Substrate processing method, semiconductor device production method, program, and substrate processing device
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- KOKUSAI DENKI KK
- Filing Date
- 2025-02-03
- Publication Date
- 2026-08-06
Smart Images
Figure JP2025003418_06082026_PF_FP_ABST
Abstract
Description
Substrate Processing Method, Method of Manufacturing a Semiconductor Device, Program, and Substrate Processing Apparatus
[0001] The present disclosure relates to a substrate processing method, a method of manufacturing a semiconductor device, a program, and a substrate processing apparatus.
[0002] As one step of a semiconductor device manufacturing process, a modification process of a film formed on a substrate may be performed (see, for example, Patent Document 1).
[0003] Japanese Patent Application Laid-Open No. 2019-175920
[0004] The present disclosure provides a technique capable of controlling the film quality of a metal-containing film formed on a substrate.
[0005] According to one aspect of the present disclosure, (a) a step of preparing a substrate having a metal-containing film containing impurities, (b) a step of supplying a carboxy group-containing fluid to the metal-containing film at a first temperature to remove the impurities from the metal-containing film, and (c) a step of heating the metal-containing film from which the impurities have been removed to a second temperature higher than the first temperature in a non-oxidizing atmosphere are provided.
[0006] According to the present disclosure, it becomes possible to control the film quality of a metal-containing film formed on a substrate.
[0007] Figure 1 is a schematic diagram of a vertical processing furnace of a substrate processing apparatus preferably used in one embodiment of the present disclosure, showing the processing furnace 202 portion in a vertical cross-sectional view. Figure 2 is a schematic diagram of a controller 121 of a substrate processing apparatus preferably used in one embodiment of the present disclosure, showing the control system of the controller 121 in a block diagram. Figure 3 is a diagram showing a processing sequence in one embodiment of the present disclosure. Figure 4(a) is a partially enlarged cross-sectional view of a wafer 200 having a metal-containing film 400 in a recess. Figure 4(b) is a partially enlarged cross-sectional view of the wafer 200 after impurities 305 have been removed from the metal-containing film 400 by supplying a carboxyl group-containing fluid to the metal-containing film 400 at a first temperature. Figure 4(c) is a partially enlarged cross-sectional view of the wafer 200 after the metal-containing film 410 from which impurities 305 have been removed has been heated in a non-oxidizing atmosphere. Figure 5(a) is a partially enlarged view of the crystal grains 300 in the metal-containing film 400 of the wafer 200 prepared in step A. Figure 5(b) is a partially enlarged view of the crystal grains 310 contained in the metal-containing film 410 after step B is performed. Figure 5(c) is a partially enlarged view of the crystal grains 320 contained in the metal-containing film 420 after step C is performed. Figure 6(a) is a partially enlarged view of the crystal grains contained in the metal-containing film in Comparative Example 1. Figure 6(b) is a partially enlarged view of the crystal grains contained in the metal-containing film in Comparative Example 2. Figure 7 is a schematic configuration diagram of a vertical processing furnace of a substrate processing apparatus preferably used in other embodiments of the present disclosure, and shows the processing furnace 302 portion in a vertical cross-sectional view.
[0008] <An Embodiment of the Disclosure> An embodiment of the disclosure will be described below with reference to the drawings. The drawings used in the following description are all schematic, and the dimensional relationships and ratios of each element shown in the drawings do not necessarily correspond to reality. Furthermore, the dimensional relationships and ratios of each element do not necessarily correspond between multiple drawings.
[0009] (1) As shown in the configuration diagram 1 of the substrate processing apparatus, the processing furnace 202 is equipped with a reaction tube 203. The reaction tube 203 is made of, for example, quartz (SiO ２It is constructed of a heat-resistant material such as silicon carbide (SiC) and is configured as a cylindrical member having a gas supply port 203p at the upper end and a furnace opening at the lower end. A processing chamber 201 is formed in the hollow part of the reaction tube 203. The processing chamber 201 is configured to accommodate multiple wafers 200 as substrates.
[0010] Below the reaction tube 203, a seal cap 219 is provided, which serves as a lid capable of airtightly closing the lower end opening of the reaction tube 203. The seal cap 219 is made of a non-metallic material, such as quartz. Below the seal cap 219, a rotating mechanism 267 is installed. The rotating shaft 255 of the rotating mechanism 267 is connected to the boat 217. The rotating mechanism 267 is configured to rotate the wafer 200 by rotating the boat 217. The seal cap 219 is configured to be raised and lowered vertically by a boat elevator 115, which serves as a lifting mechanism.
[0011] The boat 217, which serves as a substrate support, is configured to support multiple wafers 200, for example 25 to 200 wafers 200, in a horizontal position and aligned vertically in multiple stages, that is, to arrange them with spacing between them. The boat 217 is made of a heat-resistant material such as quartz or SiC, and is equipped with a top plate 217a and a bottom plate 217b at the top and bottom. The heat-insulating body 218, which is supported in multiple stages in a horizontal position below the boat 217, is made of a heat-resistant material such as quartz or SiC.
[0012] A heater 207 is provided on the outside of the reaction tube 203 as a heating unit. The heater 207 heats the wafer 200 housed in the wafer housing area to a predetermined temperature, and also functions as a liquefaction suppression mechanism that imparts thermal energy to the gas supplied into the processing chamber 201 to suppress its liquefaction, and as an excitation mechanism that activates this gas with heat. Inside the processing chamber 201, a temperature sensor 263 is provided along the inner wall of the reaction tube 203 as a temperature detection unit.
[0013] A gas supply port 203p, located at the upper end of the reaction tube 203, is connected to a gas supply pipe 232a. The gas supply pipe 232a is equipped with a gas generator 250a as a vaporizer, a mass flow controller (MFC) 241a as a flow control unit, and a valve 243a as an on / off valve.
[0014] A supply pipe 232c is connected to the gas generator 250a to supply a liquid containing a carboxyl group (-COOH) (hereinafter sometimes referred to as "first liquid"). The supply pipe 232c is equipped with a tank 250t for storing the first liquid, an MFC 241c, and a valve 243c. Details of the first liquid will be described later.
