a reaction chamber, a substrate heating device, a shower head and the like, during processing, to suppress a reaction between the etching material, and materials constituting the apparatus.
For example, in the case where cleaning is performed to a reaction chamber or substrate heating device made of Al, with a fluorine-based cleaning material such as NF3, after a high-temperature oxide film is formed, fluorine-by-products (Fx) are likely to react with Al constituting the reaction chamber and the substrate heating device and produce aluminum fluoride (AlF3) powder. However, in the present disclosure, since etching/cleaning processes are performed in the state where a coating layer, having a low etch rate with respect to a fluorine-based cleaning material, is formed, the above problems can be solved.
Advantages and features in the present disclosure and methods for ensuring the same can be clearly understood from the embodiments that are described hereafter with reference to the accompanying drawings. The subject matter of the present disclosure, however, can be embodied in various different forms, and should not be construed as being limited to the embodiments set forth herein. Rather, the embodiments are provided as examples so that the present disclosure can be thorough and complete and that the scope of the disclosure can be fully conveyed to one having ordinary skill in the art. The subject matter of the present disclosure is to be defined only according to the scope of the appended claims.
Hereafter, a method of protecting an apparatus from an etching material and a method of forming an oxide film according to the present disclosure, with reference to the accompanying drawings.
Referring to
The step of first coating (S110) involves forming a protective layer on the exposed surface of an apparatus.
The apparatus is for processing a wafer. The apparatus in the present disclosure may be a finished product where various types of parts are assembled, such as a plasma-enhanced chemical vapor deposition (PECVD) apparatus, or may be various types of parts that are included in a finished product, i.e., a reaction chamber, a substrate heating device, a shower head and the like.
A protective layer may be a material that has a low etch rate with respect to a first cleaning material that is used in the step of first cleaning described hereafter. The protective layer suppresses direct contact of the first cleaning material or the by-products thereof with the apparatus in the step of first cleaning, thanks to its low etch rate. For example, in the case where the first cleaning material is a fluorine-based etching material such as nitrogen trifluoride (NF3), the protective layer may be an amorphous carbon layer. A fluorine-based etching material is widely used for etching/cleaning an etching material. If the protective layer is not provided or is made of a material that is easily etched by a fluorine-based etching material or the by-products thereof may contact the chamber or the substrate heating device, in a cleaning process based on the fluorine-based etching material. The contact of the fluorine containing material with the apparatus causes the contamination of the apparatus or contributes to the generation of new particles which is caused by a chemical reaction between the fluorine containing material and the materials constituting the apparatus. However, in the present disclosure, a coating layer having a low etch rate with respect to the first cleaning material is formed on the exposed surface of the apparatus, thereby making it possible to solve the problems including the contamination of the apparatus or the formation of the new particles, and the like, described above.
In particular, the protective layer is formed before the unit process such as the formation of an oxide film, and the protective layer is removed after the unit process, in the present disclosure. Accordingly, there is no need to disassemble the apparatus in the case where the protective layer is formed or removed, and since the apparatus does not need to be disassembled, a change in the settings of the apparatus is not caused because of the reassembly of the apparatus.
Additionally, the thickness of the coating layer on the inner wall of the reaction chamber may differ slightly, depending on the environment in the reaction chamber. The thickness of the coating layer is determined based on the amount of reaction gas that reaches the inner wall in a deposition process. The coating layer on a portion of the inner wall, which is reached by a large amount of reaction gas, may be relatively thick, and the coating layer on a portion of the inner wall, which is reached by a small amount of reaction gas, may be relatively thin. The amount of reaction gas reaching the relatively thick portion of the inner wall is proportional to the amount of etch gas reaching the inner wall. In the present disclosure, since the protective layer, and a seasoning layer described hereafter are formed in the deposition process and then the cleaning process is performed, the over etching and the like may be suppressed in a specific portion of the inner wall of the chamber.
Preferably, the etch rate of the protective layer with respect to the first etching material accounts for one fourth or less of the etch rate of the seasoning layer with respect to the first etching material. The effect in the protection of the apparatus may be greater at the etch rate of the protective layer with respect to the first etching material, accounting for ¼ or greater of the etch rate of the seasoning layer with respect to the first etching material than the etch rate of the protective layer with respect to the first etching material, accounting for ¼ or less of the etch rate of the seasoning layer with respect to the first etching material.
