Substrate processing method and substrate processing apparatus

Abstract

This invention provides a substrate processing method suitable for forming a thin, high-quality interfacial layer (IL). [Solution] The substrate processing method includes a silicon oxide film formation step (S2) in which an oxidizing treatment liquid is supplied to the surface of a silicon layer formed on a substrate to form a silicon oxide film on the surface of the silicon layer, and a heating step (S4) in which the substrate on which the silicon oxide film is formed is heated with a flash lamp.

Description

Technical Field

[0001] The present invention relates to a substrate processing method and a substrate processing apparatus.

Background Art

[0002] Techniques for forming a gate oxide film positioned between the gate and the channel of a field effect transistor (FET) are known. For example, Patent Document 1 describes a technique for forming an insulating oxide film on the surface of a silicon substrate. In the method for forming the oxide film of Patent Document 1, a first step of forming an oxide film on the surface of the silicon substrate is performed by supplying a gas phase or a solution containing oxygen molecules to the silicon substrate. After the first step, a second step of raising the temperature of the oxide film is performed in an inert gas atmosphere. After the second step, a third step of heat-treating the silicon substrate at a temperature higher than the temperature at the time of forming the oxide film is performed in a gas phase containing oxygen molecules. By performing the third step, the bond between the atoms constituting the substrate surface in the oxide film and oxygen is strengthened, and an oxide film thicker than the thickness of the oxide film formed on the surface of the silicon substrate in the first step is formed on the surface of the silicon substrate.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in recent years, logic devices are required to have higher performance, and the size of logic devices is being miniaturized. Along with the miniaturization of logic devices, the interfacial layer (IL) positioned between the gate and the channel of a field effect transistor (FET) needs to have an even thinner film thickness and better film quality in order to improve device performance.

[0005] One aspect of the present invention aims to provide a substrate processing method suitable for forming a thin and high-quality interfacial layer (IL). [Means for solving the problem]

[0006] To solve the above problems, a substrate processing method according to one aspect of the present invention includes a silicon oxide film forming step of supplying an oxidizing treatment liquid to the surface of a silicon layer formed on a substrate to form a silicon oxide film on the surface of the silicon layer, and a heating step of heating the substrate on which the silicon oxide film has been formed with a flash lamp.

[0007] Furthermore, in a substrate processing method according to one aspect of the present invention, an oxidizing treatment solution supply step may be further included, in which the oxidizing treatment solution is supplied again to the surface of the silicon oxide film heated by the flash lamp.

[0008] Furthermore, in a substrate processing method according to one aspect of the present invention, a transport step may be further included in which, after forming the silicon oxide film on the surface of the silicon layer, the substrate is transported through a space filled with inert gas to a place where it is heated by a flash lamp.

[0009] Furthermore, in a substrate processing method according to one aspect of the present invention, the heating step may be carried out in a space filled with an inert gas.

[0010] Furthermore, in a substrate processing method according to one aspect of the present invention, the heating step may be carried out in a space filled with oxygen.

[0011] Furthermore, in a substrate processing method according to one aspect of the present invention, a removal solution supply step may be further included in which a silicon oxide film removal treatment solution is supplied to the surface of the silicon oxide film after the heating step.

[0012] Furthermore, in a substrate processing method according to one aspect of the present invention, the oxidizing treatment solution may be at least one of ozonated deionized water, a mixture of ammonia and hydrogen peroxide, a mixture of sulfuric acid and hydrogen peroxide, and a mixture of hydrochloric acid and hydrogen peroxide.

[0013] Furthermore, in a substrate processing method according to one aspect of the present invention, in the heating step, the temperature of the substrate may be raised to 600°C or higher by heating with the flash lamp for 5ms or less.

[0014] To solve the above problems, a substrate processing apparatus according to one aspect of the present invention comprises a processing liquid supply unit that supplies an oxidizing processing liquid to the surface of a silicon layer formed on a substrate to form a silicon oxide film on the surface of the silicon layer, and a heating unit that heats the substrate on which the silicon oxide film is formed with a flash lamp. [Effects of the Invention]

[0015] According to one aspect of the present invention, a substrate processing method suitable for forming a thin and high-quality interfacial layer (IL) can be provided. [Brief explanation of the drawing]

[0016] [Figure 1] This is a schematic plan view showing the general configuration of the substrate processing device. [Figure 2] This is a schematic cross-sectional view of the substrate processing apparatus as seen from line AA in Figure 1. [Figure 3] This is a diagram showing the configuration of a circuit board processing unit. [Figure 4] This is a flowchart illustrating an example of the flow of a substrate processing method performed by a substrate processing device. [Figure 5] This figure shows the change in the thickness of the silicon oxide film on the substrate W before and after heat treatment by flash lamp annealing. [Figure 6] This graph shows the film thickness and silicon strength of the silicon oxide film after heat treatment under various heat treatment conditions. [Figure 7]It is a graph showing the film thickness of the silicon oxide film and the silicon strength after heat treatment under each heat treatment condition. [Figure 8] It is a graph showing the film thickness of the silicon oxide film and the silicon strength after heat treatment under each heat treatment condition. [Figure 9] It is a flowchart showing an example of the flow of a modified example of a substrate processing method executed by a substrate processing apparatus.