[0015] A gas supply pipe 232e is connected to the tank 250t to supply pressurized gas into the tank 250t. The gas supply pipe 232e is equipped with an MFC 241e and a valve 243e. The pressurized gas is used to push the first liquid in the tank 250t into the supply pipe 232c. As the pressurized gas, for example, a gas similar to the inert gas described later can be used. The tank 250t is also equipped with a drain pipe 232f for discharging the first liquid from its interior. The drain pipe 232f is equipped with a valve 243f.
[0016] A gas supply pipe 232d is connected to the gas generator 250a to supply a vaporization carrier gas to its interior. The gas supply pipe 232d is equipped with an MFC 241d and a valve 243d. The vaporization carrier gas is used to atomize the first liquid supplied to the gas generator 250a from the supply pipe 232c, making it easier to vaporize.
[0017] Downstream of valve 243a in gas supply pipe 232a, gas supply pipe 232b is connected to supply inert gas. MFC 241b and valve 243b are provided in gas supply pipe 232b. The inert gas acts as a purge gas, carrier gas, diluent gas, etc.
[0018] The gas generator 250a is configured to generate a -COOH-containing fluid, such as a vaporized gas of the first liquid, by heating the first liquid to a predetermined temperature, for example, under approximately atmospheric pressure, and vaporizing or atomizing it. In this embodiment, when vaporizing or atomizing the first liquid, a vaporization carrier gas is supplied to the gas generator 250a together with the first liquid, thereby atomizing the first liquid.
[0019] The -COOH-containing fluid supply system is mainly composed of a gas supply pipe 232a, an MFC 241a, and a valve 243a. A gas generator 250a may also be included in the -COOH-containing fluid supply system. The inert gas supply system is mainly composed of a gas supply pipe 232b, an MFC 241b, and a valve 243b. The first liquid supply system is mainly composed of a tank 250t, a supply pipe 232c, an MFC 241c, and a valve 243c. The vaporization carrier gas supply system is mainly composed of a gas supply pipe 232d, an MFC 241d, and a valve 243d. The pressurized gas supply system is mainly composed of a gas supply pipe 232e, an MFC 241e, and a valve 243e. The -COOH-containing fluid supply system, the first liquid supply system, the vaporization carrier gas supply system, and the pressurized gas supply system are collectively referred to as the supply unit.
[0020] An exhaust pipe 231 for exhausting the atmosphere inside the processing chamber 201 is connected to the lower side wall of the reaction tube 203. A vacuum pump 246, which acts as an exhaust device, is connected to the exhaust pipe 231 via a pressure sensor 245, which acts as a pressure detector for detecting the pressure inside the processing chamber 201, and an APC valve 244, which acts as a pressure regulator. The exhaust system mainly consists of the exhaust pipe 231 and the APC valve 244. The vacuum pump 246 may also be considered as part of the exhaust system.
[0021] As shown in Figure 2, the controller 121, which is the control unit (control means), is configured as a computer equipped with a CPU (Central Processing Unit) 121a, RAM (Random Access Memory) 121b, storage device 121c, and I / O port 121d. The RAM 121b, storage device 121c, and I / O port 121d are configured to exchange data with the CPU 121a via an internal bus 121e. An input / output device 122, configured as, for example, a touch panel, is connected to the controller 121. An external storage device 123 can also be connected to the controller 121. The board processing device may be configured to have one control unit, or it may be configured to have multiple control units. That is, the control for performing the processing sequence described later may be performed using one control unit, or it may be performed using multiple control units. Furthermore, the multiple control units may be configured as a control system connected to each other by a wired or wireless communication network, and the entire control system may perform the control necessary to carry out the processing sequence described later. In this specification, the term "control unit" may refer to a single control unit, a plurality of control units, or a control system composed of a plurality of control units.
[0022] The storage device 121c is composed of, for example, flash memory, HDD (Hard Disk Drive), SSD (Solid State Drive), etc. The storage device 121c contains, in a readable format, control programs that control the operation of the substrate processing device, and process recipes that describe the procedures and conditions for substrate processing, as described later. The process recipe functions as a program, combining the procedures in the substrate processing described later so that the controller 121 causes the substrate processing device to execute them and obtain a predetermined result. Hereinafter, process recipes and control programs will be collectively referred to simply as "programs" (program products). Similarly, process recipes will be simply referred to as "recipes." In this specification, the term "program" may include only recipes, only control programs, or both. The RAM 121b is configured as a memory area (work area) where programs and data read by the CPU 121a are temporarily held.
[0023] The I / O port 121d is connected to the MFCs 241a to 241e, valves 243a to 243f, gas generator 250a, pressure sensor 245, APC valve 244, vacuum pump 246, temperature sensor 263, heater 207, rotating mechanism 267, boat elevator 115, shutter opening / closing mechanism 115s, etc.
[0024] The CPU 121a is configured to read and execute a control program from the storage device 121c, and to read a recipe from the storage device 121c in response to input of operation commands from the input / output device 122. The CPU 121a is configured to control the following operations in accordance with the contents of the read recipe: gas generation operation by the gas generator 250a, flow rate adjustment operation of various substances (various gases) by the MFCs 241a to 241e, opening and closing operation of valves 243a to 243f, opening and closing operation of APC valve 244 and pressure adjustment operation by APC valve 244 based on pressure sensor 245, starting and stopping of vacuum pump 246, temperature adjustment operation of heater 207 based on temperature sensor 263, rotation and rotation speed adjustment operation of boat 217 by rotation mechanism 267, raising and lowering operation of boat 217 by boat elevator 115, opening and closing operation of shutter 219s by shutter opening and closing mechanism 115s, etc.
