Semiconductor manufacturing method and semiconductor manufacturing apparatus

Abstract

A semiconductor manufacturing method using a semiconductor manufacturing apparatus (100) having a processing chamber (1), wherein: a first step of supplying a complexing gas into the processing chamber in which a wafer (2) having a transition metal element-containing film formed on a surface is placed, and causing an organic compound as a component of the complexing gas to be adsorbed to the transition metal element-containing film; and a second step of heating the wafer on which the organic compound is adsorbed to the transition metal element-containing film, causing the organic compound to react with the transition metal element to be converted into an organometallic complex, and causing the organometallic complex to be desorbed, the organic compound being a multidentate ligand molecule having Lewis basicity and being capable of forming a bidentate or more coordination bond with the transition metal element.

Description

Technical Field

[0001] This invention relates to a semiconductor manufacturing method and a semiconductor manufacturing apparatus, which process a wafer having a film containing a transition metal element formed thereon to manufacture a semiconductor device. Background Technology

[0002] The ever-increasing demands for miniaturization, high speed / high performance, and power efficiency in cutting-edge semiconductor devices are driving progress in the adoption of various new materials. For example, the electromigration of Cu (copper) wiring and the high resistivity of W (tungsten) wiring pose obstacles to further miniaturization of semiconductor wiring, while a variety of transition metals such as Co (cobalt) and Ru (ruthenium) are emerging as candidates for next-generation wiring materials. To utilize conductive films containing such transition metal elements as next-generation semiconductor micro-wiring, ultra-high precision nanoscale fabrication (film deposition and etching) is crucial.

[0003] As an example of a technology for forming a circuit structure of a semiconductor device by processing a film structure containing a conductor film containing a transition metal element, there is a technology disclosed in Japanese Patent Application Publication No. 2008-244039 (Patent Document 1). Patent Document 1 discloses a technology, as a lateral etching (trimming) method for using metal silicides or metal monomers as gate materials, in which the surface of the gate portion is oxidized, and then heated while exposed to a gas containing organic acid. Furthermore, it describes a method where Co is oxidized to CoO (cobalt oxide), and then, while heated to 340°C and exposed to acetic acid vapor, the CoO is converted into volatile Co(CH3COO)2 (cobalt acetate) and released into the gas phase.

[0004] On the other hand, Japanese Patent Application Publication No. 2017-59824 (Patent Document 2) discloses a technique in which a material containing noble metal elements such as Pt is reacted with a pretreatment gas selected from a mixture of halogenated substances and NO (nitric oxide) and fluorinated nitrosyl (NOF) to form a solid compound on the surface, and then etched by reacting with β-diketone. Patent Document 2 describes that NOF contained in the pretreatment gas or NOFx (x = 1 to 3) generated from the components of the pretreatment gas in a reaction vessel is reacted with the material containing noble metals such as Pt at a temperature of 50°C to 150°C to form a solid compound containing Pt, N, O, and F. This Pt compound reacts with β-diketone to form a highly volatile complex of β-diketone and Pt, and this complex is then vaporized. Furthermore, the noble metals exemplified in Patent Document 2 are Au, Pt, Pd, Rh, Ir, Ru, and Os, all of which are classified as transition metals.

[0005] Prior art literature

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2008-244039

[0008] Patent Document 2: Japanese Patent Application Publication No. 2017-59824

[0009] In their research on nanoscale ultra-precision processing techniques for materials containing a variety of transition metal elements, the inventors specifically investigated and validated techniques for high-precision processing of multilayer films containing dozens of layers of dissimilar materials—considered the most advanced three-dimensional devices. During this research, they discovered the following problem: if a multilayer film containing multiple layers of dissimilar materials is heated to a high temperature, diffusion occurs between the layers of the dissimilar materials, or the layers, due to their different materials and therefore different coefficients of thermal expansion, shift within the multilayer film. Therefore, they concluded that etching techniques that can be performed at lower temperatures are necessary in the processing of multilayer films containing multiple layers of dissimilar materials.

[0010] The technologies disclosed in Patent Documents 1 and 2 are promising technologies based on the aforementioned understanding, as they enable selective etching at temperatures below 400°C. However, detailed verification of these prior art, as described below, has determined that each has issues requiring improvement.

[0011] In the technology disclosed in Patent Document 1, transition metal acetates are volatile but not necessarily stable at high temperatures. More specifically, it is known that cobalt acetate thermally decomposes around 220°C. That is, the etching of cobalt oxide occurs through a reaction mechanism in which cobalt oxide heated to 340°C is exposed to acetic acid vapor, causing the cobalt oxide to be converted into cobalt acetate, which is then volatilized and removed. On the other hand, cobalt acetate, as an intermediate product of the etching reaction, undergoes abnormal reactions such as thermal decomposition, generating residues containing Co and C.

[0012] As a result, at least a portion of the surface of the cobalt oxide film becomes covered with particles of residue from the decomposition of cobalt acetate. In the film directly beneath these areas, etching is hindered or ceases, while etching proceeds relatively smoothly in areas free of residue particles. Consequently, the surface of the film after etching becomes uneven, corresponding to the amount of residue particles attached. This unevenness causes significant deviations in the in-plane orientation of the wafer surface in the post-processed shape, thus failing to achieve the fine processing precision required for semiconductor device performance, resulting in reduced processing yield and efficiency.

[0013] In the technology disclosed in Patent Document 2, according to the inventors' research, when applied to transition metal elements other than noble metals, such as Zr (zirconium), highly volatile complexes can only be generated in amounts below the detection critical, making it difficult to achieve practical etching rates. When Zr reacts with NOF, it generates a solid compound without N and O, namely ZrF4 (zirconium fluoride). Compared to the solid compound containing N and O obtained from the reaction of Pt and NOF, ZrF4 has lower reactivity with β-diketones. Therefore, the reaction to generate volatile substances cannot proceed sufficiently. Consequently, it cannot be applied to the etching of films containing transition metal elements other than noble metals, limiting its applicability to certain materials. Summary of the Invention

[0014] The purpose of this invention is to provide a semiconductor manufacturing method or semiconductor manufacturing apparatus that improves the efficiency and yield of manufacturing semiconductor devices by processing films containing transition metal elements with high precision and high speed.

[0015] One embodiment of the semiconductor manufacturing method of the present invention is a semiconductor manufacturing method using a semiconductor manufacturing apparatus equipped with a processing chamber, comprising: a first step of supplying a complexing gas into a processing chamber on which a wafer containing a transition metal film having a transition metal element formed on its surface is placed, thereby causing an organic compound, which is a component of the complexing gas, to be adsorbed onto the transition metal film; and a second step of heating the wafer on which the organic compound is adsorbed onto the transition metal film, thereby causing the organic compound to react with the transition metal element to form an organometallic complex, and then detaching the organometallic complex, wherein the organic compound is a polydentate ligand molecule having Lewis basicity and capable of forming bidentate or higher coordination bonds with the transition metal element.

[0016] Furthermore, a semiconductor manufacturing apparatus according to one embodiment of the present invention includes: a chamber having a processing chamber inside; a wafer stage disposed within the processing chamber, on which a wafer having a transition metal film containing a transition metal element formed on its surface is placed; a container containing a chemical solution containing an organic compound as a component, and a complexing gas supplier supplying an organic gas that vaporizes the chemical solution as a complexing gas to the processing chamber; a heater for heating the wafer; and a control unit.

[0017] The control unit performs the following processes: First, a complexing gas is supplied to the processing chamber containing the wafer by a complexing gas supplier, causing the organic compound, a component of the complexing gas, to adsorb onto the transition metal film; Second, a heater heats the wafer on which the organic compound is adsorbed onto the transition metal film, causing the organic compound and the transition metal element to react and transform into an organometallic complex, which is then detached.

[0018] Organic compounds are polydentate ligand molecules that have Lewis basicity and can form more than bidentate coordination bonds with transition metal elements.

[0019] Invention Effects

[0020] While suppressing the surface roughness of the film containing transition metals, etching is achieved.

[0021] Other topics and new features can be illustrated by the descriptions and figures in this specification. Attached Figure Description

[0022] Figure 1 It is a diagram showing the overall structure of a semiconductor manufacturing apparatus.

[0023] Figure 2 This is a flowchart of the etching process performed on the film of the object being processed.

[0024] Figure 3 It is a time chart that schematically represents the process flow of operations corresponding to the passage of time in the etching process.

[0025] Figure 4 It is a time chart that schematically represents the process flow of operations corresponding to the passage of time in the etching process.

