Silicon oxide film surface fluorine element treatment method and etching method

Abstract

The present invention provides a method for treating the surface of a silicon oxide film layer with fluorine elements and an etching method. A plasma formed by a chlorine-containing gas is used to treat the surface of the silicon oxide film layer to reduce the binding ability between the fluorine elements on the surface of the silicon oxide film layer and the surface of the silicon oxide film layer. A plasma formed by a first inert gas is used to bombard the surface of the treated silicon oxide film layer to remove the chlorine elements and fluorine elements on the surface of the silicon oxide film layer. The method for treating the surface of a silicon oxide film layer with fluorine elements and the etching method provided by the present invention can significantly reduce the content of fluorine elements on the surface of the silicon oxide film layer on the premise of in-situ treating the wafer, so as to ensure the etching morphology and material quality.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing, and in particular to a method for treating the surface of a silicon oxide film layer with fluorine and an etching method. Background Art

[0002] Inductively Coupled Plasma (ICP) etching equipment has the advantages of high chamber vacuum, high etching accuracy, and strong morphology control. It has become a mature technical equipment for etching silicon materials such as polysilicon and silicon dielectric layers in the preparation of ultra-large-scale silicon-based integrated circuit devices.

[0003] As the process development of advanced silicon-based chips in the future gradually enters the atomic level precision, the requirements for the control of etching products and the residual etching elements are becoming more and more stringent. The industry usually uses fluorine-containing gases (such as CF gases) as etching gases to perform plasma etching on the silicon oxide film layer on the wafer (wafer) (for example, to form grooves), or to perform plasma etching on other film layers located on the silicon oxide film layer to expose the surface of the silicon oxide film layer. However, after the etching process is completed, a small amount of fluorine elements (F) may remain on the surface of the unetched silicon oxide film layer. If these F elements are not removed immediately, they may corrode the surface of the silicon oxide film layer, or even drill into the surface of the silicon oxide film layer, making it more difficult to clean up later, thereby possibly damaging the surface morphology and material quality after etching. In addition, after the fluorine-containing silicon oxide film layer is formed or after etching with fluorine-containing gases (such as CF gases), there are also F elements on its surface, and if these F elements are not removed immediately, they may also corrode the fluorine-containing silicon oxide film layer, affecting the stability of the film layer. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art, and proposes a method for treating fluorine on the surface of a silicon oxide film layer and an etching method, which can significantly reduce and control the fluorine content on the surface of the silicon oxide film layer under the premise of in-situ processing of the wafer, thereby ensuring the quality and morphology of the film layer before and after the etching process, thereby ensuring the etching morphology and material quality of the final process.

[0005] To achieve the purpose of the present invention, a method for treating the surface of a silicon oxide film layer with fluorine is provided, comprising: treating the surface of the silicon oxide film layer with a plasma formed by a chlorine-containing gas to reduce the ability of the fluorine element on the surface of the silicon oxide film layer to bind to the surface of the silicon oxide film layer;

[0006] The surface of the silicon oxide film layer after the bombardment treatment is formed by plasma formed by the first inert gas to remove chlorine and fluorine elements on the surface of the silicon oxide film layer.

[0007] Optionally, the surface of the silicon oxide film layer after the plasma bombardment treatment using the first inert gas includes:

[0008] The kinetic energy of ions in the plasma formed by the first inert gas is reduced by adjusting the process parameters related to the kinetic energy of ions, so as to avoid damaging the surface of the silicon oxide film layer.

[0009] Optionally, the process parameters related to the ion kinetic energy include: at least one of chamber gas pressure, flow rate of the first inert gas, and lower electrode power.

[0010] Optionally, after treating the surface of the silicon oxide film layer with plasma formed by chlorine-containing gas and before bombarding the surface of the silicon oxide film layer treated with plasma formed by the first inert gas, the method further includes:

[0011] A purge gas is introduced into the chamber to remove the chlorine-containing gas in the chamber.