[0025] The controller 121 can be configured by installing the above-mentioned program, which is recorded and stored in the external storage device 123, onto a computer. The external storage device 123 includes, for example, magnetic disks such as HDDs, optical disks such as CDs, magneto-optical disks such as MOs, and semiconductor memory such as USB memory and SSDs. The storage device 121c and the external storage device 123 are configured as computer-readable recording media. Hereinafter, these will be collectively referred to simply as recording media. In this specification, when the term recording media is used, it may include only the storage device 121c, only the external storage device 123, or both. Note that the program may be provided to the computer using communication means such as the Internet or a dedicated line, without using the external storage device 123.
[0026] (2) Substrate Processing Process Using the substrate processing apparatus described above, a method for processing a substrate as one step in the semiconductor device manufacturing process, specifically, an example of a processing sequence for processing a wafer 200 as a substrate on which a metal-containing film 400 is formed on its surface, will be explained mainly with reference to Figures 3 and 4(a) to 4(c). In this embodiment, as an example, a case in which a wafer 200 with recesses such as trenches, grooves, and holes, which are three-dimensional structures, is formed on its surface will be described.
[0027] In this specification, the term "recess" is not limited to shapes having a bottom surface, but may also include structures such as gaps or through-holes that do not have a bottom surface. In the case of structures that do not have a bottom surface, "bottom side" may mean the direction (side) from each of the two or more openings toward the back of the structure.
[0028] Furthermore, in this embodiment, as an example, a case in which a metal-containing film 400 is formed as wiring in a recess formed in a wafer 200 will be described (see Figure 4(a)). The metal-containing film 400 is formed to fill the inside of the recess from the top (opening side) to the bottom (deep side, bottom side), for example. In this embodiment, a case in which the metal-containing film 400 is exposed in the upper part of the recess and the metal-containing film 400 has a structure comprising a plurality of crystal grains 300 will be described. In the following description, the operation of each part constituting the substrate processing apparatus is controlled by the controller 121.
[0029] In this embodiment, the processing sequence includes: (a) step A, which is to prepare a wafer 200 having a metal-containing film 400 containing impurities 305; (b) step B, which is to supply a -COOH-containing fluid to the metal-containing film 400 at a first temperature to remove the impurities 305 from the metal-containing film 400; and (c) step C, which is to heat the metal-containing film 410 from which the impurities 305 have been removed to a second temperature higher than the first temperature in a non-oxidizing atmosphere.
[0030] The following example describes a case where a purge is performed between step B and step C to discharge any remaining impurities 305 in the processing chamber 201 to the outside of the processing chamber 201.
[0031] In the following example, as shown in Figure 3, step C includes step c1, which is a first heating step to raise the temperature of the metal-containing film 410 from a first temperature to a second temperature, and step c2, which is a second heating step to maintain the temperature of the metal-containing film 410 at the second temperature. In Figure 3, steps B, C, c1, c2, and the purging period are represented as B, C, c1, c2, and P, respectively.
[0032] The impurities 305 contained in the metal-containing film 400 include, for example, nitrogen (N), oxygen (O), and carbon (C) that are incorporated via grain boundaries (boundaries between crystal grains) when the wafer 200 equipped with the metal-containing film 400 is exposed to the atmosphere. Alternatively, examples include O and C contained in the residue of the plating solution used in the electroplating process performed when forming the metal-containing film 400 in the recesses of the wafer 200. Below, as an example, the case where the impurities 305 contained in the metal-containing film 400 are O will be described.
[0033] As used herein, the term "fluid" includes at least one of gas, liquid, and vapor. Below, as an example, we will describe the case where the -COOH-containing fluid is a gas (gas, gaseous) obtained by vaporizing the first liquid described above.
[0034] In this specification, the term "wafer" may refer to the wafer itself or to a laminate of a wafer and a predetermined layer or film formed on its surface. In this specification, the term "surface of the wafer" may refer to the surface of the wafer itself or to the surface of a predetermined layer formed on the wafer. In this specification, when it is stated that "a predetermined layer is formed on the wafer," it may mean that the predetermined layer is formed directly on the surface of the wafer itself or that the predetermined layer is formed on a layer already formed on the wafer. In this specification, the term "substrate" has the same meaning as when it is used with the term "wafer."
[0035] (Step A: Substrate preparation process) Multiple wafers 200, each having a metal-containing film 400 containing impurities 305, are loaded into the boat 217. Then, as shown in Figure 1, the boat 217 supporting the multiple wafers 200 is lifted by the boat elevator 115 and transported into the processing chamber 201. In this state, the seal cap 219 seals the lower end of the reaction tube 203.
[0036] (Pressure and Temperature Adjustment Process) The processing chamber 201, i.e., the space where the wafer 200 is located, is evacuated (reduced pressure exhaust) by a vacuum pump 246 so that it reaches the desired pressure (vacuum level). At this time, the pressure inside the processing chamber 201 is measured by a pressure sensor 245, and the APC valve 244 is feedback controlled based on this measured pressure information. The wafer 200 is also heated by a heater 207 so that it reaches the desired processing temperature. At this time, the amount of power supplied to the heater 207 is feedback controlled based on the temperature information detected by a temperature sensor 263 so that the processing chamber 201 has the desired temperature distribution. The rotation of the wafer 200 by a rotation mechanism 267 is also started. The exhaust of the processing chamber 201, the heating of the wafer 200, and the rotation are all carried out continuously at least until the processing of the wafer 200 is completed.
[0037] (Preparation process for Step B) In Step B, the gas generator 250a starts generating vaporized gas in order to supply the -COOH-containing fluid to the wafer 200. In this embodiment, the -COOH-containing fluid (vaporized gas) is generated by vaporizing the first liquid.
[0038] Specifically, first, valves 243c and 243d are opened, and the supply of the first liquid and vaporization carrier gas to the gas generator 250a is started while controlling the flow rate with MFCs 241c and 241d, and the gas generator 250a generates a vaporized gas (-COOH-containing fluid) of the first liquid. At this time, the flow rate of the -COOH-containing fluid generated in the gas generator 250a is adjusted by controlling MFC 241c with the controller 121. The first liquid stored in tank 250t is pushed out of tank 250t into the supply pipe 232c by opening valve 243e and supplying pressurized gas to tank 250t while controlling the flow rate with MFC 241e. This step may be started during or before the execution of the pressure and temperature adjustment process.
