JP2009088225A - Method for manufacturing semiconductor device, semiconductor manufacturing apparatus, and storage medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a semiconductor device capable of improving the etching resistance of a resist film while suppressing throughput from reducing. <P>SOLUTION: A substrate to be processed W, which includes a laminate 901 on which a pattern mask including a resist film 97, an anti-reflection film 96, and a film to be etched 902 are laminated from top in this order, is transported into a first air-tight processing container 2, the surface of the substrate to be processed is irradiated with electron beams in a vacuum atmosphere at a level of energy that improves the etching resistance of the resist film 97 but does not give etching resistance to the anti-reflection film 96, and then the substrate to be processed is transported in a second air-tight processing container 3 and the anti-reflection film 97 and the film to be etched 902 are etched via the pattern mask. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a technique for improving the etching resistance of a resist film serving as a mask when etching a film to be etched.

  In general, in a manufacturing process of a semiconductor device (semiconductor device), a multilayered fine wiring structure is formed on a semiconductor wafer (hereinafter referred to as a wafer) that is a substrate to be processed by using a photolithography technique. In the photolithography technique, for example, a mask having an opening is stacked on an upper layer side of an etching target film such as an insulating film, and the etching target film is etched through the opening, and then the ashing process is performed on the mask. The wiring structure is patterned by forming and removing.

  The mask is formed by coating a resist film made of a photosensitive resin on the surface of the substrate to be processed, and patterning openings corresponding to the above-described wiring structure in the resist film through exposure and development processes. The resin used in the process is required to have various performances such as transparency to the wavelength of the exposure light source and etching resistance. Responding to such demands, resin for resist films (hereinafter referred to as “ArF excimer lasers such as methacrylic polymer) (wavelength: 193 nm), which has been adopted with the further miniaturization of semiconductor device wiring structures in recent years. The resist for ArF) has a lower etching resistance than the aromatic polymer used in the conventional KrF excimer laser (wavelength 248 nm). For this reason, the resist film is shaved during etching, which may cause etching defects such as the occurrence of vertical stripes on the inner wall of the opening called striation.

  In order to solve such a problem, Patent Document 1 discloses that the resist film and the antireflection film are irradiated with an electron beam at an acceleration voltage of 50 keV to modify these films to improve etching resistance, and then oxidized. A technique for etching a film is described. It also describes that when a resist pattern is laminated on the antireflection film, the resist pattern is irradiated with an electron beam after etching the antireflection film. This is probably because when the electron beam irradiation is performed in this state, the antireflection film exposed at the opening of the resist pattern also has etching resistance.

However, according to this method, when an antireflection film and a resist film are laminated, electron beam irradiation must be performed after etching the antireflection film, and these processes must be performed in different modules. Don't be. For this reason, the process of etching the antireflection film with the etching module, subsequently irradiating the electron beam with the electron beam irradiation module, and further etching the film to be etched with the etching module is required. There was room for further improvement from the point of view.
JP 2000-221699 A: Paragraphs 0003 to 0004, 0029 to 0032, FIG.

  The present invention has been made based on such circumstances, and an object of the present invention is to provide a method for manufacturing a semiconductor device, a semiconductor manufacturing apparatus, and a semiconductor manufacturing apparatus capable of improving the etching resistance of a resist film while suppressing a decrease in throughput. It is to provide a storage medium storing a manufacturing method.

A method for manufacturing a semiconductor device according to the present invention includes: a substrate to be processed having a laminated body in which a pattern mask made of a resist film, an antireflection film, and an etching target film are stacked in this order from the top; A process of carrying in,
In the first processing container, an electron beam is applied to the surface of the substrate to be processed with energy sufficient to improve the etching resistance of the resist film in a vacuum atmosphere but not to provide etching resistance to the antireflection film. Irradiating with,
Thereafter, the substrate to be processed is transferred from the first processing container into an airtight second processing container, and the antireflection film is formed in the second processing container through a pattern mask made of the resist film. And a step of etching the film to be etched.

  The electron beam is irradiated from an electron gun or a neutralizing gun, and the resist film is selected from a resist film group consisting of an ArF resist film, a KrF resist film, an EUV resist film, and an EB resist film. It is preferable that the acceleration voltage for accelerating the electron beam is in the range of 0.1 keV to 1.8 keV.

Next, a semiconductor manufacturing apparatus according to the present invention is a semiconductor manufacturing apparatus that processes a substrate to be processed in which a resist film, an antireflection film, and an etching target film constituting a pattern mask are stacked in this order from above.
A substrate transfer means is provided, and a vacuum transfer chamber for transferring a substrate to be processed in a vacuum atmosphere;
Etching resistance of the resist film is improved with respect to the processing container that is hermetically connected to the vacuum transfer chamber and provided with a mounting table on which the processing substrate is mounted, and the processing substrate mounted on the mounting table. An electron beam irradiation module that irradiates an electron beam with energy that does not give etching resistance to the antireflection film, and
A processing vessel that is airtightly connected to the vacuum transfer chamber and provided with a mounting table on which the substrate to be processed is mounted, and means for etching the processing substrate mounted on the mounting table by plasma with plasma An etching module comprising:
The substrate to be processed irradiated with the electron beam by the electron beam irradiation module is carried into the etching module through the substrate transfer means, and the antireflection film and the etching target on the substrate to be processed are etched by the etching module. And a control unit that outputs a control signal so as to etch the film with plasma.