[0012] Optionally, the treatment of the surface of the silicon oxide film layer by using plasma formed by chlorine-containing gas and the bombardment of the surface of the silicon oxide film layer by using plasma formed by a first inert gas are performed in a cycle at least once, and the remaining fluorine content on the surface of the silicon oxide film layer is controlled by adjusting the number of cycles.

[0013] Optionally, the chlorine-containing gas includes chlorine gas.

[0014] Optionally, the treating the surface of the silicon oxide film layer by using plasma formed by chlorine-containing gas includes:

[0015] While the chlorine-containing gas is introduced into the chamber, a second inert gas is introduced into the chamber.

[0016] As another technical solution, the present invention also provides an etching method, comprising:

[0017] Providing a silicon monoxide film layer;

[0018] Etching the silicon oxide film layer using plasma formed by fluorine-containing gas;

[0019] The fluorine element on the surface of the silicon oxide film layer provided by the present invention is removed by using the fluorine element treatment method on the surface of the silicon oxide film layer that has not been etched.

[0020] As another technical solution, the present invention also provides an etching method, comprising:

[0021] Providing a silicon oxide film layer, and having at least one functional film layer on the silicon oxide film layer;

[0022] Etching the at least one functional film layer using plasma formed by fluorine-containing gas until the surface of the silicon oxide film layer is exposed;

[0023] The fluorine element on the surface of the silicon oxide film layer is removed by using the fluorine element treatment method on the surface of the silicon oxide film layer provided by the present invention.

[0024] As another technical solution, the present invention also provides an etching method, comprising:

[0025] Providing a fluorine-containing silicon oxide film layer;

[0026] Etching the fluorine-containing silicon oxide film layer;

[0027] Before and / or after etching the fluorine-containing silicon oxide film layer, the fluorine element on the surface of the fluorine-containing silicon oxide film layer is removed by using the fluorine element treatment method on the surface of the silicon oxide film layer provided by the present invention.

[0028] The present invention has the following beneficial effects:

[0029] The method for treating the surface of a silicon oxide film layer with fluorine provided by the present invention is applied to the scene where there is fluorine on the surface of the silicon oxide film layer. The method first uses a plasma formed by a chlorine-containing gas to treat the surface of the silicon oxide film layer to reduce the binding ability of the fluorine with the surface of the silicon oxide film layer, and then uses a plasma formed by a first inert gas to bombard the treated surface of the silicon oxide film layer to remove the chlorine and fluorine elements on the surface of the silicon oxide film layer, thereby significantly reducing and controlling the fluorine content on the surface of the silicon oxide film layer, thereby ensuring the etching morphology and material quality. At the same time, the method for treating the surface of a silicon oxide film layer with fluorine provided by the present invention can treat the wafer in situ, that is, the fluorine on the surface of the silicon oxide film layer can be treated without moving the wafer, thereby improving the process efficiency.

[0030] The etching method provided by the present invention can significantly reduce and control the fluorine content on the surface of the silicon oxide film layer by adopting the above-mentioned silicon oxide film surface fluorine element treatment method provided by the present invention, thereby ensuring the etching morphology and material quality; at the same time, the wafer can be processed in situ, thereby improving the process efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A flowchart of a method for treating the surface of a silicon oxide film layer with fluorine element provided in the first embodiment of the present invention;

[0032] Figure 2 A flowchart of an etching method provided in accordance with a second embodiment of the present invention;

[0033] Figure 3A process diagram of an etching method provided for a second embodiment of the present invention;

[0034] Figure 4 A flowchart of an etching method provided in a third embodiment of the present invention;

[0035] Figure 5 A process diagram of an etching method provided in a third embodiment of the present invention;

[0036] Figure 6 A flowchart of an etching method provided in a fourth embodiment of the present invention;

[0037] Figure 7 A process diagram of an etching method provided in a fourth embodiment of the present invention;

[0038] Figure 8 A flowchart of an etching method provided as a variant of the fourth embodiment of the present invention;