[0039] (Step B: Impurity Removal Process) In this step, a -COOH-containing fluid is supplied to the metal-containing film 400 at a first temperature to remove impurities 305 from the metal-containing film 400.
[0040] Specifically, valve 243a is opened, and the -COOH-containing fluid generated in gas generator 250a is supplied into processing chamber 201 via MFC 241a, gas supply pipe 232a, and gas supply port 203p.
[0041] The -COOH-containing fluid supplied into the processing chamber 201 flows downwards within the processing chamber 201 and is discharged to the outside of the processing chamber 201 via the exhaust pipe 231. At this time, the -COOH-containing fluid is supplied to the wafer 200. At this time, valve 243b may be opened, and inert gas may be supplied into the processing chamber 201 via gas supply pipes 232b, 232a and gas supply port 203p while adjusting the flow rate with MFC 241b.
[0042] When supplying the -COOH-containing fluid in this step, the processing conditions are as follows: Processing temperature (first temperature): 80 to 120°C, preferably 90 to 100°C; Processing pressure: 700 to 1400 hPa, preferably 800 to 1100 hPa; Supply flow rate of the -COOH-containing fluid: 5 to 400 ccm, preferably 50 to 300 ccm; Supply time of the -COOH-containing fluid: 10 to 120 minutes, preferably 30 to 60 minutes; Vaporization carrier gas supply flow rate: 0.5 slm to 10 slm, preferably 1 slm to 5 slm; Inert gas supply flow rate: 0 to 10 slm. It should be noted that the processing time of this step is preferably shorter than the processing time of step C described later.
[0043] In addition, the notation of a numerical range such as "80 to 120°C" in this specification means that the lower limit value and the upper limit value are included in that range. Therefore, for example, "80 to 120°C" means "80°C or higher and 120°C or lower". The same applies to other numerical ranges. Also, the processing temperature in this specification means the temperature of the wafer 200 or the temperature in the processing chamber 201, and the processing pressure means the pressure in the processing chamber 201, in other words, the pressure in the space where the wafer 200 exists. Also, the processing time means the time for continuing that processing. Also, when 0 ccm is included in the supply flow rate, 0 ccm means the case where that substance is not supplied. These are the same in the following description.
[0044] By supplying the -COOH-containing fluid to the wafer 200 under the above conditions, the metal-containing film 400 can be modified into the metal-containing film 410 (see FIGS. 4(a) and 4(b)). Specifically, impurities 305 can be removed from the metal-containing film 400 formed on the wafer 200. More specifically, by supplying the -COOH-containing fluid as a reducing agent to the wafer 200 under the above conditions, for example, the O component existing inside the metal-containing film 400 (for example, grain boundaries) can be reacted with the components of the -COOH-containing fluid that has penetrated into the metal-containing film 400, and the O component can be desorbed from the inside of the metal-containing film 400.
[0045] By supplying the -COOH-containing fluid to the wafer 200 under the above conditions, the -COOH-containing fluid can penetrate through the entire metal-containing film 400, specifically from the upper part to the lower part of the concave portion.
[0046] By supplying the -COOH-containing fluid to the wafer 200 under the above conditions, specifically, by setting the processing temperature (first temperature) to a relatively low temperature, the diameter (size of the crystal grains 310) of the crystal grains 310 contained in the metal-containing film 410 can be maintained below a predetermined value (see FIGS. 5(a) and 5(b)). At this time, at each of the upper and lower parts of the concave portion, specifically, from the upper part to the lower part of the concave portion, the diameter of the crystal grains 310 can be maintained below a predetermined value. Thus, by maintaining the diameter of the crystal grains 310 below a predetermined value, the grain boundary energy between adjacent crystal grains 310 can be kept high.
[0047] Note that when the processing temperature is 80°C or lower, there is a risk that the -COOH-containing fluid will condense in the processing chamber 201. As a result, the -COOH-containing fluid may not penetrate through the entire metal-containing film 400, and it may be difficult to remove the impurities 305 from the metal-containing film 400. By setting the processing temperature to a temperature higher than 80°C, it is possible to avoid the condensation of the -COOH-containing fluid, allow the -COOH-containing fluid to penetrate through the entire metal-containing film 400, and remove the impurities 305 from the metal-containing film 400.
[0048] If the processing temperature is 120°C or higher, the crystallization rate of the metal-containing film 400 may exceed the rate at which impurities 305 contained in the metal-containing film 400 are removed (the impurity removal rate). Specifically, for example, the diameter of the crystal grains 300 contained in the metal-containing film 400 may exceed a predetermined value before the impurities 305 are removed from the metal-containing film 400 and the concentration of impurities 305 reaches the desired concentration. This can make it difficult to maintain high grain boundary energy between adjacent crystal grains. By setting the processing temperature to a temperature lower than 120°C, the removal rate of impurities 305 can be made higher than the crystallization rate of the metal-containing film 400. In other words, the concentration of impurities 305 in the metal-containing film 400 can be set to the desired concentration before the diameter of the crystal grains 300 exceeds a predetermined value. This allows the impurities 305 to be removed from the metal-containing film 400 before the diameter of the crystal grains 300 contained in the metal-containing film 400 exceeds a predetermined value, and the grain boundary energy between adjacent crystal grains can be kept high.
[0049] Examples of the first liquid include formic acid (HCOOH) and acetic acid (CH₃). ３ Liquids containing -COOH, such as HCOOH and CH, can be used. ３ The -COOH-containing fluid, which is the vaporized gas of COOH, acts as a reducing agent to remove impurities 305 (e.g., O component) from the metal-containing film 400. It is preferable to use an HCOOH-containing liquid with higher reducing power as the first liquid. Since -COOH contains carbon, oxygen, and hydrogen, the -COOH-containing fluid is also called a carbon, oxygen, and hydrogen-containing fluid. Similarly, the -COOH-containing gas is also called a carbon, oxygen, and hydrogen-containing gas.
