Semiconductor manufacturing apparatus and cleaning method for semiconductor manufacturing apparatus

Abstract

The object of this invention is to provide a technique that can reduce reaction products and residual HF within a chamber. A semiconductor manufacturing apparatus includes: an inlet for introducing a processing gas containing hydrogen fluoride and alcohol vapor into a processing chamber inside a processing container; a sample stage disposed within the processing chamber, on the upper surface of which a wafer to be processed is mounted; and an inlet mechanism for introducing a polar molecular gas into the inlet.

Description

Technical Field

[0001] The present invention relates to a semiconductor manufacturing apparatus for manufacturing semiconductor devices by processing a film disposed on a substrate-shaped sample such as a semiconductor wafer, and a cleaning method for the semiconductor manufacturing apparatus. Background Technology

[0002] As described above, the manufacture of semiconductor devices involves processing a film pre-formed on a sample such as a semiconductor wafer to form a circuit structure. In the manufacture of such semiconductor devices, the demand for higher precision processing techniques increases with the miniaturization of semiconductor devices. In particular, SiO2 films composed of or containing silicon dioxide (SiO2) are used in the circuits of various semiconductor devices, and the techniques for etching them have been continuously researched and improved over the years. In recent years, the development of so-called vapor phase etching has advanced the processing of SiO2 films. This method does not use plasma; instead, it supplies the vapor of a specific substance to the surface of the SiO2 film as a processing gas, causing the atoms or molecules of that substance to react with SiO2. Existing methods for removing SiO2 films mainly utilize wet etching with hydrofluoric acid. However, with the miniaturization of semiconductor devices in recent years, issues such as pattern collapse due to surface tension have emerged. Therefore, for example, vapor phase etching using a mixture of hydrogen fluoride (HF) and alcohol, as described in Non-Patent Document 1, Non-Patent Document 2, or Patent Document 1, has been proposed. In addition, in recent years, low-temperature processes below -10°C have been considered promising in vapor phase etching of HF and alcohols in order to improve the selectivity of etching SiO2 relative to silicon nitride (SiN).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: JP Japanese Patent Application Publication No. 2005-161493

[0006] Non-patent literature

[0007] Non-patent document 1: Chun Su Lee et al., "Modeling and Characterization of Gas-Phase Etching of Thermal Oxide and TEOS Oxide Using Anhydrous HF and CH3OH", J. Electrochem. Soc., vol. 143, No. 3pP. 1099-1103 (1996)

[0008] Non-patent literature 2: Keiichi Shimaoka et al., “Characteristic of Silicon Nitride Reaction to Vapor-Phase HF Gas Treatment”, IEEJ Trans.SM, vol.126, No.9, pp.516-521 (2006) Summary of the Invention

[0009] The problem that the invention aims to solve

[0010] One of the challenges in semiconductor manufacturing apparatuses that perform vapor phase etching (conveniently referred to as plasma-free dry processing apparatuses) lies in the cleaning method of the interior of the vacuum chamber (also called the reaction chamber). While existing dry etching apparatuses can perform plasma-based cleaning of the interior of the chamber (using oxidation / physical energy assistance, etc.), it is difficult to perform plasma-based cleaning of the interior of the chamber in plasma-free dry processing apparatuses without a plasma source. Furthermore, in the aforementioned low-temperature processes utilizing HF, the problem of degradation of the device characteristics of semiconductor elements formed on semiconductor wafers due to the influence of fluorine caused by the reaction products generated during etching becomes apparent.

[0011] exist Figure 1 A schematic diagram of vapor phase etching in the stacked structure 33 of SiN film 31 and SiO2 film 32 is shown. Here, hydrogen fluoride HF and methanol CH3OH are used as the etching gases for vapor phase etching. Figure 1 The mixture 34 is shown as ALC. The SiO2 film 32 is etched according to the following reaction formula 1 (Non-Patent Document 1).

