Chamber apparatus, gas laser apparatus, and method for producing electronic device

Abstract

A chamber apparatus according to one aspect of the present disclosure comprises: a metal housing in which is formed an opening for accommodating therein a laser gas and a discharge electrode, and an end section of the opening has a stepped shape spanning the entire periphery thereof; a ceramic electrical insulation plate having a planar shape surrounded by two sets of opposing linear edges and four corners, and having a stepped end section that spans the entire periphery of the opening and fits with the end section of the opening so as to cover the opening; a pressing member which presses the two sets of opposing linear edges against the end section of the opening when the four corners are in an open state; a groove which is formed in a receiving surface of the end section of the opening, said receiving surface receiving the end section of the electrical insulation plate, and which is formed so as to surround the opening; and an O-ring disposed in the groove. The surface of at least one of the four corners opposes the receiving surface of the end section of the electrical insulation plate and encompasses: a contact surface that contacts the receiving surface and covers the groove; and a separation surface that is separated further from the receiving surface at the outer peripheral side than the contact surface.

Description

Chamber apparatus, gas laser apparatus, and method for manufacturing electronic device

[0001] The present disclosure relates to a chamber apparatus, a gas laser apparatus, and a method for manufacturing an electronic device.

[0002] In recent years, semiconductor exposure apparatuses have been required to improve their resolution in response to the miniaturization and high integration of semiconductor integrated circuits. To this end, the wavelength of light emitted from exposure light sources has been shortened. For example, KrF excimer laser devices that output laser light with a wavelength of approximately 248 nm and ArF excimer laser devices that output laser light with a wavelength of approximately 193 nm are used as gas laser devices for exposure.

[0003] The spectral linewidth of the spontaneously oscillating light from KrF excimer laser devices and ArF excimer laser devices is as wide as 350 to 400 pm. Therefore, constructing a projection lens using a material that transmits ultraviolet light, such as KrF and ArF laser light, can result in chromatic aberration. This can result in a decrease in resolution. Therefore, it is necessary to narrow the spectral linewidth of the laser light output from a gas laser device to a level where chromatic aberration is negligible. Therefore, a line narrowing module (LNM) containing a line narrowing element (e.g., an etalon or grating) may be installed within the laser resonator of the gas laser device to narrow the spectral linewidth. Hereinafter, a gas laser device with a narrowed spectral linewidth is referred to as a line narrowing gas laser device.

[0004] U.S. Patent No. 4,942,999 U.S. Patent No. 5,028,162 JP 2001-102490 A overview

[0005] A chamber device according to one aspect of the present disclosure comprises: a metal casing having an opening for accommodating laser gas and a discharge electrode therein, the edge of the opening being stepped around its entire periphery; a ceramic electrically insulating plate having a planar shape surrounded by two sets of opposing straight edges and four corners, the ceramic electrically insulating plate having stepped edges that fit into the edge of the opening around its entire periphery to cover the opening; a pressing member that presses the two sets of opposing straight edges against the edge of the opening while leaving the four corners open; a groove formed in a receiving surface that receives the edge of the electrically insulating plate at the edge of the opening, the groove surrounding the opening; and an O-ring placed in the groove; and at at least one of the four corners, the surface of the end of the electrically insulating plate that faces the receiving surface includes a contact surface that contacts the receiving surface and covers the groove, and a separation surface that is spaced apart from the receiving surface and outer circumferentially of the contact surface.

