JP2015170572A - Observation window of processing unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an observation widow excellent in visibility and heating by microwaves is less, in a device for processing a processed substrate by introducing microwaves into a processing container.SOLUTION: An observation window 30 of a microwave processing unit for processing a workpiece in a processing container by irradiating with microwaves has a conductive metal plate 60 in which an opening 63, having a size not to leak the microwaves irradiated in the processing container, is formed, and an optical fiber 61 provided through the opening 63 of the metal plate 60. Ends of the optical fiber 61 are exposed, respectively, to the inside and the outside of the processing container, and the optical fiber 61 is tapered so that the end exposed to the outside of the processing container has a cross-sectional area larger than that at a place where it is inserted through the opening 63 of the metal plate 60.

Description

  The present invention relates to a structure of an observation window in a microwave processing apparatus for processing a substrate to be processed by introducing a microwave into a processing container.

  For example, in the manufacture of semiconductor devices, ions as impurities are implanted into a silicon substrate, and amorphous silicon generated on the substrate surface due to crystal defects caused by this ion implantation is repaired and crystallized, and a diffusion layer is formed on the surface layer of the silicon substrate. Heat treatment for forming is performed. For this heat treatment, a heat treatment apparatus using a microwave may be used.

  By the way, the heat treatment apparatus using the microwave is provided with an observation window for observing the inside, but the observation window has a window so that the microwave does not leak to the outside of the apparatus through the observation window. Microwave shielding measures are taken.

  As a microwave shielding measure, a metal mesh is generally sandwiched between quartz glass portions of an observation window. As a countermeasure to replace the metal mesh, for example, Patent Document 1 proposes forming a conductive transparent film on a quartz glass portion.

JP-A-3-53085

  By the way, in monitoring the inside of the heat treatment apparatus, for example, a monitoring camera may be used. However, when a metal mesh is used for the observation window as in the prior art, the metal mesh itself is not focused inside the heat treatment device due to the autofocus of the surveillance camera, and the internal monitoring may not be performed properly. .

  In order to solve the problem of focusing due to autofocus, it is conceivable to use a conductive transparent film as disclosed in Patent Document 1 described above. However, a conductive film is more likely to absorb microwaves than a metal mesh. As a result, the conductive film generates heat, and the quartz glass on which the film is formed has low thermal conductivity and less heat is dissipated from the conductive film. There is a problem that there is a risk of burns.

  Therefore, there is a demand for an observation window that has excellent visibility inside the microwave processing apparatus and can suppress heat generation due to absorption of microwaves.

  The present invention has been made in view of the above points, and provides an observation window that is excellent in visibility and less heated by microwaves in an apparatus for processing a substrate to be processed by introducing microwaves into a processing container. It is an object.

  In order to achieve the above object, the present invention is an observation window of a processing apparatus that performs processing on a target object by introducing a microwave into a processing container, and the microwave introduced into the processing container does not leak A conductive metal plate having an opening of a size, and an optical fiber provided through the opening of the metal plate, and an end portion of the optical fiber is disposed inside the processing container and the processing Each of the optical fibers is exposed to the outside of the container, and the end of the optical fiber exposed to the outside of the processing container has a tapered shape having a larger cross-sectional area than a portion through which the opening of the metal plate is inserted. It is said.

  According to the present invention, the microwave is shielded by the conductive metal plate in which the opening having a size that does not leak the microwave is formed. And since the optical fiber which has a taper shape is penetrated in opening of a metal plate, the inside of a processing container can be observed from the edge part of the said optical fiber. At that time, since the metal plate does not enter the field of view of the observation window, high visibility can be ensured. In addition, since the metal plate reflects most of the microwave and the depth of penetration of the microwave is about several μm, the heat generated in the metal plate is dissipated from the surface of the metal plate and the inside of the metal plate To disperse. Therefore, heat generation due to absorption of microwaves can be suppressed.