[0026] Figure 5 It is a time chart that schematically represents the process flow of operations corresponding to the passage of time in the etching process. Detailed Implementation

[0027] The inventors verified and re-examined the reaction mechanism of films containing transition metals during etching from various perspectives, discovering the following phenomenon: when the valence of the transition metal element in the film to be processed is controlled and exposed to an organic gas containing a Lewis base with a specific molecular structure, a highly thermally stable and highly volatile organometallic complex can be formed. This invention utilizes this phenomenon to achieve highly efficient etching.

[0028] Lewis bases, by definition, possess non-shared electron pairs within their molecules. Lewis bases donate these non-shared electron pairs to the positive charge of the transition metal element in the membrane being treated, thereby forming strong electron-donating + feedback coordination bonds and creating thermally stable organometallic complexes (coordination compounds). Furthermore, within the resulting organometallic complex, the positive charge of the metal element in the membrane being treated is neutralized by the non-shared electron pairs donated by the Lewis base contained in the organic gas. This charge neutralization eliminates the electrostatic attraction between adjacent molecules, increasing volatility (sublimation).

[0029] The following uses Figures 1 to 5The embodiments of the present invention will be described. Furthermore, in this specification and the accompanying drawings, constituent elements that have substantially the same function are given the same reference numerals, thereby omitting redundant descriptions.

[0030] Figure 1 It is a longitudinal sectional view schematically representing the overall structure of a semiconductor manufacturing apparatus.

[0031] The processing chamber 1 consists of a base chamber 11, which is a cylindrical metal container, and a wafer stage 4 (hereinafter referred to as stage 4) is provided therein for placing the wafer 2, which is the sample to be processed. The plasma source uses ICP (Inductively Coupled Plasma) discharge. Above the processing chamber 1, a plasma source equipped with a quartz chamber 12, an ICP coil 34, and a high-frequency power supply 20 is provided. The ICP coil 34 is located outside the quartz chamber 12.

[0032] The high-frequency power supply 20 for plasma generation is connected to the ICP coil 34 via an integrator 22. The frequency of the high-frequency power supply uses a frequency band of tens of MHz, such as 13.56 MHz. A top plate 6 is provided on the upper part of the quartz chamber 12. A cluster plate 5 is provided on the top plate 6, and a gas dispersion plate 17 is provided below it. The gas (processing gas) supplied to the processing chamber 1 for processing the wafer 2 is introduced into the processing chamber 1 from the outer periphery of the gas dispersion plate 17.

[0033] The flow rate of the gas is adjusted by a mass flow controller 50 configured in the integrated mass flow controller control unit 51 for each gas. Figure 1 In this example, at least Ar, O2, and H2 are supplied to the processing chamber 1 as processing gases, and mass flow controllers 50-1, 50-2, and 50-3 are provided respectively for these gas types. Furthermore, the supplied gases are not limited to these. Additionally, a mass flow controller 50-4 is also provided in the integrated mass flow controller control unit 51, which regulates the flow rate of He gas supplied between the back surface of the wafer 2 and the upper surface of the dielectric film on the stage 4 on which the wafer 2 is placed, as described later.

[0034] In this embodiment, a complexed gas generated from a liquid raw material is used as at least a part of the processed gas. The complexed gas is generated by vaporizing the liquid raw material through a complexed gas supply 47. Inside the complexed gas supply 47, there is a container 45 containing a chemical solution 44, which is a liquid raw material. The chemical solution 44 is heated by a heater 46 covering the surrounding area, and the upper part of the container 45 is filled with the vapor of the raw material. The chemical solution 44 is a raw material liquid used to convert a film containing a transition metal element (hereinafter referred to as a transition metal film) pre-formed on the wafer 2 into a volatile organometallic complex, i.e., the complexed gas. The generated raw material vapor is controlled by a mass flow controller 50-5 and is introduced at a predetermined flow rate and speed to become a gas of a desired concentration suitable for processing in the processing chamber 1. During the period when the raw material vapor is not introduced into the processing chamber 1, valves 53 and 54 are closed to isolate the liquid raw material from the processing chamber 1. Furthermore, the piping through which the raw material vapor flows is preferably heated in a manner that prevents the raw material vapor from condensing within the piping.

[0035] To depressurize the processing chamber 1, the lower part of the processing chamber 1 is connected to the exhaust mechanism 15 via a vacuum exhaust pipe 16. The exhaust mechanism 15 is, for example, composed of a turbomolecular pump, a mechanical booster pump, or a dry pump. Furthermore, to adjust the pressure in the processing chamber 1 and the discharge region 3, the flow path cross-sectional area (the cross-sectional area of ​​the plane perpendicular to the axial direction of the vacuum exhaust pipe 16) of the vacuum exhaust pipe 16 is increased or decreased to regulate the flow rate of the internal gas and plasma particles discharged from the processing chamber 1. For this purpose, a pressure regulating mechanism 14 is provided upstream of the exhaust mechanism 15. This pressure regulating mechanism 14 has a shaft arranged in a direction tangential to the flow path and is composed of multiple plate-shaped dampers rotating around the shaft and plate members that move tangentially to the axial direction within the flow path.

[0036] Between the stage 4 and the quartz chamber 12 constituting the ICP plasma source, an IR (Infrared) lamp unit for heating the wafer 2 is provided. The IR lamp unit includes: IR lamps 62 arranged in a ring above the upper surface of the stage 4; a reflector 63 arranged above the IR lamps 62 to cover them and reflect IR light; and an IR light-transmitting window 74. The IR lamps 62 are multiple circular lamps arranged concentrically or spirally around the central axis in the vertical direction of the base chamber 11 or the cylindrical stage 4. The light emitted from the IR lamps 62 is predominantly infrared light in the visible light spectrum; this light is referred to here as IR light. Figure 1 In the example shown, the IR lamp 62 is provided with three rings of IR lamps 62-1, 62-2, and 62-3, but it can also be two rings, four rings, etc.

[0037] An IR lamp power supply 64 is connected to the IR lamp 62, and a high-frequency shear filter 25 is provided to prevent noise from the high-frequency power used for plasma generation generated by the high-frequency power supply 20 from flowing into the IR lamp power supply 64. In addition, the IR lamp power supply 64 has the function of independently controlling the power supplied to the IR lamps 62-1, 62-2, and 62-3, and can adjust the radial distribution of the heating amount of the wafer 2.

[0038] In the center of the IR lamp unit, a gas flow path 75 is formed, which allows gas supplied from the mass flow controller 50 to the interior of the quartz chamber 12 to flow to the processing chamber 1. A slit plate (ion shielding plate) 78 with multiple openings is disposed in the gas flow path 75. The slit plate 78 is used to shield ions and electrons generated in the plasma inside the quartz chamber 12, allowing only neutral gas and neutral radicals to pass through and irradiate the wafer 2.

[0039] In the stage 4, a flow path 39 for cooling the stage 4 is formed inside, and the refrigerant is circulated and supplied by the cooler 38. In addition, in order to fix the wafer 2 to the stage 4 by electrostatic adsorption, electrostatic adsorption electrodes 30, which are plate-shaped electrode plates, are embedded in the stage 4 and are connected to a DC (Direct Current) power supply 31 for electrostatic adsorption.

[0040] Furthermore, to efficiently cool the wafer 2, He gas is supplied between the back side of the wafer 2 and the upper surface of the stage 4. The He gas is supplied through a supply path equipped with a switching valve 52, and the flow rate and speed are appropriately regulated by a mass flow controller 50-4. The He gas is introduced into the gap between the back side of the wafer 2 and the upper surface of the stage 4 through a passage connected to the supply path and an opening on the upper surface of the stage 4 on which the wafer 2 is placed. This promotes heat transfer between the wafer 2, the stage 4, and the refrigerant flowing in the internal flow path 39.

[0041] In addition, in order to heat and cool the wafer 2 even when the electrostatic adsorption electrode 30 is in operation and the wafer 2 is electrostatically adsorbed, the wafer mounting surface of the stage 4 is coated with a resin such as polyimide.

[0042] Inside the stage 4, a thermocouple 70 is installed for measuring the temperature of the stage 4, and this thermocouple is connected to a thermocouple thermometer 71. Furthermore, optical fibers 92-1 and 92-2, used for measuring the temperature of the wafer 2, are respectively located near the center of the wafer 2, near the radial center of the wafer 2, and near the outer periphery of the wafer 2. Optical fiber 92-1 guides IR light from the external IR light source 93 to the back surface of the wafer 2 to illuminate it. On the other hand, optical fiber 92-2 collects the IR light absorbed and reflected by the wafer 2 from the IR light illuminated by optical fiber 92-1 and transmits it to the beam splitter 96.