[0006] a chamber device including: a metal casing having an opening for accommodating laser gas and a discharge electrode therein, the edge of the opening being stepped around its entire periphery; a ceramic electrically insulating plate having a planar shape surrounded by two sets of opposing straight edges and four corners, the ceramic electrically insulating plate having the stepped edge fitting with the edge of the opening around its entire periphery so as to cover the opening; a pressing member for pressing the two sets of opposing straight edges against the edge of the opening while leaving the four corners open; a receiving surface that receives the edge of the electrically insulating plate at the edge of the opening, the receiving surface having a groove formed therein so as to surround the opening, and an O-ring disposed in the groove;

[0007] A method for manufacturing an electronic device according to one aspect of the present disclosure includes a metal housing having an opening for accommodating laser gas and a discharge electrode therein, the opening having a stepped edge along its entire periphery; a ceramic electrically insulating plate having a planar shape surrounded by two sets of opposing linear edges and four corners, the stepped edge fitting with the opening edge along its entire periphery so as to cover the opening; a pressing member for pressing the two sets of opposing linear edges against the opening edge while leaving the four corners open; a receiving surface for receiving the edge of the electrically insulating plate at the opening edge, the receiving surface having a groove formed to surround the opening; and an O-ring embedded in the gas laser apparatus, wherein at least one of the four corners of the gas laser apparatus includes a chamber apparatus, a pulse power module connected to a discharge electrode via a plurality of feedthroughs embedded in the gas laser apparatus, and an O-ring embedded in the gas laser apparatus, and a charger that supplies a charging voltage to the pulse power module, the gas laser apparatus including: a chamber apparatus having an O-ring embedded in the gas laser apparatus, and a surface of the gas laser apparatus facing the receiving surface at the end of the electrical insulating plate including a contact surface that contacts the receiving surface and covers the groove, and a separation surface that is spaced from the receiving surface on the outer circumferential side of the contact surface;

[0008] Some embodiments of the present disclosure are described below, by way of example only, with reference to the accompanying drawings. FIG. 1 is a side view schematically illustrating the configuration of a gas laser apparatus according to a comparative example. FIG. 2 is a plan view illustrating the planar shape of an electrically insulating plate. FIG. 3 is a plan view illustrating the configuration of an electrically insulating plate and a housing viewed from above with a pulsed power module (PPM) removed. FIG. 4 is a diagram illustrating the configuration of an electrically insulating plate and a housing. FIG. 5 is a cross-sectional view taken along line B1-B1 of FIG. 3. FIG. 6 is a cross-sectional view taken along line B1-B1 of FIG. 3 when the housing and the electrically insulating plate are heated by laser gas. FIG. 7 is a plan view illustrating the configuration of a corner of an electrically insulating plate viewed from below. FIG. 8 is a plan view illustrating the configuration of an electrically insulating plate and a housing according to a first embodiment viewed from above with a PPM removed. FIG. 9 is a diagram illustrating the configuration of an electrically insulating plate and a housing according to the first embodiment. FIG. 10 is a cross-sectional view taken along line B2-B2 of FIG. 8. FIG. 11 is a cross-sectional view taken along line B2-B2 in FIG. 8 when the housing and the electrically insulating plate are heated by laser gas. FIG. 12 is a plan view showing the configuration of a corner of the electrically insulating plate as viewed from below. FIG. 13 is a graph showing the dependency of the maximum value of stress applied to the boundary portion on the length of line segment AE. FIG. 14 is a plan view showing a modified planar shape of the separating surface. FIG. 15 is a plan view showing a modified planar shape of the separating surface. FIG. 16 is a plan view showing a modified planar shape of the separating surface. FIG. 17 is a plan view showing a modified planar shape of the separating surface. FIG. 18 is a cross-sectional view showing a modified cross-sectional shape of the separating surface. FIG. 19 is a cross-sectional view showing a modified cross-sectional shape of the separating surface. FIG. 20 is a cross-sectional view showing a modified cross-sectional shape of the separating surface. FIG. 21 is a plan view showing the configuration of the electrically insulating plate and housing according to the second embodiment as viewed from above with the pulse power module removed. FIG. 22 is a diagram showing the configuration of the electrically insulating plate and housing according to the second embodiment. Fig. 23 is a cross-sectional view taken along line B3-B3 in Fig. 21. Fig. 24 is a cross-sectional view taken along line B3-B3 in Fig. 21 when the housing and the electrical insulating plate are heated by laser gas.Fig. 25 is a plan view showing the configuration of the housing and the corners of the electrical insulating plate as viewed from below. Fig. 26 is a plan view showing a modified example of the planar shape of the cutout portion. Fig. 27 is a plan view showing a modified example of the planar shape of the cutout portion. Fig. 28 is a plan view showing a modified example of the planar shape of the cutout portion. Fig. 29 is a diagram schematically showing an example of the configuration of an exposure apparatus. Embodiment