  Further, in this semiconductor manufacturing apparatus, when the substrate to be processed is transferred between the air atmosphere and the vacuum transfer chamber, the load lock chamber into which the substrate to be processed is once loaded, and the atmosphere in the load lock chamber as the air atmosphere. And a means for switching between a vacuum atmosphere and a processing container of the electron beam irradiation module may be configured to also serve as the load lock chamber.

  Here, the resist film is selected from a resist film group consisting of an ArF resist film, a KrF resist film, an EUV resist film, and an EB resist film. The resist film is an electron beam irradiated by the electron beam irradiation means. The acceleration voltage is preferably in the range of 0.1 keV to 1.8 keV, and the antireflection film is preferably an aromatic polymer.

  In addition, a storage medium according to the present invention is a storage medium that is used in a semiconductor manufacturing apparatus and stores a program that runs on a computer. The program executes any of the semiconductor device manufacturing methods described above. It is characterized in that steps are set up for this purpose.

  According to the present invention, since the resist film is irradiated with an electron beam having an energy that does not give etching resistance to the antireflection film while ensuring the etching resistance of the resist film, the etching resistance of the resist film is improved. Etching defects can be suppressed. In addition, after the electron beam irradiation, the antireflection film and the etching target film can be continuously etched, and a decrease in throughput due to the addition of a pre-process of electron beam irradiation can be suppressed.

  Embodiments of a semiconductor manufacturing apparatus for carrying out the semiconductor device manufacturing method of the present invention will be described below. FIG. 1 shows the overall configuration of a semiconductor manufacturing apparatus 1 called a so-called multi-chamber system. This semiconductor manufacturing apparatus 1 includes a load port 11 into which a carrier C storing a predetermined number of wafers W, which are substrates to be processed, and an atmosphere. A loader module 12 for transferring the wafer W under an atmosphere, a load lock chamber 13 for switching the room between a normal pressure atmosphere and a vacuum atmosphere to wait for the wafer W, and a vacuum transfer chamber for transferring the wafer W under a vacuum atmosphere A transfer module 14 and, for example, four processing modules 2, 3 a to 3 c for performing process processing on the loaded wafer W. Here, the processing module 2 is an electron beam irradiation module 2 for improving the etching resistance of the resist film formed on the surface of the wafer W, and the processing modules 3a to 3c are etching modules 3a to 3c. The devices in the semiconductor manufacturing apparatus 1 are arranged in the order of the load port 11, the loader module 12, the load lock chamber 13, the transfer module 14, and the processing modules 2, 3 a to 3 c in the wafer W loading direction. The matching devices are hermetically connected via the door 111 and the gate valves G1 to G3. The load lock chamber 13 described above constitutes a load lock module together with, for example, a vacuum pump and a pressure adjustment valve (not shown) for switching the atmosphere in the load lock chamber 13 between an air atmosphere and a vacuum atmosphere. . In the following description, the direction in which the load port 11 is installed will be described as the front side.

  The load port 11 is composed of three mounting tables arranged in front of the loader module 12, and serves to connect the carrier C transported from the outside and mounted on the load port 11 to the main body of the semiconductor manufacturing apparatus 1. Fulfill. Inside the semiconductor manufacturing apparatus 1, a first substrate transfer means 121 that is capable of rotating, expanding and contracting, raising and lowering and moving left and right is provided for taking out and transferring the wafers W from the carrier C one by one.

  The load lock chamber 13 is interposed between the loader module 12 and the transfer module 14 in a state where two load lock chambers 13 are arranged side by side when viewed from the front side. Each load lock chamber 13 includes a mounting table 131 on which the loaded wafer W is placed, and is connected to a vacuum pump and a leak valve (not shown) for switching each load lock chamber 13 between a normal pressure atmosphere and a vacuum atmosphere. Has been. The planar shape of the transfer module 14 is formed in, for example, an elongated hexagonal shape, and the two sides on the front side are connected to the load lock chamber 13 described above, and the processing modules 2, 3 a to 3 c are arranged on the two opposing long sides. Is connected. The transfer module 14 is provided with a second substrate transfer means 141 that can rotate and expand and contract to transfer the wafer W between the load lock chamber 13 and each of the processing modules 2, 3 a to 3 c in a vacuum atmosphere. In addition, a vacuum pump (not shown) is connected to keep the inside in a vacuum atmosphere.

  Next, the structure of the electron beam irradiation module 2 for improving the etching resistance of the resist film among the processing modules 2, 3a to 3c connected to the transfer module 14 will be described with reference to FIGS. The electron beam irradiation module 2 includes, for example, a processing container (first processing container) 21 configured as a vacuum chamber whose inside is a sealed space, a mounting table 22 fixed to the center of the bottom plate in the processing container 21, and a mounting table A single or a plurality of, for example, 19 electron tubes 23 provided so as to face the mounting table 22 are provided above 22.