Mode for Carrying Out the Invention

[0017] 〔Embodiment 1〕 Hereinafter, an embodiment of the present invention will be described in detail. For the sake of convenience of explanation, as shown in FIGS. Ⅰ and Ⅱ, the front-rear direction, left-right direction, and up-down direction of the substrate processing apparatus 100 are defined. The up-down direction is based on the state where the substrate processing apparatus 100 is installed on the floor. Also, in this specification, unless otherwise specified, "A~B" representing a numerical range means "A or more and B or less".

[0018] 〔Schematic Configuration of Substrate Processing Apparatus 100〕 Referring to FIGS. Ⅰ and Ⅱ, an example of the configuration of the substrate processing apparatus 100 will be described. FIG. Ⅰ is a schematic plan view showing the schematic configuration of the substrate processing apparatus 100. FIG. Ⅱ is a schematic cross-sectional view of the substrate processing apparatus 100 as viewed from the A-A line in FIG. Ⅰ.

[0019] Note: In the above translation, "Ⅰ" and "Ⅱ" are used to represent "1" and "2" respectively to avoid confusion with the numbers in the text. You can adjust them according to your actual needs.The substrate processing apparatus 100 is a device that performs various processes on a substrate W. The substrate W is a semiconductor substrate on which a silicon layer is formed, for example, a silicon wafer. The substrate processing apparatus 100 forms an interfacial layer (IL) located between the gate and channel of a field-effect transistor (FET). The IL is a layer that constitutes part of the gate oxide film. In this embodiment, the substrate processing apparatus 100 forms an IL on the substrate W between the Si channel and the High-K metal of the metal gate portion of a MOSFET (metal-oxide-semiconductor field-effect transistor), for example. The substrate processing apparatus 100 is a single-wafer type device that processes substrates W one at a time. As shown in Figure 1, the substrate processing apparatus 100 includes a load port LP, an indexer unit 10, a processing unit 20, a fluid cabinet 30, a transport unit 40, and a controller 50.

[0020] Multiple load ports LP are provided on the front of the substrate processing apparatus 100. Transport containers P for accommodating multiple substrates W are placed on the load ports LP. The transport containers P are, for example, FOUPs (front opening unified pods). Note that the transport containers P are not limited to FOUPs and may also be SMIFs (Standard Mechanical Interfaces). The load ports LP are preferably filled with an inert gas to make it difficult for a native oxide film to form on the substrates W. In this specification, the inert gas is a gas that makes it difficult for the substrates W to undergo oxidation reactions. Examples of inert gases include nitrogen gas (N2) and argon gas (Ar).

[0021] The indexer unit 10 transports substrates W contained in transport containers P placed on each load port LP to the processing unit 20, and places the substrates W discharged from the processing unit 20 into transport containers P. The indexer unit 10 is equipped with a transport device 12 (see Figure 2), which transports the substrates W contained in the transport containers P to the buffer station 43. A chemical filter may be provided at the top of the indexer unit 10 to purify the air taken into the inside of the indexer unit 10.

[0022] The processing unit 20 is equipped with various devices for performing various processes on the substrate W. In the processing unit 20, processes are performed to form IL on the substrate W and to modify the formed IL. The processing unit 20 comprises multiple towers 21, a liquid box 22, and an FLA device 23.

[0023] The towers 21 are located on both sides of the conveying unit 40 in the left-right direction. In the following description, the tower 21 located to the right of the conveying unit 40 may be denoted with "R", and the tower 21 located to the left of the conveying unit 40 may be denoted with "L". Each tower 21 has multiple chambers stacked vertically, in which various processing units are installed.

[0024] Referring to Figure 2, the processing units installed in each chamber of the tower 21L will be described. Figure 2 shows an example of the processing units installed in each chamber of the tower 21L of the substrate processing apparatus 100. Note that the tower 21R has basically the same configuration as the tower 21L. Therefore, in the following description, only the parts that differ between the configuration of tower 21R and the configuration of tower 21L will be described.

[0025] As shown in Figure 2, in tower 21L, four chambers are stacked vertically. Note that the number of chambers stacked in each tower 21L is not limited to four; for example, there may be six. Also, the number of chambers stacked in each tower 21L may differ. Tower 21R is similar to tower 21L, with four chambers stacked vertically. The number of chambers stacked in tower 21R may differ from the number of chambers stacked in tower 21L.

[0026] A notch aligner (AL) 212 may be installed in the chamber located at the top of the tower 21L. The AL 212 is a processing unit that aligns the substrate W to be processed. In each of the three chambers located below the chamber in which the AL 212 is installed, a processing unit, a device (hereinafter referred to as a WET device) 211, is installed, which processes the substrate W by supplying a processing liquid to the substrate W. The substrate W, which has been aligned by the AL 212, is transported to each WET device 211 by the center robot 41.

[0027] The WET apparatus 211 is a device for supplying an oxidizing treatment solution as a treatment solution to the surface of a silicon layer formed on a substrate W, thereby forming a silicon oxide film (SiO2) on the surface of the silicon layer. The silicon oxide film is formed as IL. Preferably, at least one of the following is used as the oxidizing treatment solution: ozonated deionized water (DIO3), ammonia hydrogen peroxide solution (SC-1), sulfuric acid hydrogen peroxide solution (SPM), and hydrochloric acid hydrogen peroxide solution (SC-2). By using the above oxidizing treatment solution, a silicon oxide film can be efficiently and sufficiently produced.