  A plurality of the openings are formed in the metal plate, optical fibers are inserted through the openings, and both ends of the plurality of optical fibers are bundle fiber shapes in which a plurality of optical fibers are bundled. It may be configured.

  A plurality of the tapered optical fibers may be inserted into the opening of the metal plate.

  In the opening of the metal plate, the length of the portion having the largest opening width may be 1/10 or less of the wavelength of the microwave introduced into the processing container.

  ADVANTAGE OF THE INVENTION According to this invention, in the apparatus which introduce | transduces a microwave into a process container and processes a to-be-processed substrate, it can provide the observation window excellent in visibility and with little heating by a microwave.

It is a longitudinal cross-sectional view which shows an example of the outline of a structure of the microwave processing apparatus provided with the observation window which concerns on this Embodiment. It is sectional drawing which shows an example of the outline of a structure of an observation window. It is explanatory drawing which shows the outline of a structure of a metal plate. It is an arrow view of the AA cross section of FIG. It is explanatory drawing which shows the state of the edge part of a some optical fiber. It is a cross-sectional enlarged view which shows another example of a structure of an observation window.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol. FIG. 1 is a longitudinal sectional view schematically showing a microwave processing apparatus 1 in which an observation window according to the present embodiment is formed. In the present embodiment, an example will be described in which the microwave processing apparatus 1 is a heat treatment apparatus that heats a semiconductor wafer (hereinafter referred to as a “wafer”) W as an object to be processed, for example. .

  As shown in FIG. 1, the microwave processing apparatus 1 includes a processing container 10 that accommodates a wafer W as an object to be processed, a microwave introduction mechanism 11 that introduces a microwave into the processing container 10, and a processing container 10. Are provided with a gas supply mechanism 12 for supplying a predetermined processing gas and a support portion 13 for supporting the wafer W in the processing container 10. The processing container 10 is made of a metal such as aluminum or stainless steel.

  The processing container 10 is, for example, a substantially rectangular parallelepiped container as a whole, and has, for example, a square cylindrical side wall 20 in plan view, a substantially square ceiling plate 21 covering the upper end of the side wall 20, and a lower end of the side wall 20. The bottom plate 22 has a substantially square shape.

  A gas supply mechanism 12 is connected to the side wall 20 of the processing container 10 via a supply pipe 23. Further, on the side wall 20 of the processing container 10, between the observation window 30 provided in the opening 20 a of the side wall 20 for observing the inside of the processing container 10 and the outside of the processing container 10, A loading / unloading port (not shown) for loading / unloading is formed. Details of the configuration of the observation window 30 will be described later.

  An exhaust port 22 a is formed in the bottom plate 22 of the processing container 10, and an exhaust mechanism 41 such as a vacuum pump is connected to the exhaust port 22 a through an exhaust pipe 40.

  A shaft 31 extending through the center of the bottom plate 22 in the vertical direction and extending to the outside of the processing container 10 is provided in the center of the support portion 13. The support portion 13 is supported by the shaft 31. A plurality of support pins 32 are provided on the upper surface of the support portion 13 to support the wafer W by contacting the upper surface thereof. A driving mechanism 33 that rotates and lifts the shaft 31 is connected to a lower end of the shaft 31 and at a position outside the processing container 10. The position in the height direction of the wafer W in the processing container 10 is adjusted by driving the support portion 13 that supports the wafer W up and down by the drive mechanism 33.

  An opening 50 that functions as a microwave introduction port for introducing a microwave into the processing container 10 is formed in the ceiling plate 21 of the processing container 10, and a transmission window 51 is formed so as to close the opening 50. Is provided. The microwave introduction mechanism 11 is provided above the transmission window 51, and the microwave introduction mechanism 11 has a microwave unit 52 that generates a microwave and a power supply unit 53 connected to the microwave unit. . The microwave unit 52 includes devices such as a magnetron, a waveguide, a circulator, a detector, and a tuner. In addition, when performing the heat processing of the wafer W as a to-be-processed object with the microwave processing apparatus 1, it is preferable that the frequency of the microwave generated by the microwave unit 52 is 2.45 GHz or more, for example, 5.8 GHz. Microwave is more preferred. The frequency of the microwave in the present embodiment is, for example, 5.8 GHz. In addition, FIG. 1 illustrates a state in which one power supply unit 53 is provided for a plurality of microwave units 52, but the arrangement and the number of installed units of the plurality of microwave units 52 and power supply units 53 are as follows. Can be set arbitrarily.

