Insulating film manufacturing method for semiconductor process

Abstract

The present invention provides a method for manufacturing a semiconductor process, comprising the steps of: placing a wafer in a processing chamber; supplying a source gas to the processing chamber at a first pressure higher than atmospheric pressure so that an insulating film is formed on the wafer by performing at least one of an oxidation process and a nitriding process; supplying a purge gas to the processing chamber to purge the source gas; and supplying an atmospheric gas to the processing chamber at a second pressure higher than atmospheric pressure so that the insulating film is strengthened by performing a heat treatment process.

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing an insulating film used in semiconductor manufacturing processes. [Background technology]

[0002] Generally, semiconductor manufacturing processes are roughly divided into front-end and back-end processes, which include oxidation, deposition, exposure, etching, ion implantation, wiring, etc.

[0003] An insulating film is formed on the wafer through an oxidation or deposition process. The insulating film prevents leakage current even after the circuit pattern is formed. The insulating film also acts as a protective film during subsequent etching processes. Therefore, the quality characteristics of the insulating film, such as density, must be maintained at a certain level.

[0004] However, insulating films formed by conventional deposition or oxidation processes do not have sufficient quality characteristics. To solve this problem, a long process time is required or the process temperature must be excessively high. A long process time reduces the efficiency of the semiconductor manufacturing process. Summary of the Invention [Problem to be solved by the invention]

[0005] SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing an insulating film in a semiconductor process, which can manufacture an insulating film having excellent qualitative properties without requiring excessive process time and temperature. [Means for solving the problem]

[0006] To achieve the above object, according to one aspect of the present invention, a method for manufacturing an insulating film in a semiconductor process may include the steps of: placing a wafer in a process chamber; supplying a source gas into the process chamber at a first pressure higher than atmospheric pressure to perform at least one of an oxidation process and a nitridation process to form an insulating film on the wafer; supplying a purge gas into the process chamber to purge the source gas; and supplying an ambient gas into the process chamber at a second pressure higher than atmospheric pressure to perform a heat treatment process to strengthen the insulating film.

[0007] Here, the first pressure may be determined within a range of 5 ATM to 20 ATM.

[0008] Here, the step of supplying a source gas into the processing chamber at a first pressure higher than atmospheric pressure to perform at least one of an oxidation process and a nitridation process to form an insulating film on the wafer may include the step of maintaining the source gas at a first temperature, and the first temperature may be a value determined in the range of 400°C to 600°C.

[0009] Here, the source gas may include at least one of oxygen gas, water vapor, and ammonia gas.

[0010] Here, the step of purging the source gas by supplying a purge gas into the processing chamber is performed while maintaining the processing chamber at the first pressure and the first temperature.

[0011] Here, the purge gas may include any one of nitrogen gas, argon gas, and helium gas.

[0012] Here, the second pressure may be a value determined within a range of 5 ATM to 20 ATM.

[0013] Here, the atmospheric gas may contain at least one of hydrogen gas, deuterium gas, and nitrogen gas.

[0014] Here, the method may further include maintaining an accommodation space that accommodates the processing chamber at a pressure higher than either the first pressure or the second pressure while the processing chamber is maintained at either the first pressure or the second pressure. [Effects of the Invention]