[0009] <Contents> 1. Comparative Example 1.1 Gas Laser Apparatus 1.1.1 Configuration 1.1.2 Operation 1.2 Electrically Insulating Plate 1.3 Issues 2. First Embodiment 2.1 Configuration 2.2 Actions and Effects 2.3 Modification of First Embodiment 3. Second Embodiment 3.1 Configuration 3.2 Actions and Effects 3.3 Modification of Second Embodiment 4. Method for Manufacturing Electronic Device

[0010] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The embodiments described below show some examples of the present disclosure and do not limit the content of the present disclosure. Furthermore, not all of the configurations and operations described in the embodiments are necessarily essential as the configurations and operations of the present disclosure. Note that the same components are given the same reference symbols, and redundant explanations will be omitted.

[0011] 1. Comparative Examples First, comparative examples of the present disclosure will be described. Comparative examples of the present disclosure are forms that the applicant recognizes as being known only by the applicant, and are not publicly known examples that the applicant acknowledges.

[0012] 1.1 Gas Laser Apparatus 1.1.1 Configuration The configuration of a gas laser apparatus 2 according to a comparative example will be described using Fig. 1. Fig. 1 shows a schematic configuration of the gas laser apparatus 2. The gas laser apparatus 2 is a discharge excitation type gas laser apparatus that excites laser gas by electric discharge, such as an excimer laser apparatus.

[0013] 1, the traveling direction of pulsed laser light PL output from gas laser device 2 is defined as Z direction, the discharge direction described below is defined as Y direction, and the direction perpendicular to the Z direction and Y direction is defined as X direction.

[0014] 1, a gas laser device 2 includes a chamber device 3, a charger 4, a pulsed power module (PPM) 5, a monitor module 6, a processor 7, and an optical resonator. The optical resonator is composed of a line-narrowing module 8 and an output coupling mirror 9.

[0015] The chamber device 3 is configured to include a housing 10 and an electrical insulating plate 11. An opening 10a for accommodating the laser gas and the discharge electrode 12 is formed at the upper end of the housing 10. For example, the chamber device 3 is a container made of a metal such as aluminum with a nickel-plated surface. The electrical insulating plate 11 is fixed to the housing 10 so as to close the opening 10a of the housing 10. The electrical insulating plate 11 is made of alumina (Al ２ O ３ ) and other ceramics.

[0016] Discharge electrode 12, ground plate 13, and fan 14 are provided inside housing 10. Furthermore, laser gas containing fluorine is sealed inside housing 10 as a laser medium. The laser gas contains, for example, rare gases such as argon, krypton, and xenon, buffer gases such as neon and helium, and halogen gases such as fluorine and chlorine.

[0017] The electrically insulating plate 11 is fixed to the housing 10 so as to cover the opening 10a of the housing 10. A plurality of feedthroughs 15 are embedded in the electrically insulating plate 11. The PPM 5 is disposed on the electrically insulating plate 11. The housing 10 is grounded.

[0018] The PPM 5 is connected to the discharge electrode 12 via a plurality of feedthroughs 15. The PPM 5 includes a switch SW for discharging the discharge electrode 12. The charger 4 is connected to a charging capacitor (not shown) provided in the PPM 5, and supplies a voltage to the PPM 5.