[0043] Specifically, the external IR light generated by the external IR light source 93 is transmitted to the optical path switch 94 for turning the optical path on / off. The optical path is then split into multiple (three in this example) by the beam splitter 95, and these beams are transmitted via the optical fibers 92-1 of the three systems to illuminate various positions on the back side of the wafer 2. Furthermore, the IR light absorbed and reflected by the wafer 2 is transmitted via the optical fiber 92-2 to the beam splitter 96, where the wavelength dependence data of the spectral intensity is obtained by the detector 97. This wavelength dependence data is sent to the arithmetic unit 41 of the control unit 40 to calculate the absorption wavelength, which can then be used as a reference to determine the temperature of the wafer 2. Additionally, an optical add-drop multiplexer 98 is provided along the optical fiber 92-2, allowing switching between measuring the light at the wafer center, wafer middle, and wafer periphery. Therefore, the arithmetic unit 41 can separately determine the temperatures of the wafer center, wafer middle, and wafer periphery.

[0044] exist Figure 1 In the middle, 60 is a container covering the quartz chamber 12, and 81 is an O-ring used for vacuum sealing between the stage 4 and the bottom surface of the base chamber 11.

[0045] The control unit 40 controls the on / off switching of the high-frequency power supply from the high-frequency power source 20 to the ICP coil 34. Additionally, the integrated mass flow controller control unit 51 adjusts the type and flow rate of the gas supplied to the interior of the quartz chamber 12 from each mass flow controller 50. In this state, the control unit 40 operates the exhaust mechanism 15 and controls the pressure regulating mechanism 14 to adjust the pressure inside the processing chamber 1 to achieve the desired pressure.

[0046] Furthermore, the control unit 40 operates the DC power supply 31 for electrostatic adsorption to electrostatically adsorb the wafer 2 onto the stage 4. While the mass flow controller 50-4, which supplies He gas between the wafer 2 and the stage 4, is operating, the calculation unit 41 calculates the temperature distribution information of the wafer 2 based on the internal temperature of the stage 4 measured by the thermocouple thermometer 71 and / or the spectral intensity information near the center, near the middle in the radial direction, and near the outer periphery of the wafer 2 measured by the detector 97. Based on this temperature distribution information, the IR lamp power supply 64 and the cooler 38 are controlled to keep the temperature of the wafer 2 within a specified temperature range.

[0047] Next, use Figures 2 to 4 The process of processing wafer 2 in the semiconductor manufacturing apparatus of this embodiment will be described. Figure 2 yes Figure 1 The flowchart shown illustrates a process in which a semiconductor manufacturing apparatus etches a film formed on a wafer to be processed. The film to be processed is a film containing a transition metal. Operations performed in each step of the etching process in the semiconductor manufacturing apparatus 100, such as the introduction and exhaust of processing gas into the processing chamber 1 and the heating of the wafer 2 by irradiation with IR light from the IR lamp 62, are controlled by the control unit 40.

[0048] A vacuum transport container, serving as another vacuum container, is connected to the side wall of the base chamber 11. Inside the vacuum transport container, a transport robot equipped with multiple arms is arranged. The wafer 2 is held by the hand at the end of the arm and transported within the transport space of the vacuum transport container, then introduced into the processing chamber 1 through the door of the base chamber 11. On the upper surface of the mounting surface of the stage 4, which constitutes the wafer 2, a dielectric film containing aluminum oxide and yttrium oxide is disposed. The wafer 2 is held on the dielectric film of the stage 4 and is adsorbed and fixed by the holding force of the upper surface of the film generated by the electrostatic force produced by the DC power supplied to the tungsten or other metal film disposed within the dielectric film.

[0049] On the upper surface of wafer 2, a stacked film structure is formed, the stacked film structure including a transition metal film pre-processed into a pattern shape constituting a circuit structure of a semiconductor device, and a state in which part of the surface of the film (including the transition metal film) to be processed is exposed.

[0050] Examples of transition metal films include, but are not limited to, films containing the transition metal elements exemplified herein. The film structure containing the film to be processed can be formed using known methods such as sputtering, PVD (Physical Vapor Deposition), ALD (Atomic Layer Deposition), and CVD (Chemical Vapor Deposition) to achieve a film thickness sufficient to form the desired circuit. Alternatively, it can be fabricated using photolithography to form a shape conforming to a circuit pattern.

[0051] The semiconductor manufacturing apparatus 100 selectively removes the transition metal film exposed on the surface of the object to be processed by etching. When selectively etching, a dry etching technique without plasma, as described below, is applied. Furthermore, prior to the etching process, oxidation or reduction treatment may be performed to adjust the valence of the transition metal element in the transition metal film. This is because, depending on the valence of the transition metal element, it combines with a complexing gas without forming an organometallic complex. Therefore, in this embodiment, the transition metal film to be processed can be either an oxide film or a metal film. Regardless of the type of film, by performing oxidation or reduction treatment during the etching process, the transition metal element in the film is controlled to an appropriate valence, thus enabling the etching process of this embodiment to be applied. The process of adjusting the valence of the transition metal element can also be performed in each cycle of the etching process, as described later, depending on the thickness of the film being etched.

[0052] With the wafer 2 held on the stage 4, He gas, the flow rate or speed of which is regulated by the mass flow controller 50-4, is introduced from an opening on the upper surface of the stage 4 into the gap between the wafer 2 and the stage 4. This promotes heat transfer between the two and regulates the temperature of the wafer 2. If the temperature of the wafer 2 (hereinafter referred to as the substrate temperature) detected by the control unit 40 reaches a first temperature T1 or below (in this example, after cooling), the etching process containing the transition metal film of the object to be processed begins. The control unit 40 can measure the temperature of the wafer 2 as the substrate temperature using a spectrometer using an optical fiber 92, or it can estimate the substrate temperature based on the temperature of the stage 4 measured by the thermocouple thermometer 71.

[0053] Step S101 is a step of determining the residual film thickness to be etched for the transition metal film formed on the surface of the wafer 2. In this step, whether the etching process is performed for the first time after the wafer 2 is moved in or after an etching process has been performed, the residual film thickness (hereinafter referred to as processing allowance) of the film to be processed is calculated in the control unit 40 with reference to the design and specifications of the manufactured semiconductor device. The arithmetic unit 41 of the control unit 40 reads the software stored in the storage device of the control unit 40, follows its algorithm, calculates the value of the cumulative processing amount (cumulative processing amount) formed by the processing performed on the wafer 2 before it was moved into the processing chamber 1, and the value of the cumulative processing amount formed by the processing performed after it was moved into the processing chamber 1, and determines whether additional processing is required based on the design and specifications of the wafer 2.

[0054] If the machining allowance is very small, reaching 0 or being considered as 0, and is determined to be less than the predetermined allowable value δ0, the etching process of the film to be processed ends. On the other hand, if the machining allowance is determined to be non-zero (or greater than the allowable value δ0), the process proceeds to step S102. In step S102, the machining allowance is compared with a predetermined threshold to determine whether it is more or less (greater or less). If it is determined to be more than the threshold, the process proceeds to step S103B; if it is determined to be less than the threshold, the process proceeds to step S103A.

[0055] For the wafer 2 transported to the processing chamber 1 in the semiconductor manufacturing apparatus 100, the following is implemented: Figure 2 The cumulative processing amount obtained from processing more than once can be easily calculated based on the cumulative number of processing cycles constituted by steps S102 to S109 and the processing amount (processing rate) of each processing cycle obtained in advance. Alternatively, the processing amount can be calculated based on the surface analysis of wafer 2 or the output from a residual film thickness detector (not shown), or a combination thereof.

[0056] If the machining allowance is determined to be greater than a predetermined threshold in step S102, the process proceeds to step S103B, and the process up to step S106B (process B) is performed. On the other hand, if the machining allowance is determined to be less than the predetermined threshold in step S102, the process proceeds to step S103A, and the process up to step S107A (process A) is performed. Through process A or process B, the film to be processed is etched to reduce the residual film thickness.