  The transmission window 51 is formed of a dielectric material such as quartz or ceramics. A space between the transmission window 51 and the ceiling plate 21 is hermetically closed by a seal member (not shown).

  Next, the configuration of the observation window 30 formed on the side wall 20 will be described. For example, as shown in FIG. 2, the observation window 30 includes a metal plate 60 provided in parallel with the side wall 20 inside the opening 20 a of the side wall 20, and tapered light whose cross-sectional area varies along the longitudinal direction. A fiber 61 is provided. For example, as shown in FIG. 3, the metal plate 60 in the present embodiment is a metal mesh in which a plurality of conductive metal wires 62 are alternately arranged in, for example, a lattice shape, and openings 63 having a predetermined width L are formed. is there. The width L of the opening 63 is, for example, 1/10 or less of the wavelength of the microwave irradiated into the processing container 10 so as to prevent leakage of microwaves from the opening 20a of the side wall 20 to the outside of the processing container 10. Is set. Further, the metal plate 60 is fitted into the entire inner surface of the opening 20a without any gap, for example. Note that, as in the present embodiment, when the frequency of the microwave is 5.8 GHz, the wavelength of the microwave is about 51.7 mm. Accordingly, the width L of the opening 63 may be about 5.1 mm or less, and in the present embodiment, the width L of the opening 63 is set to about 1.2 mm. Further, the diameter of the metal wire 62 is set to approximately 0.9 mm.

  For example, as shown in FIG. 2, the optical fiber 61 extends in the vertical direction with respect to the metal plate 60, in other words, extends in the vertical direction with respect to the side wall 20. FIG. 4 is a cross-sectional view taken along the line AA of FIG. 2, and the plurality of optical fibers 61 are respectively inserted through the openings 63 of the metal plate 60 as shown in FIG. 4, for example. Further, the optical fiber 61 has the smallest cross-sectional area at the portion where the opening 63 of the metal plate 60 is inserted, and the cross-sectional area gradually increases toward both ends, that is, the surfaces exposed to the inside and outside of the processing container 10. It has a tapered shape. The tapered optical fiber 61 has, for example, a diameter of about 1.0 mm at a portion having the smallest cross-sectional area and a diameter of about 2.1 mm at both ends. The “exposure” referred to here is exposure in the sense that it can be visually recognized, and a plate-like quartz glass or the like is interposed so as to face the exposed surface of the optical fiber 61, and the processing vessel 10 is made of this quartz glass. You may make it the structure which maintains a sealing state.

  At both ends of the optical fiber 61, a plurality of optical fibers 61 are bundled together, for example, compressed in a state where heat is applied, so that the clads of the optical fibers are fused and integrated with no gap so-called bundle fiber shape Is formed. Therefore, as shown in FIG. 5, for example, the end portion of the optical fiber 61 is bundled adjacent to a hexagonal honeycomb shape. The optical fiber 61 has substantially the same length as the thickness of the side wall 20, and both end portions of the optical fiber 61 are located at substantially the same place as the side surface inside the processing container 10 and the side surface outside the processing container. Yes.

  The outer end of the processing container 10 of the optical fiber 61 is supported by a support frame 70, for example, as shown in FIG. The support frame 70 is provided so as to airtightly close a gap between the end of the optical fiber 61 and the opening 20a of the side wall 20. Thereby, the observation window 30 is airtightly attached to the side wall 20.

  The microwave processing apparatus 1 according to the present embodiment is configured as described above. Next, processing of the wafer W in the microwave processing apparatus 1 and the operation of the observation window during processing will be described.