[0019] The discharge electrode 12 consists of a cathode electrode 12a and an anode electrode 12b. The cathode electrode 12a and the anode electrode 12b are arranged inside the housing 10 so that their discharge surfaces face each other. Hereinafter, the space between the cathode electrode 12a and the anode electrode 12b will be referred to as the discharge space. The discharge direction is the direction in which the cathode electrode 12a and the anode electrode 12b face each other.

[0020] The cathode electrode 12a has its surface opposite to the discharge surface supported by an electrically insulating plate 11 and connected to a plurality of feedthroughs 15. The anode electrode 12b has its surface opposite to the discharge surface supported by a ground plate 13.

[0021] Fan 14 is a cross-flow fan for circulating laser gas within housing 10, and is disposed in the space opposite the discharge space with respect to ground plate 13. A motor 14a that rotates and drives fan 14 is connected to housing 10. A heat exchanger (not shown) is disposed inside housing 10.

[0022] Windows 16a and 16b are provided on the side walls of the housing 10 to allow light generated within the housing 10 to exit to the outside. The housing 10 is positioned so that the optical path of the optical resonator passes through the discharge space and the windows 16a and 16b.

[0023] The line narrowing module 8 includes a prism 8a, a grating 8b, and a rotation stage 8c. The prism 8a expands the beam width of the light emitted from the chamber device 3 through the window 16a and transmits the expanded beam toward the grating 8b.

[0024] The grating 8b is arranged in a Littrow configuration, in which the angle of incidence and the angle of diffraction are the same. The prism 8a is supported by a rotation stage 8c, and the rotation stage 8c rotates the prism 8a, changing the angle of incidence of light on the grating 8b. The grating 8b is a wavelength selection element that selectively extracts light near a specific wavelength depending on the diffraction angle. The spectral width of the light returning from the grating 8b through the prism 8a to the chamber device 3 is narrowed.

[0025] The output coupling mirror 9 transmits a portion of the light emitted from the chamber device 3 through the window 16b and reflects the other portion back to the chamber device 3. The surface of the output coupling mirror 9 is coated with a partially reflective film.

[0026] The light emitted from the chamber apparatus 3 travels back and forth between the line narrowing module 8 and the output coupling mirror 9, and is amplified each time it passes through the discharge space. A portion of the amplified light is output as pulsed laser light PL via the output coupling mirror 9. The pulsed laser light PL is an example of the "laser light" according to the technology of the present disclosure.

[0027] The monitor module 6 is disposed in the optical path of the pulsed laser light PL output via the output coupling mirror 9. The monitor module 6 includes a beam splitter 6a, a focusing optical system 6b, and an optical sensor 6c.

[0028] The beam splitter 6 a transmits the pulsed laser beam PL with high transmittance and reflects a portion of the pulsed laser beam PL toward the focusing optical system 6 b. The focusing optical system 6 b focuses the light reflected by the beam splitter 6 a on the light-receiving surface of the optical sensor 6 c. The optical sensor 6 c measures the pulse energy E and wavelength λ of the light focused on the light-receiving surface and outputs the measurement values ​​to the processor 7.

[0029] The processor 7 is a processing device that transmits and receives various signals to and from an exposure apparatus controller 110 provided in the exposure apparatus 100. For example, the target pulse energy Et, target wavelength λt, oscillation trigger signal, etc. of the pulsed laser light PL output to the exposure apparatus 100 are transmitted to the processor 7 from the exposure apparatus controller 110.

[0030] The processor 7 comprehensively controls the operation of each component of the gas laser device 2 based on various signals sent from the exposure apparatus controller 110, measurement values ​​of the pulse energy E and wavelength λ, and the like.

[0031] 1.1.2 Operation Next, a description will be given of the operation of the gas laser apparatus 2 according to the comparative example. The processor 7 receives the target pulse energy Et, the target wavelength λt, and the oscillation trigger signal from the exposure apparatus controller 110 of the exposure apparatus 100.