[0050] As used herein, the term "agent" includes at least one of gaseous substances and liquid substances. Liquid substances include mist-like substances. That is, a reducing agent may contain gaseous substances, may contain liquid substances such as mist-like substances, or may contain both.
[0051] Examples of inert gases include nitrogen (N ２Other gases such as argon (Ar), helium (He), neon (Ne), and xenon (Xe) can be used. One or more of these can be used as the inert gas. This also applies to each of the steps described later.
[0052] As the vaporization carrier gas, for example, a gas similar to the inert gas mentioned above can be used.
[0053] (Purge process) After a predetermined time has elapsed and the impurities 305 have been removed from the metal-containing film 400, valve 243a is closed to stop the supply of the -COOH-containing fluid to the wafer 200. Then, the processing chamber 201 is evacuated to remove any -COOH-containing fluid, by-products, and atmosphere remaining in the processing chamber 201. At this time, valve 243b is opened to supply an inert gas as a purge gas into the processing chamber 201, and any remaining impurities 305 in the processing chamber 201 are discharged (purged) from the processing chamber 201.
[0054] Examples of processing conditions when purging in this step include: processing temperature: 80 to 120°C, preferably 90 to 100°C; processing pressure: 100 to 3000 hPa; processing time: 5 to 60 minutes, preferably 5 to 10 minutes; and inert gas supply flow rate: 5 to 30 slm. As described above, it is preferable that the processing temperature when purging is the same as the processing temperature (first temperature) when performing step B.
[0055] (Step C: Heat Treatment and Annealing Treatment) After the purging process is completed, the metal-containing film 410, which has had impurities removed, is heated (annealed) to a second temperature higher than the first temperature in a non-oxidizing atmosphere. This step is performed sequentially according to steps c1 and c2 described later. The non-oxidizing atmosphere referred to here is an atmosphere in which oxidation of the metal-containing film 410, etc., can be suppressed. For example, a non-oxidizing atmosphere refers to an inert gas atmosphere, or an inert gas atmosphere that does not contain oxygen. In this step, as an example, the case in which the metal-containing film 410 is heated in an inert gas atmosphere will be described.
[0056] [Step c1: Heating step] In this step, the output of the heater 207 is adjusted to raise the temperature of the metal-containing film 410 from the first temperature to the second temperature while performing the annealing process.
[0057] In this step, the processing conditions for annealing the metal-containing film 410 while increasing its temperature are exemplified as follows: Processing pressure: 150 to 3500 hPa Processing time: 20 to 40 minutes, preferably 25 to 35 minutes Inert gas supply flow rate: 10 to 50 slm. It is preferable that the processing time in step c1 is shorter than the processing time in step c2, which will be described later.
[0058] [Step c2: Temperature maintenance process]
[0059] Once the temperature of the metal-containing film 410 reaches the second temperature, the annealing process is performed while maintaining the metal-containing film 410 (specifically, the metal-containing film 420) at the second temperature (see Figures 5(b) and 5(c)).
[0060] Examples of processing conditions when performing the annealing treatment while maintaining the metal-containing film 420 at the second temperature in this step include: Processing temperature (second temperature): 130 to 200°C, preferably 130 to 180°C; Processing pressure: 150 to 3500 hPa; Processing time: 30 to 300 minutes, preferably 60 to 180 minutes; Inert gas supply flow rate: 5 to 30 slm.
[0061] Under the conditions described above, by raising the processing temperature (specifically, the temperature of the metal-containing film 410) from the first temperature to the second temperature and maintaining it at the second temperature, the metal-containing film 410 can be modified into a metal-containing film 420 (see Figures 4(b) and 4(c)). Specifically, the crystal grains 310 contained in the metal-containing film 410 can be grown into larger crystal grains 320 (see Figures 5(b) and 5(c)). In this way, the diameter of the crystal grains 320 in the metal-containing film 420 in this step can be made larger than the diameter of the crystal grains 310 in the metal-containing film 410 in step B.
[0062] Under the conditions described above, by raising the processing temperature from the first temperature to the second temperature and maintaining it at the second temperature, the diameter of the crystal grains 320 contained in the metal-containing film 420 can be made larger than a predetermined value (see Figure 5(c)). In this case, the diameter of the crystal grains 320 can be made larger than a predetermined value in both the upper and lower parts of the recess, specifically from the upper part to the lower part of the recess.
[0063] Furthermore, by raising the processing temperature from the first temperature to the second temperature under the above conditions and maintaining it at the second temperature, the impurities 305 remaining in the metal-containing film 410 that could not be removed in step B can be removed (see Figures 5(b) and 5(c)).
[0064] As described above, as the diameter of the crystal grains 320 becomes larger than the diameter of the crystal grains 310, the number of crystal grain boundaries per unit volume in the metal-containing film 420 becomes smaller than the number of crystal grain boundaries per unit volume in the metal-containing film 410. For this reason, the grain boundary energy between adjacent crystal grains 320 in step C is lower than the grain boundary energy between adjacent crystal grains 310 in step B.
[0065] (Atmospheric pressure restoration process) Subsequently, the processing chamber 201 is evacuated using a vacuum pump 246. Then, an inert gas is supplied into the processing chamber 201 to restore the internal pressure to atmospheric pressure, thereby increasing the heat capacity of the processing chamber 201. This allows the wafer 200 and the components inside the processing chamber 201 to be heated uniformly, and makes it possible to remove particles, impurities 305, outgassing, etc. that could not be removed by vacuum evacuation from the processing chamber 201. After a predetermined time has elapsed, the temperature inside the processing chamber 201 is lowered to a predetermined discharge temperature.
[0066] (Substrate Removal Process) The seal cap 219 is lowered by the boat elevator 115, and the lower end of the reaction tube 203 is opened. The processed wafer 200, supported by the boat 217, is then removed from the reaction tube 203 through the lower end. After being removed from the reaction tube 203, the processed wafer 200 is taken out of the boat 217.
[0067] (3) Effects of this embodiment According to this embodiment, one or more of the following effects can be obtained.
