Apparatus for processing substrate and method for measuring temperature and concentration of processing gas

Abstract

To provide a technique for measuring the temperature and concentration of processing gas supplied to a processing space of substrate processing with the use of a laser beam.SOLUTION: A processing gas supply part arranged in a device to process a substrate supplies processing gas to a processing space. A light projection part projects a laser beam whose wavelength is changed within mutually different wavelength ranges with respect to the processing space to which the processing gas has been supplied. A light reception part receives the laser beam that has passed the processing space. A temperature calculation section calculates the temperature of the processing gas based on an absorption spectrum of the laser beam within each one of the wavelength ranges. A concentration calculation section calculates the concentration of the processing gas based on an absorbance of the laser beam of the specified wavelength within the wavelength range.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to an apparatus for processing a substrate and a method for measuring the temperature and concentration of a processing gas. [Background technology]

[0002] For example, some devices for processing a semiconductor wafer (hereinafter also referred to as a "wafer"), which is a substrate, perform processing by supplying a processing gas to a processing space in which the wafer is placed. The temperature and concentration of the processing gas supplied to the processing space are important measurement items for controlling and designing the processing of the wafer.

[0003] For example, Patent Document 1 describes a technique for measuring the concentration of a gas supplied to a semiconductor manufacturing device based on the results of irradiating the gas flowing through a gas flow passage with two types of light with different wavelengths. Patent Document 2 describes a technique for measuring the concentration of a material gas supplied to a substrate holding chamber of a film forming device using an optical detection device. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2016 / 080532 [Patent Document 2] JP 2012-122101 A Summary of the Invention [Problem to be solved by the invention]

[0005] The present disclosure provides a technique for using laser light to measure the temperature and concentration of a process gas supplied to a processing space in which substrate processing takes place. [Means for solving the problem]

[0006] The present disclosure provides an apparatus for processing a substrate, comprising: a processing vessel that accommodates the substrate and defines a processing space in which the processing is performed; a processing gas supply unit that supplies a processing gas to the processing space for processing the substrate or processing an apparatus disposed in the processing vessel; a light projection unit that projects a laser light into the processing space to which the processing gas is supplied; a light source unit that supplies, via an optical waveguide, a laser beam whose wavelength changes within a first wavelength range that is a preset wavelength range, and a laser beam whose wavelength changes within a second wavelength range different from the first wavelength range, to the light projection unit; a light receiving unit that receives the laser light that has passed through the processing space; a temperature calculation unit that calculates a temperature of the process gas based on an absorption spectrum of the laser light in the first wavelength range received by the light receiving unit and an absorption spectrum of the laser light in the second wavelength range; a concentration calculation unit that calculates a concentration of the process gas based on the absorbance of laser light of a specific wavelength within the first wavelength range or the second wavelength range. 、 a gas shower head having a surface facing the substrate and a gas supply port formed in the surface for supplying the processing gas to the processing space, the gas shower head having a surface facing the substrate and a gas supply port formed in the surface for supplying the processing gas to the processing space, the light-projecting unit and the light-receiving unit are disposed on the mounting table such that the laser light projected from the light-projecting unit is reflected by the opposing surface and then received by the light-receiving unit. It is a device. Effect of the Invention

[0007] According to the present disclosure, a laser beam can be used to measure the temperature and concentration of a process gas supplied to a processing space in which a substrate is processed. [Brief description of the drawings]

[0008] [Figure 1] 1 is a vertical sectional side view of a wafer processing apparatus according to the present disclosure; [Diagram 2] 2 is a schematic diagram of a mounting table and a gas shower head provided in the wafer processing apparatus. FIG. [Figure 3A] FIG. 2 is a plan view showing a first layout example of a light projector and receiver set. [Figure 3B] FIG. 13 is a plan view showing a second layout example of a light projector and light receiver set. [Figure 4] FIG. 2 is an enlarged schematic view of a mounting table on which a reflecting portion is provided. [Diagram 5] FIG. 13 is a vertical sectional side view of a wafer processing apparatus according to another configuration example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, a configuration example of an apparatus for processing a substrate (wafer processing apparatus 1) according to an embodiment of the present disclosure will be described with reference to FIGS. The wafer processing apparatus 1 of this embodiment is configured as an apparatus that supplies a processing gas in the form of plasma to the upper surface of a wafer W, which is a substrate, to perform a film forming process.