[0039] Fig. 9 A process diagram of an etching method provided for a variant embodiment of the fourth embodiment of the present invention;

[0040] Fig.10 A comparison diagram of TEM test results of the surface of a silicon oxide film layer before and after the fluorine element treatment method for the surface of a silicon oxide film layer provided by an embodiment of the present invention is adopted;

[0041] Fig.11 It is a comparison diagram of the etching amount on the surface of the silicon oxide film layer detected after completing step S1 and step S3 respectively. DETAILED DESCRIPTION

[0042] In order to enable those skilled in the art to better understand the technical solution of the present invention, the method for treating the surface of a silicon oxide film layer with fluorine provided by the present invention is described in detail below in conjunction with the accompanying drawings.

[0043] First embodiment

[0044] See also Figure 1, an embodiment of the present invention provides a method for treating fluorine on the surface of a silicon oxide film layer, the method being applied to a scenario where fluorine exists on the surface of a silicon oxide film layer, the silicon oxide film layer being, for example, disposed on a substrate, the substrate being comprised of materials such as polysilicon and silicon nitride. The silicon oxide film layer is, for example, a silicon oxide film layer, and after the silicon oxide film layer is etched by a plasma formed by a fluorine-containing gas, fluorine will remain on the surface of the silicon oxide film layer; or, there is at least one functional film layer on the silicon oxide film layer, and after the at least one functional film layer is etched by a plasma formed by a fluorine-containing gas to expose the surface of the silicon oxide film layer, fluorine will remain on the surface of the exposed silicon oxide film layer; if these fluorine elements are not removed immediately, they may corrode the surface of the silicon oxide film layer, or even penetrate into the interior of the silicon oxide film layer, making it more difficult to clean up later, thereby possibly damaging the surface morphology and material quality after etching. There is also a scenario where there is fluorine on the surface of the silicon oxide film layer, that is, the silicon oxide film layer is, for example, a fluorine-containing silicon oxide film layer. After film formation or after etching with a fluorine-containing gas (such as a CF-type gas), the fluorine-containing silicon oxide film layer has fluorine on its surface. In this scenario, there is also F on its surface, and if these F elements are not immediately removed, they may corrode the fluorine-containing silicon oxide film layer and affect the stability of the film layer. The embodiments of the present invention are not limited to the above-mentioned scenarios. In practical applications, they can be applied to any scenario where there is fluorine on the surface of the silicon oxide film layer and the fluorine content on the surface of the film layer needs to be adjusted.

[0045] To this end, the method for treating the surface of a silicon oxide film layer with fluorine element provided in an embodiment of the present invention comprises:

[0046] S1. treating the surface of the silicon oxide film layer with plasma formed by chlorine-containing gas to reduce the bonding ability between the fluorine element on the surface of the silicon oxide film layer and the surface of the silicon oxide film layer;

[0047] S2, introducing a purge gas into the chamber to remove the chlorine-containing gas in the chamber;

[0048] S3, bombarding the surface of the silicon oxide film layer after the treatment with plasma formed by the first inert gas to remove chlorine and fluorine elements on the surface of the silicon oxide film layer.

[0049] The bond energies between the four elements Si, F, Cl, and O are from large to small in the following order: Si-F>Si-O>Si-Cl. Based on this, by using the plasma formed by the chlorine-containing gas to treat the surface of the silicon oxide film layer in the above step S1, the high-energy Si-F can be converted into low-energy Si-Cl, that is, the binding ability of the fluorine element with the surface of the silicon oxide film layer is reduced. Combined with the subsequent step S3, the surface of the silicon oxide film layer after bombardment with the plasma formed by the first inert gas can be interrupted by the kinetic energy of the plasma (such as Ar ions) formed by the first inert gas to avoid the introduction of the Cl element, thereby removing the chlorine and fluorine elements on the surface of the silicon oxide film layer. Therefore, the fluorine element treatment method for the surface of the silicon oxide film layer provided in the embodiment of the present invention can significantly reduce and control the fluorine element content on the surface of the silicon oxide film layer, thereby ensuring the etching morphology and material quality. At the same time, the fluorine element treatment method for the surface of the silicon oxide film layer provided in the embodiment of the present invention can process the wafer in situ, that is, the fluorine element on the surface of the silicon oxide film layer can be treated without moving the wafer, thereby improving the process efficiency.