[0032] The processor 7 sets a charging voltage corresponding to the target pulse energy Et in the charger 4. Then, the processor 7 operates the switch SW in the PPM 5 in synchronization with the oscillation trigger signal to apply a high voltage between the cathode electrode 12a and the anode electrode 12b. As a result, a discharge occurs in the discharge space, exciting the laser gas and causing laser oscillation in the optical resonator. At this time, the pulsed laser light PL, which has been narrowed in line by the line-narrowing module 8, is output from the output-coupling mirror 9.

[0033] The pulsed laser beam PL output from the output coupling mirror 9 enters the monitor module 6, and the pulse energy E and wavelength λ are measured by the monitor module 6. The pulsed laser beam PL transmitted through the beam splitter 6 a of the monitor module 6 enters the exposure apparatus 100.

[0034] The processor 7 controls the charging voltage so that the difference between the target pulse energy Et and the measured value of the pulse energy E approaches 0. The processor 7 also controls the rotation stage 8c so that the difference between the target wavelength λt and the measured value of the wavelength λ approaches 0.

[0035] Although FIG. 1 illustrates an excimer laser device as the gas laser device 2, the gas laser device 2 may be an F2 laser device or the like that uses laser gas containing fluorine gas and buffer gas.

[0036] 1.2 Electrical Insulation Plate Next, we will explain the configuration of the electrical insulation plate 11. Fig. 2 shows the planar shape of the electrical insulation plate 11. Fig. 3 shows the configuration of the electrical insulation plate 11 and the housing 10 viewed from above with the PPM 5 removed.

[0037] The upper surface 11a of the electrical insulating plate 11 is substantially rectangular and has a planar shape surrounded by a pair of first edges H1 facing each other in the X direction, a pair of second edges H2 facing each other in the Y direction, and four corners 11b. The first edges H1 and the second edges H2 are each linear. The corners 11b connect the first edges H1 and the second edges H2. The pair of first edges H1 and the pair of second edges H2 correspond to "two sets of opposing linear edges" according to the technology of the present disclosure.

[0038] 2, the corner 11b includes a chamfered portion BV formed by cutting off the end of the electrical insulating plate 11 obliquely with respect to the first edge H1 and the second edge H2. K indicates the cut-off portion.

[0039] 3, the electrical insulating plate 11 is fixed in a pressed state to the housing 10 using four pressure plates 20 and a plurality of bolts 21. For example, the pressure plates 20 are made of stainless steel. The four pressure plates 20 are an example of a "pressing member" according to the technology of the present disclosure.

[0040] Specifically, the four presser plates 20 are arranged to cover two pairs of opposing linear edges H1, H2 around the periphery of the electrical insulating plate 11. While it is desirable for the four presser plates 20 to cover the entire periphery of the electrical insulating plate 11, the four corners 11b of the electrical insulating plate 11 are left open and uncovered for structural reasons, such as the need to place other components near the corners 11b. In other words, the four presser plates 20 press the two pairs of opposing linear edges H1, H2 against the ends of the opening 10a, with the four corners 11b left open.

[0041] The plurality of feedthroughs 15 are arranged at equal intervals in the Z direction, which is the longitudinal direction of the electrical insulating plate 11 .

[0042] Figure 4 shows the configuration of the electrical insulating plate 11 and the housing 10. Figure 4(A) shows a cross section taken along line A1-A1 in Figure 3. Figure 4(B) shows the configuration of the electrical insulating plate 11 as seen from below.

[0043] As shown in Figure 4(A), the electrically insulating plate 11 is composed of a base portion 30 and an electrode fixing portion 31 that is smaller in planar shape than the base portion 30. The base portion 30 and the electrode fixing portion 31 are integrally formed from the ceramic described above. The electrode fixing portion 31 is located closer to the interior of the housing 10 than the base portion 30. In other words, the upper surface 11a of the electrically insulating plate 11 is the upper surface of the base portion 30. The cathode electrode 12a is fixed to the lower surface 11c of the electrically insulating plate 11, i.e., the surface of the electrode fixing portion 31.