[0028] The WET apparatus 211 includes, for example, a processing liquid supply unit 211A for supplying an oxidizing processing liquid and a substrate holding unit 211B for holding the substrate W. The processing liquid supply unit 211A supplies the oxidizing processing liquid to the substrate W held by the substrate holding unit 211B. The substrate holding unit 211B may be rotatable. The centrifugal force generated by the rotation of the substrate holding unit 211B may be used to scatter the oxidizing processing liquid on the substrate W and discharge the oxidizing processing liquid to the outside of the substrate W. The WET apparatus 211 uses a well-known apparatus for supplying processing liquid to the surface of a substrate. An example of a specific configuration of the WET apparatus 211 is the apparatus described in Japanese Patent Application Publication No. 2024-33671.

[0029] As shown in Figure 1, a cooling unit (CL) 213 may be installed in the chamber located at the top of tower 21R. CL213 is a unit for cooling the substrate W after heat treatment. Heat treatment is a process of heating the substrate W using a heating unit described later. CL213 may, for example, be equipped with a metal cool plate for cooling the substrate W. In tower 21R, a WET device 211 is installed in each of the three chambers located below the chamber in which CL213 is installed. Note that CL213 may also be installed in the chamber of tower 21L, and AL212 may be installed in the chamber of tower 21R.

[0030] As shown in Figure 2, a liquid box 22 is installed in the tower 21L. The liquid box 22 is provided in each tower 21L and is a box in which various devices for supplying processing liquid to each WET device 211 in the corresponding tower 21L are installed. The liquid box 22 is equipped with a processing liquid supply pipe (not shown) for supplying processing liquid supplied from a fluid cabinet 30 (described later) to the corresponding WET device 211. The liquid box 22 may also be equipped with a valve (not shown) for adjusting the flow rate of processing liquid supplied to the processing liquid supply section 211A of the corresponding WET device 211. The liquid box 22 may also be equipped with a flow sensor for measuring the flow rate of processing liquid flowing through the processing liquid supply pipe. The liquid box 22 may also be equipped with a gas supply pipe (not shown) for supplying gas supplied from a fluid cabinet 30 (described later) to the corresponding WET device 211. The gas may be supplied through the gas supply pipe to the space of the WET device 211 where the substrate W held by the substrate holding section 211B is located.

[0031] A flash lamp annealing (FLA) apparatus 23, which heats the substrate W with a flash lamp, is installed on the rear side of the tower 21L located at the rear of the apparatus as a processing unit. The FLA apparatus 23 is an example of a heating unit. The chamber in which the FLA apparatus 23 is installed contains a halogen lamp 232, a holding unit 233, and a flash lamp 234. A well-known apparatus can be used for the FLA apparatus 23. An example of a specific configuration of the FLA apparatus 23 is the apparatus described in Japanese Patent Application Publication No. 2018-6513.

[0032] The FLA apparatus 23 is equipped with multiple halogen lamps 232, which heat the substrate W placed on the holding section 233 from below.

[0033] The holding section 233 is the part on which the substrate W to be heat-treated is placed. The chamber of the FLA apparatus 23 is filled with an inert gas such as N2 or oxygen (O2). Therefore, the holding section 233 is filled with an inert gas or O2. When the chamber in which the FLA apparatus 23 is installed is filled with an inert gas, the proportion of the inert gas is preferably 80% to 100%. In addition, the chamber in which the FLA apparatus 23 is installed may be filled with an inert gas other than N2. Furthermore, when the chamber in which the FLA apparatus 23 is installed is filled with O2, the proportion of O2 is preferably 80% to 100%.

[0034] The FLA apparatus 23 is equipped with a plurality of flash lamps 234 that irradiate the substrate W with flash light. The flash lamps 234 include xenon flash lamps and krypton flash lamps. The flash lamps 234 heat the substrate W, which is placed on the holding section 233, by irradiating it with flash light from above.

[0035] Returning to Figure 1, the fluid cabinet 30 supplies processing liquid to the processing liquid supply section 211A of each WET device 211. The fluid cabinet 30 supplies processing liquid to the processing liquid supply section 211A of each WET device 211 via the processing liquid supply pipe of the liquid box 22. The fluid cabinet 30 comprises a processing liquid tank (not shown) for containing the processing liquid, processing liquid piping (not shown) connected to the processing liquid supply pipe of the liquid box 22, and a pump (not shown) for supplying the processing liquid contained in the processing liquid tank to the processing liquid piping. The fluid cabinet 30 may also be equipped with an adjustment circuit or the like for adjusting the flow rate of the processing liquid flowing through the processing liquid piping. The fluid cabinet 30 may supply the same type and the same mixing ratio of processing liquid to each processing liquid supply section 211A. Furthermore, the fluid cabinet 30 may supply a different type or a different mixing ratio of processing liquid to the processing liquid supply unit 211A of a specific WET device 211 installed in the tower 21, which is different from the processing liquid supplied to the processing liquid supply unit 211A of other WET devices 211.

[0036] The fluid cabinet 30 supplies gas to the space for performing various processes on the substrate W and to the space for transporting the substrate W. The fluid cabinet 30 supplies inert gas or O2 to the chamber where the FLA device 23 is installed via gas piping (not shown). The fluid cabinet 30 also supplies inert gas to the space 42 in the transport section 40 where the substrate W is transported. The fluid cabinet 30 may also supply gas to, for example, the transport space for the substrate W in the indexer section 10 and to the chambers of each tower 21 in the processing section 20 where various processes are performed on the substrate W.

