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 producing an insulating film used in a semiconductor process. [Background technology]

[0002] Generally, semiconductor manufacturing processes are roughly divided into front-end and back-end processes. Front-end processes 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 from occurring even after the circuit pattern is formed. The insulating film also acts as a protective film in the subsequent etching process. Therefore, the quality characteristics of the insulating film, such as density, must be maintained at a certain level.

[0004] However, the insulating film formed by the conventional deposition or oxidation process does 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 PRESENTLY PREFERRED EMBODIMENTS 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 at a first pressure higher than atmospheric pressure into the process chamber 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 at a second pressure higher than atmospheric pressure into the process chamber 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 to 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 includes the step of maintaining the source gas at a first temperature, and the first temperature may be a value determined within a 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 supplying a purge gas to the process chamber to purge the source gas is performed while maintaining the process 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, while the processing chamber is maintained at either the first pressure or the second pressure, maintaining a storage space that accommodates the processing chamber at a pressure higher than either the first pressure or the second pressure. Effect of the Invention

[0015] According to the method of 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 having a first pressure higher than atmospheric pressure, and then a heat treatment process is performed using an atmospheric gas having a second pressure higher than atmospheric pressure, thereby strengthening the insulating film. Therefore, the quality characteristics of the insulating film can be improved without relying on excessive process time and temperature. [Brief description 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. [Diagram 2] FIG. 2 is a block diagram for explaining the control operation of the wafer high pressure processing apparatus 100 of FIG. [Diagram 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 flow chart illustrating pressure and temperature control for proceeding with a method of manufacturing an insulating film in a semiconductor process according to an embodiment of the present invention. [Diagram 5] 4 is a comparative graph showing step coverage of an insulating film 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 PREFERRED EMBODIMENTS

[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 even 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 high pressure wafer processing apparatus 100 may include an inner chamber 110 , an outer chamber 120 , an intake module 130 , and an exhaust module 140 .

[0020] The inner chamber 110 has a processing chamber 115 for processing semiconductor wafers at high pressure. 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 is inserted into the processing chamber 115 while still attached to a holder (not shown). The temperature of the processing chamber 115 may reach several hundred degrees Celsius by operation of a heater (not shown) disposed outside the inner chamber 110. The holder may be a wafer boat in which semiconductor wafers can be stacked in multiple layers. The wafer boat may also be made of quartz.

[0021] The outer chamber 120 is configured to accommodate 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 a metal material. The outer chamber 120 has an accommodation space 125 that accommodates the inner chamber 110. The outer chamber 120 also has a door (not shown) at the bottom, which can be lowered together with the door of the inner chamber 110 to open the accommodation space 125.

[0022] The gas supply module 130 is configured to supply gas to the chambers 110 and 120. The gas supply module 130 includes a gas supplier 131 that is connected to a utility of a semiconductor factory. The gas supplier 131 can supply a source gas, a purge gas, and an atmosphere gas to the inner chamber 110, specifically the processing 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 atmosphere gas may include, for example, hydrogen gas, deuterium gas, tritium gas, nitrogen gas, or argon gas. The gas supplier 131 can provide, for example, nitrogen gas, argon gas, or helium gas as a protective gas to the accommodation space 125. The protective gas may be the same type of gas as the purge gas. The protective gas injected into the accommodation space 125 is specifically filled in the accommodation space 125 except for the inner chamber 110. These gases are injected into the process chamber 115 or the containing space 125 via an inner gas line 133 or an outer gas line 135, respectively.

[0023] The source gas, the purge gas, the ambient gas, and the protective gas are supplied to the chambers 110, 120 to form a pressure higher than atmospheric pressure, for example, a high pressure reaching several atmospheres to several tens of atmospheres. In addition, 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 atmosphere gas, and the protective gas from the chambers 110 and 120. An exhaust pipe 141 is connected to an upper portion of the inner chamber 110 in order to exhaust the source gas, the purge gas, and the atmosphere 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 and stops exhaust of the source gas and the atmosphere 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. Since the exhaust pipes 141 and 145 communicate with each other, the source gas and the atmospheric gas are diluted with the protective gas and 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 high pressure wafer 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 reach a process temperature.