[0015] According to the method for manufacturing an insulating film in a semiconductor process according to the present invention, an insulating film is formed on a wafer by performing an oxidation process or a nitridation process using a source gas at a first pressure higher than atmospheric pressure, and then a heat treatment process is performed using an ambient gas at a second pressure higher than atmospheric pressure, thereby strengthening the insulating film. This improves the quality and properties of the insulating film without relying on excessive process time and temperature. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a conceptual diagram of a wafer high-pressure processing apparatus 100 used to perform a method for manufacturing an insulating film in a semiconductor process according to an embodiment of the present invention. [Figure 2] FIG. 2 is a block diagram for explaining the control operation of the wafer high-pressure processing apparatus 100 of FIG. [Figure 3] 2 is a flowchart illustrating a method for manufacturing an insulating film in a semiconductor process according to an embodiment of the present invention. [Figure 4] 2 is a flowchart illustrating pressure and temperature control for a method of manufacturing an insulating film in a semiconductor process according to an embodiment of the present invention. [Figure 5] 4 is a graph comparing step coverage of insulating films manufactured through some steps of the insulating film manufacturing method of the semiconductor process of FIG. 3; [Figure 6] 4 is a graph comparing wet etching rates of insulating films manufactured by the insulating film manufacturing method of the semiconductor process of FIG. 3; DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, a method for manufacturing an insulating film in a semiconductor process according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. In this specification, the same or similar reference numerals are used to refer to the same or similar components in different embodiments, and the description thereof supersedes the first description.

[0018] FIG. 1 is a conceptual diagram of a wafer high-pressure processing apparatus 100 used to perform a method for manufacturing an insulating film in a semiconductor process according to an embodiment of the present invention.

[0019] Referring to this figure, a wafer high pressure processing apparatus 100 may include an inner chamber 110 , an outer chamber 120 , an air supply module 130 , and an exhaust module 140 .

[0020] The inner chamber 110 includes a processing chamber 115 for high-pressure processing of semiconductor wafers. The inner chamber 110 may be made of a non-metallic material, such as quartz, to reduce the possibility of contaminants (particles) being generated in the process environment. Although simplified in the drawing, a door (not shown) for opening the processing chamber 115 is provided at the bottom of the inner chamber 110. The processing chamber 115 is opened by lowering the door, and a semiconductor wafer attached to a holder (not shown) is inserted into the processing chamber 115. The temperature of the processing chamber 115 can reach several hundred degrees Celsius by operating a heater (not shown) located outside the inner chamber 110. The holder may be a wafer boat capable of stacking multiple semiconductor wafers. The wafer boat may also be made of quartz.

[0021] The outer chamber 120 is configured to house the inner chamber 110. Unlike the inner chamber 110, the outer chamber 120 is free from the problem of contamination of semiconductor wafers and may be made of metal. The outer chamber 120 has a housing space 125 that houses the inner chamber 110. The outer chamber 120 also has a door (not shown) at its bottom, which can be lowered together with the door of the inner chamber 110 to open the housing space 125.

[0022] The gas supply module 130 supplies gas to the chambers 110 and 120. The gas supply module 130 includes a gas supplier 131 connected to a utility system of a semiconductor factory. The gas supplier 131 supplies a source gas, a purge gas, and an ambient gas to the inner chamber 110, specifically the process chamber 115. The source gas may include, for example, oxygen gas, water vapor, or ammonia gas. The purge gas may include, for example, nitrogen gas, argon gas, or helium gas. The ambient gas may include, for example, hydrogen gas, deuterium gas, tritium gas, nitrogen gas, or argon gas. The gas supplier 131 may supply a protective gas, for example, nitrogen gas, argon gas, or helium gas, to the receiving space 125. The protective gas may be the same gas as the purge gas. The protective gas injected into the receiving space 125 specifically fills the receiving space 125 except for the inner chamber 110. These gases are injected into the process chamber 115 or the containing space 125 via an internal gas line 133 or an external gas line 135, respectively.

[0023] The source gas, the purge gas, the ambient gas, and the protective gas are supplied to the chambers 110 and 120 to form a pressure higher than atmospheric pressure, for example, a pressure ranging from several atmospheres to several tens of atmospheres. The pressure of the protective gas may be set to have a certain relationship with the pressures of the source gas, the purge gas, and the ambient gas. For example, the latter may be set to be slightly higher than the former to prevent the source gas, the purge gas, and the ambient gas from leaking from the process chamber 115.