[0012] (Reaction 1) SiO2 + 4HF + 2CH3OH → SiF4(↑) + 2H2O + 2CH3OH

[0013] In this process, residual HF is attached as a residual gas to the SiN / SiO2 laminate 33. The amount of HF attached tends to increase as the temperature decreases. In the low-temperature process described in Patent Document 2, which utilizes a mixed gas 34 of HF and CH3OH, residual hydrogen fluoride 35 is present. Figure 1 In this process, the amount of residual hydrogen fluoride 35 (shown by a white circle ○) increases. Furthermore, in etching with HF / CH3OH vapor gas, it is known that ammonium hexafluorosilicate (NH4)2SiF6, as a modifier, is formed on the SiN film 31 (Non-Patent Document 2). Ammonium hexafluorosilicate is typically a substance that sublimates upon heating, but in cases where a so-called cold point below the sublimation temperature exists inside the chamber, instances occur where ammonium hexafluorosilicate, as a reaction product 36, is deposited inside the chamber. Figure 1In the diagram, reaction product 36 is shown as a white triangle △.

[0014] A method was considered to sublimate ammonium hexafluorosilicate deposited on a semiconductor wafer within a cavity by heating with infrared (IR) lamps and hot gas. However, there are many areas within the cavity that cannot be directly exposed to the infrared light emitted by the IR lamp. For example, the lower part of the stage (sample stage) on which the semiconductor wafer is mounted for processing cannot be directly exposed to the infrared light emitted by the IR lamp, thus the deposition of reaction products and residual HF becomes a problem, and it is difficult to reduce residual fluorine using only IR lamps.

[0015] Furthermore, in the maintenance of semiconductor manufacturing equipment, if HF remains in the chamber, it can turn into hydrofluoric acid when exposed to the atmosphere, posing a significant risk to human health. Therefore, careful purging before atmospheric exposure is necessary. The purging time constitutes a large proportion of the downtime of semiconductor manufacturing equipment, which contributes to reduced maintainability.

[0016] The purpose of this invention is to provide a technique that can reduce reaction products and residual HF within the chamber.

[0017] Methods for solving problems

[0018] If we were to briefly describe the outline of a representative solution in this invention, it would be as follows.

[0019] One embodiment of a semiconductor manufacturing apparatus includes: an inlet for introducing a processing gas containing hydrogen fluoride and alcohol vapor into a processing chamber inside a processing container; a sample stage disposed within the processing chamber, on the upper surface of which a wafer to be processed is mounted; and an inlet mechanism for introducing a polar molecular gas into the inlet.

[0020] The effects of the invention

[0021] According to the semiconductor manufacturing apparatus of the above embodiment, there is an effect of reducing reaction products and residual HF in the chamber (reaction chamber). Furthermore, since the presence of residual hydrogen fluoride in the chamber raises concerns about variations in the etching rate of SiO2 and their impact on the device characteristics of semiconductor elements, reducing these reaction products and residual HF prevents unintended consequences such as variations in the etching rate between semiconductor wafers and degradation of the device characteristics of semiconductor elements. Therefore, in the etching of films containing SiO2, the yield of the etching process can be improved. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of residue adhesion to a SiN / SiO2 laminated film utilizing HF and methanol.

[0023] Figure 2This is a schematic diagram showing the residue adhering to the etching chamber.

[0024] Figure 3 This is a cross-sectional view of a semiconductor manufacturing apparatus having a first oxide film removal etching chamber with a cleaning mechanism having an embodiment.

[0025] Figure 4 This is a cross-sectional view of a semiconductor manufacturing apparatus having a second oxide film removal etching chamber with a cleaning mechanism having an embodiment.

[0026] Figure 5 This is a cross-sectional view of a semiconductor manufacturing apparatus having a third oxide film removal etching chamber with a cleaning mechanism having an implementation method.

[0027] Figure 6 It has Figure 3 A structural diagram of the semiconductor manufacturing apparatus for removing the first oxide film in the etching chamber.

[0028] Figure 7 It has Figure 4 The overall structure diagram of the semiconductor manufacturing apparatus for removing the second oxide film in the etching chamber.

[0029] Figure 8A This is a process flow diagram showing the case where a certain amount of CH3OH gas and the output of the second infrared lamp are set to fixed values ​​during the cleaning process.

[0030] Figure 8B This is a process flow diagram showing the pulsed introduction of CH3OH during the cleaning process.

[0031] Figure 8C This is a process flow diagram showing the pulsed application of the output of the second infrared lamp during the cleaning process.

[0032] Figure 9A This is a flowchart showing the gas flow rate when no cleaning process is performed after etching.

[0033] Figure 9B This refers to the time-lapse of residual hydrogen fluoride in cases where no cleaning process is performed after etching.

[0034] Figure 10A This is a flowchart showing the gas flow rate after etching, indicating the flow of CH3OH gas.

[0035] Figure 10B This refers to the time progression of residual hydrogen fluoride after etching, when CH3OH gas flows through the area.

