A surface treatment process for a wafer

Abstract

This invention discloses a wafer surface treatment process, comprising: providing a pre-cleaning chamber; introducing a wafer with an oxide layer formed on its surface into the pre-cleaning chamber and heating the wafer to 100°C to 300°C; introducing an etching gas with a first flow rate into the pre-cleaning chamber to perform a surface pre-treatment on the wafer for 1s to 3s; introducing the etching gas with a second flow rate, the second flow rate being less than the first flow rate, into the pre-cleaning chamber to remove the oxide layer on the surface of the wafer; wherein the pressure in the pre-cleaning chamber is maintained in the range of 0.8 Torr to 1.2 Torr. By synergistically utilizing temperature, flow rate, and pressure, the surface reactivity of the wafer is improved, the difference in reaction rates between new and old wafers is reduced, thereby ensuring the stability of the etching results.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and more specifically to a wafer surface treatment process. Background Technology

[0002] In semiconductor manufacturing processes, wafer surface pre-cleaning is a crucial step. Its purpose is to remove the natural oxide layer and contaminants from the wafer surface, providing a clean and activated surface for subsequent processes such as thin film deposition and epitaxial growth. Currently, mainstream pre-cleaning processes typically involve a complexation reaction between fluorine-containing gases and nitrogen-containing hydrogen gases at a specific temperature to generate volatile substances, which are then volatilized through annealing, thereby achieving the cleaning purpose.

[0003] However, in actual production, significant differences in etching performance were observed when using the same process formulation to process wafers with different historical conditions. Specifically, in the pre-cleaning process, the etching amount was lower and the etching uniformity was poor for new wafers that had not undergone any etching treatment; while for older wafers that had already undergone etching, both the etching amount and etching uniformity were improved. This difference in etching rate and uniformity caused by the different historical conditions of the wafers seriously affected the stability and consistency of the process.

[0004] The statements herein provide only background information in relation to the present invention and do not necessarily constitute prior art. Summary of the Invention

[0005] The purpose of this invention is to overcome the defect that when the same etching process is performed on new and old wafers in a pre-cleaning cavity, there will be a significant difference in etching rate and etching uniformity.

[0006] To achieve the above objectives, the present invention provides a wafer surface treatment process, comprising: A pre-cleaning chamber is provided, into which a wafer with an oxide layer formed on its surface is introduced, and the wafer is heated to 100°C~300°C. An etching gas with a first flow rate is introduced into the pre-cleaning chamber to perform a surface pretreatment on the wafer to be processed for a duration of 1s to 3s. The etching gas with a second flow rate, which is less than the first flow rate, is introduced into the pre-cleaning chamber to remove the oxide layer on the surface of the wafer to be processed. The pressure inside the pre-cleaning chamber is maintained within the range of 0.8 Torr to 1.2 Torr.

[0007] Optionally, the etching gas includes a first etching gas and a second etching gas, wherein the first etching gas contains a nitrogen-containing hydrogen gas and the second etching gas contains a fluorine-containing gas.

[0008] Optionally, the nitrogen-containing hydrogen gas includes NH3 and / or N2H4, and the fluorine-containing gas includes at least one of HF, CF4, CHF3, CH2F2, CH3F, NF3, and SF6.

[0009] Optionally, the flow rate ratio of the first etching gas to the second etching gas is 1:1.

[0010] Optionally, the flow rate of the first flow rate is in the range of 40 sccm to 60 sccm.

[0011] Optionally, during the surface pretreatment, a carrier gas is also introduced into the pre-cleaning chamber; the carrier gas includes a first gas and a second gas, wherein the first gas includes at least one of Ar, N2, and Xe, and the second gas includes at least one of H2 and He.

[0012] Optionally, the first gas is Ar and the second gas is H2.

[0013] Optionally, the flow rate ratio of the first gas to the second gas ranges from 0.125 to 0.375.

[0014] Optionally, the flow rate of the carrier gas is 200 sccm to 1600 sccm.

[0015] Optionally, before performing the surface pretreatment, the wafer to be treated is placed in a pre-cleaning chamber and heated to 150°C~200°C.

[0016] Optionally, during the surface pretreatment process and the removal of the oxide layer from the surface of the wafer to be treated, the temperature of the wafer to be treated is 20°C to 60°C.

[0017] Optionally, the wafer to be processed is an unetched wafer or a wafer that has been etched at least once.