[0010] 1, the wafer processing apparatus 1 includes a cylindrical container body 11 made of a conductive material, for example, aluminum whose inner wall surface is anodized, and the container body 11 is electrically grounded. An opening is formed in the upper surface of the container body 11, and the opening is airtightly closed by a top plate portion 12. The container body 11 and the top plate portion 12 constitute a processing container 10 for accommodating a wafer W. The internal space of the processing container 10 serves as a processing space 100 for the wafer W. Further, a side wall of the processing vessel 10 is provided with a load / unload port 101 for loading / unloading the wafer W and a gate valve 102 for opening / closing the load / unload port 101 .

[0011] A mounting table 2 for mounting a wafer W thereon is provided at the lower side of the processing space 100 so as to face the above-mentioned top plate portion 12. The mounting table 2 includes a mounting table main body 21 made of a conductive metal material, for example, aluminum whose surface is anodized. A heating unit (not shown) made of a resistance heating element or the like is provided inside the mounting table 2.

[0012] An electrostatic chuck 22, which is formed by disposing a chuck electrode (not shown) in a ceramic layer, is provided on the upper surface of the mounting table main body 21. The electrostatic chuck 22 can switch between attracting and holding the wafer W and releasing it by supplying and cutting off power from a DC power supply (not shown). The mounting table main body 21 is housed in a cover part 24 made of an insulating material, and is installed on the bottom surface of the container main body 11 via the cover part 24.

[0013] The mounting table 2 also has three or more lift pins 23 for transferring the wafer W to and from an external substrate transfer mechanism (not shown) that has entered the processing space 100 via the load / unload port 101. These lift pins 23 serve to lift and transfer the wafer W between an adsorption / holding position on the electrostatic chuck 22 and a transfer position above the adsorption / holding position. Each lift pin 23 is provided so as to vertically penetrate the mounting table main body 21 and the bottom plate of the container main body 11, and the lower ends of these lift pins 23 are connected to a common lift plate 211 provided outside the container main body 11.

[0014] The lift plate 211 is further connected to a drive unit 212, which is used to raise and lower the lift plate 211 and protrude and retract the upper ends of the lift pins 23 from the electrostatic chuck 22. This operation lifts and transports the wafer W between the suction-holding position and the transfer position. Note that bellows 213 are provided between the lift plate 211 and the bottom plate of the vessel body 11, through which the lift pins 23 penetrate, to keep the vessel body 11 (processing space 100) airtight.

[0015] A first high frequency power supply 232 is connected to each mounting table 2 via a matching box 231. High frequency power is supplied to the mounting table 2 from the first high frequency power supply 232 via the matching box 231. As a result, the processing gas supplied into the processing space 100 is turned into plasma by capacitive coupling with a shower head 31 (described later), and a desired film formation process can be performed.

[0016] The means for generating plasma from the processing gas is not limited to a parallel plate type using capacitive coupling. For example, plasma may be generated using an inductively coupled antenna, or plasma may be generated by supplying microwaves from a microwave antenna to the processing gas.

[0017] Furthermore, a second high frequency power supply 222 is connected to the mounting table 2 via a matching box 221. The second high frequency power supply 222 applies a high frequency bias power to the mounting table 2. A self-bias generated by the high frequency bias power can attract ions in the plasma generated in the processing space 100 to the wafer W.

[0018] 1, an exhaust port 103 is formed on the bottom surface of the vessel body 11, and a vacuum exhaust unit 13 including a vacuum pump and the like is connected to the exhaust port 103. The inside of the processing space 100 is evacuated by the vacuum exhaust unit 13 until a pressure required for processing is reached. Furthermore, in order to ensure that the gas supplied into the processing space 100 flows uniformly in the circumferential direction of the mounting table 2, a flow straightening plate 104 having a large number of small holes may be disposed between the side peripheral surface of the mounting table 2 (cover part 24) and the inner wall surface of the vessel body 11.