[0036] Figure 11A This is a flowchart showing the gas flow rate when heated CH3OH gas flows through the area after etching.

[0037] Figure 11B This refers to the time progression of residual hydrogen fluoride after etching, when heated CH3OH gas flows through the area.

[0038] Figure 12A This is a flowchart showing the gas flow rate when heated N2 gas flows through the area after etching.

[0039] Figure 12B This refers to the time progression of residual hydrogen fluoride after etching, when heated N2 gas flows through the area. Detailed Implementation

[0040] The embodiments of the present invention are illustrated below using the accompanying drawings. However, in the following description, the same reference numerals are used to denote the same constituent elements, and sometimes repeated descriptions are omitted. Furthermore, the drawings may schematically represent aspects different from the actual embodiments for the purpose of clarity; however, this is merely an example and does not limit the interpretation of the present invention.

[0041] Figure 1 This diagram illustrates the adhesion of residues to a SiN / SiO2 laminated film utilizing HF and methanol. In the etching process of the SiO2 film 32, where a mixed gas 34 of hydrogen fluoride (HF) and methanol (CH3OH) is used as the etching gas, residual hydrogen fluoride, as shown in the diagram, remains as residual hydrogen fluoride 35 within the chamber (also called the reaction chamber) of the semiconductor manufacturing apparatus. Furthermore, reaction products 36, such as ammonium hexafluorosilicate, are formed on the SiN film 31. If these reaction products 36 are removed, for example, by heating, they may remain within the chamber. In the case of the aforementioned low-temperature etching, these residual hydrogen fluoride 35 and reaction products 36 readily adhere to the laminated film 33 of the SiN film 31 and SiO2 film 32 formed on the semiconductor wafer (also called the semiconductor substrate) 30 to be processed.

[0042] Figure 2 This diagram illustrates the generation and adhesion of reaction products in an etching chamber used for etching an oxide film using HF and alcohol. The semiconductor manufacturing apparatus 300 includes a vacuum container 1, a gas introduction unit 2, a first infrared lamp 3, a semiconductor wafer to be etched 4, and a cryogenic stage 5 with temperature control via a cooler, etc. Figure 2 In the diagram, 36 represents the reaction product represented by ammonium hexafluorosilicate, and 35 represents residual hydrogen fluoride. The low-temperature stage 5 is a sample stage on which the semiconductor wafer 4 to be etched is mounted. The vacuum container 1 constitutes an etching chamber (also called a chamber) 21 having a processing chamber 20 inside, which has the sample stage 5 on which the semiconductor wafer 4 to be etched is placed.

[0043] The characteristic feature is that, in order to obtain a selectivity ratio for SiO2 etching relative to SiN, the temperature of the low-temperature stage 5 is maintained at, for example, below -20°C. The characteristic feature is that the first infrared lamp 3 heats the wafer 4 and a portion of the low-temperature stage 5 by adjusting its output. The aforementioned residual hydrogen fluoride 35 and reaction products 36 not only adhere to the wafer 4 during the low-temperature process but also readily adhere to the components within the chamber 21. The vacuum container 1 attempts to suppress adhesion to the wall material by heating with a heater, but residual hydrogen fluoride 35 and reaction products 36 readily adhere to areas such as the sides and bottom of the low-temperature stage 5 where heating by the infrared lamp 3 is not possible. Furthermore, these adhered residual hydrogen fluoride 35 and reaction products 36 contribute to the degradation of the semiconductor characteristics of the semiconductor elements formed on the semiconductor wafer 4 and reduce the maintainability of the semiconductor manufacturing apparatus 300 including the vacuum container 1.

[0044] Therefore, in this invention, as a method to reduce residual hydrogen fluoride 35 and reaction products 36, a method is proposed to use a heated polar molecular gas as a cleaning gas after etching. Hydrogen fluoride molecules are known to be polar molecules that are electrically polarized due to the strong electronegativity of fluorine. Therefore, in order to efficiently remove residual hydrogen fluoride 35 adhering to the chamber 21, it is desirable to utilize the electrochemical removal of polar molecules such as alkyl alcohols or water. Furthermore, since the low-temperature etching, which is the object of this invention, has a high adhesion coefficient as described above, high-temperature gas irradiation is desirable for the removal of residual hydrogen fluoride 35. For the above reasons, it is believed that the removal of residual hydrogen fluoride 35 based on a heated polar molecular gas can be achieved.