  The processing vessel 21 is made of aluminum or the like, similar to the second processing vessel, and an exhaust port 211 provided in the bottom plate thereof is provided with a vacuum exhaust means 213 including, for example, a vacuum pump via an exhaust pipe 212. The inside of the processing container 21 can be maintained in a high vacuum state. In addition, an intake port 216 is provided at the upper part of the side surface of the processing container 21, and the intake port 216 is connected to an intake pipe 217 provided with a main valve 218 so as to introduce an inert gas into the processing container 21. By doing so, the pressure in the processing container 21 can be made comparable to that of the transfer module 14. In the figure, reference numeral 214 denotes a transfer port for loading and unloading the wafer W into and from the processing container 21, and reference numeral 215 denotes a gate valve for opening and closing the transfer port 214.

  The mounting table 22 is made of aluminum or the like, and plays a role of holding the wafer W with the surface of the wafer W facing the electron tube 23 described above. The mounting table 22 includes lifting pins (not shown), and the wafer W can be transferred between the second substrate transfer means 141 in the transfer module 14 and the mounting table 22 via the lifting pins.

  The electron tube 23 is configured as a known thermionic emission type electron gun having a cathode and an acceleration anode, for example, and an electron beam in which a predetermined acceleration voltage is applied to the surface of the wafer W placed on the placement table 22. It plays a role as an electron beam irradiation means for irradiating. For example, as shown in FIG. 3, the electron tube 23 can irradiate the entire surface of the wafer W (shown by a broken line in the drawing) placed on the mounting table 22 with the ceiling portion of the processing vessel 21. Are evenly installed in a circular area. The electron beam irradiating means is not limited to the electron tube 23 formed of the above-described thermionic emission type electron gun. For example, a field emission type electron gun may be used. It may be a neutralizing gun for irradiating with electrons.

  These electron tubes 23 are connected to a high-voltage DC acceleration power source 232 via a control box 231, and a high voltage is applied to each electron tube 23 from the acceleration power source 232 so that an electron beam is emitted. .

  Next, the remaining processing modules 3a to 3c, which are etching modules 3a to 3c, will be described with reference to the longitudinal sectional view of FIG. The semiconductor manufacturing apparatus 1 includes, for example, three etching modules 3a to 3c having the same performance in order to absorb a difference in processing time between an electron beam irradiation module 2 and an etching module 3a to 3c, which will be described later. . Since these three etching modules 3a to 3c have a common structure to each other, in FIG. 4, reference numeral “3”, which generally indicates them, is attached. The etching module 3 shown in FIG. 4 is configured as a well-known parallel plate type plasma etching module. For example, a processing container (second processing container) 31 configured as a vacuum chamber whose inside is a sealed space, and this processing A mounting table 32 fixed to the center of the bottom plate in the container 31 and an upper electrode 33 provided above the mounting table 32 so as to face the mounting table 32 are provided.

  The processing container 31 is made of aluminum or the like and is electrically grounded, and a vacuum exhaust means 313 including, for example, a vacuum pump is connected to an exhaust port 311 provided in the bottom plate of the processing container 31 via an exhaust pipe 312. It is connected. A transfer port 314 for the wafer W is provided on the side surface of the processing container 31, and the transfer port 314 can be opened and closed by a gate valve 315.

  The mounting table 32 includes a lower electrode 321 and a support body 322 that supports the lower electrode 321 from below. The support body 322 is disposed on the bottom surface of the processing container 31 via an insulating member 323. In the figure, reference numeral 324 denotes an electrostatic chuck for electrostatically adsorbing the wafer W onto the mounting table 32 by applying a high-voltage DC voltage, and reference numeral 325 is used to focus the plasma generated in the processing vessel 31 on the mounting table 32. The focus ring. Reference numeral 326 denotes a temperature control flow path for adjusting the temperature of the mounting table 32, and reference numeral 327 denotes a gas supply path for supplying a heat conductive gas such as He (helium) gas to the back surface of the wafer W as a backside gas. . The mounting table 32 includes lifting pins (not shown), and the wafer W can be transferred between the second substrate transfer means 141 in the transfer module 14 and the mounting table 32 via the lifting pins. It can be done.

The lower electrode 321 is connected to a bias applying high frequency power supply 301 having a frequency of, for example, 13.56 MHz via a matching unit 302 and grounded via a high pass filter (HPF) 303. On the other hand, the upper electrode 33 is formed in a hollow shape and constitutes a gas shower head provided with a large number of process gas supply holes 331. Further, a processing gas supply pipe 332 is provided at the center of the upper surface of the upper electrode 33, and the processing gas supply pipe 332 passes through the center of the upper surface of the processing container 31 through an insulating member 333. A processing gas supply unit 334 is connected upstream of the processing gas supply pipe 332, and various etching gases (for etching various films stacked on the wafer W by a valve or a flow rate control unit (not shown)). The supply amount of argon (Ar) gas for adjusting the concentration of CF ₄ , CO, CO ₂ ) and the etching gas, and O ₂ gas for ashing and the supply / disconnection of the gas can be controlled. .

  Further, the upper electrode 33 is connected to a high-frequency power source 335 for generating plasma of 60 MHz, for example, having a higher frequency than the high-frequency power source 301 on the lower electrode 321 side via a matching unit 336, and a low-pass filter (LPF) 337 is connected to the upper electrode 33. Is grounded.