[0018] Compared to the prior art, the beneficial effects of the present invention include at least the following: This invention adds a surface pretreatment step before removing the oxide layer from the wafer surface. Before surface pretreatment, the wafer is heated to 100°C to 300°C, increasing the initial activation energy of the new wafer surface and compensating for the activity difference between it and the old wafer. During surface pretreatment, a large flow rate of etching gas is introduced to increase the concentration of the etching gas, ensuring sufficient contact and collision frequency between the etching gas and the wafer surface, thus enabling the etching gas to react fully with the wafer surface. In addition, the high concentration of etching gas allows the reactive gas to more evenly cover and act on all areas of the wafer surface, reducing uneven etching caused by insufficient local etching gas. During both the surface pretreatment and the formal etching to remove the oxide layer, the pressure in the pre-cleaning chamber is maintained at 0.8 Torr to 1.2 Torr. By reducing the pressure and increasing the molecular free path, the etching gas distribution becomes more uniform, and the reactive particles can more effectively reach all positions on the wafer surface. By working synergistically with temperature, flow rate, and pressure, the surface reactivity of the wafer is improved, and the difference in reaction rate between new and old wafers is reduced, thereby ensuring the stability of the etching results (etching amount and uniformity). Attached Figure Description

[0019] Figure 1 Atomic force scanning electron microscopy (AFM) images of the surface morphology of new and old wafers after etching using existing etching processes; where (a) is the new wafer and (b) is the old wafer.

[0020] Figure 2 This diagram illustrates the comparison of activation energies on the surfaces of new and old wafers after etching using existing etching processes. Both Old and Used represent old wafers, but Old indicates an old wafer that has been idle for a long period after etching, while Used indicates an old wafer that has not been idle for a long period after etching. New represents a new wafer.

[0021] Figure 3 This is a schematic flowchart of a wafer surface treatment process according to the present invention.

[0022] Figure 4 The images show the film thickness distribution on the surface of a new wafer and an old wafer under different flow ratios of the first gas Ar and the second gas H2, according to the present invention. Among them, (a1) and (a2) are the new wafer and the old wafer under the condition of Ar:H2=400::1600, respectively; (b1) and (b2) are the new wafer and the old wafer under the condition of Ar:H2=100:800, respectively; (c1) and (c2) are the new wafer and the old wafer under the condition of Ar:H2=200:800, respectively; and (d1) and (d2) are the new wafer and the old wafer under the condition of Ar:H2=300:800, respectively.

[0023] Figure 5The images show the film thickness distribution on the surface of a new wafer and an old wafer under different flow ratios of the first etching gas NH3 and the second etching gas HF, according to the present invention. Among them, (a1) and (a2) are the new wafer and the old wafer under the condition of NH3:HF=20:20, (b1) and (b2) are the new wafer and the old wafer under the condition of NH3:HF=40:40, and (c1) and (c2) are the new wafer and the old wafer under the condition of NH3:HF=60:60.

[0024] Figure 6 The image shows the film thickness distribution on the surfaces of three groups of new and old wafers under a pressure of 1 Torr in the pre-cleaning chamber of the present invention; wherein (a1) and (a2) are the first group of new and old wafers, respectively, (b1) and (b2) are the second group of new and old wafers, respectively, and (c1) and (c2) are the third group of new and old wafers, respectively. Detailed Implementation

[0025] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] In the description of this invention, it should be noted that the terms "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0027] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0028] It should be noted that the accompanying drawings are all in a very simplified form and use non-precise ratios, and are only used to facilitate and clearly illustrate the purpose of this invention.

[0029] definition New wafer: The new wafer mentioned in this invention refers to a wafer that has not undergone etching, such as a wafer that has just been polished / cleaned.

[0030] Used wafers: In this invention, used wafers refer to wafers that have undergone at least one etching process, such as wafers after process transfer.

[0031] In advanced semiconductor manufacturing processes, atomic-level precision is required for the etching amount, cleanliness, and surface condition of wafers. In the pre-cleaning chamber, after performing pre-cleaning processes on new and old wafers respectively, differences in etching amount and uniformity will appear. These differences will cause the wafers to deviate from the process's preset "target state," and the surface condition of wafers within and between batches will exhibit irregular fluctuations, affecting the stability and consistency of the process. Ultimately, this leads to the failure of subsequent core processes, deviations in device performance, and significant fluctuations in yield.