[0045] Furthermore, in this invention, as a method for removing residual fluorinated compounds such as hydrogen fluoride (HF) and ammonium hexafluorosilicate from areas adhering to the interior of a chamber (reaction chamber) that cannot be directly heated by infrared light emitted from an infrared (IR) lamp, a cleaning method utilizing a heated polar molecular gas is proposed. The heating method for the polar molecular gas can employ a heater, an IR lamp, or the addition of a hot polar molecular gas. HF is a polar gas due to hydrogen bonding, but it is characterized by its ease of mixing with polar molecular gases such as alcohols. In particular, alcohols have high infrared absorption in the infrared band, thus allowing for efficient heating at the molecular level using an IR lamp. Therefore, alcohols heated by IR heating can efficiently remove residual fluoride even from areas where infrared light emitted from an IR lamp cannot directly reach.

[0046] This reduces the reaction products and residual HF within the chamber (reaction chamber). Furthermore, in the event of residual hydrogen fluoride within the chamber, concerns arise regarding variations in the SiO2 etching rate and their impact on the semiconductor device's characteristics. By reducing these reaction products and residual HF, variations in the etching rate between semiconductor wafers and the degradation of the semiconductor device's characteristics can be prevented.

[0047] Figure 3 This is a cross-sectional view of a semiconductor manufacturing apparatus having an etching chamber for removing the first oxide film, as described in this invention. Semiconductor manufacturing apparatus 100 and... Figure 2 Similarly, the description includes a vacuum container (processing container) 1, a gas inlet (also called an inlet port) 2, a first infrared lamp 3, a semiconductor wafer 4 to be etched, and a low-temperature stage 5 with temperature control by a cooler. The low-temperature stage 5 is a sample stage on which the semiconductor wafer 4 to be etched is mounted. The vacuum container 1 constitutes an etching chamber (also called a chamber) 21 with a processing chamber 20 inside, which has the sample stage 5 on which the semiconductor wafer 4 to be etched is placed. The gas inlet 2 introduces a processing gas containing hydrogen fluoride (HF) and alcohol vapor (HF and polar molecular gases) into the processing chamber 20.

[0048] The semiconductor manufacturing apparatus 100 also includes a flow controller 6 for HF, a flow regulator 7 for polar gases containing hydroxyl (OH) groups, and a flow regulator 8 for preheated gases. The flow regulator 7 for polar gases is an introduction mechanism for introducing polar molecular gases into the gas inlet section 2.

[0049] In addition, polar gases containing OH groups refer to alcohols such as methanol (CH3OH), ethanol (C2H5OH), propanol (C3H7OH), and water (H2O), but in this invention, the form of any polar molecular gas with OH groups in its molecular structure and polarity bias is not limited.

[0050] Furthermore, in the flow regulator 8 for the heating gas, it is desirable to use gases such as argon (Ar), helium (He), and nitrogen (N2) that do not directly contribute to the etching of SiO2. Figure 3 The example shown is nitrogen (N2) being heated. Furthermore, the heating method is not limited in this invention.

[0051] The method for removing the SiO2 film using the etching chamber 21 for removing the first oxide film uses an HF flow controller 6 and a polar molecular gas flow adjuster 7 to set the flow ratio of HF and polar molecular gas to be suitable for etching in order to perform the etching of the SiO2 film.

[0052] On the other hand, regarding the cleaning process inside the etching chamber 21 for removing the first oxide film, the polar molecular gas is substantially heated by mixing it with the heated gas using a polar gas flow regulator 7 and a heated gas flow regulator 8. Furthermore, there is no problem in maintaining the function of the first infrared lamp 3 during the cleaning process. With such mechanisms (7, 8), residual hydrogen fluoride 35 can be removed by heating the polar molecular gas.

[0053] Figure 4 This is a cross-sectional view of a semiconductor manufacturing apparatus having an etching chamber for removing the second oxide film according to the present invention. Semiconductor manufacturing apparatus 100a, as shown... Figure 3 As shown, the semiconductor manufacturing apparatus 100a includes a vacuum container 1, a gas inlet 2, a first infrared lamp 3, a semiconductor wafer 4, a cryogenic stage 5, a flow controller for HF 6, a flow regulator for polar gases containing hydroxyl (OH) groups 7, a processing chamber 20, and an etching chamber 21. The semiconductor manufacturing apparatus 100a also includes a gas heating mechanism 9. The gas heating mechanism 9 refers, for example, a mechanism that heats the piping using a heater. Furthermore, the location of the heating mechanism is not limited here.