[0057] The following will Figure 2 and Figure 3 or Figure 4 Together with the above, we will explain the process of etching a transition metal film by a semiconductor manufacturing apparatus 100. Figure 3 and Figure 4It is a timeline diagram schematically representing the time progression of the etching process containing a transition metal film on a wafer performed by a semiconductor manufacturing apparatus. Figure 3 The chart shows the timeline of process B performed when "processing allowance > threshold" (step S102). Figure 4 The time chart represents the time of process A performed when "processing allowance ≤ threshold" (step S102). It schematically shows the heating and cooling, gas supply and exhaust operations of wafer 2 in the etching process. The actual temperature, temperature gradient and required control time vary depending on the type of etched material (including transition metal film), complexing material (organic compound), and the structure of semiconductor device.

[0058] When the determination result of step S102 is "processing allowance > threshold", the process proceeds to step S103B, and the supply of complexing gas to the processing chamber 1 begins. The complexing gas is a gas containing organic matter used to convert the transition metal film into a volatile organometallic complex. The vapor of the chemical solution 44 remaining in container 45 is supplied via the complexing gas supply mass flow controller 50-5, and the supply is regulated to achieve a flow rate or speed within a suitable range for processing. The supply conditions of the complexing gas (supply quantity, supply pressure, supply time, gas temperature, etc.) and the type of complexing gas are determined considering the elemental composition, shape, film thickness, and boiling point of the transition metal film. The control unit 40 selects the supply conditions according to the algorithm described in the software stored in its storage device and sends corresponding instruction signals to each mechanism.

[0059] Step S103B is a process in which a physical adsorption layer of complexing gas particles is formed on the surface of the transition metal film of the object being processed. This process maintains the substrate temperature within a temperature range equal to or lower than the boiling point of the complexing gas. Figure 3 The process is carried out at a first temperature T1. After forming a physical adsorption layer with the absolute minimum number of layers required for etching in one process, this step ends. This number of layers is selected considering the desired processing accuracy and processing volume. The formed physical adsorption layer is mainly determined by the surface condition, temperature, and gas pressure of the film being processed; therefore, after a predetermined time has elapsed according to the supply conditions, the process proceeds to step S104B.

[0060] In step S104B, with the complexing gas continuously supplied, power is supplied from the IR lamp power supply 64 to the IR lamp 62 to emit IR light. The wafer 2 is heated by the IR light, and the substrate temperature rapidly rises to the second temperature T2. During the period when the wafer 2 is heated to the second temperature T2, which is higher than the first temperature T1, and maintained, the reactivity of the material containing the transition metal film is activated, and the adsorption state of the complexing gas particles on the film changes from physical adsorption to chemical adsorption.

[0061] In the next step S105B, with the complexing gas continuously supplied, the wafer 2 is further heated by the IR lamp 62, raising the substrate temperature to a fourth temperature T4, which is higher than the second temperature T2. As the wafer 2 is heated, the particles of the complexing gas chemically adsorbed on the membrane are given activation energy, thereby initiating the conversion of the membrane into an organometallic complex. During the period when the wafer 2 is heated to and maintained at the fourth temperature T4, which is higher than the second temperature T2, (1) the organometallic complex generated on the surface of the transition metal-containing membrane volatilizes and is removed from the membrane surface, a first phenomenon, and (2) the continuously supplied complexing gas reacts with the transition metal-containing membrane to convert into a volatile organometallic complex, a second phenomenon, occurs simultaneously. If a specific small area of ​​the membrane surface of the processed object is viewed microscopically during this period, the removal and conversion of new complexes due to the volatilization (detachment) of the complexes on the membrane surface in that area, in the order of (1)→(2)→(1)→(2), occurs intermittently or in stages. However, when viewing the film of the object being processed as a whole, what can be captured is essentially continuous etching.

[0062] During a specified period, a complexing gas is supplied to the wafer 2, and the substrate temperature is maintained at a fourth temperature T4, thereby enabling substantially continuous etching. Once the desired etching amount is reached, the process proceeds to step S106B, where the supply of the complexing gas is stopped. On the other hand, exhaust is continuously performed in the processing chamber 1 by the exhaust mechanism 15 through the vacuum exhaust pipe 16. This exhaust is also performed in multiple processes, including stopping the supply of the complexing gas in step S106B and cooling the wafer 2 (S108). As a result, the gas and product particles in the processing chamber 1 are discharged to the outside of the processing chamber 1.

[0063] In contrast, when the determination result of step S102 is "processing allowance ≤ threshold", the process moves to step S103A, where complexing gas is supplied into the processing chamber 1. In step S103A, after forming a physical adsorption layer with an absolute minimum number of layers, the process moves to step S104A, where the wafer 2 is heated by irradiation from IR light from IR lamp 62, causing the substrate temperature to rise rapidly to the second temperature T2.

[0064] Similar to step B, in step A, the supply conditions and type of complexing gas are determined by considering the elemental composition, shape, film thickness, and boiling point of the transition metal film. The control unit 40 selects the supply conditions according to the algorithm described in the software stored in its storage device and sends the corresponding instruction signals to each mechanism. During the period when the wafer 2 is heated to a second temperature T2 higher than the first temperature T1 and maintained, the reactivity of the material on the surface of the transition metal film is activated. Similar to the case in step B, the adsorption state of the complexing gas particles on the film surface changes from physical adsorption to chemical adsorption.

[0065] When a complexed gas is chemisorbed onto a transition metal film, the molecules of the complexed gas and the transition metal atoms contained in the transition metal film are firmly fixed by chemical bonds. In other words, the complexed gas molecules are "pinned" to the surface of the transition metal film, resulting in a slow diffusion rate of the chemisorbed complexed gas molecules.

[0066] In the next step S105A, the supply of complexing gas is stopped, and the interior of the processing chamber 1 is vented. By venting the interior of the processing chamber 1, except for the complexing gas remaining in the state of chemical adsorption on the transition metal film, the complexing gas in the unadsorbed state and the physically adsorbed state is completely discharged outside the processing chamber 1 and removed.

[0067] Next, according to the command signal from the control unit 40, the irradiation amount of IR light from the IR lamp 62 continuously irradiating the wafer 2 from step S104A is increased, causing the substrate temperature to rise to the third temperature T3 (step S106A). Thereafter, the wafer 2 is maintained at the third temperature T3 for a predetermined period. During the period when the wafer 2 is heated to and maintained at the third temperature T3, particles of the complexed gas that are chemically adsorbed on the surface of the transition metal film slowly transform into volatile organometallic complexes through reaction with the material on the film surface. At this time, complexed gases other than those fixed by chemical adsorption are not present in the processing chamber 1, therefore the thickness of the generated organometallic complex layer becomes equal to or less than the thickness of the chemically adsorbed layer.

[0068] Subsequently, the irradiation intensity of the IR light from the IR lamp 62 is further increased, raising the substrate temperature to a fourth temperature T4 (step S107A). The wafer 2 is then maintained at the fourth temperature T4 for a predetermined period. During the period when the wafer 2 is heated to and maintained at the fourth temperature T4, the organometallic complex formed on the film surface detaches and is thus removed from the film surface of the object being processed.

[0069] As described above, process A, consisting of the series of steps S103A → S104A → S105A → S106A → S107A, and process B, consisting of the series of steps S103B → S104B → S105B → S106B, are the same up to the formation of a chemisorption layer on the surface of the transition metal film on wafer 2. However, the operation flow differs after the chemisorption layer is converted into an organometallic complex.

[0070] In process A, while the substrate temperature is raised to and maintained at a fourth temperature T4 with the complexing gas supply stopped, the detachment of approximately one to several layers of organometallic complexes converted from the chemisorption layer ends, exposing the transition metal film directly beneath it, thus halting the reaction. In contrast, in process B, because the substrate temperature is raised to and maintained at a fourth temperature T4 with a continuous supply of complexing gas, even after the detachment of approximately one to several layers of organometallic complexes converted from the chemisorption layer ends, the unreacted transition metal film directly beneath it is exposed. This exposed film is also heated to the fourth temperature T4, increasing its activity. Therefore, if the complexing gas comes into contact with the transition metal film, the processes of physical adsorption, chemisorption, and complex conversion occur continuously, with direct conversion to organometallic complexes occurring from the moment of contact with the complexing gas. Furthermore, due to the rapid detachment of the generated organometallic complexes, the etching of the film being processed is performed continuously throughout.

[0071] Therefore, during the etching process in step B, where the substrate temperature is raised to and maintained at a fourth temperature T4, highly active micro-regions containing transition metal films, such as metal crystal boundaries or specific crystal orientations, are preferably converted into organometallic complexes and removed, resulting in increased unevenness and surface roughening. This is because the conversion to organometallic complexes occurs directly upon contact with the complexing gas. Therefore, if the surface of the film in contact with the complexing gas happens to be a highly active region, it is directly converted into an organometallic complex and removed. On the other hand, if the surface of the film in contact with the complexing gas is not a highly active region, physical adsorption does not occur, and the organic compounds that are components of the complexing gas leave the film surface.