Additionally, the protective layer may be a layer having compressive stress. The layer having compressive stress is denser than a layer having tensile stress. Thus, the layer having compressive stress shows a lower etch rate with respect to the first etching material than the layer having tensile stress. Thus, the layer having compressive stress may produce a greater effect in the protection of the apparatus than the layer having tensile stress.
The step of forming a seasoning layer (S120) involves forming a seasoning layer on the protective layer.
The seasoning layer prevents the exposure of the protective layer in the unit process. For example, in the case where an amorphous carbon layer is formed on the inner wall of the chamber, carbon particles may flake off from the amorphous carbon layer, and a wafer may be contaminated, in the step of forming an oxide film. However, in the case where the seasoning layer is formed, the above-described risk can be avoided. The seasoning layer may be made of a material that has a high etch rate with respect to the first etching material. For example, in the case where the first etching material is nitrogen trifluoride (NF3), the seasoning layer may be formed of an oxide.
Additionally, the seasoning layer is preferably formed into the layer of the same sort as the deposition film that is formed on the seasoning layer by wafer processing. For example, in the case where a silicon oxide film is formed in the unit process, the seasoning layer is also a silicon oxide layer, preferably. At this time, the deposition film and the seasoning layer may be removed together with the first etching material, in the step of first cleaning.
Then the step of performing a unit process (S130) involves performing a deposition process on a wafer inserted into the apparatus where the protective layer and the seasoning layer are formed. Specifically, the step of performing a unit process (S130) involves performing a unit process comprising loading and depositing a wafer in the apparatus where the protective layer and the seasoning layer are formed, and unloading the wafer from the apparatus.
The step of processing a wafer may involve various types of deposition processes such as a process of forming an oxide film, a process of forming a nitride layer and the like.
The unit process may be performed twice or more when necessary. In the case where the protective layer and the seasoning layer remain after a unit process for one wafer, a unit process may also be performed for another wafer, and then the step of etching/cleaning may be performed. As a result, productivity can be improved. In another example, the step of forming a seasoning layer (S120), the step of performing a unit process (S130) and a step of first cleaning (S140) described hereafter may be performed twice or more. In the case where the protective layer remains, a cycle in which a seasoning layer is formed, a unit process is performed and the seasoning layer is removed may be performed a plurality of times.
The step of first cleaning (S140) involves removing the seasoning layer with the first etching material. The step of second cleaning (S150) involves removing the protective layer with a second etching material. In the step of first cleaning (S140), the deposition film that is formed on the seasoning layer in the unit process is also removed.
The seasoning layer is a layer that has a high etch rate with respect to the first etching material, and the protective layer is a layer that has a high etch rate with respect to the second etching material and has a low etch rate with respect to the first etching material.
In the present embodiment, the protective layer having a low etch rate with respect to the first etching material may help to suppress contact of the first etching material with the exposed surface of the apparatus in the step of first cleaning (S140). Accordingly, the apparatus may be protected from the etching material.
For example, in the case where the seasoning layer is a silicon oxide layer, the first etching material may be NF3, the protective layer may be an amorphous carbon layer that has a relatively low etch rate with respect to NF3, and the second etching material may be an oxygen containing etching material that has a high etch rate with respect to an amorphous carbon layer.
In another example, in the case where the seasoning layer is a silicon oxide layer, the first etching material may be HF, the protective layer may be an amorphous carbon layer that has a relatively low etch rate with respect to HF, and the second etching material may be an oxygen containing etching material that has a high etch rate with respect to an amorphous carbon layer.
Hereafter, a method of forming an oxide film according to the present disclosure is described with reference to
As illustrated in
Referring to
As the etch rate of the protective layer 210 with respect to a fluorine-based etching material decreases, the effect in the protection of an apparatus increases. In this respect, the etch rate of the protective layer 210 with respect to a fluorine-based etching material may account for one fourth or less, preferably one tenth or less, more preferably one twentieth or less of the etch rate of the seasoning layer with respect to a fluorine-based etching material.
The protective layer 210 may be selected from an amorphous carbon layer, a boron-doped carbon layer, and a tungsten-doped carbon layer. These carbon layers may exhibit a very low etch rate with respect to a fluorine-based etching material.
Additionally, the protective layer 210 may be a layer having compressive stress. In the case where a thin layer has compressive stress rather than tensile stress, the thin layer may be a dense layer. Thus, the etch rate of the protective layer 210 with respect to a fluorine-based etching material may become very low. For example, the etch rate of an amorphous carbon layer having compressive stress is much lower than that of an amorphous carbon layer having tensile stress, with respect to nitrogen trifluoride.