  In the heat treatment of the wafer W, first, a loading / unloading port (not shown) provided on the side wall 20 is opened, and the processing container 10 is moved by a transfer mechanism (not shown) provided outside the microwave processing apparatus 1. The wafer W is loaded into the inside. The loaded wafer W is placed on the support pins 32. Next, the loading / unloading port is closed, and the inside of the processing container 10 is exhausted by the exhaust mechanism 41. Next, the processing gas is supplied from the gas supply mechanism 12 into the processing container 10 at a predetermined flow rate.

  Next, a voltage is applied from the power supply unit 53 to the microwave unit 52, and a microwave of, for example, 5.8 GHz generated by the microwave unit 52 is introduced into the processing container 10 through the transmission window 51. .

  The microwave introduced into the processing container 10 is irradiated on the surface of the wafer W, and the wafer W is heated. At this time, the output of the irradiated microwave is adjusted, the wafer W is heated to a predetermined temperature, and heated for a predetermined period.

  In addition, the microwave introduced into the processing container 10 is reflected by the side wall 20, the ceiling plate 21, and the bottom plate 22, and a part thereof is irradiated toward the observation window 30. Here, since the metal plate 60 of the observation window 30 has the width L of the opening 63 set to 1/10 or less of the wavelength of the microwave, the microwave irradiated toward the observation window 30 is caused by the metal plate 60. The shielding of the microwave from the observation window 30 is suppressed. Since both ends of the plurality of optical fibers 61 of the observation window 30 are bundled and integrated into a bundle fiber shape, a wide field of view is secured at both ends of the optical fiber 61. Therefore, the inside of the processing container 10 can be satisfactorily observed from the observation window 30 without leakage of microwaves from the observation window 30. At this time, since the metal plate 60 reflects most of the microwave and the depth of penetration of the microwave is about several μm from the surface, the heat generated in the metal plate 60 due to the absorption of the microwave is generated by the metal plate 60. It diffuses from the surface and is dispersed inside the metal plate 60. Therefore, it can be avoided that the observation window 30 is heated due to the heat generated by the microwave and the operator is burned.

  When the heating process of the wafer W by the microwave is finished, the application of voltage from the power supply unit 53 to the microwave unit 52 is stopped, and the microwave introduced into the processing container 10 is also stopped. At the same time, the supply of the processing gas from the gas supply mechanism 12 is also stopped. Thereafter, the loading / unloading opening is opened, and the wafer W is unloaded from the processing container 10. Thereby, a series of heat treatment of the wafer W is completed.

  According to the observation window 30 of the above embodiment, the microwave is shielded by the conductive metal plate 60 in which a plurality of openings 63 having a size that does not leak the microwave are formed. A plurality of tapered optical fibers 61 are inserted into the openings 63 of the metal plate 60, and both ends of the plurality of optical fibers 61 are bundled into one bundle fiber. A wide field of view is secured at the end of 61. Therefore, the inside of the processing container 10 can be observed well from the observation window 30. In particular, since the optical fiber is inserted through the opening 63, the metal plate 60 does not enter the field of view of the observation window 30. Therefore, for example, when observing the inside of the processing container 10 through the observation window 30 with a monitoring camera or the like, the metal plate 60 is not focused by the autofocus of the monitoring camera, and the monitoring camera or the like is used. Remote monitoring can be performed well.

  Further, the metal plate 60 constituting the observation window 30 reflects most of the microwave, and the depth of penetration of the microwave is about several μm from the surface. Therefore, the metal plate 60 is generated on the surface of the metal plate 60 due to absorption of the microwave. Heat is dissipated from the surface of the metal plate 60. At the same time, the heat of the surface of the metal plate 60 is also dispersed inside the metal plate 60. Therefore, it can be avoided that the observation window 30 is heated due to the heat generated by the microwave and the operator is burned. However, since some heat generation is expected, it is preferable to use a material of the optical fiber 61 having a high heat resistance compared to the plastic type.