  As shown in FIGS. 1 to 2 and 4, the main body of the semiconductor manufacturing apparatus 1 and the processing modules 2, 3 a to 3 c are connected to the control unit 4. The control unit 4 is composed of, for example, a computer including a CPU and a program (not shown). The program includes the operations of the semiconductor manufacturing apparatus 1 and the processing modules 2, 3a to 3c, that is, the load port 11 and the processing modules 2, 3a to 3c. Steps for controlling the sequence of transporting the wafer W to and from the wafer, adjusting the irradiation timing and irradiation time of the wafer W in the electron beam irradiation module 2, and controlling the etching sequence in the etching modules 3a to 3c ( Command) group, and plays a role of outputting control signals based on these steps to each of the substrate transfer means 121, 141 and the processing modules 2, 3a to 3c. This program is stored in a storage medium such as a hard disk, a compact disk, a magnetic optical disk, or a memory card, and installed in the computer therefrom.

  Next, a semiconductor device manufacturing process for etching the wafer W using the semiconductor manufacturing apparatus 1 having the configuration described above will be described with reference to FIG. FIG. 5 is a cross-sectional view showing how the semiconductor device is manufactured in stages in the manufacturing process of the semiconductor device. In the following description, etching for forming a gate pattern on the lower insulating film 92, the gate electrode film 93, and the upper insulating film 94 as the etching target film 902 laminated on the silicon substrate 91 which is the main body of the wafer W is performed. The process to be performed will be described.

  First, as shown in FIG. 1, when the carrier C storing the wafer W therein is placed on the load port 11 on the front surface of the semiconductor manufacturing apparatus 1, the wafer W is transferred from the carrier C by the first substrate transfer means 121. It is taken out, transported through the loader module 12, delivered to either the left or right load lock chamber 13 and waits. When the inside of the load lock chamber 13 becomes a vacuum atmosphere, it is taken out from the load lock chamber 13 by the second substrate transfer means 141 and carried into the transfer module 14 in a vacuum atmosphere.

At this time, on the wafer W, as shown in FIG. 5A, the bottom resist film 95 for reinforcing etching resistance is formed on the etching target film 902, and the incident light is reflected when the resist film is exposed. A photoresist film 97 in which an opening portion 971 corresponding to the gate pattern and a photoresist film 97 for preventing the above are stacked in this order from the lower side. Here, the photoresist film 97 applied to the surface of the wafer W according to the present embodiment is an ArF resist film used for exposure using an ArF excimer laser, for example, (—CH ₂ C (CH ₃ ) ( COOR)-) _n (R is a methacrylic polymer having a structural unit such as an adamantyl group or a lactone group). On the other hand, the antireflection film 96 and the bottom resist film 95 are made of, for example, an aromatic polymer having (—CH ₂ CHC ₆ H ₄ OH—) _n as a structural unit. Hereinafter, the laminated structure of the etching target film 902, the bottom resist film 95, the antireflection film 96, and the photoresist film 97 is referred to as a laminated body 901.

The wafer W having such a laminated structure is first carried into the electron beam irradiation module 2 in order to improve the etching resistance of the photoresist film 97. When the wafer W is mounted on the mounting table 22 shown in FIG. 2, the gate valve 215 and the main valve 218 are closed, and the inside of the processing container 21 is, for example, 133.2 × 10 ⁻³ Pa (1.0 × 10 ^−3). Torr) is set to a high vacuum state, and an electron beam is applied to, for example, the entire surface of the wafer W from each electron tube 23 under a condition where the acceleration voltage is in the range of 0.1 to 1.8 keV, for example, 1.5 keV. Irradiate for 1.0 × 10 ⁻⁹ seconds. At this time, as shown in FIG. 5B, the irradiated electron beam is applied to, for example, a photoresist film 97 applied to the surface of the wafer W, and the reflection is prevented through the opening 971 of the photoresist film 97. The film 96 is also irradiated. Further, the temperature of the wafer W at this time is about the same room temperature as when the wafer C is unloaded.

  Here, as described above, when the electron beam is irradiated to the photoresist film 97 made of the ArF resist composed of methacrylic polymer as a raw material, the plasma is applied to the photoresist film 97 as compared with the case where the irradiation is not performed. It has been confirmed that the etching rate (thickness reduction rate) when etching is performed, that is, the etching resistance of the photoresist film 97 is improved. The mechanism presumed about the reason why the etching resistance is improved by the electron beam irradiation will be briefly described. The energy of the electron beam is absorbed by the methacrylic polymer, so that the region where the electron beam is absorbed, particularly the photoresist film 97. In the vicinity of the surface of the polymer, protecting groups (such as adamantyl group and lactone group) in the polymer are eliminated from the polymer. As a result, an atom such as an oxygen atom bonded to the detached protecting group is radicalized, and the radicalized atom is bonded to other surrounding atoms, thereby forming a new crosslinked structure in the polymer. It is considered that the hardness in the vicinity of the surface of the photoresist film 97 is increased by increasing the cross-linked structure in the polymer in this way, and as a result, the etching resistance is improved.