[0019] 1, a shower head 31 for supplying a processing gas into the processing space 100 is provided on the lower surface side of the top plate 12. A flat diffusion space 311 capable of supplying a processing gas or the like toward the entire surface of the wafer W attracted and held by the electrostatic chuck 22 is formed in the shower head 31. A large number of gas supply ports 312 are formed on the lower surface side of the shower head 31, and the gas diffused into the diffusion space 311 is dispersed and supplied toward the processing space 100 via these gas supply ports 312.

[0020] A gas supply line 32 communicating with the diffusion space 311 is connected to the upper surface of the shower head 31. An adjustment unit 321 having an opening / closing valve and a flow rate adjustment mechanism (neither of which are shown) for cutting off the supply of processing gas and adjusting the flow rate, and a processing gas source 322 storing a raw material gas are provided upstream of the gas supply line 32. The shower head 31, the gas supply line 32, the adjustment unit 321, and the processing gas source 322 correspond to the processing gas supply unit in this example.

[0021] The film formation process performed in the wafer processing apparatus 1 may be plasma CVD (Chemical Vapor Deposition). In the plasma CVD, a raw material gas and a reactive gas, which are processing gases for the film formation process, are continuously supplied to the processing space 100, and these gases are activated by plasma to form a film on the wafer W. Alternatively, a film may be formed by plasma ALD (Atomic Layer Deposition). In plasma ALD, in the processing space 100, adsorption of a source gas onto the wafer W and reaction of the adsorbed source gas with, for example, a reactive gas activated by plasma are alternately repeated to deposit a layer of a film material on the wafer W. In the case of ALD, a plurality of control systems 321 and a processing gas source 322 for supplying source gas, reactive gas, and purge gas are connected to the shower head 31.

[0022] 1, the wafer processing apparatus 1 is further provided with a control unit 6. The control unit 6 is made up of a computer equipped with a CPU (Central Processing Unit) and a storage unit (not shown), and the storage unit stores a program including a group of steps (commands) for evacuating the processing space 100 in which the wafer W is placed, applying high-frequency power to the mounting table 2 to turn the processing gas into plasma, and outputting a control signal for processing the wafer W. The program is stored in a storage medium, such as a hard disk, a compact disk, a magnet optical disk, or a memory card, and is installed from there into the storage unit.

[0023] Furthermore, the wafer processing apparatus 1 according to this embodiment includes a mechanism for measuring the temperature and concentration of the processing gas supplied from the processing gas supply unit to the processing space 100 . The concentration is measured by a known spectrophotometric analysis, which involves irradiating the processing space 100 to which the processing gas is supplied with light of a wavelength that is absorbed by the processing gas, and determining the concentration of the processing gas based on the ratio between the intensity of the incident light and the intensity of the light that has passed through the processing space 100.

[0024] In addition, in the wafer processing apparatus 1 of this embodiment, the absorbance of light irradiated to the processing gas is used for temperature measurement as well as concentration measurement. Some gases have multiple absorption wavelengths. In addition, real gases exhibit an absorption spectrum in which the absorbance is greatest at an absorption wavelength, and the absorbance gradually decreases in the wavelength range around that wavelength as the wavelength moves away from the absorption wavelength. It is known that there is a correspondence between the area ratio or peak intensity ratio of the two absorption spectra and the temperature of the gas, and gas temperature measurement techniques utilizing this relationship have also been proposed (e.g., JP 2000-74830, JP 2020-6724).

[0025] The wafer processing apparatus 1 of this embodiment calculates the temperature and concentration of the process gas based on an absorption spectrum obtained by irradiating a laser beam in a predetermined wavelength range onto the processing space 100 to which the process gas is supplied. In order to perform these temperature and concentration measurements, as shown in FIG. 2, the wafer processing apparatus 1 is equipped with a light-projecting unit 41 that projects laser light into the processing space 100, a light source unit 43 that supplies laser light to the light-projecting unit 41, and a light-receiving unit 42 that receives the laser light that has passed through the processing space 100.

[0026] The light projecting unit 41 includes a light projecting lens 411 from which a laser beam is projected, and an optical fiber 400 which is an optical waveguide that supplies the laser beam to the light projecting lens 411. As shown in Fig. 1 and Fig. 2, in the wafer processing apparatus 1 of this example, the light projecting lens 411 is provided on a mounting table 2 in a processing vessel 10. In addition, a plurality of light projecting lenses 411 are provided on the mounting table 2.