[0054] During the etching process of removing the SiO2 film from the etching chamber 21 using the second oxide film, the HF flow controller 6 and the polar molecular gas flow adjuster 7 are used to set the flow ratio of HF and polar molecular gas (here, methanol CH3OH) to a suitable level for etching to carry out the etching of the SiO2 film. At this time, the gas heating mechanism 9 is not activated, and the process gas at the most suitable etching temperature is supplied.

[0055] On the other hand, during the cleaning process of the etching chamber 21 for removing the second oxide film, the HF supply is stopped using the HF flow controller 6, and only the polar molecular gas is supplied using the polar molecular gas flow adjuster 7. At this time, the gas heating mechanism 9 is activated to heat the polar molecular gas to a temperature higher than room temperature. Additionally, with... Figure 3 Similarly, there is no problem in making the first infrared lamp 3 function during the cleaning process.

[0056] By having such a gas heating mechanism 9 (and a first infrared lamp 3), residual hydrogen fluoride 35 can be removed by heating a polar molecular gas to a temperature higher than room temperature.

[0057] Figure 5 This is a cross-sectional view of a semiconductor manufacturing apparatus having a third oxide film removal etching chamber for implementing the present invention. Semiconductor manufacturing apparatus 100b, as shown... Figure 3As shown, the semiconductor manufacturing apparatus 100b includes a vacuum container 1, a gas inlet 2, a first infrared lamp 3, a semiconductor wafer 4, a cryogenic stage 5, a flow controller 6 for HF, a flow regulator 7 for polar gases containing hydroxyl (OH) groups, a processing chamber 20, and an etching chamber 21. The semiconductor manufacturing apparatus 100b also includes a second infrared lamp 10. The second infrared lamp 10 is designed to heat the polar molecular gas whose flow rate has been adjusted by the flow regulator 7 using infrared irradiation, and is, for example, preferably located in the gas inlet 2 within the vacuum container 1.

[0058] During the etching process that utilizes the third oxide film to remove the SiO2 film from the etching chamber 21, and... Figure 4 Similarly, using the HF flow controller 6 and the polar molecular gas flow adjuster 7, the flow ratio of HF and polar molecular gas (here, methanol CH3OH) is set to a suitable ratio for etching to perform the etching of the SiO2 film. At this time, heating with the second infrared lamp 10 is not performed. However, depending on the process, the wafer 4 may be heated with the first infrared lamp 3. Therefore, to increase the heating speed, it is desirable to use a near-infrared wavelength of 3 μm or less for the first infrared lamp 3.

[0059] Next, in the cleaning process inside the third oxide film removal etching chamber 21, with Figure 4 Similarly, the HF supply is stopped using the HF flow controller 6, and only the polar molecular gas is supplied using the polar molecular gas flow adjuster 7. During this cleaning process, the polar molecular gas is heated to a temperature higher than room temperature by the second infrared lamp 10. The wavelength of the second infrared lamp 10 depends on the type of polar molecular gas, but for example, when CH3OH is used as the cleaning gas, it is desirable to use the near-mid-infrared region with a wavelength of 1 to 3 μm. Regarding the mid-infrared in this wavelength band, the infrared absorption in CH3OH molecules is large, causing molecular stretching vibrations in the CO and CH bonds within the CH3OH molecules. As a result, the CH3OH molecules can be efficiently heated by infrared radiation. Furthermore, as mentioned above, it is not a problem to have the first infrared lamp 3 function during the cleaning process.

[0060] By having such a second infrared lamp 10 (and a first infrared lamp 3), residual hydrogen fluoride 35 can be reduced by heating polar molecular gas.

[0061] Figure 6 Indicates having Figure 3 A structural diagram of the semiconductor manufacturing apparatus for removing the first oxide film from the etching chamber. The semiconductor manufacturing apparatus 100 includes: Figure 3The first oxide film removal etching chamber 21, the flow controller 6 for HF, the flow regulator 7 for polar gas containing hydroxyl (OH) groups, the flow regulator 8 for preheated gas, the HF supplier 11, the alcohol supplier 12, the carrier gas supplier other than HF and alcohol 13, the vacuum exhaust device 15, the cooler 16, etc. are described in the document.