[0044] Since the electrode fixing portion 31 has a smaller planar shape than the base portion 30, the outer edge portion 30a of the base portion 30 protrudes outward over the entire periphery beyond the electrode fixing portion 31. Therefore, the end of the electrical insulating plate 11 is formed in a stepped shape that includes a boundary portion 32 between the base portion 30 and the electrode fixing portion 31.

[0045] The housing 10 is formed with a receiving portion 40 that receives the electrical insulating plate 11. The receiving portion 40 protrudes inward from the entire periphery of the inner wall of the housing 10. The end of the receiving portion 40 forms the opening 10a described above. Therefore, the housing 10 is formed with a stepped shape that fits with the end of the stepped electrical insulating plate 11 so as to close the opening 10a. The outer edge 30a of the base portion 30 contacts the upper surface of the receiving portion 40. The outer edge 30a is sandwiched and fixed between the receiving portion 40 and the presser plate 20. The electrode fixing portion 31 is positioned inside the end of the opening 10a.

[0046] An annular groove 41 is formed on the upper surface of the receiving portion 40 so as to surround the opening 10a in the XZ plane. An O-ring 42 having a cross-sectional diameter larger than the depth of the groove 41 is disposed in the groove 41 to maintain the airtightness of the housing 10. The O-ring 42 is made of a material such as metal, elastomer, or resin. The O-ring 42 receives a pressing force from the outer edge portion 30a of the base portion 30, and seals the gap between the upper surface of the receiving portion 40 and the outer edge portion 30a.

[0047] As shown in FIG. 4B , the O-ring 42 surrounds the boundary portion 32 in the XZ plane, and the boundary portion 32 surrounds the electrode fixing portion 31 .

[0048] Figure 5 shows a cross section taken along line B1-B1 in Figure 3. For the sake of explanation, Figure 5 shows the electrical insulating plate 11 separated from the housing 10 in the Y direction. The upper surface of the receiving portion 40 is the surface that receives the outer edge portion 30a of the base portion 30, and is hereinafter referred to as the receiving surface 43. The receiving surface 43 is flat except for the groove 41. The lower surface of the outer edge portion 30a is the surface that contacts the receiving surface 43, and is hereinafter referred to as the contact surface 33. The contact surface 33 is flat, and the entire surface contacts the receiving surface 43.

[0049] 1.3 Issues When the gas laser device 2 is operating, the laser gas sealed within the housing 10 becomes hot, which heats the housing 10 and the electrical insulating plate 11. The housing 10 is made of a metal such as aluminum, while the electrical insulating plate 11 is made of a ceramic such as alumina, so the thermal expansion coefficients of the housing 10 and the electrical insulating plate 11 are different.

[0050] 6 shows a cross section taken along line B1-B1 in FIG. 3 when the housing 10 and the electrical insulating plate 11 are heated by laser gas. Because the housing 10 has a larger thermal expansion coefficient than the electrical insulating plate 11, when the housing 10 and the electrical insulating plate 11 are heated, the contact surface 33 of the electrical insulating plate 11 is subjected to stress in the Y direction from the receiving surface 43 of the housing 10. Because no pressing plate 20 is disposed at the corners 11b of the electrical insulating plate 11, a bending moment is generated with the boundary 32 as a fulcrum due to the stress applied to the contact surface 33. This bending moment can occur at any of the four corners 11b.

[0051] Fig. 7 shows the configuration of the corner 11b of the electrical insulating plate 11 as viewed from below. The housing 10 is not shown in Fig. 7. As shown in Fig. 7, at the corner 11b, the boundary 32 has an arc shape with the center point O as the center.