  On the other hand, regarding the antireflection film 96 irradiated with the electron beam together with the photoresist film 97, the aromatic polymer constituting the antireflection film 96 has a rigid structure as compared with the methacrylic polymer. The degree of modification by irradiation was small, and further improvement in etching resistance could hardly be confirmed. From the above, as shown in FIG. 5 (b), when both the photoresist film 97 and the antireflection film 96 are irradiated with an electron beam, the etching resistance of the photoresist film 97 is improved and peeling during etching is caused. On the other hand, since the etching resistance of the antireflection film 96 is hardly changed, the etching can be performed under the same conditions as in the prior art.

The wafer W that has been processed in the electron beam irradiation module 2 in this way is subjected to the second substrate transfer means 141 that has entered from the transfer port 214 based on the transfer schedule, and one of the three etching modules 3a to 3c. It is carried in and placed on the mounting table 32 shown in FIG. Then, the transfer port 314 is closed, and in order to first etch the antireflection film 96, Ar gas is supplied from the processing gas supply unit 334 into the processing container 31, and CF ₄ gas is supplied at a flow rate in the range of, for example, 100 to 300 sccm. However, the pressure in the processing container 31 is maintained at a pressure of, for example, 10 Pa (75 mTorr) in the range of 6.7 to 13.3 Pa (50 to 100 mTorr). Then, a high frequency power in the range of 500 to 1000 W, for example, 750 W, for example, is applied to the upper electrode 33 and the lower electrode 321 to turn the supplied gas into plasma, and the antireflection film 96 is made to correspond to the pattern of the photoresist film 97. Etch.

  At this time, the photoresist film 97 and the antireflection film 96 are exposed to the plasma atmosphere under the same conditions. However, since the etching resistance of the photoresist film 97 is improved in the preceding electron beam irradiation step, etching is performed. It becomes difficult to be scraped off. On the other hand, since the antireflection film 96 has almost no change in etching resistance even when irradiated with an electron beam, it corresponds to the opening 971 of the photoresist film 97 at almost the same etching rate as in the conventional case where no electron beam is irradiated. The part is scraped off.

After the antireflection film 96 is thus etched and a predetermined time has elapsed, the application of the high frequency power and the supply of gas are stopped to evacuate the processing container 31, and the bottom resist film 95 is subjected to CO gas and CO _2. For the gas, the upper insulating film 94, the gate electrode film 93, and the lower insulating film 92, the CF ₄ gas and the processing gas supplied to the processing vessel 31 are sequentially switched, and these processing gases are suitable for each of 92 to 95. Then, the film is turned into plasma, and the films 92 to 94 are etched. As a result, holes 903 are formed in the stacked body 901 as shown in FIG.

After forming the hole 903 through the steps described above, ashing is subsequently performed in the etching module 3. This ashing step is performed, for example, by supplying O ₂ gas from the processing gas supply unit 334 into the processing container 31 and applying high frequency power to the upper electrode 33 to generate plasma. Then, the plasma removes the photoresist film 97, the antireflection film 96, and the bottom resist film 95 shown in FIG. 5C by ashing, and the etched film 902 corresponds to the gate pattern as shown in FIG. 5D. Hole 903 is formed.

  The wafer W on which the gate pattern has been formed is transferred to the load lock chamber 13 and the loader module 12 by the second substrate transfer means 141 via the transfer module 14 via the transfer module 14 and transferred to the carrier CA again. Stored.

  The embodiment described above has the following effects. Since the surface of the wafer W is irradiated with an electron beam and the acceleration voltage is selected so as not to exhibit resistance to the antireflection film 96, the etching resistance of the photoresist film 97 is selectively improved. Can do. Therefore, the antireflection film 96 and the etching target film 902 can be continuously etched, and etching failure due to the removal of the photoresist film 97 serving as a mask can be prevented. In addition, the resist film for ArF which can improve etching tolerance by electron beam irradiation is not limited to the methacrylic polymer illustrated in the embodiment, for example, cycloolefin polymer or different kinds of ArF polymers Even if it has a structure in which two or more layers are laminated, the same effect can be obtained. In addition, for example, KrF excimer laser compatible KrF resist, EUV (Extreme Ultraviolet: wavelength 13.5 nm) EUV resist, or EB (Electron Beam) exposure EB resist etching is used. It can also be applied to improve tolerance. In the case of the resist for EB, for example, the acceleration voltage of the electron beam irradiated to the resist for EB in the EB exposure apparatus is, for example, several tens keV, while the acceleration voltage of the semiconductor manufacturing apparatus according to the present invention is, for example, 0. Applicable when the amount of energy irradiated to the resist is different between the time of exposure and the process of improving the etching resistance, such as about 1 to 1.8 keV, and the solubility of the resist in the etching solution changes due to this difference. can do.

  In addition, the electron beam irradiation module 2 is incorporated as one of the processing modules of the multi-chamber system, and the etching resistance of the resist film 97 is improved by the electron beam irradiation module 2, and then the etching module 3a without breaking the vacuum atmosphere. The stacked body 901 including the antireflection film 96 and the etching target film 902 is etched at a stroke. Therefore, defects such as striations during etching can be suppressed, and the etching process can be performed at a high throughput while adding a pre-process of electron beam irradiation. Further, when the multi-layer resist in which a lower resist film called a bottom resist film 95 is disposed under the photoresist film 97 and the antireflection film 96 is applied to etch the etching target film 902, the antireflection film 96 is etched and then the electrons are etched. Irradiation with an electron beam before the etching of the antireflection film 96 is effective because the etching resistance of the bottom resist film 95 is improved notably when the irradiation with the beam is performed.