[0032] To investigate the reasons for the differences in etching amount and uniformity between new and old wafers, this invention first analyzes the surface activation energy and surface undulation degree of new and old wafers. For example... Figure 1 As shown, the surface undulation of the old wafer is significantly greater than that of the new wafer, such as... Figure 2 As shown, surface activation energies were measured at different sites on wafers in different historical states. Here, C represents the central region of the wafer, and M represents the ring region between the central and edge regions. The results showed that the older wafers had higher chemical potential energy and stronger activity. Therefore, the difference in etching amount and uniformity between new and old wafers is due to the greater surface undulation of the older wafers compared to the newer wafers. This results in more reaction sites and a higher surface activation energy on the older wafers, leading to more complete reactions and more uniform etching. Conversely, the newer wafers have less surface undulation, fewer reaction sites, and a lower surface activation energy, resulting in a significantly lower etching amount compared to the older wafers.

[0033] To address the aforementioned differences between new and old wafers, namely, to ensure the activation energy of the wafer surface while mitigating the impact of surface undulations on the etching amount, the goal is to ensure that even with fewer surface reaction sites, the new wafer achieves an etching amount and etching rate no less than that of the old wafer, thereby guaranteeing the stability and uniformity of the process. This invention provides a wafer surface treatment process. Before the formal etching to remove the oxide layer, a surface pretreatment step is added. Before the surface pretreatment step, the wafer is heated to 100℃~300℃ to increase the initial activation energy of the wafer and reduce the activity difference between wafers with different historical states. During the surface pretreatment, a large flow rate of etching gas (greater than the flow rate during the formal etching to remove the oxide layer) is introduced for 1s~3s to increase the concentration of the etching gas, so that the reactive gas can uniformly cover and act on all areas of the wafer surface, reducing etching unevenness caused by insufficient local etching gas concentration. During both the surface pretreatment and the formal etching to remove the oxide layer, the pressure in the pre-cleaning chamber is maintained at 0.8Torr~1.2Torr. By reducing the pressure, the molecular free path is increased, resulting in a more uniform distribution of etching gas. This invention achieves consistency and stability in etching amount and uniformity between new and old wafers by adjusting temperature, pressure, and flow rate to activate the surface activation energy and control the etching rate.

[0034] like Figure 3 As shown, the present invention provides a surface treatment process for wafers, including: Step S1: A pre-cleaning chamber is provided, and the wafer to be processed with an oxide layer formed on its surface is introduced into the pre-cleaning chamber and heated to 100°C~300°C.

[0035] It should be noted that the wafer to be processed in this invention is an unetched wafer (i.e., a new wafer) or a wafer that has been etched at least once (i.e., an old wafer).

[0036] In low-temperature environments, the thermal kinetic energy of atoms on the surface of a new wafer is extremely low, and collisions with etching gas molecules are mostly "ineffective collisions," making it difficult to initiate a reaction, resulting in low etching depth and slow etching rate. Before performing surface pretreatment on the wafer to be processed, this invention heats the wafer to 100°C to 300°C, which exponentially increases the thermal kinetic energy of the atoms on the surface of the new wafer, significantly increasing the probability of effective collisions. Complexation reactions that originally required high energy to initiate can now occur spontaneously and uniformly after heating, effectively increasing the initial activation energy of the new wafer surface, narrowing the activity gap with the old wafer, and improving the etching rate of the new wafer. In some embodiments, the wafer to be processed is heated to 150°C to 200°C before performing the surface pretreatment.

[0037] Step S2: Introduce etching gas with a first flow rate into the pre-cleaning chamber to perform surface pretreatment on the wafer to be processed for a duration of 1s to 3s.

[0038] The etching gas described in this invention comprises a first etching gas and a second etching gas. The first etching gas contains a nitrogen-hydrogen gas, and the second etching gas contains a fluorine-containing gas. During the surface pretreatment, a carrier gas is also introduced into the pre-cleaning chamber. After the wafer to be processed is introduced into the pre-cleaning chamber, the nitrogen-hydrogen gas, the fluorine-containing gas, and the carrier gas are introduced. The fluorine-containing gas and a suitable amount of carrier gas form a first mixed gas, which is introduced through a first pipe. The nitrogen-hydrogen gas and a suitable amount of carrier gas form a second mixed gas, which is introduced through a second pipe. The surface oxide layer of the wafer to be processed undergoes a complexation reaction with the introduced fluorine-containing gas and nitrogen-hydrogen-containing gas to form volatile (NH4)2SiF6. During the subsequent annealing reaction, (NH4)2SiF6 gradually volatilizes. In some embodiments, the complexation reaction temperature is 20°C to 60°C, preferably 30°C to 50°C. The annealing reaction temperature is 100°C to 200°C, preferably 120°C to 180°C.