[0072] In contrast, in the etching process of step A, the formation of the chemisorption layer is limited to the period during which the substrate temperature is raised to and maintained at a second temperature T2. During the formation of the chemisorption layer at such a lower temperature, the surface of the processed transition metal film is planarized due to the planar orientation growth of the chemisorption layer within its own structure. That is, the change from physisorption to chemisorption occurs rapidly when molecules of the complexed gas with a three-dimensional structure are oriented and adsorbed onto the film surface in a specific direction. When the activity of the film surface is low, the complexed gas held by physisorption does not leave the film surface but is stabilized by changing its orientation (planar orientation growth), thereby suppressing the influence of the microscopic activity of the film surface from manifesting in the etching result.

[0073] Furthermore, regardless of whether it is process A or process B, the fourth temperature T4 is set in a manner that is lower than the decomposition start temperature of the complexed gas molecules and the decomposition start temperature of the organometallic complex molecules, and is the same as or higher than the vaporization evaporation (vaporization evaporation) start temperature of the organometallic complex molecules. Also, the phenomenon of organometallic complexes detaching from the transition metal film can strictly be volatilization, sublimation, etc., but the distinction between these phenomena is not important here, and will be generally described as vaporization or vaporization evaporation. When the temperature difference between the decomposition start temperature and the vaporization evaporation start temperature of the organometallic complex molecules is small, for the specifications of the semiconductor manufacturing apparatus 100, for example, when the temperature uniformity in the planar direction on the upper surface of the stage 4 is insufficient, existing methods for lowering the vaporization evaporation start temperature of the organometallic complex molecules can be applied, such as methods for reducing pressure in the processing chamber 1 to expand the mean free process.

[0074] If process A or process B is completed, the process proceeds to step S108 to begin cooling of wafer 2. In step S109, cooling of wafer 2 continues until the substrate temperature is detected to have reached the first temperature T1 by the output control unit 40 using the spectrum measurement of the optical fiber 92 or the thermocouple thermometer 71.

[0075] In step S108, it is preferable to supply cooling gas between the stage 4 and the wafer 2. Suitable cooling gases include, for example, He or Ar. If He gas is supplied, cooling can be achieved in a short time, thus resulting in high processing productivity. However, since a refrigerant flow path 39 connected to the cooler 38 is provided inside the stage 4, if electrostatic adsorption occurs on the stage 4, the wafer 2 can be cooled even when no cooling gas is flowing.

[0076] If the control unit 40 detects that the temperature of the wafer 2 has reached the first temperature T1, it returns to step S101 to determine whether the processing allowance has reached 0. If it is determined that the processing allowance has reached 0, the etching process of the film to be processed on the wafer 2 ends. If it is determined that the processing allowance is greater than 0, it returns to step S102 to perform one of the processes of process A or process B.

[0077] When processing of wafer 2 ends, according to the command signal from the control unit 40, the supply of He gas from the mass flow controller 50-4 through the He gas supply path to the gap between the upper surface of the stage 4 and the back surface of wafer 2 is stopped. Furthermore, the valve 52, located on the waste gas path connecting the He gas supply path and the vacuum exhaust pipe 16, is changed from a closed state to an open state, venting the He gas in the gap outside the processing chamber 1. This brings the pressure in the gap to the same level as the pressure in the processing chamber 1, and removes the electrostatic adsorption of wafer 2, including electrostatic removal. Afterward, the door of the base chamber 11 is opened, and wafer 2 is transferred to the arm of the transport robot entering from the vacuum transport container. If there are wafers 2 to be processed next, the transport robot arm again carries unprocessed wafers 2 in; if there are no wafers 2 to be processed, the door is closed, and the operation of manufacturing semiconductor devices by the semiconductor manufacturing apparatus 100 is stopped.

[0078] Furthermore, the second and fourth temperatures set in process A or process B can be the same or different between processes A and B. Additionally, the etching process is repeated to etch the film of the object being processed. Figure 2 When a cycle including process A or process B is performed more than once, the first to fourth temperatures may be the same or different between cycles. These temperatures have been carefully studied before the etching process of wafer 2, and appropriate temperature ranges have been set for each of the first to fourth temperatures. The control unit 40 reads the set temperature range information stored in its storage device and sets the temperature of each step as one of the conditions for processing wafer 2 in each cycle of process A and process B, based on the performance required by the semiconductor manufacturing apparatus 100 and the specifications of the target wafer 2.

[0079] Next, specific examples will be given while the semiconductor manufacturing method implemented by the semiconductor manufacturing apparatus 100 will be explained.

[0080] First, the etching process of wafer 2 begins ( Figure 2Before the process begins, wafer 2 is first adsorbed onto stage 4 and held there. Then, the interior of processing chamber 1 is depressurized and wafer 2 is heated. As wafer 2 is heated, the substrate temperature rises, thereby removing gases (water vapor, etc.) and foreign matter adsorbed on the surface of wafer 2. If it is confirmed that the gas components adsorbed on the surface of wafer 2 have been sufficiently removed, the heating of wafer 2 is stopped directly while the interior of processing chamber 1 is depressurized, and cooling of wafer 2 begins. In this process, heating and cooling can be performed using known methods. Furthermore, in the removal of foreign matter, known methods such as surface ashing and cleaning by plasma formed in processing chamber 1 can also be used.

[0081] If the control unit 40 detects that the substrate temperature has decreased to or below a predetermined first temperature T1, then it follows... Figure 2 The flowchart shown illustrates the processing of wafer 2. Furthermore, before processing begins, for example, before wafer 2 is placed into processing chamber 1, the control unit 40 selects a processing formula, which specifies the type and flow rate of the gas used to process the transition metal film containing wafer 2, the pressure within processing chamber 1, and other processing conditions. For example, an ID number for each wafer 2 is obtained through marking or similar means. Data such as the processing history of the wafer 2 corresponding to that ID number, the composition and thickness of the film to be etched, the amount of film etched (target residual film thickness, etching depth), and the conditions at the etching endpoint are obtained from a production management database via a communication device (not shown) connected to the control unit 40.

[0082] For example, if the processing performed on wafer 2 is an etching process to remove a lanthanum oxide film with an initial thickness of less than a specified threshold of 0.3 nm, since the ionic radii of lanthanum (3+) and oxygen (2−) are approximately 1.0 Å and 1.3 Å respectively, it is determined to be a process that substantially removes one atomic or molecular layer of lanthanum oxide, and follows the... Figure 2 After determining in step S102 that "processing allowance ≤ threshold", the process of transferring to process A is performed to process the film, and in this way, the control unit 40 sends instruction signals to each part constituting the semiconductor manufacturing apparatus 100 to adjust their operation.

[0083] On the other hand, if the processing performed on wafer 2 involves removing a lanthanum oxide film exceeding a specified threshold of 3 nm, then approximately 10 or more layers of lanthanum oxide must be removed. If the etching process of step A is performed layer by layer, repeating step A more than 10 times could potentially reduce productivity. Therefore, the following process is performed: first, multiple layers (e.g., 5-6 layers) are removed simultaneously, and then the remaining film layers are removed layer by layer. Specifically, if it is determined in step S102 that "processing allowance > threshold", the process proceeds to step S103B, and after processing the film to be processed according to the process of step B, the process of step A is performed at least once.

[0084] As the initial steps of processes A and B, namely steps S103A and S103B, a process is performed to form a physical adsorption layer of complexing gas on the surface containing the transition metal film, while maintaining the wafer 2 at a temperature equal to or lower than the boiling point of the complexing gas. Details of the complexing gas will be described later; it is a gas (organic gas) containing an organic compound with a Lewis base as the main active ingredient. For example, when using an organic compound with a boiling point of approximately 200°C, the process is performed within a temperature range of approximately 180°C or, at a maximum temperature of approximately 200°C.

[0085] When salicylaldehyde (boiling point approximately 200°C) is used as a component of an organic gas, the preferred first temperature T1 is between approximately 100°C and 180°C, more preferably between 120°C and 160°C. If the first temperature T1 is below 100°C, it takes a long time to raise or lower the temperature, which may reduce productivity. On the other hand, if the first temperature T1 is above 180°C, the adsorption efficiency of salicylaldehyde decreases, and the flow rate of salicylaldehyde gas must be increased to achieve adsorption in a shorter time, which may increase operating costs.