[0050] The above steps S1 and S3 both use a plasma etching process to process the surface of the silicon oxide film layer. The process is implemented, for example, by an inductively coupled plasma (ICP) etching device. Specifically, the plasma etching process includes: introducing a process gas into the chamber (the process gases introduced into the chamber in steps S1 and S3 are chlorine-containing gas and a first inert gas, respectively), and turning on the upper electrode power supply to load the upper electrode power to the upper electrode (e.g., a coil) to excite the process gas in the chamber to form a plasma. In this process, optionally, the lower electrode power supply can be turned on to load the lower electrode power (also known as bias power) to the lower electrode (e.g., a base) to attract the plasma to move toward the wafer. The above base is, for example, a mechanical chuck or an electrostatic chuck, and a heating device can also be provided in the base to control the surface temperature of the wafer. The above upper electrode power is, for example, a radio frequency power or a combination of radio frequency power and direct current power. The above plasma usually contains electrons, positive ions, free radicals, etc. The free radicals in the plasma can diffuse to the surface of the wafer and react physically and chemically with it, thereby realizing the processing of the wafer. In addition, the chamber also has an exhaust port, which is connected to a vacuum pump (such as a molecular pump) to exhaust the gas in the chamber to achieve control of the chamber air pressure.

[0051] It should be noted that the above step S2 is used to remove the chlorine-containing gas in the chamber by introducing a purge gas into the chamber, thereby avoiding the introduction of chlorine into the chamber. However, the embodiment of the present invention is not limited thereto. In practical applications, the above step S2 can be performed after the above step S1 is completed and before the above step S3 is performed, or the above step S2 can be omitted, that is, the above step S3 can be performed directly after the above step S1 is completed.

[0052] In some optional embodiments, in order to avoid damaging the surface of the silicon oxide film layer, the above step S3 includes:

[0053] The ion kinetic energy of the plasma formed by the first inert gas is reduced by adjusting the process parameters related to the ion kinetic energy to avoid damaging the surface of the silicon oxide film layer.

[0054] By adjusting the process parameters related to the kinetic energy of the ions, a process window can be formed that can interrupt Si-Cl while not damaging Si-O, so as to reduce the kinetic energy of the ions of the plasma formed by the first inert gas. The ions can bombard the surface of the silicon oxide film layer with a relatively low kinetic energy, and the etching rate of the surface of the silicon oxide film layer is very low, thereby interrupting Si-Cl to avoid introducing additional chlorine elements on the surface of the silicon oxide film layer on the basis of removing the fluorine elements on the surface of the silicon oxide film layer, and avoiding damage to the surface of the silicon oxide film layer caused by ion bombardment.

[0055] In some optional embodiments, the process parameters related to ion kinetic energy include at least one of chamber pressure, flow rate of the first inert gas, and power of the lower electrode. However, the embodiments of the present invention are not limited thereto. In practical applications, any process parameters that can reduce ion kinetic energy fall within the protection scope of the embodiments of the present invention.

[0056] In some optional embodiments, the above steps S1, S2 and S3 are cyclically performed at least once, or the above steps S1 and S3 (omitting the above step S2) are cyclically performed at least once, and the remaining fluorine content on the surface of the silicon oxide film layer can be controlled by adjusting the number of cycles. Specifically, the more cycles, the less the remaining fluorine content; conversely, the more.

[0057] In some optional embodiments, in the above step S1, the chlorine-containing gas includes, for example, chlorine gas.