[0062] The HF supplier 11 can supply HF gas, for example, through a high-pressure gas cylinder, to the etching chamber 21 via the HF flow regulator 6.

[0063] The alcohol supply unit 12 produces alcohol vapor by heating the liquid alcohol stored in the tank, which is then supplied to the etching chamber 21 via the alcohol flow regulator 7.

[0064] The carrier gas supplier 13, other than HF and alcohol, is a high-pressure gas cylinder that characterizes carrier gases with low reactivity such as Ar, He, and N2. In addition, these carrier gases are supplied to the chamber 21 in advance by a hot gas flow regulator 8 while being heated by a heater or the like.

[0065] The vacuum exhaust device 15, for example, is composed of a dry pump, a turbomolecular pump, etc., to exhaust the gas and reaction products in the etching chamber 21.

[0066] Cooler 16 can control the temperature of the low-temperature stage 5 inside the etching chamber 21.

[0067] Figure 7 Indicates having Figure 4 A structural diagram of a semiconductor manufacturing apparatus for removing the second oxide film in an etching chamber. The semiconductor manufacturing apparatus 100a includes: Figure 4 The document describes an etching chamber 21 for oxide film removal, a flow controller 6 for HF, a flow adjuster 7 for polar gases containing hydroxyl (OH) groups, an HF supplier 11, an alcohol supplier 12, a vacuum exhaust system 15, a cooler 16, and a piping heating mechanism 17. The HF supplier 11, alcohol supplier 12, vacuum exhaust system 15, and cooler 16 are... Figure 6 The structure described in the text.

[0068] The piping heating mechanism 17 is configured to heat the piping from the gas flow control unit 7 to the oxide film removal etching chamber 21 up to the gas inlet unit 2. Through the piping heating mechanism 17, polar molecular gases can be heated to temperatures higher than room temperature. While heating is generally performed using a heater, the heating method in this invention is not limited to this.

[0069] Figures 8A to 8CA process flow diagram characterizing the residue cleaning process (also known as the cleaning step) CL. Here, an example is given where a mixture of HF and CH3OH is used as the etching gas, and CH3OH is used as the cleaning gas. Furthermore, an example using a mixture of HF and CH3OH as the etching gas is also described. Figure 5 The semiconductor manufacturing apparatus 100b, which removes the third oxide film from the etching chamber as described in the document, will be used as an example for explanation.

[0070] Figure 8A This describes a process flow in which a certain amount of CH3OH gas and the output of the second infrared lamp 10 are set to a fixed value in the cleaning step CL. In the etching step ET, the flow ratio of HF to CH3OH is adjusted to 2:1 to mix them. However, this flow rate is not limited in this invention. In the cleaning step CL, the HF supply is zero, and the flow rate of CH3OH is greater than that used in the etching step ET. Furthermore, increasing the CH3OH flow rate increases the cleaning effect, but it is desirable to use it below the lower explosive limit. The output of the second infrared lamp 10 is fixed in the cleaning step CL. Regarding the output value, since it largely depends on the performance of the second infrared lamp 10, it is desirable to use an output value that efficiently heats the CH3OH. Therefore, the maximum flow rate of the cleaning gas and the output value of the infrared lamp 10 are not limited to these in this invention.

[0071] Figure 8B This describes the process flow where CH3OH is pulsedly introduced during the cleaning step CL. Figure 8B The example shown illustrates how CH3OH is pulsed multiple times (here, 3 times) into the etching chamber 21 during the cleaning process CL.

[0072] Figure 8C This describes the process flow where the output of the second infrared lamp 10 is applied pulsedly during the cleaning process CL. Figure 8C The example illustrates how, during the cleaning process CL, the second infrared lamp is pulsed on more than 10 times (3 times in this case) to heat the etching chamber 21.

[0073] If we were to summarize the cleaning methods for semiconductor manufacturing equipment, it would look like this:

[0074] Cleaning methods for semiconductor manufacturing equipment, for example, Figure 5The semiconductor manufacturing apparatus 100b shown performs the following operations: 1) a wafer 4 is placed on a sample stage 5 within a processing chamber 20; 2) (etching process) within the processing chamber 20, a silicon dioxide film 32 formed on the wafer 4 is etched using a mixed gas (gas) containing hydrogen fluoride and a vapor of a polar molecular gas; 3) (cleaning process) afterward, an alcohol (CH3OH) flow rate exceeding that of the alcohol (CH3OH) introduced into the processing chamber 20 during the etching process of the silicon dioxide film 32 is applied (see reference). Figures 8A to 8C The process chamber 20 is cleaned by introducing polar molecular gas (CH3OH) that has been irradiated by infrared rays through a heating mechanism (second infrared lamp 10). This removes residual hydrogen fluoride (HF) from the process chamber 20.