[0086] After a physical adsorption layer is formed on the surface containing the transition metal film, in steps S104A and S104B, the wafer 2 is rapidly heated to a second temperature T2, causing the adsorption state of the complexed gas on the surface containing the transition metal film to change from a physical adsorption state to a chemical adsorption state. This heating process provides activation energy to change the adsorption state of the particles of the complexed gas adsorbed on the film surface.

[0087] The second temperature T2 is determined by considering the influence of both the surface state of the transition metal film and the characteristics (reactivity) of the complexing compound. For example, when supplying an organic gas for complexing a lanthanum oxide film, which is the target film, with salicylaldehyde as the main component, the suitable range for the second temperature T2 is approximately 120°C to 210°C. If the second temperature T2 is below 120°C, the time required for conversion to the chemisorption layer is longer; if the second temperature T2 is above 210°C, it is impossible to remain in the chemisorption state and convert to the organometallic complex, increasing the likelihood of reduced controllability of the film thickness.

[0088] When the etching amount is large, for example, when removing a lanthanum oxide film with a thickness of more than 3 nm by etching, following the process of step B, while maintaining the supply of complexing gas such as salicylaldehyde, infrared heating is further continued to raise the temperature to a fourth temperature T4 (step S105B). The fourth temperature T4 is set to be lower than the temperature at which the volatile organometallic complex generated by the reaction of the transition metal element containing the transition metal film with the complexing gas and the thermal decomposition of the complexing gas occur, and is the same as or higher than the temperature at which the organometallic complex begins to vaporize. In step S106B, until the supply of the complexing gas stops, the temperature of wafer 2 is maintained at a temperature above the fourth temperature T4, and the surface of wafer 2 containing the transition metal film is substantially continuously etched.

[0089] When the etching amount is small, for example, when etching away a 0.3 nm thick lanthanum oxide film, following the process of step A, the supply of complexing gases such as salicylaldehyde is stopped, the interior of the processing chamber 1 is vented to remove particles that affect the processing (step S105A), and then the wafer 2 is heated to a third temperature T3 (step S106A). The temperature of the transition metal film becomes the third temperature T3 and is maintained for a specified period, thereby converting the chemisorbed layer formed on the film surface into an organometallic complex.

[0090] The third temperature T3 is set to a temperature within a range that is equal to or higher than the second temperature T2, but lower than the vaporization and evaporation start temperature of the organometallic complex molecules. Considering the stability of temperature control in the semiconductor manufacturing apparatus 100 and the accuracy of thermometer measurements of the substrate temperature, the temperature is set within the aforementioned appropriate temperature range. When using a lanthanum oxide film as the transition metal film and a mixed gas with salicylaldehyde as the main component for etching, since the vaporization and evaporation start temperature of the organometallic complex molecules is approximately 320°C, the appropriate temperature range for the third temperature T3 is 120°C to 310°C.

[0091] The IR light from the IR lamp 62 continues to irradiate the wafer 2. After the temperature of the wafer 2 is maintained at the third temperature T3 set in step S106A for a predetermined period, the irradiation intensity of the IR light is further increased in step S107A to raise the temperature of the wafer 2 to the fourth temperature T4. By maintaining the temperature of the wafer 2 at the fourth temperature T4, one to several layers of organometallic complexes converted from the chemisorption layer volatilize and are removed.

[0092] The reaction subsides when the organometallic complex is removed, exposing the layer containing the transition metal directly beneath it, or the layer of silicon compounds disposed beneath the transition metal complex. Furthermore, when using a lanthanum oxide film as the transition metal film and a mixed gas primarily composed of salicylaldehyde as the etching organic gas, the appropriate range for the fourth temperature T4 is 310°C to 390°C. This is because if the fourth temperature T4 is lower than 310°C, the vaporization rate is slow, and the processing efficiency is compromised; conversely, if the fourth temperature T4 is higher than 390°C, the possibility of decomposition of the organometallic complex increases.

[0093] Figure 5 This is a timeline schematically representing the time progression of operations performed by a semiconductor manufacturing apparatus to etch a transition metal film onto a wafer, positioned as a backup process for process A. Therefore, in Figure 5 In the text, replacing the symbols of the corresponding steps with the symbols of C represents the equivalent of... Figure 2 The timing of the steps in the flowchart. However, Figure 5 The workflow of time charts is not... Figure 2 The flowchart is shown as reference information for comparison with process A.

[0094] After the control unit 40 detects that the temperature of the wafer 2 has reached or fallen below a predetermined first temperature T1, it begins the following process (step S103C): an organic gas is supplied to the processing chamber 1 as a processing gas, causing organic gas particles to be adsorbed on the surface of the transition metal film of the object being processed, forming a physical adsorption layer. In this process, immediately after step S103C begins, power is supplied to the IR lamp 62 to emit IR light, thereby heating the wafer 2 and rapidly raising the substrate temperature to a second temperature T2. As a result, the adsorption state of the organic gas particles on the surface of the film of the object being processed changes from a physical adsorption state to a chemical adsorption state.

[0095] During a predetermined period, while wafer 2 is maintained at a second temperature T2, organic gas is continuously supplied to the upper surface of the wafer within processing chamber 1. Therefore, during this period, the reaction of forming a physical adsorption layer of organic gas components on the surface containing the transition metal film, and the conversion reaction of the physical adsorption layer to a chemisorption layer, proceed in parallel and continuously.

[0096] As described above, the rate at which organic gas molecules diffuse into the interior of the transition metal film via the chemisorption layer formed on the surface of the transition metal film is slow, thus the thickness of the chemisorption layer saturates with respect to the processing time. While maintaining the substrate temperature at a second temperature T2, organic gas is continuously supplied for a specified period, and the supply of organic gas is stopped after the thickness of the chemisorption layer becomes saturated (S105C).

[0097] Before the supply of organic gas begins, the semiconductor manufacturing apparatus 100 maintains the internal pressure of the processing chamber 1 in a reduced-pressure state via the exhaust mechanism 15 and the pressure regulating mechanism 14. Therefore, if the supply of organic gas is stopped, all organic gas in both the unadsorbed and physically adsorbed states, except for the organic gas chemically adsorbed on the membrane surface, is discharged outside the processing chamber 1 and removed. Furthermore, to facilitate the discharge of organic gas physically adsorbed on the inner walls of the processing chamber 1, a small amount of Ar gas is preferably continuously supplied to the interior of the processing chamber 1.

[0098] The Ar gas supply and the pressure inside the processing chamber 1 need to be appropriately adjusted according to the composition of the film being processed and the etching organic gas. However, when etching lanthanum oxide films using salicylaldehyde as the main component and the etching organic gas, it is preferable that the Ar supply is below 200 sccm and the processing chamber pressure is around 0.5 to 3 Torr. More preferably, the Ar supply is approximately 100 sccm and the processing chamber pressure is around 1.5 Torr. When the processing chamber pressure is higher than 3 Torr, the Ar supply increases and exceeds 200 sccm, the effective concentration of the etching organic gas inside the processing chamber 1 decreases, the adsorption efficiency on the surface of the film being processed decreases, and the etching rate is likely to decrease. On the other hand, if the processing chamber pressure is lower than 0.5 Torr, the residence time of the etching organic gas inside the processing chamber 1 becomes shorter, and therefore the utilization efficiency of the etching organic gas is likely to decrease.

[0099] Next, the temperature is raised to a fourth temperature T4 (S107C) by infrared heating using an IR lamp 62, and maintained at approximately this temperature for a specified period. During the heating to the fourth temperature T4 and the temperature maintenance, the conversion from the chemisorbed layer to the organometallic complex and the volatilization removal of the organometallic complex take place.

[0100] At the moment when the volatilization and removal of the organometallic complex is completed, and the layer containing the transition metal film directly beneath it, or the layer of silicon compound disposed beneath the transition metal film, is exposed, one etching cycle ends. Thereafter, infrared heating using the IR lamp 62 is stopped, and the temperature begins to decrease due to heat dissipation from the wafer 2. If the substrate temperature reaches a second temperature T2 or a temperature below it (S108), one processing cycle ends.

[0101] Subsequently, by repeatedly performing the second and subsequent cycles starting from step S103C, etching to the specified film thickness can be achieved. If compared with... Figure 4The process comparison of step A shown can reduce the third temperature level T3, and in particular, shorten the temperature range of the time-consuming step S108 (cooling step) from (T4-T1) to (T4-T2), thereby reducing the time of each cycle. Due to the reduction of the third temperature level T3, the etched surface may be rougher compared to the process of step A, but this can be controlled to a level that is not a problem in practical use.