[0037] The fluid cabinet 30 includes a gas tank (not shown) for containing gas, and gas piping for supplying the gas contained in the gas tank to the spaces to be supplied. The fluid cabinet 30 may also include an adjustment circuit for adjusting the flow rate of gas flowing through the gas piping, and filters for purifying the gas supplied to each space. The fluid cabinet 30 may supply gases of different types or with different mixing ratios depending on the space to be supplied. The fluid cabinet 30 may adjust the gas flow rate for each space to which gas is supplied to adjust the air pressure of the target space. The fluid cabinet 30 may be installed outside the housing that constitutes the external shape of the substrate processing apparatus 100, or it may be installed inside the housing.

[0038] The transport unit 40 transports the substrate W. The transport unit 40 is equipped with a center robot 41. The center robot 41 is a robot that can rotate. The center robot 41 is also a robot that can travel in the forward and backward direction, which is the travel direction D. The center robot 41 is equipped with one or more hands for gripping the substrate W. The center robot 41 grips the substrate W placed on the buffer station 43 with its hands, and then rotates and travels in the travel direction D to transport the substrate W to each part.

[0039] The space 42 where the central robot 41 is located is preferably filled with an inert gas. For example, the space 42 is filled with nitrogen (N2). However, the space 42 may be filled with an inert gas other than N2. In the space 42, the proportion of inert gas is preferably 80% to 100%. The space 42 is the space in which the substrates W that have undergone various processing are transported.

[0040] The controller 50 controls each part of the substrate processing apparatus 100. The configuration of the controller 50 will be described with reference to Figure 3. Figure 3 is a block diagram showing the configuration of the substrate processing apparatus 100. As shown in Figure 3, the controller 50 includes a processor 51 that performs various calculations according to a program, and a memory 52 that stores various information such as programs. The processor 51 executes various processes according to a program pre-stored in the memory 52. ​​Examples of the processor 51 include a CPU (Central Processing Unit), a DSP (Digital Signal Processor), a GPU (Graphic Processing Unit), and an MPU (Micro Processing Unit). Examples of the memory 52 include a ROM (Read Only Memory), RAM (Random Access Memory), flash memory, and an HDD (Hard Disk Drive).

[0041] The controller 50 controls the WET device 211, AL 212, various devices in the liquid box 22, halogen lamp 232, and flash lamp 234 of the processing unit 20. The controller 50 also controls various devices in the fluid cabinet 30. Furthermore, the controller 50 controls the center robot 41 of the transport unit 40.

[0042] [Substrate processing method] Referring to Figure 4, an example of a substrate processing method performed by the substrate processing apparatus 100 will be described. Figure 4 is a flowchart showing an example of the flow of a substrate processing method performed by the substrate processing apparatus 100.

[0043] In step S1, the substrate processing apparatus 100 transports the substrate W to the WET apparatus 211. More specifically, in step S1, the controller 50 controls the center robot 41 to transport the substrate W to the WET apparatus 211. In step S1, the controller 50 sequentially transports the substrate W to the WET apparatus 211 where no processing is currently being performed.

[0044] In step S2, the substrate processing apparatus 100 supplies an oxidizing treatment solution to the surface of the silicon layer formed on the substrate W to form a silicon oxide film on the surface of the silicon layer. More specifically, in step S2, the controller 50 controls the WET apparatus 211 to supply the oxidizing treatment solution from the treatment solution supply unit 211A to the surface of the silicon layer on the substrate W for a predetermined time. When the oxidizing treatment solution is supplied to the surface of the silicon layer on the substrate W, a silicon oxide film is formed on the surface of the silicon layer as a native oxide film. In step S2, the controller 50 sequentially starts the operation of each WET apparatus 211 to which the substrate W has been transported to perform the process of forming the silicon oxide film.

[0045] In step S3, the substrate processing apparatus 100 transports the substrate W on which the silicon oxide film has been formed to the FLA apparatus 23. More specifically, in step S3, the controller 50 controls the center robot 41 to transport the substrate W on which the silicon oxide film has been formed from the WET apparatus 211 to the holding section 233 of the FLA apparatus 23. The substrate W processed in the WET apparatus 211 is transported to the holding section 233 of the FLA apparatus 23 via space 42. In step S3, the controller 50 sequentially transports the substrate W processed in each WET apparatus 211 to the holding section 233.

[0046] In step S4, the substrate processing apparatus 100 heats the substrate W on which the silicon oxide film is formed using a flash lamp. More specifically, in step S4, the controller 50 controls the flash lamp 234 to irradiate the substrate W held in the holding section 233 with flash light from the flash lamp 234 for a predetermined time, thereby heating the silicon oxide film formed on the substrate W. In step S4, the controller 50 maintains the halogen lamp 232 lit and heats the substrate W from below. In step S4, the controller 50 may heat the substrate W so that its temperature reaches 600°C or higher by heating with the flash lamp 234 for 5ms or less. In step S4, it is preferable that the controller 50 controls the flash lamp 234 so that the lower limit of the temperature of the substrate W heated by the flash lamp 234 is 600°C to 800°C.

[0047] In step S5, the substrate processing apparatus 100 transports the heated substrate W to the CL213. More specifically, in step S5, the controller 50 controls the center robot 41 to transport the heated substrate W from the holding section 233 of the FLA apparatus 23 to the CL213. The heated substrate W is cooled in the CL213 for a predetermined time.