[0029] The sensing module 160 is configured to sense the environments 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 among 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 a method for manufacturing an insulating film in a semiconductor process 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 above-described wafer high pressure processing apparatus 100 will be described with reference to FIGS.

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

[0037] 1 and 2, a wafer is placed in the processing chamber 115 (S1). The wafer is 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 process or the nitridation process is completed, the gas used in the oxidation process or the nitridation process is purged (S5), so that the process chamber 115 is ready to perform a process other than the oxidation process or the 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 proceeding with a method for manufacturing an insulating film in a semiconductor process according to an embodiment of the present invention.

[0042] Continuing with reference to this figure, for the oxidation process or the nitridation process, the source gas is supplied to the process chamber 115 at the first pressure (S11). Of the source gases, the oxygen gas is supplied for dry oxidation, and the water vapor is supplied for wet oxidation. The 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 so that the source gas reaches the process temperature (S13). 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 required for the oxidation process or the nitridation process.

[0045] To perform the heat treatment process, the atmospheric gas is supplied to the process 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 atmospheric gas to the process chamber 115 and exhaust the purge gas from the process 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. Since the ambient gas acts at a high pressure (the second pressure), the second temperature may be set to 600° C. or lower. 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 comparative graph of 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 comparative graph of wet etching rate of insulating films manufactured by the insulating film manufacturing method of the semiconductor process of Fig. 3. Specifically, Fig. 5 shows a comparison result of step coverage of silicon dioxide films (SiO2) formed on patterned silicon wafers by the oxidation process. Fig. 6 shows a comparison result of wet etch rate (WER) of the strengthened silicon dioxide films strengthened by the heat treatment process.

[0048] The oxidation process was performed as a wet oxidation process. In the heat treatment process, the atmospheric gas was hydrogen gas. The process temperature was maintained at 600° C. in 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 under high pressure conditions (in the range of 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 in the oxidation process increases from 1 ATM to 20 ATM, 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 increases significantly 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. In order to obtain the highest step coverage, the first pressure is set to 20 ATM.

[0053] 6, for the silicon dioxide film manufactured in the oxidation process (20 ATM), the heat treatment process was performed at the second pressure. It can be seen that as the second pressure increases from 1 ATM to 20 ATM, the wet etching rate of the silicon dioxide film decreases. The wet etching rate is inversely proportional to the density of the silicon dioxide film. Considering this relationship, the effect of improving the film quality (increasing density) of the oxide film according to this embodiment can be confirmed from the wet etching rate.

[0054] However, when the second pressure is between 1 ATM and 3 ATM, the wet etch rate is greater than 1 Angstrom / sec. To obtain a wet etch rate less than 1 Angstrom / sec, the second pressure must be set to 5 ATM or greater. Specifically, at 5 ATM, the wet etch rate is 0.99 Angstrom / 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 Å / sec, 0.95 Å / sec, and 0.91 Å / sec.

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

[0057] The method of manufacturing an insulating film in a semiconductor process as described above is not limited to the configurations and operation modes of the above-described embodiments, and the above-described embodiments may be configured to be modified in various ways 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 a wafer into 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 to the process chamber to purge the source gas; and 23. A method for manufacturing an insulating film in a semiconductor process, comprising: supplying an ambient gas at a second pressure higher than atmospheric pressure into the processing chamber, and performing a heat treatment process to strengthen the insulating film.

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 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, 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° C. to 600° C.

4. The source gas is 2. The method for producing 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 method for manufacturing an insulating film in a semiconductor process according to claim 1, wherein the method is performed while maintaining the processing chamber at the first pressure and the first temperature.

6. The purge gas is 2. The method for producing 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. The atmospheric 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 hydrogen gas, deuterium gas, and nitrogen gas.

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

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