[0102] Also, you can also Figure 5 The operation process of timing diagrams and Figure 3 or Figure 4 The timeline diagrams can be combined. For example, in process A, the period of maintaining the third temperature T3 can be removed, the supply of complexing gas can be stopped, the excess complexing gas can be discharged from processing chamber 1, and the temperature can be immediately raised to the fourth temperature T4. Additionally, in processes A and B, such as... Figure 5 The timing diagram operation can also keep the temperature after cooling (step S109) at the second temperature T2.

[0103] Next, the composition of suitable organic gases for etching will be explained.

[0104] The main active component of the etching organic gas is an organic compound capable of forming at least bidentate coordination bonds with transition metal atoms. A polydentate ligand molecule is an organic compound that does not contain halogens and has any one of the following molecular structural formulas (1) to (3). The organic compound used as the etching organic gas can also be a mixture of one or more organic compounds, which is dissolved in a suitable diluent as a chemical solution 44 as needed. By dissolving it in the diluent, the diluent promotes the vaporization of the component represented by the molecular structural formula shown below. Furthermore, the vaporized diluent functions as a carrier gas, thereby ensuring a smooth supply of the organic gas.

[0105] The molecular structure (1) is the molecular structure shown in (chemical formula 1). It is an aromatic compound having a benzene ring, etc., with at least one carbonyl group attached to the aromatic ring. The carbon atom adjacent to the carbon atom on the aromatic ring with the carbonyl group has a Lewis basic substituent (Y-X), such as an OH group, an OCH3 group, an NH2 group, or an N(CH3)2 group. As the carbonyl group attached to the aromatic ring, suitable compounds do not have OH or NH2 attached at the Z position, but rather H or CH3.

[0106] [Chemical Formula 1]

[0107]

[0108] The molecular structure (2) is the molecular structure shown in (chemical formula 2), which has at least one Lewis basic N (nitrogen atom) in the aromatic ring, and a substituent (C=R2) with C=C or C=O bond is attached above the carbon atom adjacent to the N atom.

[0109] [Chemical Formula 2]

[0110]

[0111] The molecular structure (3) is a compound of aliphatic triamine (n=1), aliphatic tetraamine (n=2), and aliphatic pentamine (n=3) exemplified by (chemical formula 3), which has a C2 carbon chain between any two N atoms.

[0112] [Chemical Formula 3]

[0113]

[0114] The molecular structure shown in Formula 1 has at least one carbonyl group bonded to the benzene ring, and an atom (Y) with a non-shared electron pair bonded three atoms away from the carbon atom of the carbonyl group. In Formula 1, O or N is exemplified as the atom with a Lewis basicity and a non-shared electron pair. Atom (Y) can also be replaced with other atoms with non-shared electron pairs, such as S or P, but in this case, care must be taken to adjust the procedure to account for the increase in the vaporization and evaporation start temperature of the corresponding organometallic complex.

[0115] In the molecular structure shown in (Chemical Formula 1), the carbonyl group is bonded with H or CH3, which does not have a non-shared electron pair. When the carbonyl group is bonded with O or N, which has a non-shared electron pair, for example, Z = OH, its boiling point increases, and the tendency to be difficult to supply as an organic gas for etching increases. Also, in (Chemical Formula 1), when X = H, Y = O, Z = H, and R = H, it is salicylaldehyde.

[0116] In salicylaldehyde, two coordinate bonds are formed by the donation of electron pairs from the atom (Y), i.e., the non-shared electron pair of O, and the non-shared electron pair of the carbonyl group to a transition metal element, thus forming an organometallic complex. These coordinate bonds are strong, electron-donating + feedback type bonds, and since they are formed at two positions, the resulting salicylaldehyde metal complex is a thermally stable coordination compound. For example, in the transition metal acetates or formates obtained by reacting acetic acid or formic acid with a transition metal element, as exemplified in the prior art, there is only one coordinate bond. By combining two coordinate bonds, the organometallic complex formed intermediately using the etching organic gas exemplified in this embodiment exhibits significantly improved thermal stability compared to its carboxylates.

[0117] Furthermore, in the case of salicylaldehyde, the OH group (substituent (Y-X)) located three atoms from the carbonyl group is a Brønsted acid, but due to the electron-attracting properties of the carbonyl group and the Lewis basicity of the carbonyl O atom, the molecule is in a partially neutralized state. If the molecular structure contains polar groups, the intermolecular attraction generally increases, but localized charge neutralization within the molecule can suppress its effect.

[0118] In the molecular structure shown in (Chemical Formula 1), the benzene ring, which constitutes part of the molecular structure and bears the aromaticity, also enhances the thermal stability of the intermediate organometallic complex. The benzene ring can also be replaced with other aromatic structures such as a naphthyl ring / tropeneone ring. When replacing it with other aromatic structures, care must be taken to adjust the procedure to account for the increase in the vaporization and evaporation start temperature of the corresponding organometallic complex.

[0119] The molecular structure shown in (Chemical Formula 2) has a side chain bonded to the carbon atom adjacent to the N atom of the pyridine ring. This side chain contains a C=C (carbon-carbon double bond) or C=O (carbon-oxygen double bond) and an atom (Y) with a non-shared electron pair exhibiting Lewis basicity. In (Chemical Formula 2), the atom (Y) with a non-shared electron pair exhibiting Lewis basicity is exemplified by O or N.

[0120] When the side chain is a carbon-carbon double bond, the N atom of the pyridine ring can also be linked to a carbon chain (R1) extending from the two adjacent carbon atoms. Examples of side chains linked by carbon-carbon double bonds to carbon chains extending from the two adjacent carbon atoms of the N atom in the pyridine ring include quinolinols with X = H, Y = O, and R1-R2 = benzene rings. In quinolinols, two coordinate bonds are formed by the non-shared electron pair of the O atom (Y) and the non-shared electron pair of the N atom in the pyridine ring being donated to a transition metal element, forming a quinolinol metal complex.

[0121] Similar to the case of molecular structure (1), the coordinate bond is a strong electron-donating and feedback type bond, and this bond is formed in two positions, so the resulting organometallic complex is a thermally stable coordination compound. In addition, in the case of quinolinol, the OH group (substituent (Y-X)) located 3 atoms away from the N atom of the pyridine ring is a substituent exhibiting Brønsted acidity, but due to the Lewis basicity of the N atom of the pyridine ring, the molecule is partially neutralized. By suppressing the intermolecular attraction of quinolinol, in other words, increasing the volatility of quinolinol, the load on the etching organic gas supply unit 47 and the control unit 40 can be reduced, and the heating of the etching gas supply piping can also be omitted.

[0122] In the molecular structure shown in (Chemical Formula 2), X = H, Y = O, R1 = H, and R2 = O constitute pyridinecarboxylic acid. In pyridinecarboxylic acid, two coordinate bonds are formed by donating the unshared electron pair of the O atom (Y) and the unshared electron pair of the N atom in the pyridine ring to the transition metal element, thus forming an organometallic complex. Therefore, the resulting pyridinecarboxylic acid metal complex is a thermally stable coordination compound. Furthermore, similar to quinolinol, the OH group located three atoms from the N atom in the pyridine ring is a substituent exhibiting Brønsted acidity, but due to the Lewis basicity of the N atom in the pyridine ring, it is partially neutralized within the molecule.

[0123] In (Formula 2), the aromatic ring structure exhibiting Lewis basicity is shown as an example of a pyridine ring, but it can also be replaced by pyrrole, pyrazole, imidazole, furan, oxazole, indole, quinoline, coumarin, etc. However, organic materials with these alternative structures are generally more expensive than those with the pyridine ring structure, which is something to be aware of.

[0124] The molecular structure shown in (Formula 3) is an aliphatic polyfunctional amine, more specifically, a trimer, tetramer, or pentamer of ethyleneimine (CH2-CH2-NX-) and its derivatives. Ethyleneimine is a structure in which N atoms with non-shared electron pairs exhibiting Lewis basicity are bonded to both sides of the C2 chain. In the molecular structure shown in (Formula 3), either H or CH3 is bonded to the N atom. Coordinate bonds are formed by donating non-shared electron pairs from the N atoms on both sides of the ethyleneimine C2 chain to transition metal elements, thereby forming organometallic complexes. The molecular structure shown in (Formula 3) does not possess a heat-resistant structure like an aromatic ring, but it can be bonded to transition metal elements through strong bonds of at least 3 electron donation + feedback, thus yielding thermally stable coordination compounds.