[0058] In some optional embodiments, the above step S1 includes:

[0059] While the chlorine-containing gas is introduced into the chamber, a second inert gas is introduced into the chamber.

[0060] By simultaneously introducing a chlorine-containing gas and the above-mentioned second inert gas, plasma ignition can be more easily achieved. Optionally, the second inert gas includes, for example, helium, neon, argon, xenon, and the like. Optionally, the kinetic energy of ions in the plasma formed by the second inert gas can be reduced by adjusting the process parameters related to the kinetic energy of the ions. The kinetic energy can be, for example, lower than the kinetic energy of ions in the plasma formed by the first inert gas in step S3, so as to further reduce or even avoid the bombardment of the surface of the silicon oxide film layer, and ensure that the surface of the silicon oxide film layer is not damaged. The above-mentioned process parameters related to the kinetic energy of the ions include: at least one of the chamber pressure, the flow rate of the second inert gas, and the lower electrode power. However, the embodiments of the present invention are not limited to this. In practical applications, all process parameters that can reduce the kinetic energy of ions belong to the protection scope of the embodiments of the present invention.

[0061] In some optional embodiments, the process parameters adopted in the above step S1 include: the chamber gas pressure is greater than or equal to 20mT and less than or equal to 60mT; the flow rate of the chlorine-containing gas is greater than or equal to 20sccm and less than or equal to 200sccm; the flow rate of the second inert gas is greater than or equal to 0sccm and less than or equal to 80sccm; the upper electrode power is greater than or equal to 400W and less than or equal to 900W; the lower electrode power is greater than or equal to 0W and less than or equal to 15W.

[0062] In some optional embodiments, the process parameters adopted in the above step S3 include: the chamber gas pressure is greater than or equal to 5mT and less than or equal to 20mT; the flow rate of the first inert gas is greater than or equal to 100sccm and less than or equal to 500sccm; the upper electrode power is greater than or equal to 300W and less than or equal to 800W; the lower electrode power is greater than or equal to 0W and less than or equal to 15W.

[0063] In some optional embodiments, the first inert gas includes, for example, helium, neon, argon, xenon, etc.

[0064] In the following scenario where fluorine element exists on the surface of the silicon oxide film layer, XPS tests (i.e., element content test on the surface of the silicon oxide film layer) are performed on the surface of the silicon oxide film layer before and after the fluorine element treatment method on the surface of the silicon oxide film layer provided by the embodiment of the present invention, and the test results are shown in Table 1 below.

[0065] Table 1. Test results of element content (at%) on the surface of silicon oxide film layer

[0066]

[0067] It can be seen from Table 1 that after the fluorine element treatment method for the surface of the silicon oxide film layer provided by the embodiment of the present invention is adopted, the residual fluorine element content (atomic percentage) on the surface of the silicon oxide film layer is reduced from 5.39at% before the fluorine element treatment method for the surface of the silicon oxide film layer provided by the embodiment of the present invention is adopted to 2.55at%, and by adjusting the process parameters related to the ion kinetic energy in the above step S3 to reduce the ion kinetic energy of the plasma formed by the above first inert gas, no Cl element is detected on the surface of the silicon oxide film layer, that is, no additional chlorine element is introduced.

[0068] In the following scenario where fluorine element exists on the surface of the silicon oxide film layer, TEM tests (i.e., image detection of the surface of the silicon oxide film layer) are performed on the surface of the silicon oxide film layer before and after the fluorine element treatment method on the surface of the silicon oxide film layer provided by the embodiment of the present invention is used. The test results are as follows: Fig.10 shown. Fig.10 Figures (a) and (b) in the figure are TEM test images of the surface of the silicon oxide film layer before and after the fluorine element treatment method for the silicon oxide film layer provided by the embodiment of the present invention is adopted. By comparing the images of Figure (a) and Figure (b), it can be seen that before and after the fluorine element treatment method for the silicon oxide film layer provided by the embodiment of the present invention is adopted, there is no obvious change on the surface of the silicon oxide film layer (the surface of the silicon oxide film layer is the boundary of the black and white images). It can be explained that the fluorine element treatment method for the surface of the silicon oxide film layer provided by the embodiment of the present invention reduces the ion kinetic energy of the plasma formed by the first inert gas by adjusting the process parameters related to the ion kinetic energy in the above step S3, and the damage to the surface of the silicon oxide film layer is extremely low.