[0075] In this invention, it will be made Figures 8A to 8C The cleaning process CL combines multiple process flows and is also included in the scope of the invention.

[0076] The following uses Figures 9A to 12B To illustrate the experimental results.

[0077] Figures 9A to 12B This indicates that when using [something] Figure 5 In the case of a semiconductor manufacturing apparatus where the third oxide film is removed from the etching chamber, the etching conditions of the etching process ET are set to be common while the cleaning conditions of the cleaning process CL are different. This is the result of the time progression of residual hydrogen fluoride HF in several examples.

[0078] Figure 9A , Figure 9B This indicates a situation where the cleaning process CL is not implemented (cleaning conditions without the flow of CH3OH gas and without infrared heating). Figure 9A This is a flowchart representing the gas flow rate. Figure 9B This is a graph showing the time progression of residual hydrogen fluoride (HF).

[0079] Figure 10A , Figure 10B In the CL cleaning process, only CH3OH gas flows through the process, and no infrared heating is applied. Figure 10A This is a flowchart representing the gas flow rate. Figure 10B This is a graph showing the time progression of residual hydrogen fluoride (HF).

[0080] Figure 11A , Figure 11B The cleaning conditions in cleaning process CL involve heating CH3OH gas with an infrared lamp 10. Figure 11A This is a flowchart representing the gas flow rate. Figure 11B This is a graph showing the time progression of residual hydrogen fluoride (HF).

[0081] Figure 12A , Figure 12B In the cleaning process CL, nitrogen (N2) gas is used instead of CH3OH gas, and the nitrogen (N2) gas is heated by an infrared lamp 10. Figure 12A This is a flowchart representing the gas flow rate. Figure 12B This is a graph showing the time progression of residual hydrogen fluoride (HF).

[0082] In this example, in the third oxide film removal etching chamber 21, in order to measure the residual amount of residual hydrogen fluoride (HF) after the etching process ET, a SiO2 film 32 (reference) is prepared in the etching process ET by using a mixture of HF / CH3OH as the etching gas. Figure 1 The etching process of the SiO2 film 32 was performed using Q-mass to measure the residual amount of hydrogen fluoride (HF) after the etching process ET. The flow rates of the mixed gas used in the etching of the SiO2 film 32 were set to HF = 0.9 (L / min) and CH3OH = 0.45 (L / min). In addition, the etching temperature in the etching process ET was set to -20°C and the etching time was set to 1 minute.

[0083] As a post-treatment process for the removal of residual hydrogen fluoride (HF), in Figure 9B The cleaning conditions shown are as follows: no cleaning gas (CH3OH gas) is supplied and no infrared lamp 10 is irradiated (reference). Figure 9A The residual amount of hydrogen fluoride (HF) under the conditions of etching is the result of time-varying. Starting 2 minutes after the etching of the SiO2 film 32 is completed, vacuum venting is initiated in chamber 21 via vacuum venting device 15. Through this vacuum venting, the residual amount of HF continuously decreases. For convenience, the intensity of Q-mass, which serves as a threshold for the residual fluoride amount, is set to 3.0 × 10⁻⁶. -11 In the case of (counts), relying solely on vacuum exhaust, it will not become 3.0 × 10 even after at least 5 hours. -11 (counts) below.

[0084] Next, in Figure 10B The cleaning conditions shown are as follows: methanol (CH3OH) gas flows through the gas as a cleaning gas, and heating with infrared lamp 10 is not performed (reference). Figure 10A The results showed the residual amount of hydrogen fluoride under [condition]. Additionally, methanol, introduced as a cleaning gas, was introduced at a flow rate of CH3OH = 0.15 (L / min) and flowed through the cleaning gas for 100 minutes. Based on these results, without heating with infrared lamp 10, the residual hydrogen fluoride intensity based on Q-mass was reduced to 3.0 × 10 [units unclear] by flowing through CH3OH. -11 (Counts) It takes approximately 150 minutes. Based on these results, it can be concluded that using methanol (CH3OH) as a cleaning gas can shorten the exhaust time of residual hydrogen fluoride.