[0027] Each of the projector lenses 411 is disposed in a direction to project laser light from the upper surface side of the mounting table 2 toward the opposing surface 310 of the shower head 31 disposed opposite the upper surface. In order to prevent the projector lenses 411 from being contaminated by the process gas, a cover made of a material that transmits laser light may be provided on the upper surface side of the projector lenses 411. The planar arrangement of the multiple projector lenses 411 will be described later.

[0028] Each of the light projecting lenses 411 is connected to a common changeover switch 412 via an optical fiber 400. The changeover switch 412 plays a role in switching the light projecting lens 411 to which the laser light supplied from the light source unit 43 is to be supplied.

[0029] The light source unit 43 includes a first semiconductor laser device 431 , a second semiconductor laser device 432 , and a coupler 433 . The first and second semiconductor laser devices 431 and 432 generate laser light of a desired wavelength using a semiconductor diode. The first semiconductor laser device 431 can change the wavelength of the laser light within a preset wavelength range (first wavelength range) around the central wavelength, which is the absorption wavelength λ1 of the process gas. Similarly, the second semiconductor laser device 432 can change the wavelength of the laser light within a preset wavelength range (second wavelength range) around the central wavelength, which is the absorption wavelength λ2 different from the above-mentioned absorption wavelength λ1.

[0030] There is no particular limitation on the setting of the absorption wavelengths λ1 and λ2. Laser light having a wavelength in the range of invisible light such as infrared light or ultraviolet light may be used, or laser light having a wavelength in the range of visible light may be used.

[0031] The first wavelength range and the second wavelength range are set so as to include a region in which the absorbance at both ends of each absorption spectrum is sufficiently small and reaches the baseline of the absorbance in the process gas. In addition, when determining the absorption spectrum, the first and second semiconductor laser devices 431, 432 may be configured to output reference light indicating the intensity of laser light with zero absorbance or laser light used as an etalon signal for a filter toward the main body 426 of the photometric measurement device described later.

[0032] The laser beams supplied from the first and second semiconductor laser devices 431 and 432 are coupled by a coupler 433 , and then input to a changeover switch 412 via an optical fiber 400 , and supplied to a selected light projecting lens 411 .

[0033] Next, the light receiving unit 42 includes a light receiving lens 421 on which the laser light is incident, and an optical fiber 400 that guides the laser light received via the light receiving lens 421. As shown in Fig. 1 and Fig. 2, in the wafer processing apparatus 1 of this example, the light receiving lenses 421 are also provided on the mounting table 2, similarly to the light projecting lenses 411. In addition, the mounting table 2 is provided with the same number of light receiving lenses 421 as the light projecting lenses 411.

[0034] Each light-receiving lens 421 is disposed in a direction to receive the laser light reflected by the opposing surface 310 of the shower head 31. As in the case of the light-projecting lens 411, a cover made of a material that transmits laser light may be provided on the upper surface of the light-receiving lens 421. The planar arrangement of the multiple light-receiving lenses 421 will be described later. In Figs. 1 to 3A and 3B, the light-receiving lenses 421 are indicated with a gray tone.

[0035] Each light receiving lens 421 is connected to a common changeover switch 422 via an optical fiber 400. The changeover switch 422 plays a role in switching the light receiving lens 421 from which the laser light is to be extracted.

[0036] The same number of projector lenses 411 and receiver lenses 421 provided on the mounting table 2 are associated with each other via the optical path L of the laser light, constituting a projector / receiver set 40. That is, the projector lenses 411 and receiver lenses 421 constituting the common projector / receiver set 40 are arranged to be located at one end and the other end of the optical path L of the laser light. With this configuration, the laser light projected from the selected projector lens 411 can be reflected by the opposing surface 310 of the showerhead 31, and then received by the receiver lens 421 associated with the projector lens 411. Here, the shower head 31 may be made of metal or the surface of the ceramic shower head 31 may be coated with silicon so that the facing surface 310 can reflect the laser light.