[0069] Fig.11 The comparison diagram is a diagram of the etching amount of the silicon oxide film layer surface detected after completing step S1 and step S3. Under the condition of using the same etching equipment, the above steps S1 and S3 are respectively performed, and the execution time is 600s; then, the etching amount of the silicon oxide film layer surface after completing step S1 and step S3 is respectively detected. Fig.11 As shown in Figure (a), after completing step S1, the etching amount on the surface of the silicon oxide film layer is approximately like Fig.11 As shown in Figure (b), after completing step S3, the etching amount on the surface of the silicon oxide film layer is approximately And the etching rate is as low as This shows that the method for treating the surface of a silicon oxide film layer with fluorine element provided in an embodiment of the present invention reduces the ion kinetic energy of the plasma formed by the first and second inert gases by adjusting the process parameters related to the ion kinetic energy in the above-mentioned steps S1 and S3. The above-mentioned step S1 has almost no etching, while the physical etching speed generated by the above-mentioned step S3 is extremely slow and has a large operating space, thereby effectively reducing or even avoiding damage to the surface of the silicon oxide film layer.

[0070] In summary, the method for treating the surface of a silicon oxide film layer with fluorine provided in an embodiment of the present invention is applied to a scenario where there is fluorine on the surface of a silicon oxide film layer. The method first uses a plasma formed by a chlorine-containing gas to treat the surface of the silicon oxide film layer to reduce the binding ability of the fluorine with the surface of the silicon oxide film layer, and then uses a plasma formed by a first inert gas to bombard the treated surface of the silicon oxide film layer to remove the chlorine and fluorine on the surface of the silicon oxide film layer, thereby significantly reducing and controlling the fluorine content on the surface of the silicon oxide film layer, thereby ensuring the etching morphology and material quality. At the same time, the method for treating the surface of a silicon oxide film layer with fluorine provided in the present invention can treat the wafer in situ, that is, the fluorine on the surface of the silicon oxide film layer can be treated without moving the wafer, thereby improving the process efficiency.

[0071] Second embodiment

[0072] As another technical solution, please also refer to Figure 2 and Figure 3 , an embodiment of the present invention provides an etching method, comprising:

[0073] S101, providing a silicon oxide film layer 1, such as Figure 3 As shown in Figure (a);

[0074] S102, etching the silicon oxide film layer 1 using plasma formed by fluorine-containing gas;

[0075] like Figure 3 As shown in FIG. 1 (b), the above step S102 is used to etch a groove on the silicon oxide film layer 1, and after etching, fluorine element 2 will remain on the bottom surface of the groove. FIG. 1 (b) only schematically shows the presence of fluorine element 2.

[0076] S103, using the fluorine element treatment method on the surface of the silicon oxide film layer provided by the embodiment of the present invention, remove the fluorine element 2 on the surface of the unetched silicon oxide film layer 1, such as Figure 3 As shown in Figure (c).

[0077] In some optional embodiments, the above step S103 may be performed at least once to control the fluorine content on the surface of the silicon oxide film layer.

[0078] In practical applications, after executing the above step S103 at least once, the process may be terminated, or other steps may be performed. The other steps may be, for example, etching steps of another film layer, or may be transition steps for achieving certain functions.