[0068] (a) Step B involves supplying a carboxyl group-containing fluid to the metal-containing film 400 at a first temperature to remove impurities 305 from the metal-containing film 400, and Step C involves heating the metal-containing film 410, from which the impurities 305 have been removed, to a second temperature higher than the first temperature in a non-oxidizing atmosphere. This makes it possible to lower the resistivity of the metal-containing film 420. This will be explained below.
[0069] In step B, by setting the temperature of the metal-containing film 400 (processing temperature) to a relatively low first temperature, the growth of crystal grains 300 in the metal-containing film 400 can be suppressed while removing impurities 305 from the metal-containing film 400. Thus, in step B, by setting the processing temperature to a relatively low first temperature, the growth of crystal grains 300 in the metal-containing film 400 can be suppressed, and the diameter of the grown crystal grains 310 can be maintained below a predetermined value (see Figures 5(a) and 5(b)). This prevents a decrease in the number of crystal grain boundaries per unit volume in the metal-containing film 410, thus maintaining high grain boundary energy. Therefore, in step C, the atomic migration speed (migration rate) can be increased, making it possible to increase the diameter of the crystal grains 320. Furthermore, in step B, by removing impurities 305 in the metal-containing film 400 (specifically, impurities 305 present at the crystal grain boundaries), the grain boundary energy can be increased. This allows the atomic migration speed to be increased in step C, making it possible to increase the diameter of the crystal grains 320.
[0070] In step C, the diameter of the crystal grains 320 can be increased by performing a heat treatment (annealing treatment) at a second temperature higher than the first temperature. In addition, in step C, by performing the annealing treatment in a non-oxidizing atmosphere, the penetration of component O into the metal-containing film 410, which would otherwise hinder the increase in the diameter of the crystal grains 310, can be avoided.
[0071] In step C, increasing the diameter of the crystal grains 320 reduces the number of grain boundaries per unit volume in the metal-containing film 420, thereby reducing electron scattering at the grain boundaries. As a result, electrons flow more easily through the metal-containing film 420, and the resistivity of the metal-containing film 420 can be reduced. Consequently, the device characteristics can be improved.
[0072] Comparative Examples 1 and 2 will be described below in comparison to the present disclosure.
[0073] (Comparative Example 1) Figure 6(a) shows the crystal grains 520 contained in the metal-containing film 620 after processing the wafer using a processing sequence in which the processing temperature of step B is set to the second temperature, and steps A to C are performed in this order. In this comparative example, since the processing temperature of step B is the relatively high second temperature, it becomes difficult to suppress the growth of crystal grains in the metal-containing film. As a result, the number of crystal grain boundaries per unit volume in the metal-containing film after step B is reduced, making it difficult to maintain high grain boundary energy. Therefore, the diameter of the crystal grains 520 after step C is smaller than the diameter of the crystal grains 320 in this embodiment (see Figures 5(c) and 6(a)).
[0074] (Comparative Example 2) Figure 6(b) shows the crystal grains 720 contained in the metal-containing film 820 after processing the wafer using a processing sequence in which step B is omitted and steps A and C are performed in that order. In this comparative example, by not performing step B, it becomes difficult to remove the impurities 725 in the metal-containing film, and therefore the grain boundary energy at the start of step C is low. As a result, the diameter of the crystal grains 720 after step C is smaller than the diameter of the crystal grains 320 in this embodiment (see Figures 5(c) and 6(b)).
[0075] (b) In step C, the metal-containing film 410 is heated while exposed to the atmosphere in the processing chamber 201, thereby efficiently removing impurities 305 (residual impurities) that could not be removed in step B.
[0076] (c) The first temperature is the temperature at which the removal rate of impurities 305 is greater than the crystallization rate of the metal-containing film 400. Therefore, in step B, high grain boundary energy can be maintained while removing impurities 305 from the metal-containing film 400. As a result, in step C, the crystal grains 320 can be grown significantly in a short time. This ensures that the resistivity of the metal-containing film 420 is reduced.
[0077] (d) In step C, by making the processing time of step c1 shorter than the processing time of step c2, it is possible to prevent a decrease in grain boundary energy due to an increase in the diameter of the crystal grains 310 in step c1. As a result, the atomic migration speed can be increased in step c2, so that larger crystal grains 320 can be grown. This makes it possible to reliably reduce the resistivity of the metal-containing film 420.
[0078] (e) By making the processing time of step B shorter than the processing time of step C, the diameter of the crystal grains 310 can be kept small and the impurities 305 in the metal-containing film 410 can be removed while performing step C (annealing), thereby increasing the diameter of the crystal grains 320. This ensures that the resistivity of the metal-containing film 420 is reliably reduced.
[0079] (f) By supplying the -COOH-containing fluid in gaseous form, it can permeate the entire metal-containing film 400. This makes it possible to reliably remove impurities 305 from the metal-containing film 400. In addition, by supplying the -COOH-containing fluid in gaseous form, the utilization efficiency of the -COOH-containing liquid can be increased.
[0080] (g) In step B, the above-mentioned effects can be reliably obtained by removing impurities 305 while maintaining the diameter of the crystal grains 310 contained in the metal-containing film 410 to a predetermined value or less.
[0081] (h) In step C, the above effect can be reliably obtained by making the diameter of the crystal grain 320 larger than a predetermined value.
[0082] (i) In step C, the above-mentioned effects can be reliably obtained by removing the impurities 305 that remained in the metal-containing film 410 in step B.
[0083] (j) In step C, the above effect can be reliably obtained by heating the metal-containing film 420 so that the amount of impurities 305 contained in the film is less than the amount of impurities 305 in step B, and the diameter of the crystal grains 320 is larger than the diameter of the crystal grains 310 in step B.
[0084] (k) The above effect can be reliably obtained by making the grain boundary energy between adjacent crystal grains 310 in step B higher than the grain boundary energy between adjacent crystal grains 320 in step C.