[0037] By providing these multiple light emitter / receiver sets 40 at different positions on the mounting table 2, the laser light can be passed through different regions in the processing space 100, and the temperature and concentration of the processing gas in these regions can be measured. By measuring the temperature and concentration of the processing gas in multiple different regions, the temperature distribution and concentration distribution of the processing gas in the processing space 100 can be identified.

[0038] 3A and 3B show variations in the arrangement of a plurality of light projector and light receiver sets 40 on the mounting table 2. FIG. During the period in which processing is performed using the processing gas, a wafer W is placed on the upper surface of the mounting table 2. Therefore, when the light projector / receiver set 40 is disposed in the mounting area in which the wafer W is placed, the light projector lens 411 and the light receiver lens 421 are covered by the wafer W during the processing.

[0039] 3A shows an example in which light-projecting and light-receiving sets 40 are arranged around the periphery of the mounting area of ​​the wafer W to prevent the light-projecting lens 411 and the light-receiving lens 421 from being covered by the wafer W. In the example shown in Fig. 3A, a plurality of light-projecting and light-receiving sets 40 are arranged at equal intervals along the circumferential direction of the mounting table 2, which is circular when viewed from above.

[0040] 3B, the light projector / receiver sets 40 may be arranged in an area where the wafer W is placed. In this example, a plurality of light projector / receiver sets 40 are arranged radially along the radial direction of the circular wafer W placement area. If a light projecting and receiving set 40 is provided in the area where the wafer W is placed, laser light may be projected from the light projecting lens 411, for example, during a period when the wafer W is not placed on the mounting table 2, to measure the temperature and concentration of the processing gas.

[0041] Furthermore, for example, at a heating temperature of 0 to 270° C., a silicon wafer W transmits light with a wavelength in the range of 1.8 to 6.0 μm. When the absorption wavelength of the process gas is included in this wavelength range, the temperature and concentration of the process gas can be measured with the wafer W placed on the mounting table 2 by projecting a laser beam with a wavelength that transmits the wafer W.

[0042] 2, the laser light output from the light receiving unit 42 via the changeover switch 422 is split into a laser light of a first wavelength range and a laser light of a second wavelength range by a splitter 423 equipped with an optical filter. After that, the laser light of each wavelength range is converted into an electric signal by photodiodes 425a, 425b, and then input to the main body 426 of the light intensity measuring device.

[0043] In main body 426, by comparing the intensity of the reference light supplied from first and second semiconductor laser devices 431 and 432, an absorption spectrum indicating the change in absorbance with respect to the wavelength of the laser light can be obtained. The main body 426 outputs information specifying the absorption spectrum to the control unit 6 described above.

[0044] The control unit 6 in this example has the functions of a temperature calculation unit 61 and a concentration calculation unit 62 . The temperature calculation unit 61 calculates the temperature of the process gas based on the correspondence relationship between the area ratio and the peak intensity ratio of the absorption spectrum in the first wavelength range and the absorption spectrum in the second wavelength range with respect to the temperature of the process gas. The correspondence relationship between the temperature of the process gas and the above-mentioned area ratio and peak intensity ratio is obtained in advance by an experiment or the like, and is stored in the storage unit of the control unit 6 as a table or a function.

[0045] The concentration calculation unit 62 calculates the concentration of the process gas based on the absorbance of the laser light at a specific wavelength included in the first and second wavelength ranges, for example, the maximum peak wavelength of the absorption spectrum. The concentration calculation may be performed, for example, using the well-known Beer-Lambert law.

[0046] The operation of the wafer processing apparatus 1 having the above-described configuration will now be described. First, the gate valve 102 is opened, and an external transfer device (not shown) is used to load the wafer W to be processed into the processing chamber 10. Thereafter, the wafer W is raised from the underside by the lift pins 23 to receive it, and the transfer mechanism is retracted to the outside of the apparatus, and the gate valve 102 is closed. Next, the lift pins 23 are lowered, and the wafer W is placed on the mounting table 2.

[0047] The mounting table 2 is heated to a preset temperature by a heating unit (not shown) provided inside the mounting table 2, and the wafer W is heated to a processing temperature by heat transfer from the mounting table 2. Here, the areas where the light projecting lens 411, the light receiving lens 421, and the optical fiber 400 are arranged may be surrounded by a heat insulating material to prevent the influence of heating by the heating unit on these devices.