[0024] The exhaust module 140 is configured to exhaust the source gas, the purge gas, the ambient gas, and the protective gas from the chambers 110 and 120. An exhaust pipe 141 is connected to the upper part of the inner chamber 110 to exhaust the source gas, the purge gas, and the ambient gas from the inner chamber 110, specifically the process chamber 115. A gas exhauster 143 may be installed in the exhaust pipe 141. The gas exhauster 143 may be a valve that allows or blocks the exhaust of the source gas and the ambient gas.

[0025] In order to exhaust the protective gas from the outer chamber 120, specifically from the receiving space 125, an exhaust pipe 145 communicating with the outer chamber 120 and a gas exhauster 147 installed therein are provided. These exhaust pipes 141 and 145 communicate with each other, so that the source gas and the ambient gas are diluted with the protective gas and then exhausted.

[0026] The control configuration of the wafer high pressure processing apparatus 100 will be described with reference to Fig. 2. Fig. 2 is a block diagram for explaining the control operation of the wafer high pressure processing apparatus 100 of Fig. 1.

[0027] Referring to this figure (and FIG. 1), the wafer high-pressure processing apparatus 100 may further include a heating module 150, a sensing module 160, a control module 170, and a storage module 180 in addition to the aforementioned gas supply module 130 and the like.

[0028] The heating module 150 includes the heater described above. The heater may be disposed in the receiving space 125. The heater heats the source gas, the purge gas, and the ambient gas to a process temperature.

[0029] The sensing module 160 is configured to sense the environment of the chambers 110 and 120. The sensing module 160 includes a pressure gauge 161 and a temperature gauge 165. The pressure gauge 161 and the temperature gauge 165 may be installed in each of the chambers 110 and 120.

[0030] The control module 170 is configured to control the air supply module 130, the exhaust module 140, etc. The control module 170 can control the air supply module 130, etc. based on the detection result of the detection module 160.

[0031] The storage module 180 is configured to store data, programs, etc. that the control module 170 can refer to for control purposes. The storage module 180 may include at least one type of storage medium selected from the group consisting of a flash memory, a hard disk, a magnetic disk, and an optical disk.

[0032] According to this configuration, the control module 170 can control the air supply module 130 and the like to perform the insulating film manufacturing method for semiconductor processing according to an embodiment of the present invention.

[0033] Specifically, the control module 170 can control the operation of the gas supply module 130 based on the pressures of the chambers 110 and 120 obtained by the pressure gauge 161. By operating the gas supply module 130, the inner chamber 110 is filled with the source gas, the purge gas, or the ambient gas at a process pressure, while the outer chamber 120 is filled with the protective gas.

[0034] The control module 170 can also control the operation of the heating module 150 based on the temperature of the chambers 110, 120 obtained by the temperature gauge 165. The operation of the heating module 150 can allow the source gas, the purge gas, or the ambient gas to reach a process temperature.

[0035] A specific method for forming an insulating film on a wafer using the wafer high-pressure processing apparatus 100 described above will be described with reference to FIGS.

[0036] FIG. 3 is a flowchart illustrating a method for manufacturing an insulating film in a semiconductor process according to an embodiment of the present invention.

[0037] Referring to this figure (and FIGS. 1 and 2), wafers are placed in the processing chamber 115 (S1). The wafers are loaded into the processing chamber 115 while still seated on the wafer boat.

[0038] An insulating film is formed on the wafer in the processing chamber 115 (S3). The insulating film may be a silicon oxide film (SiO) made of silicon oxide, a silicon nitride film (SiN) made of silicon nitride, or a silicon nitride film (SiON) containing both silicon oxide and silicon nitride. To form the insulating film, an oxidation process or a nitridation process is performed in the processing chamber 115 at a first pressure. The first pressure is higher than atmospheric pressure.

[0039] After the oxidation or nitridation process is completed, the gas used in the oxidation or nitridation process is purged (S5), thereby making the process chamber 115 ready for a process other than the oxidation or nitridation process.