  Note that although the case where a gate pattern is formed in the film to be etched 902 has been described as an example in this embodiment mode, processing that can be performed in the semiconductor manufacturing apparatus 1 is limited to formation of a gate pattern. It is not a thing. For example, the semiconductor manufacturing apparatus 1 of the present invention can be applied to etching for forming a contact hole in an insulating film, etching for forming a trench for wiring, and the like.

  Further, the control box 231 has a function of adjusting the irradiation amount of the electron beam applied to a specific area on the wafer W, and the degree to which the etching resistance of the photoresist film 97 is improved by using this function is adjusted. It may be changed within. For example, when the photoresist film 97 is thin only in a specific region in the wafer W surface or the plasma density is high only in a specific region in the etching modules 3a to 3c, the etching resistance of the photoresist film 97 is uniform. Even if it is improved, etching failure may occur only in that region. Further, if the irradiation amount of the electron beam to the entire wafer W is increased so as not to cause such a defect, unnecessary energy is consumed in a region where no etching defect occurs.

  Therefore, in the electron beam irradiation module 2 according to the present embodiment, the timing for turning off the electron tube 23 is delayed in the region where such an etching defect occurs, and the electron beam irradiation time is lengthened, compared with other regions. You may increase the irradiation amount of an electron beam. As a result, the etching resistance of the photoresist film 97 in this region is improved as compared with other regions, and a state in which etching failure is likely to occur due to a thin photoresist film 97 or a high etching rate is suppressed.

  The irradiation conditions such as the region where the irradiation amount is changed and the irradiation amount are determined by, for example, which coating apparatus is used to apply the photoresist film 97 to the wafer W in the electron beam irradiation module 2 or the electron beam irradiation module 2. After finishing the processing in step (1), it may be determined on the basis of information such as which etching module 3a to 3c is used for etching, based on the device characteristics of these coating devices and etching modules 3a to 3c. The device characteristics include, for example, the in-plane distribution of the film thickness of the photoresist film 97 in each coating apparatus, the in-plane distribution of the etching rates of the etching modules 3a to 3c, and the like. It is preferable to set such that a state in which etching defects are likely to occur is suppressed by increasing the amount of electron beam irradiation in a fast region. Such electron beam irradiation conditions may be stored in advance in, for example, a storage unit in the control unit 4 so as to correspond to the former coating apparatus and the subsequent etching modules 3a to 3c. As a result, the energy consumption can be reduced as compared with the case where the electron beam irradiation amount on the entire wafer W surface is increased. As a method of adjusting the electron beam irradiation amount, for example, the control box 231 has a function of adjusting the ON / OFF timing of each electron tube 23, and the interval between ON and OFF of a specific electron tube 23 is increased. It is conceivable to increase or decrease the amount (irradiation amount) of the electron beam irradiated to a specific region by shortening it.

  Further, the method of irradiating the wafer W with the electron beam is not limited to the case where a large number of electron tubes 23 are provided in the electron beam irradiation module 2 as shown in FIG. For example, one electron tube 23 configured to be movable in the horizontal direction is installed so as to face the wafer W, and the entire surface of the wafer W is scanned by irradiating the surface of the W with an electron beam while moving the electron tube 23. You may comprise.

  Next, a semiconductor manufacturing apparatus 1a according to a second embodiment will be described. As shown in FIG. 6, the semiconductor manufacturing apparatus 1 a according to the second embodiment has a function as the electron beam irradiation module 2 a on one side of the load lock chamber 13 that waits for the wafer W carried into the transfer module 14. This is different from the first embodiment in which the electron beam irradiation module 2 is configured as one of the processing modules in that the processing container 21 of the electron beam irradiation module 2a is also used as the load lock chamber 13. .

  The electron beam irradiation module 2a according to the second embodiment has substantially the same configuration as the electron beam irradiation module 2 according to the first embodiment as shown in FIG. In order to fulfill the functions of the electron beam according to the first embodiment, the transport port 214 communicates with the loader module 12 and the transfer module 14 respectively, and the transport ports 214 are opened and closed by the gate valves G1 and G2, respectively. Different from the irradiation module 2.

  As an operation of irradiating the wafer W with the electron beam by the electron beam irradiation module 2a, for example, after the wafer W is carried into the load lock chamber 13 from the loader module 12, the chamber is placed in a vacuum atmosphere where the electron beam irradiation can be performed. The atmosphere is switched and the wafer W is irradiated with an electron beam from each electron tube 23. After that, the inside of the load lock chamber 13 is readjusted to a vacuum atmosphere similar to that of the transfer module 14, and then the wafer W is transferred to the transfer module 14. Etching is performed in each of the etching modules 3a to 3d. As shown in FIG. 6, when the function of the electron beam irradiation module 2a is provided on one side of the two load lock chambers 13, the load lock chamber 13 is loaded into the transfer module 14. For example, an operation method in which the load lock chamber 13 having no other electron beam irradiation function is used for carrying out the wafer W can be considered.