[0048] After the wafer W is placed on the mounting table 2, the inside of the processing chamber 10 (processing space 100) is evacuated by the vacuum exhaust unit 13. Next, processing gas is supplied to the processing space 100 to perform a film formation process. That is, when forming a film by plasma CVD, a source gas and a reactive gas are continuously supplied, and high frequency power is applied from the high frequency power sources 222 and 232 to the mounting table 2 to turn these gases into plasma and promote a reaction to form a film material. As a result, the film material is deposited on the surface of the wafer W, and a desired film is formed.

[0049] When forming a film by plasma ALD, the supply of raw material gas and reactive gas and the exhaust of these gases (including the case where exhaust is performed while supplying purge gas) are repeated in sequence. During the supply period of the processing gas to be turned into plasma, high frequency power is applied to the mounting table 2 to turn the processing gas into plasma and promote the reaction. As a result, layers of the film material formed on the surface of the wafer W are stacked to form the desired film.

[0050] At this time, when the temperature and concentration of the process gas are measured in-situ using a laser beam, the temperature and concentration of the process gas are measured during the film formation process. In this case, the wafer W is placed on the mounting table 2. Therefore, the measurement may be performed using a light projecting and receiving set 40 arranged around the mounting area of ​​the wafer W as shown in FIG. 3A. Alternatively, the measurement may be performed using a laser beam having a wavelength that passes through the wafer W, using the light projecting and receiving set 40 arranged on the mounting area of ​​the wafer W as shown in FIG. 3B.

[0051] In addition, in the case of a gas that has been converted into plasma, it may be difficult to measure the temperature and concentration of the processing gas using the absorption spectrum of laser light. In such a case, after the processing gas is supplied, a period may be set during which the processing gas is not converted into plasma and the temperature and concentration are measured.

[0052] When measuring the temperature and concentration of the process gas, one or more (or all) light projecting and receiving sets 40 are selected, which are arranged at a position where the laser light passes through the region where the temperature and concentration are to be measured. Then, the selected light projecting and receiving set 40 is connected to the light source unit 43 and the main body unit 426 using the changeover switches 412 and 422. Thereafter, the first and second semiconductor laser devices 431 and 432 supply laser light while gradually changing the wavelength within the first and second wavelength ranges (sweeping operation).

[0053] The laser beams are coupled by a coupler 433, and then supplied to a projecting lens 411 selected by a switch 412, and projected into the processing space 100. The laser beam passes through the processing space 100 to which the processing gas is supplied, and is reflected by the opposing surface 310 of the shower head 31, and then reaches a receiving lens 421 selected by a switch 422. During the period when the laser beam passes through this optical path, the laser beam is absorbed by the processing gas, and the intensity of the laser beam decreases.

[0054] The laser light received by the light receiving lens 421 is separated into laser light of each wavelength range by the splitter 423, and then converted into an electrical signal having a voltage corresponding to the intensity of the laser light by the photodiodes 425a, 425b and input to the main body 426. In the main body 426, for example, a comparison is made with the intensity of a reference light to generate absorption spectra in the first and second wavelength ranges.

[0055] Data representing the created absorption spectrum is output to the control unit 6, and the temperature of the processing gas is calculated by the temperature calculation unit 61 and the concentration of the processing gas is calculated by the concentration calculation unit 62 based on the calculation method described above. When measurements are performed using a plurality of light projecting and receiving sets 40, the selected light projecting and receiving sets 40 are switched in sequence and the above-described measurement operation is repeated.

[0056] Based on the measured temperature and concentration of the processing gas, the supply amount of the processing gas, the vacuum exhaust amount by the vacuum exhaust unit 13, or, for example, the temperature of the processing gas by a temperature adjustment mechanism provided in the processing gas source 322 may be adjusted. In this case, after the adjustment, a film formation process on the wafer W may be performed. When a predetermined time has elapsed and the film formation process is completed, the supply of the processing gas, the application of the high frequency power, and the heating of the wafer W are stopped. After that, the pressure inside the processing vessel 10 is adjusted, and the wafer W after the film formation is unloaded from the processing vessel 10 in the reverse order to that of the loading.