[0040] After the purging is completed, the insulating film is strengthened by a heat treatment process (S7), which is performed at a second pressure, which is higher than atmospheric pressure.

[0041] FIG. 4 is a flow chart illustrating pressure and temperature control for the progress of a method for manufacturing an insulating film in a semiconductor process according to an embodiment of the present invention.

[0042] Referring again to this figure, for the oxidation process or the nitridation process, the source gases are supplied to the process chamber 115 at the first pressure (S11). Of the source gases, oxygen gas is supplied for dry oxidation, and water vapor is supplied for wet oxidation. Ammonia gas is supplied for nitridation. The first pressure may be determined within a range of 5 ATM to 20 ATM.

[0043] The process chamber 115 is heated to a first temperature (S13) so that the source gas reaches the process temperature. The first temperature may be determined within a range of 400° C. to 950° C. Since the source gas acts under high pressure (the first pressure), the first temperature may be set to 600° C. or less. This temperature is relatively low compared to the temperature of a typical deposition process.

[0044] After the oxidation process or the nitridation process is completed, the purge gas is supplied to the process chamber 115 while maintaining the first pressure and the first temperature (S15). The control module 170 controls the exhaust module 140 together with the gas supply module 130 so that the source gas is purged and exhausted from the process chamber 115. The time required for the purge process may be shorter than that for the oxidation process or the nitridation process.

[0045] To perform the heat treatment process, the ambient gas is supplied to the processing chamber 115 at the second pressure (S17). The second pressure may be determined within a range of 5 ATM to 20 ATM. The second pressure is set independently of the first pressure. Thus, the second pressure may be the same as or different from the first pressure. The control module 170 controls the exhaust module 140 together with the gas supply module 130 to supply the ambient gas to the processing chamber 115 and exhaust the purge gas from the processing chamber 115.

[0046] The process chamber 115 is adjusted to a second temperature (S19) so that the ambient gas reaches a process temperature required for the heat treatment process. The second temperature may be determined within a range of 400°C to 950°C. Because the ambient gas acts at a high pressure (the second pressure), the second temperature may be set to 600°C or less. The second temperature may also be set independently of the first temperature. To adjust the temperature, the control module 170 may additionally operate the heating module 150, operate a cooling means (not shown), or maintain the existing temperature.

[0047] The setting of the first pressure and the second pressure will be further described with reference to FIGS. 5 and 6. FIG. 5 is a graph comparing step coverage of insulating films manufactured by some steps of the insulating film manufacturing method of the semiconductor process of FIG. 3, and FIG. 6 is a graph comparing wet etch rates of insulating films manufactured by the insulating film manufacturing method of the semiconductor process of FIG. 3. Specifically, FIG. 5 shows the results of comparing step coverage of silicon dioxide (SiO2) films formed on patterned silicon wafers by the oxidation process. FIG. 6 shows the results of comparing wet etch rates (WER) of the strengthened silicon dioxide films strengthened by the heat treatment process.

[0048] The oxidation process was performed using a wet oxidation process. The ambient gas in the heat treatment process was hydrogen gas. The process temperature was maintained at 600°C during the oxidation process, the heat treatment process, and the purge process performed between them. The oxidation process and the heat treatment process were each performed for one hour, and the purge process was performed for 20 minutes. Each process was performed in-situ in the process chamber 115. The process pressure was adjusted to a high pressure condition (ranging from 1 ATM to 20 ATM). The solution used for wet etching was a mixture of 100 parts by weight of pure water and 1 part by weight of hydrofluoric acid.

[0049] Referring to FIG. 5, when the first pressure increases from 1 ATM to 20 ATM during the oxidation process, the step coverage of the silicon dioxide film also increases.

[0050] For example, the step coverage of the silicon dioxide film is 82% at 1 ATM and 85.4% at 2 ATM. The step coverage increases to 85.9% at 3 ATM, but the increase is small.