[0039] In some embodiments, the nitrogen-containing hydrogen gas comprises NH3 and / or N2H4, and the fluorine-containing gas comprises at least one of HF, CF4, CHF3, CH2F2, CH3F, NF3, and SF6. The carrier gas comprises a first gas and a second gas, wherein the first gas comprises at least one of Ar, N2, and Xe, preferably Ar, and the second gas comprises at least one of H2 and He, preferably H2.

[0040] During the surface pretreatment of the wafer to be processed, a series of preliminary experiments were conducted. These experiments revealed that when the flow ratio of the first etching gas to the second etching gas was 1:1, the new and old wafers exhibited optimal etching rates and uniformity. Based on the 1:1 flow ratio of the first and second etching gases, this invention further investigated the first and second gases with different flow ratios. With the wafer to be processed heated to 100°C to 300°C, the pressure in the pre-cleaning chamber at 2.5 Torr, and the flow ratio of the first and second etching gases at 1:1, the first and second gases with flow ratios of 0.125 to 0.375 (e.g., Ar to H2 flow ratios of 400:1600, 100:800, 200:800, or 300:800) were introduced into the pre-cleaning chamber. The first and second gases, and the first and second etching gases, underwent a complexation reaction, thus performing surface pretreatment on the wafer to be processed. In some embodiments, the flow rate of the carrier gas is 200 sccm to 1600 sccm. For example... Figure 4As shown, the etching amount of the wafer to be processed has increased, but the uniformity between the new and old wafers has not been improved. Therefore, changing the flow ratio of the first and second carrier gases alone cannot simultaneously achieve a stable etching rate and uniformity.

[0041] like Figure 4 It can be seen that when Ar:H2=400:1600=0.25, the new and old wafers exhibit optimal uniformity. Therefore, under this flow ratio, the present invention continues to study the flow rates of the first and second etching gases. With the wafer to be processed heated to 100℃~300℃, the pressure in the pre-cleaning chamber at 2.5 Torr, and the flow ratio of the first gas Ar and the second gas H2 at 0.25, the first etching gas NH3 and the second etching gas HF with a flow ratio of 1:1 (specifically NH3:HF=20:20, NH3:HF=40:40, NH3:HF=60:60) are introduced into the pre-cleaning chamber. The first etching gas NH3 and the second etching gas HF undergo a complexation reaction with the first gas Ar and the second gas H2, performing surface pretreatment on the wafer to be processed. In some embodiments, the flow rate range of the first and second etching gases is 40 sccm~60 sccm. Figure 5 As shown, in the pretreatment step, the flow rate ratio of the first etching gas and the second etching gas is 1:1, and when the flow rate is between 40 sccm and 60 sccm, both the new and old wafers obtain stable etching amount and uniformity, and the uniformity between the two is reduced, with the uniformity difference within 2%.

[0042] In the pretreatment step of this invention, introducing a high-flow-rate etching gas increases the concentration of the etching gas in the pre-cleaning chamber. On one hand, a higher flow rate ensures sufficient contact and collision frequency between the etching gas and the wafer surface, allowing for a more thorough reaction. On the other hand, the high concentration of etching gas allows the reacting gas to more evenly cover and act on various areas of the wafer surface, reducing etching unevenness caused by insufficient local etching gas. By increasing the etching gas concentration in the pretreatment step, this invention makes the surface undulations of new and old wafers more similar, reducing the impact of differences in surface undulations on the etching amount and uniformity of the new and old wafers.