[0057] Also, it may be difficult to measure the temperature and concentration of the process gas during the period when the wafer W is being processed. Therefore, a period during which the process gas is supplied to the processing space 100 during the period when the wafer W is not being processed may be set, and the temperature and concentration may be measured. In this case, even when the light projecting and receiving set 40 arranged in the wafer W placement area is used as shown in FIG. 3B, it is not essential that the laser light used has a wavelength that transmits through the wafer W. It is needless to say that the temperature and concentration of the process gas may be measured using the light projecting and receiving set 40 arranged in the area shown in FIG. 3A.

[0058] According to the embodiment described above, by acquiring the absorption profiles of laser light in two different wavelength ranges in the processing space 100 to which a processing gas is supplied, the temperature and concentration of the processing gas can be measured simultaneously. In particular, by utilizing a plurality of light emitting / receiving sets 40 arranged at different positions, the distribution of temperature and concentration of the processing gas within the processing space 100 can be identified.

[0059] Fig. 4 shows a modified example of the configuration in which the light projector / receiver set 40 is provided on the mounting table 2, as described with reference to Fig. 1 and Fig. 2. In this example, a reflector 25 is provided on the upper surface of the mounting table 2, which reflects the laser light reflected by the opposing surface 310 of the shower head 31 toward the opposing surface 310.

[0060] 4, the laser light projected from the light projecting lens 411 can be reflected multiple times between the opposing surface 310 on the shower head 31 side and the reflecting portion 25 on the mounting table 2 side. By reflecting the laser light multiple times, the length of the optical path L becomes longer, thereby improving the sensitivity of the temperature and concentration measurement of the process gas.

[0061] Next, a configuration example of a wafer processing apparatus 1a according to a second embodiment will be described with reference to Fig. 5. In Fig. 5, components common to those described with reference to Figs. 1 to 4 are denoted by the same reference numerals as those used in these figures.

[0062] 5, a light projecting lens 411 constituting the light projecting unit 41 and a light receiving lens 421 constituting the light receiving unit 42 are provided outside the processing vessel 10 (processing space 100). A window 14 for transmitting laser light is provided on the side wall surface of the processing vessel 10 at a position different from the region where the above-mentioned loading / unloading port 101 is formed.

[0063] A projector lens 411 and a receiver lens 421 are arranged at positions facing the window unit 14 while being held by a collimator 401. Meanwhile, a reflector 15 is provided on the inner wall surface of the processing vessel 10 facing the projector lens 411 and the receiver lens 421 across the window unit 14. In this example, a two-core cable 402 is used to connect the light projector unit 41 and the light source unit 43, and to connect the light receiver unit 42 and the equipment on the main body unit 426 side. With the above-mentioned arrangement, the laser light projected from the projection lens 411 enters the processing space 100 through the window portion 14, is reflected by the reflecting portion 15, and then passes through the processing space 100 and the window portion 14 before being received by the receiving lens 421.

[0064] In the configuration of the wafer processing apparatus 1a of this example, the temperature and concentration of the processing gas can be measured simultaneously by acquiring the absorption profiles of laser light in two different wavelength ranges in the processing space 100 to which the processing gas is supplied. In addition, the window portion 14 shown in Figure 5 can be said to have a common configuration that combines a light-projecting window portion that allows the laser light projected from the light-projecting lens 411 to enter the processing space 100, and a light-receiving window portion that allows the laser light that has passed through the processing space 100 to be received by the light-receiving lens 421.

[0065] 5, the projector lens 411 and the receiver lens 421 may be separately disposed at positions facing each other across the processing vessel 10. In this case, a projector window that allows the laser light to enter the processing space 100 may be provided on the wall surface of the processing vessel 10 facing the projector lens 411, and a receiver window that receives the laser light that has passed through the processing space 100 may be provided on the wall surface of the processing vessel 10 facing the receiver lens 421.

[0066] In the above-described method, the process gas to be measured for temperature and concentration is not limited to the source gas or reaction gas used in the film forming process. It may be an etching gas used in the etching process of the substrate, an ashing gas used in the ashing process of the resist film applied to the substrate, or a cleaning gas used to clean the equipment placed in the process space 100. Furthermore, the substrate to be processed using the process gas is not limited to the example of a semiconductor wafer, but may be, for example, a glass substrate of a flat panel display (FPD).