[0085] (l) In step B, the diameter of the crystal grains 310 in the upper and lower parts of the recess is treated to be less than or equal to a predetermined value, thereby maintaining high grain boundary energy in both the upper and lower parts of the recess, specifically from the upper to the lower part of the recess. This ensures that the above-mentioned effects are obtained.
[0086] (m) In step C, the above-mentioned effect can be obtained in both the upper and lower parts of the recess, specifically from the upper part to the lower part of the recess, by processing so that the diameter of the crystal grain 320 becomes larger than a predetermined value.
[0087] (n) By performing step C in a non-oxidizing atmosphere, it is possible to avoid an increase in the resistance value of the metal-containing film 420 due to oxidation of the metal-containing film 410, and to avoid variations in the resistance value from the top to the bottom of the metal-containing film 420. These effects can be reliably obtained by performing step C in an inert gas atmosphere, specifically an inert gas atmosphere that does not contain oxygen.
[0088] <Other aspects of this disclosure>
[0089] In the embodiments described above, an example was given in which fluid is supplied to the wafer 200 from above the wafer housing area. However, this disclosure is not limited to the embodiments described above. For example, the substrate processing apparatus shown in Figure 7 may be used to supply fluid to the wafer 200 from the side of the wafer housing area.
[0090] Figure 7 is a vertical cross-sectional view of the processing furnace 302 portion of a substrate processing apparatus in which a nozzle 269 is used to supply fluid to the processing chamber 201 instead of a gas supply port 203p. As shown in Figure 7, the nozzle 269 is provided in the space between the inner wall of the reaction tube 203 and the wafer 200, rising upward in the direction of wafer 200 arrangement along the upper part of the inner wall of the reaction tube 203 from the lower part. Gas supply holes 270 are provided on the side of the nozzle 269 to supply fluid in the direction of the outer circumference of the wafer 200, that is, from the side of the wafer 200 toward the plane of the wafer 200. Multiple gas supply holes 270 are provided from the lower to the upper part of the reaction tube 203, facing the wafer arrangement region. The nozzle 269 is connected to the gas supply tube 232a. Fluid is supplied from the gas supply tube 232a to the processing chamber 201 via the nozzle 269. The -COOH-containing fluid supply system is mainly comprised of the gas supply pipe 232a, MFC 241a, and valve 243a. The nozzle 269 may also be considered as part of the -COOH-containing fluid supply system. The other components are the same as those of the substrate processing apparatus shown in Figure 1, and elements that are substantially the same as those described in Figure 1 are given the same reference numerals, and their descriptions are omitted.
[0091] Even when using a substrate processing apparatus with this configuration, the same effects as described above can be obtained.
[0092] Furthermore, in this embodiment, unlike the apparatus shown in Figure 1, the distance between the wafer 200 and the gas supply hole 270 can be reduced not only in the upper part of the wafer housing area, but also in the middle and lower parts. Moreover, the supply conditions (flow rate and velocity) of the fluid and inert gas to the wafer 200 can be made uniform from the upper to the lower part. As a result, in step B, the fluid can be supplied to the wafer 200 under uniform conditions throughout the entire wafer housing area from the upper to the lower part, thereby improving the uniformity of the impurity removal effect from the metal-containing film across the substrates. In addition, in the purging process and step C, the inert gas can be supplied to the wafer 200 under uniform conditions throughout the entire wafer housing area from the upper to the lower part, thereby improving the uniformity of the processing (removal of residues and modification of the film) performed in each step across the substrates.
[0093] Furthermore, if the metal contained in the metal-containing film is a metal that is less prone to migration than Cu (e.g., Co, Ru, W), the processing temperature in step B needs to be set to a high temperature exceeding 150°C. Under such temperature conditions, the fluid is more likely to undergo thermal decomposition, and if the fluid is supplied from the top of the wafer housing area using the apparatus shown in Figure 1, the impurity removal effect obtained may be uneven between the top and bottom of the wafer housing area. In contrast, if the fluid is supplied from the side of the wafer housing area using the apparatus shown in Figure 7, these unique problems at high temperatures are less likely to occur.
[0094] <Further Aspects of the Disclosure> The aspects of the Disclosure have been described in detail above. However, the Disclosure is not limited to the aspects described above and can be modified in various ways without departing from its essence.
[0095] In the embodiments described above, the case in which the -COOH-containing fluid is in gaseous form was used as an example. However, this disclosure is not limited to such embodiments. The -COOH-containing fluid may be, for example, vapor or liquid. In these embodiments as well, at least some of the effects described in the embodiments above can be obtained.
[0096] Although not described in the above embodiments, the metal-containing film 400 may contain at least one of copper (Cu), cobalt (Co), tungsten (W), or ruthenium (Ru). In other words, for example, Cu, Co, W, and Ru can be used as the metallic material constituting the metal-containing film 400. In this case as well, the same effects as in the above embodiments can be obtained.
[0097] Although not described in the above embodiments, for example, if a silicon (Si)-based film (e.g., an SiO film) is formed as a base layer on the inner surface of a recess formed in the wafer 200, it is preferable to form a liner film between the metal-containing film 400 and the SiO film to prevent the metal atoms contained in the metal-containing film 400 from diffusing into the SiO film.
[0098] For example, in the above-described embodiment, the substrate processing apparatus was provided with one processing chamber 201, and both steps B and C were performed within this processing chamber 201. However, the present disclosure is not limited to this embodiment. For example, the substrate processing apparatus may be provided with multiple processing chambers, and steps B and C may be performed in different chambers. However, in this case, when the wafer 200 is transported to the chamber where step C is performed after step B is performed, impurities 305 may enter the wafer 200 due to exposure to the atmosphere. In this case, it is desirable to perform a step to remove the impurities 305 from the wafer 200 before starting step C.
[0099] It is preferable that the recipes used for each process are prepared individually according to the processing content, recorded and stored in the storage device 121c via a telecommunications line or external storage device 123. When starting each process, it is preferable that the CPU 121a appropriately selects the appropriate recipe from among the multiple recipes recorded and stored in the storage device 121c according to the processing content. This makes it possible to form films of various film types, composition ratios, film quality, and film thickness with good reproducibility using a single substrate processing device. Furthermore, it reduces the burden on the operator and allows each process to be started quickly while avoiding operational errors.