[0043] Based on the above, this invention further investigated the process parameters, reducing the pressure in the original pre-cleaning chamber from 2.5 Torr to a range of 0.8 Torr to 1.2 Torr. Figure 6As shown, both new and old wafers achieved stable etching amounts and uniformity, with the uniformity difference between them further reduced to within 1.5%. This demonstrates that reducing chamber pressure (i.e., creating a low-pressure process environment) has significant advantages in improving the etching process. This is mainly because a low-pressure environment increases the mean free path of gas molecules, thereby significantly improving molecular mobility. Higher mobility allows reactants to diffuse more rapidly and uniformly across the entire surface of the wafer, ensuring effective replenishment of reactants throughout the wafer. Furthermore, low-pressure conditions help reduce the adsorption and retention of reaction byproducts on the wafer surface, promoting rapid desorption and extraction of reaction products, thus maintaining a clean reaction interface and improving the effective utilization rate of the surface reaction. Reducing chamber pressure ensures the stability of the etching amount while achieving uniformity in the etching performance of both new and old wafers.

[0044] As can be seen, in order to achieve stable etching amount and uniformity for wafers in different historical states, this invention utilizes a surface pretreatment step to regulate the etching rate and surface activation energy of new and old wafers before the formal etching removal of the oxide layer on the surface of the wafer to be processed. This is achieved through the synergistic effect of temperature, etching gas, carrier gas flow rate ratio, and pressure, ensuring the stability of the etching results. Specifically: (1) Before the surface pretreatment begins, the wafer is heated to 100℃~300℃ to activate the surface activation energy and achieve consistency in the surface undulation and surface activation energy between the new and old wafers: The surface of the new wafer has a natural low-energy passivation layer and adsorbed weakly bound impurities, and the surface atomic activity is low and the microstructure is more "regular". The old wafer has formed an activation state and surface undulation that matches the etching process due to previous process contact. The thermal activation effect of heating can break the passivation layer, improve atomic activity, and regulate the microstructure, so that the physical (surface undulation) and chemical (activation energy) states of the new wafer surface are similar to those of the old wafer. Ultimately, this ensures the consistency of etching rate, uniformity, and morphology between the new and old wafers, and avoids fluctuations in process yield due to differences in the initial state of the wafer.

[0045] (2) During surface pretreatment, a first etching gas and a second etching gas with a flow ratio of 1:1 are introduced, and a carrier gas flow ratio of 0.125 to 0.375 is introduced. The flow rate of the etching gas is between 40 sccm and 60 sccm. The old wafer has low activation energy and sufficient active sites, and can undergo a stable etching reaction even at a low etching gas concentration. However, the new wafer has a passivation layer and fewer active sites, requiring a higher etching gas concentration to compensate for its "reaction inertia" and increase the number of effective reactions per unit time. By reducing the flow ratio of the carrier gas and increasing the flow rate of the etching gas, on the one hand, the concentration of the etching gas in the pre-cleaning chamber can be increased, which significantly increases the etching rate of the new wafer. On the other hand, the etching rate of the old wafer remains basically unchanged because it has reached saturation. This reduces the difference in etching rates between the two and achieves consistency in etching rates. On the other hand, the carrier gas can also indirectly affect the actual distribution concentration of the etching gas by controlling the airflow state in the chamber.

[0046] (3) During surface pretreatment, the pressure in the pre-cleaning chamber is maintained in the range of 0.8 Torr to 1.2 Torr: The low-pressure environment reduces the movement obstacles of the etching gas (and active particles), allowing gas molecules to move further and faster (increasing the free path and mobility), and allowing the etching gas to obtain higher energy in plasma ionization (increasing the reactivity). Ultimately, the etching gas can reach the wafer surface more efficiently and in a more directional manner to participate in the etching reaction. On the basis that the wafer has been activated before surface pretreatment and the etching gas concentration is relatively high during surface pretreatment, the low-pressure environment makes the etching gas distribution more uniform, ultimately achieving stable etching amount and uniformity.

[0047] The surface pretreatment time of this invention is 1s to 3s. If the surface pretreatment time is too long, the etching amount will be higher than the target value, and the uniformity of the wafer surface will also be deteriorated. The main reason is that there are natural slight differences in the etching rate in different areas of the wafer. The longer the time, the greater the cumulative etching amount deviation of this etching rate difference. At the same time, long-term etching will cause continuous changes in the etching environment and the distribution of reactants / products, further aggravating the uneven etching effect in each area, and ultimately resulting in a significant decrease in the etching depth and morphological uniformity of the wafer surface.

[0048] Step S3: The etching gas with a second flow rate, which is less than the first flow rate, is introduced into the pre-cleaning chamber to remove the oxide layer on the surface of the wafer to be processed.