Then a seasoning layer 220 is formed on the protective layer 210, as illustrated in
Then a wafer 204 is loaded on the substrate heating device 203 in the reaction chamber 201, in the state where the protective layer 210 and the seasoning layer 220 are formed on the exposed surface of the devices, as illustrated in
Then an oxide film 230 to be formed is formed on the wafer 204, as illustrated in
For example, the step of forming an oxide film can be performed at 400° C. or greater. The step of first cleaning may also be performed at 400° C. or greater.
After the oxide film is formed, the wafer 204 is unloaded from the reaction chamber 201, as illustrated in
The unit process comprising the steps of loading a wafer, forming an oxide film and unloading the wafer may be performed only for one wafer, and when necessary, may also be performed for another wafer.
Then the step of first cleaning is performed to remove the oxide film 230 and the seasoning layer 220 with a fluorine-based etching material, as illustrated in
In the step of first cleaning, NF3, HF and the like may be used as a fluorine-based etching material. The present disclosure suggests a protective layer such as an amorphous carbon layer having a low etch rate with respect to a fluorine-based etching material. Accordingly, the fluorine-based etching material's contact with the exposed surface of an apparatus, e.g., the inner surface of the reaction chamber and the surface of the substrate heating device, may be suppressed, in the step of first cleaning. Thus, the apparatus may be protected from the etching material.
Then the protective layer may be removed by a second etching material, as illustrated in
Hereafter, the configuration and operation of the subject matter of the present disclosure are described specifically with reference to preferred embodiments of the preset disclosure. However, the preferred embodiments are provided only as an example, and in any respect, the subject matter of the present disclosure is not interpreted as being limited by the examples. Particulars that is not described herein can be technically inferred by one skilled in the art. Therefore, description of the particulars is omitted.
1. Formation of Coating Layer and Evaluation of Properties Thereof
An amorphous carbon layer was used as a protective layer. The amorphous carbon layer may exhibit a lower etch rate than an oxide layer.
Table 1 shows conditions for depositing an amorphous carbon layer, which are provided in an experiment.
Table 2 shows properties of a protective layer, based on deposition conditions.
Even if coating layers are formed with an identical deposition material (CxHy), a change in the flow rate of a deposition material significantly contributes to a change in the stress of a coating layer compared to a deposition rate. A coating layer of example 1 is a layer that has positive stress, i.e., tensile stress, and coating layers of examples 2 and 3 are layers that has negative stress, i.e., compressive stress.
Table 3 shows etch rates and selectivity, based on properties of coating layers. NF3 was used to etch the coating layers.
Referring to table 3, amorphous carbon layers of examples 1 to 3 have a much lower etch rate than a silicon oxide layer. While the etch rate of the silicon oxide layer is 232.0λ/s, the etch rates of the amorphous carbon layers are 5.3λ/s to 53.1λ/s. Etch selectivity that is a ratio between the two coating layers is 437%-4377%.
Additionally, the etch rates of the amorphous carbon layers of embodiments 2 and 3, having compressive stress, are much lower than the etch rate of the amorphous carbon layer of embodiment 1, having tensile stress, with respect to NF3. Thus, to protect an apparatus from an etching material, the amorphous carbon layer having compressive stress is preferable.
The amorphous carbon layer having a low etch rate with respect to NF3 prevents a reaction of fluorine by-products with a reaction chamber and a substrate heating device, in the step of NF3 cleaning.
As described above, the method of protecting an apparatus according to the present disclosure involves forming a protective layer having a low etch rate with respect to a first etching material, and a seasoning layer suppressing the exposure of the protective layer, and in a step of cleaning with a first etching material, a reaction of the first etching material with components constituting an apparatus may be suppressed. As a result, the apparatus may be protected from the etching material.
The embodiments are described above with reference to a number of preferred embodiments. However, one having ordinary skill in the art can understand that numerous other modifications and equivalents can be drawn from the embodiments. Therefore, the scope of the right to the present disclosure is not limited by the embodiments, and a number of modifications and improvements, which made by one skilled in the art, based on the fundamental concept of the disclosure defined in the following section of claims, also belong to the scope of the right to the disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2020-0115975 | Sep 2020 | KR | national |
This application is a National Stage Patent Application of PCT International Patent Application No. PCT/KR2021/009671 (filed on Jul. 26, 2021) under 35 U.S.C. § 371, which claims priority to Korean Patent Application No. 10-2020-0115975 (filed on Sep. 10, 2020), which are all hereby incorporated by reference in their entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/KR2021/009671 | 7/26/2021 | WO |