[0048] In step S6, the substrate processing apparatus 100 transports the cooled substrate W to the WET apparatus 211. More specifically, the controller 50 controls the center robot 41 to place the substrate W on the CL213 for a predetermined time, and then transports the substrate W from the CL213 to the WET apparatus 211. In step S8, the controller 50 sequentially transports the cooled substrates W to the WET apparatus 211 where no processing is currently being performed.

[0049] In step S7, the substrate processing apparatus 100 again supplies the oxidizing treatment solution to the surface of the silicon oxide film heated by the flash lamp 234. More specifically, in step S7, the controller 50 controls the WET device 211 to supply the oxidizing treatment solution from the treatment solution supply unit 211A to the silicon oxide film of the heated substrate W for a predetermined time. In step S7, the controller 50 sequentially starts the operation of each WET device 211 to which the heated substrate W has been transported, and supplies the oxidizing treatment solution to the substrate W. After step S7 is completed, the controller 50 controls each part of the substrate processing apparatus 100 in order to place the substrate W, which has undergone various treatments, into the transport container P.

[0050] According to the above method, a silicon oxide film is first formed on the surface of the silicon layer by an oxidizing treatment solution, and then flash lamp heating is performed to improve the quality of the silicon oxide film. Therefore, a substrate processing method suitable for forming a thin, high-quality IL (Iron Integrity) between the Si channel and the High-K metal in the metal gate portion of a MOSFET can be provided. Furthermore, since the substrate W on which the silicon oxide film has been formed is heated by the flash lamp 234, the silicon oxide film can be rapidly heated in a short time, further improving the quality of the silicon oxide film.

[0051] Furthermore, according to the above method, the oxidizing treatment solution is supplied again to the heated surface of the silicon oxide film. As a result, a film terminated with OH groups is formed on the surface of the silicon oxide film. Therefore, for example, when laminating a High-K metal on this silicon oxide film, the adhesion between the silicon oxide film and the High-K metal can be improved.

[0052] Furthermore, according to the above method, the substrate W on which the silicon oxide film is formed is transported to the FLA apparatus 23 through a space 42 filled with N2. Therefore, spontaneous oxidation of the silicon oxide film can be suppressed between the oxidation by the oxidizing treatment solution and the heating by the flash lamp 234. Thus, a higher quality silicon oxide film can be produced.

[0053] Furthermore, according to the above method, the substrate W is heated to a temperature of 600°C or higher by heating with a flash lamp for less than 5ms. This makes it possible to sufficiently improve the quality of the silicon oxide film.

[0054] In the substrate processing method shown in Figure 4, steps S6 and S7 may be omitted. Also, the processing performed on the surface of the substrate W by supplying processing liquid to the substrate W by the WET device 211 (WET processing) usually takes longer than the heating process. Therefore, it is desirable that the substrate processing apparatus 100 be configured to perform WET processing in parallel using multiple WET devices 211. This improves the processing efficiency of the substrate W by the substrate processing apparatus 100.

[0055] Next, referring to Figures 5 to 8, we will describe the experimental results regarding the thickness and quality of the silicon oxide film after a heat treatment in which the substrate W on which the silicon oxide film is formed is heated with a flash lamp 234. First, referring to Figure 5, we will describe the change in the thickness of the silicon oxide film on the substrate W before and after heat treatment under each heat treatment condition. Figure 5 is a diagram showing the change in the thickness of the silicon oxide film on the substrate W before and after heat treatment by flash lamp annealing.

[0056] As shown in Figure 5, the change in the thickness of the silicon oxide film on the substrate W after heat treatment under each heat treatment condition is shown by a bar graph. In the table shown in Figure 5, the vertical axis represents the thickness of the silicon oxide film, and the unit of thickness is angstroms (Å). The thickness of the silicon oxide film under each heat treatment condition is shown by two bar graphs (a plain bar graph and a shaded bar graph). The plain bar graph shows the thickness of the silicon oxide film after heat treatment. The shaded bar graph shows the increase or decrease in the thickness of the silicon oxide film before and after heat treatment, that is, the value obtained by subtracting the thickness of the silicon oxide film before heat treatment from the thickness of the silicon oxide film after heat treatment.

[0057] Figure 5 shows the change in silicon oxide film thickness before and after heat treatment, measured by varying the heat treatment conditions for O2 concentration and peak temperature. The O2 concentration is the O2 concentration in the chamber of the FLA apparatus 23 where the substrate W undergoing heat treatment is located. Other heat treatment conditions (assist temperature, heating time, etc.) are the same, as are the conditions for the formation process that creates the silicon oxide film. The O2 concentration is the O2 concentration in the chamber where the substrate W undergoing heat treatment is located. Four conditions were set for the O2 concentration: N2 concentration 100%, O2 concentration 25%, O2 concentration 50%, and O2 concentration 100%. Note that N2 concentration 100% means O2 concentration 0%. The peak temperature is the highest temperature that the surface of the substrate W is expected to reach due to heating by the flash lamp 234, and is the target temperature for heating the surface of the substrate W. Two conditions were set for the peak temperature: 950°C and 1150°C.