  In the first and second embodiments described above, the example in which the electron beam irradiation modules 2 and 2a are incorporated in the semiconductor manufacturing apparatuses 1 and 1a adopting the multi-chamber system has been described, but the semiconductor according to the present invention. The semiconductor manufacturing apparatus to which the irradiation module can be applied is not limited to the multi-chamber system. For example, a semiconductor manufacturing apparatus of a type in which an electron beam irradiation module is directly connected to a stand-alone type etching apparatus is also included in the present invention.

[Experiment 1]
In order to confirm the influence of the electron beam irradiation on the mask pattern on the photoresist film 97, the line width of the mask pattern before and after the electron beam irradiation to the photoresist film 97 on which the mask pattern was formed was measured. In the experiment, an antireflection film 96 and a photoresist film 97 made of methacrylic polymer are stacked on the surface of a silicon wafer W covered with a thermal oxide film and a polysilicon film, and a trench having a line width of 65 nm is formed in the photoresist film 97. After that, the surface of the wafer W was irradiated with an electron beam while changing the acceleration voltage. The width of the trench before and after the electron beam irradiation was measured by an ACD-SEM (Average Critical Dimension-Scanning Electron Microscope) with an acceleration voltage of 0.5 keV and a current of 5 pA.
(Example)
The acceleration voltage is changed to 0.2, 0.25, 0.3, 0.5, 0.8, 1.0, 1.2, 1.5, and 1.8 keV, and the surface of the wafer W is irradiated with an electron beam. did. The electron beam was irradiated by a scanning method, and the number of scans was one.
(Reference example)
No electron beam irradiation was performed.

  FIG. 8 shows the result of the experiment. The horizontal axis of FIG. 8 represents the acceleration voltage [keV] of the electron beam, and the vertical axis represents a value expressed as a percentage (hereinafter referred to as normalized CD) of the change rate of the trench line width with respect to the original line width measured after the electron beam irradiation. ) [%]. In FIG. 8, black circle plots are examples, and white circle plots are reference examples. The line width of the trench was measured twice before and after the electron beam irradiation, and in the case of the reference example (acceleration voltage 0 keV), the electron beam irradiation was not performed, and the line width was measured twice continuously. The normalized CD was calculated based on the second measurement result. The broken line in the figure indicates the normalized CD of the reference example, and the alternate long and short dash line indicates a range of plus or minus 1% from the normalized CD of the reference example.

  According to the result shown in FIG. 8, in the example in which the electron beam having an acceleration voltage of 0.1 to 1.8 keV is irradiated, the line width of the trench is reduced by about 1.0 to 2.5%. On the other hand, even in the reference example in which the electron beam was not irradiated, the line width of the trench is slightly reduced by 2%. This is because, after the line width of the trench is reduced due to the influence of the electron beam with the acceleration voltage of 0.5 keV when the line width is measured by the first ACD-SEM, regardless of the presence or absence of the electron beam irradiation, After that, even if the electron beam is irradiated in the range of the acceleration voltage of 0.1 to 1.8 keV, it means that the line width of the trench is affected only about plus or minus 1%. That is, the influence on the mask pattern by irradiating the electron beam in the range of the acceleration voltage of 0.1 to 1.8 keV is the influence of the conventional measurement of the line width of the mask pattern using the ACD-SEM. It can be said that there is almost no change. In addition, in the result of irradiating the electron beam of 0.8 keV, the shrinkage of the line width exceeding plus or minus 1% was observed, which is considered to be due to the influence of the measurement error.

[Experiment 2]
In order to confirm the effect of improving the etching resistance by irradiating the photoresist film 97 with the electron beam, the etching rate of the photoresist film 97 was measured when the photoresist film 97 was irradiated with the electron beam and when it was not irradiated. . In the experiment, a silicon wafer W in which a photoresist film 97 (without a mask pattern) made of methacrylic polymer was laminated on the antireflection film 96 was used. Etching of the photoresist film 97 was performed by supplying 200 sccm of CF ₄ gas into the processing vessel 31 and applying a high frequency voltage of 750 W to the upper electrode 33 and the lower electrode 321, respectively.
(Example)
The wafer W was irradiated with an electron beam having an acceleration voltage of 1.5 keV by a scanning method, and scanning was performed 16 times.
(Reference example)
No electron beam irradiation was performed.

  FIG. 9 shows the result of the experiment. The horizontal axis in FIG. 9 indicates the etching depth (nm), and the vertical axis indicates the etching rate (nm / min) at the etching depth. In FIG. 9, black circle plots are examples, and white circle plots are reference examples.

  According to the results shown in FIG. 9, in the example irradiated with the electron beam, etching was performed in the region near the surface of the photoresist film 97 having an etching depth of up to 30 nm as compared with the reference example not irradiated with the electron beam. The rate is lowered, and the etching resistance of the photoresist film 97 is improved. This is considered to be due to the fact that the protective group in the polymer is detached from the polymer in the region near the surface of the photoresist film 97 where the electron beam is absorbed, and a new crosslinked structure is formed. This is because the polymer structure of the photoresist film 97 according to the example was analyzed separately in the depth direction by TOF-SIMS (Time-of-Flight Secondary Ion Mass Spectrometry) or FTIR (Fourier transform infrared spectroscopy). This is also supported by the fact that the protective groups are reduced in the depth region of 30 nm from the surface of the film 97, that is, in the region where the etching rate is reduced. The antireflection film 96 had almost the same etching rate in both the examples and the reference examples.