  In the above embodiment, one optical fiber 61 is inserted into one opening 63. However, the number of optical fibers to be inserted into the opening 63 is limited to the contents of this embodiment. It can be set arbitrarily. For example, when inserting a plurality of optical fibers 61 into one opening 63, for example, as shown in FIG. 6, a plurality of tapered optical fibers 61 are bundled and integrated. You may make it insert in the opening 63. FIG.

  In the above embodiment, the metal plate 60 is a metal mesh formed by the conductive metal wire 62. However, the shape of the metal plate 60 is not limited to the contents of the present embodiment. Any width can be set as long as the width L of the opening 63 is set to a predetermined width L so that the microwave can be shielded. For example, instead of a metal mesh, a punching metal having openings formed in a staggered shape, a lattice shape, a dot shape, or the like may be used as the metal plate.

  In the above embodiment, the metal plate 60 has a plurality of openings 63, but the arrangement and number of the openings 63 are not limited to the contents of the present embodiment, and are required for the observation window 30. If the field of view can be secured, it is sufficient that the opening 63 is formed only at one position with respect to the metal plate 60. In this case, for example, as shown in FIG. 6, a bundle fiber in which a plurality of tapered optical fibers 61 are bundled is provided by being inserted through the opening 63 having a predetermined width L. A wide field of view can be secured.

  The microwave shielding effect increases as the thickness of the metal plate 60 increases and the width L of the opening 63 decreases. Therefore, the thickness of the metal plate 60 can be increased as much as possible, and the width of the opening 63 can be reduced as much as possible. preferable.

  In FIG. 3 of the above embodiment, the case where the opening 63 is a square having a length of L is illustrated, but the shape of the opening 63 is also the length of the portion having the largest opening width. Can be arbitrarily set as long as it is set to approximately 1/10 or less of the wavelength of the microwave irradiated into the processing container 10. That is, the opening 63 may be rectangular or circular. In order to increase the field of view of the observation window 30, the number of optical fibers 61 may be increased to increase the area of the end portion. From the viewpoint of increasing the number of installed optical fibers 61, the metal plate 60 may be It is preferable to adopt a mesh structure that can minimize the metal portion.

  The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to such examples. For example, although the microwave processing apparatus which is a heat treatment apparatus is illustrated in the embodiment, the present invention can be applied to a plasma processing apparatus using a microwave. Further, it is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can make various changes or modifications within the scope of the technical idea described in the claims. These are naturally understood to belong to the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Microwave processing apparatus 10 Processing container 11 Microwave introduction | transduction mechanism 12 Gas supply mechanism 13 Support part 20 Side wall 21 Ceiling board 22 Bottom board 23 Supply pipe 30 Observation window 41 Exhaust mechanism 50 Opening part 51 Transmission window 52 Microwave unit 53 Power supply part 60 Metal plate 61 Optical fiber 62 Metal wire 63 Opening 70 Support frame W Wafer

Claims (4)

An observation window of a processing apparatus for introducing a microwave into a processing container and processing a target object,
A conductive metal plate in which an opening of a size that does not leak microwaves introduced into the processing vessel is formed;
An optical fiber provided through the opening of the metal plate,
The end portions of the optical fibers are respectively exposed inside the processing container and outside the processing container,
An observation window of a processing apparatus, wherein the optical fiber has a tapered shape in which an end portion exposed to the outside of the processing container has a larger cross-sectional area than a portion through which the opening of the metal plate is inserted. . A plurality of the openings are formed in the metal plate,
Each of the openings is provided with an optical fiber inserted therethrough,
The observation window of the processing apparatus according to claim 1, wherein both ends of the plurality of optical fibers are configured in a bundle fiber shape in which a plurality of optical fibers are bundled. The observation window of the processing apparatus according to claim 1, wherein a plurality of the tapered optical fibers are inserted through the opening of the metal plate. The opening of the metal plate has a length of a portion having the largest opening width of 1/10 or less of a wavelength of a microwave introduced into the processing container. An observation window of the processing apparatus according to claim 1.

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