[0085] Next, in Figure 11B The cleaning conditions are shown, in which methanol (CH3OH) is passed through the gas as a cleaning gas and heated by infrared lamp 10. (Reference) Figure 1 The result is the residual amount of hydrogen fluoride at lA). The flow rate of the cleaning gas is set as... Figure 10A The methanol (CH3OH) gas used in the process was subjected to the same flow conditions (CH3OH = 0.15 L / min flow rate), and heating was performed by infrared lamp 10 during the flow of the methanol (CH3OH) gas. The heating of the methanol (CH3OH) gas by infrared lamp 10 reached a threshold of 3.0 × 10⁻⁶. -11 The time required (counts) is approximately 20 minutes. Based on this result ( Figure 11B It can be seen that, compared to the situation where cleaning is not performed inside chamber 21 ( Figure 9A , Figure 9B Compared to other methods, this method reduces cleaning time to below 94%. It also improves the cleaning conditions compared to the flow of methanol (CH3OH) gas without heating. Figure 10A , Figure 10B The comparison shows that it can reduce cleaning time by 87%.

[0086] In addition, for comparison, the cleaning effect of utilizing nitrogen (N2) gas, a nonpolar molecular gas, was also discussed. Figure 12B The results are shown. The flow rate of nitrogen (N2) gas was set to 0.15 L / min, and the heating time of infrared lamp 10 was set to 100 minutes. The cleaning time of residual hydrogen fluoride (HF) through the flow of heated nitrogen (N2) gas (reaching a threshold of 3.0 × 10⁻⁶) is also shown. -11 (Counts) The required time is 60 minutes. Compared with the cleaning time of heated methanol (CH3OH) gas (20 minutes), it can be seen that the cleaning time of heated nitrogen (N2) gas is about 3 times longer.

[0087] Based on the above results, regarding the heating performed by the infrared lamp 10, the heating efficiency of the polar molecular gas is higher than that of the non-polar molecular gas. It can be said that the IR heating of the polar molecular gas of the present invention can effectively clean up residual hydrogen fluoride.

[0088] The invention made by the inventor has been specifically described above based on the embodiments, but the invention is not limited to the above embodiments and examples, and various changes can be made, which is self-evident.

[0089] Explanation of reference numerals in the attached figures

[0090] 1…Vacuum container (processing container)

[0091] 2…Gas inlet section

[0092] 3…First infrared lamp

[0093] 4…chips

[0094] 5… Low-temperature stage (sample stage)

[0095] 6…HF gas flow regulator

[0096] 7…Polar molecular gas flow regulator

[0097] 8…Hot air flow regulator

[0098] 9… Heating mechanism

[0099] 10…Second infrared lamp

[0100] 11…HF feeder

[0101] 12…Polar molecular gas supplier

[0102] 13…Hot gas supply unit

[0103] 15…Vacuum Exhaust Device

[0104] 16…cooler

[0105] 17… Piping heating mechanism

[0106] 20…processing room

[0107] 21…Etching chamber (chamber)

[0108] 100, 100a, 100b... Semiconductor manufacturing equipment.

Claims

1. A cleaning method for a semiconductor manufacturing apparatus, the apparatus comprising: an inlet for introducing a processing gas containing hydrogen fluoride and alcohol vapor into a processing chamber inside a processing container; a sample stage disposed within the processing chamber, on the upper surface of which a wafer to be processed is mounted; an introduction mechanism for introducing a polar molecular gas into the inlet; and a heating mechanism for heating the polar molecular gas to a temperature higher than room temperature. The cleaning method for the semiconductor manufacturing apparatus is characterized in that... The polar molecular gas is an alcohol with an alkyl group or water. The wafer is placed on the sample stage within the processing chamber. In the processing chamber, the silicon dioxide of the wafer is etched using a mixture of gases containing hydrogen fluoride and polar molecular gases. Subsequently, an alcohol flow rate exceeding that of the alcohol used in the etching process of silicon dioxide is introduced into the processing chamber, and a polar molecular gas heated by the heating mechanism is introduced to clean the processing chamber.

2. The cleaning method for a semiconductor manufacturing apparatus according to claim 1, characterized in that, The semiconductor manufacturing apparatus includes the heating mechanism between the inlet and the inlet mechanism.

3. The cleaning method for a semiconductor manufacturing apparatus according to claim 1, characterized in that, The semiconductor manufacturing apparatus has a heating mechanism based on infrared irradiation at the inlet.

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