[0058] As shown in the plain bar graph of Figure 5, the thickness of the silicon oxide film after heat treatment increased as the O2 concentration under heat treatment increased. Specifically, the silicon oxide film thickness of substrate W heat-treated under 100% N2 concentration conditions was the thinnest. Also, the silicon oxide film thickness of substrate W heat-treated under 100% O2 concentration conditions was the thickest. As shown in the shaded bar graph of Figure 5, under 100% N2 concentration conditions, the increase or decrease in silicon oxide film thickness before and after heat treatment was negative. Specifically, under 100% N2 concentration conditions, the silicon oxide film thickness after heat treatment was thinner than the silicon oxide film thickness before heat treatment. Under heat treatment conditions of O2 concentration from 25% to 100%, the increase or decrease in silicon oxide film thickness before and after heat treatment was positive in all cases, and the silicon oxide film thickness after heat treatment was thicker than the silicon oxide film thickness before heat treatment. Furthermore, the results showed that setting the peak temperature to 1150°C resulted in a thicker silicon oxide film thickness after heat treatment compared to setting the peak temperature to 950°C.

[0059] From the above results, it is considered that, in terms of the thickness of the silicon oxide film after heat treatment, the thickness of the silicon oxide film after heat treatment can be reduced under heat treatment conditions that reduce the O2 concentration, especially under heat treatment conditions with an N2 concentration of 100%. Furthermore, even when the substrate W is heat-treated under heat treatment conditions with an O2 concentration of 25% to 100%, it is considered possible to reduce the increase in the thickness of the silicon oxide film after heat treatment by adjusting the temperature at which the substrate W is heated by at least one of the flash lamp 234 and halogen lamp 232 of the FLA apparatus 23. Note that the experimental results shown in Figure 5 were obtained by keeping the heat treatment conditions the same except for the O2 concentration and peak temperature, resulting in a thicker silicon oxide film after heat treatment under heat treatment conditions with an O2 concentration of 25% to 100%. However, by adjusting various heat treatment conditions (assist temperature, heating time, etc.), it is possible to adjust the film thickness to be equivalent to that of the silicon oxide film under the heat treatment conditions of 100% N2 concentration shown in Figure 5, even under heat treatment conditions of O2 concentration from 25% to 100%.

[0060] Next, with reference to Figures 6 to 8, the silicon strength of the silicon oxide film on the substrate W after heat treatment will be explained. Figures 6 to 8 are graphs showing the film thickness and silicon strength of the silicon oxide film after heat treatment under each heat treatment condition. In the graphs shown in Figures 6 to 8, the horizontal axis represents the film thickness (Å) of the silicon oxide film after heat treatment, and the vertical axis represents the silicon strength after heat treatment. The silicon strength was measured by measuring the amount of silicon (Si4+) present on the surface of the silicon oxide film using X-ray photoelectron spectroscopy (XPS).

[0061] Figure 6 is a graph showing the relationship between silicon oxide film thickness and silicon strength under heat treatment conditions with an N2 concentration of 100%. The reference line R1 in Figure 6 shows the relationship between silicon oxide film thickness and silicon strength in the untreated state. Plot A1 shows the silicon oxide film thickness and silicon strength in the untreated state. Plot A2 shows the silicon oxide film thickness and silicon strength when heat treatment is performed at an N2 concentration of 100% and a peak temperature of 1150°C. Plot A3 shows the silicon oxide film thickness and silicon strength when heat treatment is performed at an N2 concentration of 100% and a peak temperature of 950°C.

[0062] As shown in plots A2 and A3, the silicon oxide film heat-treated under conditions of 100% N2 concentration showed reduced thickness and increased silicon strength compared to before heat treatment. In other words, by performing heat treatment after forming a silicon oxide film on the substrate W, a thin and high-quality silicon oxide film was formed on the substrate W. The other heat treatment conditions in plots A2 and A3 were assist temperature: 700°C, heating time: 1.4 ms, and atmospheric pressure: 100 kPa. The assist temperature is the maximum temperature that the lower surface of the substrate W is expected to reach due to heating by the halogen lamp of the PLA apparatus, and is the target temperature for heating the lower surface of the substrate W. The heating time is the time for heating by the flash lamp 234 of the FLA apparatus 23. The atmospheric pressure is the pressure inside the chamber of the FLA apparatus 23 where the substrate W being heat-treated is located.

[0063] Next, referring to Figure 7, this graph shows the relationship between the thickness of the silicon oxide film and the silicon strength under heat treatment conditions of O2 concentration 25% and O2 concentration 100%. The reference line R2 shown in Figure 7 is a line showing the relationship between the thickness of the silicon oxide film and the silicon strength in the state without heat treatment. Plots B1 and B2 shown in Figure 7 show the thickness of the silicon oxide film and the silicon strength in the state without heat treatment. In plot B1, the time for supplying the oxidizing treatment solution to the substrate W (hereinafter referred to as the supply time of the oxidizing treatment solution) is 20 s (seconds), and in plot B2, the supply time of the oxidizing treatment solution is 60 s (seconds).