It is a top view of the substrate processing apparatus concerning an embodiment. It is a longitudinal cross-sectional view of the electron beam irradiation module mounted in the said substrate processing apparatus. It is a top view which shows the arrangement | positioning state of the electron tube mounted in the said electron beam irradiation module. It is an etching module longitudinal cross-sectional view mounted in the said substrate processing apparatus. It is explanatory drawing of the manufacturing process of the semiconductor device which concerns on embodiment. It is a top view of the substrate processing apparatus concerning a 2nd embodiment. It is a longitudinal cross-sectional view of the electron beam irradiation module which concerns on the said 2nd Embodiment. It is the characteristic view which showed the influence which irradiation of the electron beam to a photoresist film has on the line width of a mask pattern. It is the characteristic view which showed the influence which irradiation of the electron beam to a photoresist film has on the etching rate of the said photoresist film.

Explanation of symbols

W Wafer 1, 1a
Semiconductor manufacturing apparatus 11 Load port 12 Loader module 13 Load lock chamber 14 Transfer module 141 Second substrate transfer means 2, 2a
Electron beam irradiation module 21 Processing container 22 Mounting table 23 Electron tube 231 Control box 232 Acceleration power supply 3, 3 a to 3 d
Etching module 31 Processing vessel 32 Mounting table 33 Upper electrode 321 Lower electrode 4 Control unit 91 Silicon substrate 92 Lower insulating film 93 Gate electrode film 94 Upper insulating film 95 Bottom resist film 96 Antireflection film 97 Photoresist film 901 Laminate 902 Covered Etching film 903 hole 971 opening

Claims (11)

A step of carrying a substrate to be processed comprising a laminate in which a pattern mask made of a resist film, an antireflection film and an etching target film are stacked in this order from above into an airtight first processing container;
In the first processing container, an electron beam is applied to the surface of the substrate to be processed with energy sufficient to improve the etching resistance of the resist film in a vacuum atmosphere but not to provide etching resistance to the antireflection film. Irradiating with,
Thereafter, the substrate to be processed is transferred from the first processing container into an airtight second processing container, and the antireflection film is formed in the second processing container through a pattern mask made of the resist film. And a step of etching the film to be etched.   The method of manufacturing a semiconductor device according to claim 1, wherein the electron beam is irradiated from an electron gun or a neutralizing gun.   3. The semiconductor according to claim 1, wherein the resist film is selected from a resist film group consisting of an ArF resist film, a KrF resist film, an EUV resist film, and an EB resist film. Device manufacturing method.   4. The method of manufacturing a semiconductor device according to claim 3, wherein an acceleration voltage for accelerating the electron beam applied to the resist film is in a range of 0.1 keV to 1.8 keV.   The method of manufacturing a semiconductor device according to claim 1, wherein the antireflection film is an aromatic polymer. In a semiconductor manufacturing apparatus that processes a substrate to be processed in which a resist film, an antireflection film, and an etching target film constituting a pattern mask are stacked in this order from above.
A substrate transfer means is provided, and a vacuum transfer chamber for transferring a substrate to be processed in a vacuum atmosphere;
Etching resistance of the resist film is improved with respect to the processing container that is hermetically connected to the vacuum transfer chamber and provided with a mounting table on which the processing substrate is mounted, and the processing substrate mounted on the mounting table. An electron beam irradiation module that irradiates an electron beam with energy that does not give etching resistance to the antireflection film, and
A processing vessel that is airtightly connected to the vacuum transfer chamber and provided with a mounting table on which the substrate to be processed is mounted, and means for etching the processing substrate mounted on the mounting table by plasma with plasma An etching module comprising:
The substrate to be processed irradiated with the electron beam by the electron beam irradiation module is carried into the etching module through the substrate transfer means, and the antireflection film and the etching target on the substrate to be processed are etched by the etching module. And a control unit that outputs a control signal so as to etch the film with plasma. A load lock chamber into which the substrate to be processed is once transferred when the substrate to be processed is transferred between the air atmosphere and the vacuum transfer chamber, and means for switching the atmosphere in the load lock chamber between the air atmosphere and the vacuum atmosphere And a load lock module provided with,
The semiconductor manufacturing apparatus according to claim 6, wherein a processing container of the electron beam irradiation module also serves as the load lock chamber.   8. The semiconductor according to claim 6, wherein the resist film is selected from a resist film group consisting of an ArF resist film, a KrF resist film, an EUV resist film, and an EB resist film. Manufacturing equipment.   9. The semiconductor manufacturing apparatus according to claim 8, wherein an acceleration voltage of the electron beam applied to the resist film by the electron beam irradiation means is in a range of 0.1 keV to 1.8 keV.   10. The semiconductor manufacturing apparatus according to claim 6, wherein the antireflection film is an aromatic polymer. A storage medium for storing a program used in a semiconductor manufacturing apparatus and operating on a computer,
A storage medium comprising steps for executing the method of manufacturing a semiconductor device according to any one of claims 1 to 5.

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