[0100] The above-mentioned recipes are not limited to newly created ones; they may also be prepared, for example, by modifying existing recipes already installed in the board processing device. When modifying a recipe, the modified recipe may be installed in the board processing device via a telecommunications line or a recording medium on which the recipe is stored. Alternatively, existing recipes already installed in the board processing device may be directly modified by operating the input / output device 122 provided in the existing board processing device.
[0101] The above-described embodiments illustrate an example of forming a film using a batch-type substrate processing apparatus that processes multiple substrates at once. This disclosure is not limited to the above-described embodiments and can be suitably applied, for example, to forming a film using a single-wafer substrate processing apparatus that processes one or several substrates at once. Furthermore, the above-described embodiments illustrate an example of forming a film using a substrate processing apparatus having a hot-wall type processing furnace. This disclosure is not limited to the above-described embodiments and can be suitably applied to forming a film using a substrate processing apparatus having a cold-wall type processing furnace.
[0102] Even when using these substrate processing devices, each process can be carried out using the same processing procedures and conditions as described above, and the same effects as described above can be obtained.
[0103] The above-described embodiments and modifications can be used in combination as appropriate. The processing procedure and processing conditions in this case can be the same as, for example, the processing procedure and processing conditions of the above-described embodiments and modifications.
[0104] 200 Wafer (substrate) 305 Impurities 400, 410 Metal-containing film
Claims
1. A substrate processing method comprising: (a) preparing a substrate having a metal-containing film containing impurities; (b) supplying a carboxyl group-containing fluid to the metal-containing film at a first temperature to remove the impurities from the metal-containing film; and (c) heating the metal-containing film from which the impurities have been removed to a second temperature higher than the first temperature in a non-oxidizing atmosphere.
2. (c) The substrate processing method according to claim 1, wherein the metal-containing film is heated while exposed.
3. The substrate processing method according to claim 1, wherein the first temperature is a temperature at which the rate of removal of the impurities is greater than the crystallization rate of the metal-containing film.
4. The substrate processing method according to claim 1, wherein the first temperature is the temperature at which the concentration of the impurity reaches a desired concentration before the diameter of the crystal grains of the metal-containing film exceeds a predetermined value.
5. The substrate processing method according to claim 1, wherein the heating step comprises a first heating step of raising the temperature of the metal-containing film from the first temperature to the second temperature, and a second heating step of maintaining the temperature of the metal-containing film at the second temperature, and the processing time of the first heating step is shorter than the processing time of the second heating step.
6. The substrate processing method according to claim 1, wherein the processing time for the step of removing impurities is shorter than the processing time for the heating step.
7. The substrate processing method according to claim 1, wherein the metal-containing film comprises at least one of copper, cobalt, tungsten, and ruthenium.
8. The substrate processing method according to claim 1, wherein the carboxyl group-containing fluid is in gaseous form.
9. (b) The substrate processing method according to claim 1, wherein the impurities are removed while maintaining the diameter of the crystal grains contained in the metal-containing film to a state of less than or equal to a predetermined value.
10. (c) The substrate processing method according to claim 9, wherein the diameter of the crystal grains is made larger than the predetermined value.
11. The substrate processing method according to claim 1, wherein (c) removes impurities remaining in the metal-containing film in (b).
12. The substrate processing method according to claim 9, wherein in (c), the metal-containing film is heated so that the amount of impurities contained in the film is less than the amount of impurities in (b), and the diameter of the crystal grains is larger than the diameter of the crystal grains in (b).
13. The substrate processing method according to claim 9, wherein the grain boundary energy between adjacent crystal grains in (b) is higher than the grain boundary energy between adjacent crystal grains in (c).
14. The substrate processing method according to claim 9, wherein the substrate is provided with a recess, the metal-containing film is formed in the recess, and in (b), the upper and lower parts of the recess are processed so that the diameter of the crystal grains is less than or equal to the predetermined value.
15. The substrate processing method according to claim 9, wherein the substrate is provided with a recess, the metal-containing film is formed in the recess, and in (c), the upper and lower parts of the recess are processed such that the diameter of the crystal grains becomes larger than the predetermined value.
16. The substrate processing method according to claim 1, wherein the non-oxidizing atmosphere is an atmosphere capable of suppressing the oxidation of the metal-containing film.
17. The substrate processing method according to claim 1, wherein (c) is performed in an inert gas atmosphere.
18. The substrate processing method according to claim 1, wherein (c) is performed in an inert gas atmosphere that does not contain oxygen.
19. A method for manufacturing a semiconductor device, comprising: (a) preparing a substrate equipped with a metal-containing film containing impurities; (b) supplying a carboxyl group-containing fluid to the metal-containing film at a first temperature to remove the impurities from the metal-containing film; and (c) heating the metal-containing film from which the impurities have been removed to a second temperature higher than the first temperature in a non-oxidizing atmosphere.
20. A program that causes a substrate processing apparatus to perform the following steps by computer: (a) a procedure for preparing a substrate having a metal-containing film containing impurities; (b) a procedure for supplying a carboxyl group-containing fluid to the metal-containing film at a first temperature to remove the impurities from the metal-containing film; and (c) a procedure for heating the metal-containing film from which the impurities have been removed to a second temperature higher than the first temperature in a non-oxidizing atmosphere.
21. A substrate processing apparatus comprising: a supply unit capable of supplying a carboxyl group-containing fluid to a substrate; a heating unit capable of heating the substrate; and a control unit configured to control the supply unit and the heating unit to perform the following: (a) a process of preparing the substrate having a metal-containing film containing impurities; (b) a process of supplying the carboxyl group-containing fluid to the metal-containing film at a first temperature to remove the impurities from the metal-containing film; and (c) a process of heating the metal-containing film from which the impurities have been removed to a second temperature higher than the first temperature in a non-oxidizing atmosphere.