[0064] Plots B3 to B7 in Figure 7 show the relationship between the thickness of the silicon oxide film and the silicon strength under the following heat treatment conditions. Plot B8 is shown as a comparative example and shows the relationship between the thickness of the silicon oxide film and the silicon strength under heat treatment conditions with an N2 concentration of 100%. In plots B3 to B8, the supply time of the oxidizing treatment solution was set to 20 s to form a silicon oxide film on the substrate W. B3: Assist temperature 700°C, peak temperature 950°C, heating time 1.4 ms, atmospheric pressure 100 kPa, O2 concentration 100% B4: Assist temperature 700°C, peak temperature 950°C, heating time 1.4 ms, atmospheric pressure 100 kPa, O2 concentration 25% B5: Assist temperature 550°C, peak temperature 950°C, heating time 1.4 ms, atmospheric pressure 100 kPa, O2 concentration 100% B6: Assist temperature 550°C, peak temperature 950°C, heating time 1.4 ms, atmospheric pressure 100 kPa, O2 concentration 25% B7: Assist temperature 550°C, peak temperature 950°C, heating time 1.4 ms, atmospheric pressure 5 kPa, O2 concentration 25%

[0065] As shown in plots B3 to B7 of Figure 7, the strength of the silicon oxide film increased after heat treatment, i.e., the quality of the silicon oxide film improved. As shown in plots B3 to B6, the thickness of the silicon oxide film increased after heat treatment compared to the thickness of the silicon oxide film without heat treatment. From these results, it was found that even under heat treatment conditions of 25% and 100% O2 concentrations, the quality of the silicon oxide film was high, and therefore, by performing the etch-back treatment shown in the modified example described later after heat treatment, it is possible to improve the quality of the silicon oxide film while reducing its thickness.

[0066] Furthermore, as shown in plot B7, it was found that even under heat treatment conditions of 25% O2 concentration, the same results as under heat treatment conditions of 100% N2 concentration can be obtained by setting the atmospheric pressure in the chamber of the FLA apparatus 23 where the substrate W is located to 5 kPa. In other words, it was found that even under heat treatment conditions of 25% O2 concentration, it is possible to adjust the thickness of the silicon oxide film and the silicon strength by adjusting heat treatment conditions other than the O2 concentration.

[0067] Next, referring to Figure 8, we will explain the relationship between the film thickness and silicon strength of the silicon oxide film after a process in which the oxidizing treatment solution is supplied again to the surface of the heat-treated silicon oxide film. The reference line R3 shown in Figure 8 is a line that shows the relationship between the film thickness and silicon strength of the silicon oxide film in the state before heat treatment. Plots C1 and C2 show the film thickness and silicon strength of the silicon oxide film in the state before heat treatment, and the supply time of the oxidizing treatment solution differs between plot C1 and plot C2.

[0068] Plot C3 is a comparative example, showing the relationship between the thickness of the silicon oxide film and the silicon strength after heat treatment under heat treatment conditions with a 100% N2 concentration. In other words, it shows the relationship between the thickness of the silicon oxide film and the silicon strength when no further oxidizing treatment solution is supplied after heat treatment. In plots C4 and C5, the type of oxidizing treatment solution supplied again to the substrate after heat treatment is different. In plot C4, a mixture of ozone (O3) and SC-1 is used as the oxidizing treatment solution supplied again. In plot C5, only ozone (O3) is used as the oxidizing treatment solution supplied again. Note that plots C3 to C5 maintain a 100% N2 concentration and all other heat treatment conditions are the same.

[0069] As shown in plot C4 of Figure 8, when a mixture of ozone (O3) and SC-1 was supplied to the surface of a heat-treated silicon oxide film, the silicon oxide film was thinner than the silicon oxide film that was heat-treated only under the heat treatment conditions of 100% N2 concentration shown in plot C3, and the silicon strength was almost the same. As shown in plot C5, when only ozone (O3) was supplied to the surface of a heat-treated silicon oxide film, the silicon oxide film was thicker than the silicon oxide film shown in plot C3.

[0070] From the above results, when heating with the flash lamp 234 is performed in an FLA apparatus 23 filled with inert gas, the quality of the silicon oxide film can be improved without increasing the thickness of the silicon oxide film formed by the oxidizing treatment solution. Therefore, a thinner silicon oxide film can be formed. Furthermore, when heating with the flash lamp 234 is performed in an FLA apparatus 23 filled with oxygen, the quality of the silicon oxide film can be improved.

[0071] [Variation] Referring to Figure 9, a modified example of the substrate processing method performed by the substrate processing apparatus 100 will be described. Figure 9 is a flowchart showing an example of the flow of a modified example of the substrate processing method performed by the substrate processing apparatus 100. For the sake of explanation, components having the same function as those described in the above embodiment will be denoted by the same reference numerals, and their descriptions will not be repeated.

[0072] In the substrate processing method shown in Figure 9, after heat treatment is performed on the substrate W, etch-back is performed using a silicon oxide film removal treatment solution. In this modified example, for example, the WET device 211 installed in the tower 21 located at the rear of the apparatus operates as an etch-back device. Etch-back is a process in which a silicon oxide film removal treatment solution is supplied as a treatment solution to the surface of the silicon oxide film formed on the substrate W to remove a portion of the silicon oxide film formed on the substrate W. In this modified example, the treatment solution supply unit 211A of the WET device 211 installed in the tower 21 at the rear of the apparatus supplies the silicon oxide film removal treatment solution. Examples of silicon oxide film removal treatment solutions include dilute hydrofluoric acid (DHF), hydrofluoric acid hydrogen peroxide mixture (FPM), and buffered hydrofluoric acid (BHF). In this modified example, the WET device 211 located at the front of the apparatus operates as a device that supplies an oxidizing treatment solution to the surface of the silicon layer formed on the substrate W. In this modified example, the holding portion 233 of the FLA device 23 may be filled with N2, but it is preferable that it be filled with O2.

[0073] Steps S11 to S16 in the substrate processing method shown in Figure 9 are the same as steps S1 to S6 in the substrate processing method shown in Figure 4, unless otherwise specified below, so their explanation will be omitted.