[0049] After the surface pretreatment of the wafer to be processed is completed, the new and old wafers reach similar surface undulations and surface activation energies. At this point, the formal etching process is performed on the wafer to remove the oxide layer on its surface. Understandably, the flow rate of the etching gas at this time is less than that during surface pretreatment. The main reason is that when the surface states of the new and old wafers are consistent, the number of effective active sites, surface activation energies, and micro-surface undulations are almost identical, and the compensation effect of high concentration disappears. At this point, a conventional concentration of etching gas is sufficient to maintain the same etching rate for the new and old wafers. If a high concentration of etching gas continues to be used, it will cause a series of side effects in the etching process, which will instead damage the uniformity and morphological accuracy of the etching.

[0050] Similarly, during the process of removing the oxide layer, there is no need to activate the surface activation energy of the wafer to be processed. Therefore, the temperature of the wafer surface to be processed does not need to be too high. In some embodiments, during the process of removing the oxide layer, the temperature of the wafer to be processed is 20°C to 60°C. At this temperature, the first etching gas, the second etching gas, and the carrier gas undergo a complexation reaction, and the generated (NH4)2SiF6 gradually volatilizes, thereby achieving the purpose of removing the oxide layer.

[0051] In summary, before performing surface pretreatment on the wafer to be processed, the present invention first heats the wafer to be processed to 100°C~300°C to activate its surface activation energy; under a low-pressure environment, an etching gas with a first flow rate is introduced into the pre-cleaning chamber to perform surface pretreatment on the wafer to be processed for a duration of 1s~3s, so that the surface state of the new and old wafers tends to be consistent; then, the etching gas with a second flow rate, which is less than the first flow rate, is introduced into the pre-cleaning chamber to remove the oxide layer on the surface of the wafer to be processed. The above surface treatment process can enable wafers with different historical states to have stable etching amount and uniformity.

[0052] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A surface treatment process for wafers, characterized in that, include: A pre-cleaning chamber is provided, into which a wafer with an oxide layer formed on its surface is introduced, and the wafer is heated to 100°C~300°C. An etching gas with a first flow rate is introduced into the pre-cleaning chamber to perform a surface pretreatment on the wafer to be processed for a duration of 1s to 3s. The etching gas with a second flow rate, which is less than the first flow rate, is introduced into the pre-cleaning chamber to remove the oxide layer on the surface of the wafer to be processed. The pressure inside the pre-cleaning chamber is maintained within the range of 0.8 Torr to 1.2 Torr.

2. The surface treatment process as described in claim 1, characterized in that, The etching gas includes a first etching gas and a second etching gas, wherein the first etching gas contains a nitrogen-containing hydrogen gas and the second etching gas contains a fluorine-containing gas.

3. The surface treatment process as described in claim 2, characterized in that, The nitrogen-containing hydrogen gas includes NH3 and / or N2H4, and the fluorine-containing gas includes at least one of HF, CF4, CHF3, CH2F2, CH3F, NF3, and SF6.

4. The surface treatment process as described in claim 2, characterized in that, The flow rate ratio of the first etching gas to the second etching gas is 1:

1.

5. The surface treatment process as described in claim 1, characterized in that, The flow rate of the first flow rate is 40 sccm to 60 sccm.

6. The surface treatment process as described in claim 1, characterized in that, During the surface pretreatment, a carrier gas is also introduced into the pre-cleaning chamber; the carrier gas includes a first gas and a second gas, wherein the first gas includes at least one of Ar, N2, and Xe, and the second gas includes at least one of H2 and He.

7. The surface treatment process as described in claim 6, characterized in that, The first gas is Ar, and the second gas is H2.

8. The surface treatment process as described in claim 6, characterized in that, The flow rate ratio of the first gas to the second gas ranges from 0.125 to 0.

375.

9. The surface treatment process as described in claim 6, characterized in that, The flow rate of the carrier gas is 200 sccm to 1600 sccm.

10. The surface treatment process as described in claim 1, characterized in that, Before performing the surface pretreatment, the wafer to be treated is placed in a pre-cleaning chamber and heated to 150°C~200°C.

11. The surface treatment process as described in claim 1, characterized in that, During the surface pretreatment process and the removal of the oxide layer from the surface of the wafer to be treated, the temperature of the wafer to be treated is 20°C to 60°C.

12. The surface treatment process as described in claim 1, characterized in that, The wafer to be processed is either an unetched wafer or a wafer that has undergone at least one etching process.

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