[0079] Third embodiment

[0080] As another technical solution, please also refer to Figure 4 and Figure 5 , an embodiment of the present invention provides an etching method, comprising:

[0081] S201, providing a silicon oxide film layer 1, and having at least one functional film layer 3 on the silicon oxide film layer 1, such as Figure 5 Figure (a) shows;

[0082] S202, using a plasma formed by a fluorine-containing gas to etch at least one functional film layer 3 until the surface of the silicon oxide film layer 1 is exposed, such as Figure 5 As shown in Figure (b);

[0083] The above step S202 is, for example, used to etch at least one functional film layer 3 to form a through hole penetrating the thickness thereof, so as to expose the surface of the silicon oxide film layer 1 .

[0084] S203, using the fluorine element treatment method on the surface of the silicon oxide film layer provided by the embodiment of the present invention, remove the fluorine element on the surface of the exposed silicon oxide film layer 1, such as Figure 5 As shown in Figure (c).

[0085] In some optional embodiments, the above step S203 may be performed at least once to control the fluorine content on the surface of the silicon oxide film layer.

[0086] In practical applications, after executing the above step S203 at least once, the process may be terminated, or other steps may be performed. The other steps may be, for example, etching steps of another film layer, or may be transition steps for achieving certain functions.

[0087] Fourth embodiment

[0088] As another technical solution, please also refer to Figure 6 and Figure 7 , an embodiment of the present invention provides an etching method, comprising:

[0089] S301, providing a fluorine-containing silicon oxide film layer 4, such as Figure 7 Figure (a) shows;

[0090] The surface of the fluorine-containing silicon oxide film layer 4 still has fluorine elements, for example, a fluorine-silicate glass (F-SiO) layer. The fluorine-silicate glass layer can be processed by chemical vapor deposition (CVD) equipment, using silicon tetrafluoride (SiF4) / silicon tetrahydride (SiH4) gas to react with an oxidant to form fluorine-silicate glass.

[0091] S302, etching the fluorine-containing silicon oxide film layer 4, such as Figure 7 As shown in Figure (b);

[0092] The above step S302 is used, for example, to form a groove on the fluorine-containing silicon oxide film layer 4 , and fluorine element exists on the bottom surface 41 of the groove of the fluorine-containing silicon oxide film layer 4 after etching.

[0093] S303, using the fluorine element treatment method on the surface of the silicon oxide film layer provided by the embodiment of the present invention, remove the fluorine element on the surface of the fluorine-containing silicon oxide film layer 4, such as Figure 7 As shown in Figure (c).

[0094] After completing step S303, the fluorine element on the groove bottom surface 41' of the treated fluorine-containing silicon oxide film layer 4 is reduced or completely removed. In some optional embodiments, step S303 may be performed at least once to control the fluorine element content on the surface of the fluorine-containing silicon oxide film layer 4.

[0095] As a variant of this embodiment, please refer to Figure 8 and Fig. 9 , this variant embodiment provides an etching method, comprising:

[0096] S401, providing a fluorine-containing silicon oxide film layer 4, such as Fig. 9 Figure (a) shows;

[0097] Fluorine may also exist on the surface 41 of the fluorine-containing silicon oxide film layer 4 before etching.

[0098] S402, using the fluorine element treatment method on the surface of the silicon oxide film layer provided by the embodiment of the present invention, remove the fluorine element on the surface of the fluorine-containing silicon oxide film layer 4, such as Fig. 9 As shown in Figure (b);

[0099] After completing step S402, the fluorine element on the surface 41' of the treated fluorine-containing silicon oxide film layer 4 is reduced or completely removed. In some optional embodiments, step S402 may be performed at least once before performing step S403 to control the fluorine element content on the surface of the fluorine-containing silicon oxide film layer 4.

[0100] S403, etching the fluorine-containing silicon oxide film layer 4, such as Fig. 9As shown in Figure (c).

[0101] The above step S403 is, for example, used to form a groove on the fluorine-containing silicon oxide film layer 4 .

[0102] Optionally, after step S403, step S402 may be performed at least once more to remove the fluorine element present on the bottom surface of the groove of the etched fluorine-containing silicon oxide film layer 4. Of course, in practical applications, step S402 may be performed at least once before and / or after etching the fluorine-containing silicon oxide film layer 4 according to specific needs.