[0074] In step S17, the substrate processing apparatus 100 supplies silicon oxide removal processing liquid to the surface of the silicon oxide film after heating with the flash lamp 234. More specifically, in step S17, the controller 50 controls the WET device 211 in the tower 21 at the rear of the apparatus to supply silicon oxide removal processing liquid from the processing liquid supply unit 211A to the silicon oxide film of the heated substrate W for a predetermined time. In step S17, the controller 50 sequentially starts the operation of each WET device 211 in the tower 21 at the rear of the apparatus, to which the substrate W has been transported, and supplies silicon oxide removal processing liquid to the substrate W.

[0075] In step S18, the substrate processing apparatus 100 transports the substrate W after etch-back to the WET apparatus 211 which supplies an oxidizing treatment solution. More specifically, in step S18, the controller 50 controls the center robot 41 to transport the substrate W from the WET apparatus 211 in the tower 21 at the rear of the apparatus to the WET apparatus 211 in the tower 21 at the front of the apparatus.

[0076] In step S19, the substrate processing apparatus 100 again supplies the oxidizing treatment solution to the surface of the silicon oxide film heated by the flash lamp. More specifically, in step S19, the controller 50 controls the WET device 211 in the tower 21 at the front of the apparatus to supply the oxidizing treatment solution from the treatment solution supply unit 211A to the silicon oxide film of the heated substrate W for a predetermined time. In step S19, the controller 50 sequentially starts the operation of each WET device 211 to which the substrate W has been transported, and supplies the oxidizing treatment solution to the substrate W. After step S21 is completed, the controller 50 controls each part of the substrate processing apparatus 100 in order to place the substrate W, which has undergone various treatments, into the transport container P. In the substrate processing method shown in Figure 9, steps S18 and S19 may be omitted.

[0077] According to the substrate processing method of this modified example, the thickness of the silicon oxide film, which has increased in thickness, can be reduced by heating in an oxygen-filled space. Therefore, a high-quality and thin silicon oxide film can be produced.

[0078] [Other Embodiments] In the embodiment described above, the substrate processing apparatus 100 is configured to have four towers 21, but it is not limited to this configuration. The substrate processing apparatus 100 may have one or more towers. Alternatively, the substrate processing apparatus 100 may be configured to have a WET device 211 and an FLA device 23 installed in a single tower.

[0079] In the embodiment described above, AL212 and CL213 are installed in the uppermost chamber of the tower 21, but the configuration is not limited to this. AL212 and CL213 may be installed in chambers other than the uppermost chamber of the tower 21. Alternatively, AL212 and CL213 may be installed in the chamber of the tower in which the FLA device 23 is installed.

[0080] Furthermore, in the substrate processing method shown in Figures 4 and 9, the substrate processing apparatus 100 may perform substrate W alignment in the AL212 before steps S1 and S11. Specifically, the controller 50 controls the center robot 41 to transport the substrate W, which is placed on the buffer station 43 by the transport device 12, to the AL212. The controller 50 controls the AL212 to perform substrate W alignment. In this case, in steps S1 and S11, the controller 50 transports the aligned substrate W to the WET device 211.

[0081] In the embodiment described above, the substrate processing apparatus 100 is equipped with a fluid cabinet 30 for supplying processing liquid and gas, but it is not limited to this configuration. The substrate processing apparatus 100 may be equipped with a processing liquid cabinet for supplying only processing liquid, or with a gas cabinet for supplying only gas. [Explanation of symbols]

[0082] 100 Substrate Processing Equipment 211 WET device 211A Processing liquid supply unit 23 FLA device (heating section) 232 Halogen Lamp 234 Flash Lamp

Claims

1. A silicon oxide film formation step involves supplying an oxidizing treatment solution to the surface of a silicon layer formed on a substrate to form a silicon oxide film on the surface of the silicon layer, A substrate processing method comprising a heating step of heating the substrate on which the silicon oxide film is formed with a flash lamp.

2. The substrate processing method according to claim 1, further comprising an oxidizing treatment solution supply step of supplying an oxidizing treatment solution again to the surface of the silicon oxide film heated by the flash lamp.

3. The substrate processing method according to claim 1, further comprising a transport step of transporting the substrate through a space filled with inert gas to a place where it is heated by a flash lamp, after forming the silicon oxide film on the surface of the silicon layer.

4. The substrate processing method according to claim 1, wherein the heating step is carried out in a space filled with an inert gas.

5. The substrate processing method according to claim 1, wherein the heating step is carried out in a space filled with oxygen.

6. The substrate processing method according to claim 5, further comprising a removal solution supply step of supplying a silicon oxide film removal treatment solution to the surface of the silicon oxide film after the heating step.

7. The substrate treatment method according to claim 1, wherein the oxidizing treatment solution is at least one of ozonated deionized water, a mixture of ammonia and hydrogen peroxide, a mixture of sulfuric acid and hydrogen peroxide, and a mixture of hydrochloric acid and hydrogen peroxide.

8. The substrate processing method according to claim 1, wherein in the heating step, the temperature of the substrate becomes 600°C or higher by heating with the flash lamp for 5 ms or less.

9. A treatment liquid supply unit that supplies an oxidizing treatment liquid to the surface of a silicon layer formed on a substrate to form a silicon oxide film on the surface of the silicon layer, A substrate processing apparatus comprising: a heating unit for heating the substrate on which the silicon oxide film is formed using a flash lamp.

Images