[0125] Symbol Explanation

[0126] 1…processing chamber, 2…wafer, 3…discharge area, 4…wafer stage, 5…burst plate, 6…top plate, 11…base chamber, 12…quartz chamber, 14…voltage regulating mechanism, 15…exhaust mechanism, 16…vacuum exhaust piping, 17…gas dispersion plate, 20…high-frequency power supply, 22…integrator, 25…high-frequency shear filter, 30…electrode for electrostatic adsorption, 31…DC power supply, 34…ICP coil, 38…cooler, 39…refrigerant flow path, 40…control unit, 41…computing unit, 44…chemical solution, 45…container, 46…heater, 4 7… Complexing gas supplier, 50… Mass flow controller, 51… Integrated mass flow controller control unit, 52, 53, 54… Valves, 60… Container, 62… IR lamp, 63… Reflector, 64… Power supply for IR lamp, 70… Thermocouple, 71… Thermocouple thermometer, 74… IR light transmission window, 75… Gas flow path, 78… Slit plate, 81… O-ring, 92… Optical fiber, 93… External IR light source, 94… Optical path switch, 95… Spectrometer, 96… Spectrometer, 97… Detector, 98… Optical add-drop multiplexer, 100… Semiconductor manufacturing apparatus.

Claims

1. A semiconductor manufacturing method, which is a semiconductor manufacturing method using a semiconductor manufacturing apparatus having a processing chamber, wherein, have: In the first step, a complexing gas is supplied to the processing chamber on which a wafer containing a transition metal film with a transition metal element formed on its surface is placed, so that an organic compound, which is a component of the complexing gas, is adsorbed onto the transition metal film. The second step involves heating the wafer on which the organic compound is adsorbed onto the transition metal film, causing the organic compound to react with the transition metal element to form an organometallic complex, and then detaching the organometallic complex. The organic compound is any one of the following (1) and (2): (1) is an aromatic compound with a carbonyl group, which is an organic compound having a substituent with Lewis basicity on a carbon atom of the aromatic ring adjacent to the carbon atom of the aromatic ring with the carbonyl group. (2) is any one of aliphatic triamine, aliphatic tetraamine, and aliphatic pentamine.

2. The semiconductor manufacturing method according to claim 1, wherein, The complexing gas is supplied to the processing chamber through the first step. The first process includes: a first period of supplying the complexing gas while maintaining the wafer at a first temperature; and a second period of supplying the complexing gas while heating the wafer and maintaining it at a second temperature higher than the first temperature. The first temperature during the first period is set in such a way that a physical adsorption layer is formed on the surface of the transition metal film containing the organic compound, and the second temperature during the second period is set in such a way that the adsorption state of the organic compound on the transition metal film changes from a physical adsorption state to a chemisorption state.

3. The semiconductor manufacturing method according to claim 1, wherein, In the first step, the complexing gas is initially supplied to the processing chamber, and the wafer is heated and maintained at a second temperature while the complexing gas is continuously supplied. The second temperature is set in such a way that the reaction that causes the physical adsorption layer to form on the surface of the transition metal film occurs in parallel with the conversion reaction that causes the physical adsorption layer to convert into a chemisorption layer.

4. The semiconductor manufacturing method according to claim 1, wherein, The complexing gas is supplied to the processing chamber through the first and second steps. In the second process, the wafer is heated and maintained at a fourth temperature. The fourth temperature is set as follows: a temperature lower than the temperature at which the organic compound undergoes thermal decomposition and the temperature at which the organometallic complex undergoes thermal decomposition, and a temperature above the temperature at which the organometallic complex vaporizes.

5. The semiconductor manufacturing method according to claim 1, wherein, After the first process is completed, the organic compounds that have not been chemically adsorbed onto the transition metal membrane are discharged from the processing chamber, and then the second process begins.

6. The semiconductor manufacturing method according to claim 5, wherein, The second process includes: heating the wafer and maintaining it at a third temperature for a third period; and heating the wafer and maintaining it at a fourth temperature higher than the third temperature for a fourth period. The third temperature during the third period is set to a temperature above the temperature of the wafer in the first process, but lower than the temperature at which the organometallic complex vaporizes. The fourth temperature in the fourth period is set as follows: a temperature lower than the temperature at which the organic compound undergoes thermal decomposition and the temperature at which the organometallic complex undergoes thermal decomposition, and a temperature above the temperature at which the organometallic complex vaporizes.

7. The semiconductor manufacturing method according to claim 5, wherein, In the second process, the wafer is heated and maintained at a fourth temperature. The fourth temperature is set as follows: a temperature lower than the temperature at which the organic compound undergoes thermal decomposition and the temperature at which the organometallic complex undergoes thermal decomposition, and a temperature above the temperature at which the organometallic complex vaporizes.

8. The semiconductor manufacturing method according to claim 1, wherein, The organic compound has a molecular structure represented by (Chemical Formula 1). [Chemical Formula 1] In (Chemical Formula 1), X is any one of H, CH3, H2, and (CH3)2, Y is O or N, Z is H or CH3, and R is any one of H, CH3, C2H5, C3H7, and C4H9.

9. The semiconductor manufacturing method according to claim 1, wherein, The organic compounds also include the following organic compounds: aromatic compounds having a nitrogen atom with Lewis basicity on an aromatic ring, and organic compounds having a substituent having a C=C bond or a C=O bond bonded to a carbon atom adjacent to the nitrogen atom.

10. The semiconductor manufacturing method according to claim 9, wherein, The organic compound has a molecular structure represented by (Chemical Formula 2). [Chemical Formula 2] In (Chemical Formula 2), X is any one of H, CH3, H2, and (CH3)2, Y is O or N, R1 is any one of H, CH3, and the carbon chain, and R2 is any one of O or the carbon chain.

11. A semiconductor manufacturing apparatus, wherein, have: A chamber with an internal processing area; A wafer stage, which is disposed in the processing chamber and holds a wafer on which a transition metal film containing transition metal elements is formed on its surface; A complexing gas supplier, the complexing gas supplier having a container for containing a chemical solution containing an organic compound as a component, and supplying the organic gas obtained by vaporizing the chemical solution as a complexing gas to the processing chamber. A heater for heating the wafer; and Control Department The control unit performs the following steps: First, the complexing gas supplier supplies complexing gas to the processing chamber containing the wafer, causing the organic compound, a component of the complexing gas, to adsorb onto the transition metal-containing film; Second, the heater heats the wafer on the transition metal-containing film, on which the organic compound is adsorbed, causing the organic compound to react with the transition metal element to form an organometallic complex, and then detaches the organometallic complex. The organic compound is any one of the following (1) and (2): (1) is an aromatic compound with a carbonyl group, which is an organic compound having a substituent with Lewis basicity on a carbon atom of the aromatic ring adjacent to the carbon atom of the aromatic ring with the carbonyl group. (2) is any one of aliphatic triamine, aliphatic tetraamine, and aliphatic pentamine.

12. The semiconductor manufacturing apparatus according to claim 11, wherein, The control unit, through the first and second processes, supplies the complexing gas to the processing chamber via the complexing gas supplier. In the second process, the wafer is heated by the heater and maintained at a fourth temperature. The fourth temperature is set as follows: a temperature lower than the temperature at which the organic compound undergoes thermal decomposition and the temperature at which the organometallic complex undergoes thermal decomposition, and a temperature higher than the temperature at which the organometallic complex vaporizes.

13. The semiconductor manufacturing apparatus according to claim 11, wherein, It has an exhaust mechanism for venting the processing chamber. After the first process is completed, the control unit continues to exhaust the processing chamber by the exhaust mechanism while stopping the supply of complexing gas by the complexing gas supplier, thereby discharging organic compounds that have not been chemically adsorbed on the transition metal film from the processing chamber.

14. The semiconductor manufacturing apparatus according to claim 13, wherein, In the second process, the control unit heats the wafer using the heater and maintains it at a fourth temperature. The fourth temperature is set as follows: a temperature lower than the temperature at which the organic compound undergoes thermal decomposition and the temperature at which the organometallic complex undergoes thermal decomposition, and a temperature above the temperature at which the organometallic complex vaporizes.

15. The semiconductor manufacturing apparatus according to any one of claims 11 to 14, wherein, have: A thermometer for detecting the temperature of the wafer stage; A detector that illuminates the wafer with infrared light and detects the spectral intensity of the infrared light absorbed and reflected by the wafer. The control unit controls the heater based on the temperature of the wafer stage estimated by the temperature detected by the thermometer, or based on the temperature of the wafer detected by the detector.

Images