[0103] The etching method provided in the embodiment of the present invention can significantly reduce and control the fluorine content on the surface of the silicon oxide film layer by adopting the above-mentioned silicon oxide film layer surface fluorine element treatment method provided in the embodiment of the present invention, thereby ensuring the etching morphology and material quality; at the same time, the etching process is completed in the same chamber, and the wafer can be processed in situ, thereby improving the process efficiency.

[0104] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A method for treating the surface of a silicon oxide film with fluorine element, It is characterized in that include: Treating the surface of the silicon oxide film layer with plasma formed by chlorine-containing gas to reduce the ability of the fluorine element on the surface of the silicon oxide film layer to bind to the surface of the silicon oxide film layer; The surface of the silicon oxide film layer after the bombardment treatment is formed by plasma formed by the first inert gas to remove chlorine and fluorine elements on the surface of the silicon oxide film layer.

2. The method for treating the surface of a silicon oxide film with fluorine according to claim 1, It is characterized in that The surface of the silicon oxide film layer bombarded with plasma formed by the first inert gas comprises: The kinetic energy of ions in the plasma formed by the first inert gas is reduced by adjusting the process parameters related to the kinetic energy of ions, so as to avoid damaging the surface of the silicon oxide film layer.

3. The method for treating the surface of a silicon oxide film with fluorine according to claim 2, It is characterized in that The process parameters related to the ion kinetic energy include: at least one of the chamber pressure, the flow rate of the first inert gas, and the lower electrode power.

4. The method for treating the surface of a silicon oxide film with fluorine according to claim 1, It is characterized in that After the surface of the silicon oxide film layer is treated by plasma formed by chlorine-containing gas, and before the surface of the silicon oxide film layer is bombarded by plasma formed by the first inert gas, the method further includes: A purge gas is introduced into the chamber to remove the chlorine-containing gas in the chamber.

5. The method for treating the surface of a silicon oxide film with fluorine according to any one of claims 1 to 4, It is characterized in that The process of treating the surface of the silicon oxide film layer with plasma formed by chlorine-containing gas and bombarding the surface of the silicon oxide film layer after treatment with plasma formed by a first inert gas are performed in a cycle at least once, and the remaining fluorine content on the surface of the silicon oxide film layer is controlled by adjusting the number of cycles.

6. The method for treating the surface of a silicon oxide film with fluorine according to claim 1, It is characterized in that The chlorine-containing gas includes chlorine gas.

7. The method for treating the surface of a silicon oxide film with fluorine according to claim 1 or 6, It is characterized in that The method of treating the surface of the silicon oxide film layer with plasma formed by chlorine-containing gas comprises: While the chlorine-containing gas is introduced into the chamber, a second inert gas is introduced into the chamber.

8. An etching method, It is characterized in that include: Providing a silicon monoxide film layer; Etching the silicon oxide film layer using plasma formed by fluorine-containing gas; The fluorine element on the surface of the silicon oxide film layer that has not been etched is removed by using the fluorine element treatment method on the surface of the silicon oxide film layer as described in any one of claims 1 to 7.

9. An etching method, It is characterized in that include: Providing a silicon oxide film layer, and having at least one functional film layer on the silicon oxide film layer; Etching the at least one functional film layer using plasma formed by fluorine-containing gas until the surface of the silicon oxide film layer is exposed; The fluorine element on the surface of the silicon oxide film layer is removed by using the fluorine element treatment method on the surface of the silicon oxide film layer as described in any one of claims 1 to 7.

10. An etching method, It is characterized in that include: Providing a fluorine-containing silicon oxide film layer; Etching the fluorine-containing silicon oxide film layer; Before and / or after etching the fluorine-containing silicon oxide film layer, the fluorine element on the surface of the silicon oxide film layer is removed by using the fluorine element treatment method on the surface of the fluorine-containing silicon oxide film layer according to any one of claims 1 to 7.

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