[0051] However, at 5 ATM, the step coverage significantly increases to 96.7%. As the first pressure increases to 10 ATM, 15 ATM, and 20 ATM, the step coverage increases to 97.1%, 98.2%, and 98.9%.

[0052] Considering these results, it is preferable that the first pressure is 5 ATM or more from the viewpoint of the step coverage. To obtain the best step coverage, the first pressure is set to 20 ATM.

[0053] Referring to Figure 6, the heat treatment process was performed at the second pressure for the silicon dioxide film formed through the oxidation process (20 ATM). As the second pressure increased from 1 ATM to 20 ATM, the wet etching rate of the silicon dioxide film decreased. The wet etching rate was inversely proportional to the density of the silicon dioxide film. Considering this relationship, the wet etching rate confirmed the improvement in film quality (density increase) of the oxide film according to this embodiment.

[0054] However, when the second pressure is between 1 ATM and 3 ATM, the wet etching rate is greater than 1 Å / sec. To obtain a wet etching rate less than 1 Å / sec, the second pressure must be set to 5 ATM or greater. Specifically, at 5 ATM, the wet etching rate is 0.99 Å / sec, which is within the desired range.

[0055] Furthermore, as the second pressure increases to 10 ATM, 15 ATM, and 20 ATM, the wet etching rate becomes 0.97 angstroms / sec, 0.95 angstroms / sec, and 0.91 angstroms / sec.

[0056] Considering these results, it is preferable that the second pressure is 5 ATM or more in terms of the wet etching rate. To obtain the highest wet etching rate, the second pressure is set to 20 ATM.

[0057] The insulating film manufacturing method for semiconductor processes as described above is not limited to the configurations and operation modes of the above-described embodiments, and various modifications can be made by selectively combining all or part of each embodiment. [Industrial Applicability]

[0058] The present invention has industrial applicability in the field of insulating film manufacturing in semiconductor processes.

Claims

1. placing the wafer in a processing chamber; supplying a source gas into the processing chamber to a first pressure higher than atmospheric pressure, thereby performing at least one of an oxidation process and a nitridation process to form an insulating film on the wafer; supplying a purge gas into the process chamber to purge the source gas; and supplying an ambient gas into the processing chamber to reach a second pressure higher than atmospheric pressure, thereby performing a heat treatment process to strengthen the insulating film; The atmospheric gas contains at least one of hydrogen gas and deuterium gas. A method for manufacturing insulating films in semiconductor processes.

2. The first pressure is 2. The method for manufacturing an insulating film in a semiconductor process according to claim 1, wherein the value is determined within a range of 5 ATM to 20 ATM.

3. supplying a source gas into the processing chamber to reach a first pressure higher than atmospheric pressure, thereby performing at least one of an oxidation process and a nitridation process to form an insulating film on the wafer; maintaining the source gas at a first temperature; The first temperature is 2. The method for manufacturing an insulating film in a semiconductor process according to claim 1, wherein the temperature is determined within a range of 400 to 600 degrees Celsius.

4. The source gas is 2. The method for manufacturing an insulating film in a semiconductor process according to claim 1, wherein the gas contains at least one of oxygen gas, water vapor, and ammonia gas.

5. supplying a purge gas into the process chamber to purge the source gas; 2. The insulating film manufacturing method for semiconductor manufacturing according to claim 1, wherein the method is carried out while maintaining the processing chamber at the first pressure and the first temperature.

6. The purge gas is 2. The method for manufacturing an insulating film in a semiconductor process according to claim 1, wherein the gas contains any one of nitrogen gas, argon gas, and helium gas.

7. The second pressure is 2. The method for manufacturing an insulating film in a semiconductor process according to claim 1, wherein the value is determined within a range of 5 ATM to 20 ATM.

8. 2. The method of claim 1, further comprising: while the processing chamber is maintained at one of the first pressure and the second pressure, maintaining a containing space that contains the processing chamber at a pressure higher than one of the first pressure and the second pressure.

Images