[0067] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The above-described embodiments may be omitted, substituted, or modified in various forms without departing from the scope and spirit of the appended claims. [Explanation of symbols]

[0068] L optical path W wafer 1, 1a Wafer processing device 100 Processing Space 10 Processing vessel 31 Shower Head 411 Projection lens 421 Receiving lens 6 Control section 61 Temperature calculation section 62 Concentration calculation section

Claims

1. In an apparatus for processing a substrate, a processing vessel that accommodates the substrate and defines a processing space in which the processing is performed; a processing gas supply unit that supplies a processing gas to the processing space for processing the substrate or processing an apparatus disposed in the processing vessel; a light projection unit that projects a laser light into the processing space to which the processing gas is supplied; a light source unit that supplies, via an optical waveguide, a laser beam whose wavelength changes within a first wavelength range that is a preset wavelength range, and a laser beam whose wavelength changes within a second wavelength range different from the first wavelength range, to the light projection unit; a light receiving unit that receives the laser light that has passed through the processing space; a temperature calculation unit that calculates a temperature of the process gas based on an absorption spectrum of the laser light in the first wavelength range received by the light receiving unit and an absorption spectrum of the laser light in the second wavelength range; a concentration calculation unit that calculates a concentration of the process gas based on an absorbance of laser light having a specific wavelength within the first wavelength range or the second wavelength range, a gas shower head having a surface facing the substrate facing the substrate, the gas shower head having a gas supply port formed in the surface for supplying the processing gas into the processing space, The light-projecting unit and the light-receiving unit are arranged on the mounting table such that the laser light projected from the light-projecting unit is reflected by the opposing surface and then received by the light-receiving unit.

2. The apparatus of claim 1, wherein the mounting table is provided with a plurality of light-emitting and receiving sets each consisting of the light-emitting section and the light-receiving section which are associated with each other so that the laser light passes through different areas within the processing space, and the temperature calculation section and the concentration calculation section calculate the temperature and concentration of the processing gas in the area through which the laser light emitted and received by each of the light-emitting and receiving sets passes.

3. The apparatus according to claim 1 , wherein the mounting table is provided with a reflecting portion that reflects the laser light reflected by the facing surface toward the facing surface.

4. 4. The apparatus according to claim 1, wherein the light projecting section and the light receiving section are provided around an area on the stage where the substrate is placed.

5. 4. The apparatus according to claim 1, wherein the light-projecting unit and the light-receiving unit are provided in an area on the stage where the substrate is placed, and the light-projecting unit projects the laser light during a period when the substrate is not placed on the stage.

6. 4. The apparatus according to claim 1, wherein the light-projecting unit and the light-receiving unit are provided in an area of ​​the mounting table where the substrate is placed, and the light source unit supplies the light-projecting unit with laser light having a wavelength that is transmitted through the substrate.

7. 1. A method for measuring a temperature and a concentration of a process gas for processing a substrate, comprising: supplying a processing gas for processing the substrate or processing an equipment disposed in a processing vessel to a processing space where the processing is performed; projecting a laser beam having a wavelength that changes within a first wavelength range, which is a preset wavelength range, and a laser beam having a wavelength that changes within a second wavelength range, which is different from the first wavelength range, into the processing space into which the processing gas is supplied; receiving the laser light that has passed through the processing space; calculating a temperature of the process gas based on an absorption spectrum of the received laser light in the first wavelength range and an absorption spectrum of the received laser light in the second wavelength range; calculating a concentration of the process gas based on an absorbance of laser light of a specific wavelength within the first wavelength range or the second wavelength range; a gas shower head having a surface facing the substrate facing the substrate, the gas shower head having a gas supply port formed in the surface for supplying the processing gas into the processing space, The step of projecting a laser beam and the step of receiving the laser beam are performed on the mounting table such that the projected laser beam is reflected by the opposing surface and then received.

8. In the step of projecting the laser light into the processing space and the step of receiving the laser light, a plurality of projections and receptions of the laser light are performed so that the laser light passes through different regions in the processing space; The method according to claim 7 , wherein the steps of calculating the temperature of the process gas and calculating the concentration of the process gas include calculating the temperature and the concentration of the process gas in each region through which the laser light passes.

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