[0052] 7, A to D are imaginary points located at the ends of the outer edge 30a of the electrical insulating plate 11. E is the intersection point where an imaginary line extending line segment AB intersects with an imaginary line extending line segment DC. Triangle BCE corresponds to the cut-off portion K described above. Line segment BC corresponds to the chamfered portion BV described above. The positions of imaginary points B and C are selected so that line segment BC does not contact the outermost end of groove 41. In this comparative example, the angle of line segment BC is set so that it intersects with the X and Z directions at an angle of 45°.

[0053] The imaginary point A is located at the end of the outer edge 30a in the Z direction. F1 is the intersection point where the line connecting the center point O and the imaginary point B intersects with the boundary 32. F2 is the intersection point where the line connecting the center point O and the imaginary point A intersects with the boundary 32. The distance between the intersection point F1 and the imaginary point B is defined as L. Ｆ１Ｂ The distance between the intersection point F2 and the virtual point A is L Ｆ２Ａ In this case, L Ｆ１Ｂ >L Ｆ２Ａ The relationship always holds.

[0054] The magnitude of the bending moment generated at boundary 32 is proportional to the distance from boundary 32 to the end of contact surface 33. Because imaginary point B is farther from boundary 32 than imaginary point A, the bending moment acting on imaginary point B is always larger than that acting on imaginary point A. The same can be said for the relationship between imaginary point D and imaginary point C, which are located at the ends of outer edge 30a in the X direction.

[0055] In this way, the bending moment generated at the boundary 32 is large at the corner 11b of the electrical insulating plate 11. If the bending moment becomes large, cracks may occur at the boundary 32. Therefore, it is desirable to reduce the bending moment generated at the boundary 32.

[0056] 2. First Embodiment 2.1 Configuration A gas laser device 2 according to a first embodiment of the present disclosure has the same configuration as the gas laser device 2 according to the comparative example, except that the configuration of the electrical insulating plate 11 is different.

[0057] Fig. 8 shows the configuration of the electrically insulating plate 11 and housing 10 according to the first embodiment, viewed from above, with the PPM 5 removed. Fig. 9 shows the configuration of the electrically insulating plate 11 and housing 10 according to the first embodiment. Fig. 9(A) shows a cross section taken along line A2-A2 in Fig. 8. Fig. 9(B) shows the configuration of the electrically insulating plate 11 according to the first embodiment, viewed from below. The electrically insulating plate 11 according to the first embodiment differs from the comparative example only in that notches 50 are formed on the underside of each of the four corners 11b.

[0058] Figure 10 shows a cross section taken along line B2-B2 in Figure 8. For the sake of explanation, Figure 10 shows the electrical insulating plate 11 separated from the housing 10 in the Y direction. At the corner 11b of the electrical insulating plate 11, a cutout 50 is formed by cutting out the end of the surface of the outer edge 30a that faces the receiving surface 43. By forming the cutout 50 in the electrical insulating plate 11, a separating surface 34 separated from the receiving surface 43 in the Y direction is formed.

[0059] The separation surface 34 is spaced from the receiving surface 43 on the outer circumferential side of the contact surface 33. In other words, the separation surface 34 is a non-contact surface that does not contact the receiving surface 43. In this embodiment, the separation surface 34 and the receiving surface 43 are each flat, and the distance between the separation surface 34 and the receiving surface 43 is constant. The contact surface 33 contacts the receiving surface 43 so as to cover the groove 41.

[0060] 11 shows a cross section taken along line B2-B2 in FIG. 8 when the housing 10 and the electrical insulating plate 11 are heated by laser gas. In this embodiment, the separating surface 34 is not subjected to stress from the receiving surface 43, and therefore the magnitude of the bending moment with the boundary portion 32 as the fulcrum is smaller than in the comparative example. The depth of the cutout portion 50 in the Y direction is preferably equal to or greater than the amount of thermal deformation of the housing 10, for example, 0.1 mm or greater, so that the separating surface 34 does not come into contact with the receiving surface 43.

[0061] 12 shows the configuration of the corner 11b of the electrical insulating plate 11 as viewed from below. The separation surface 34 is formed between the area corresponding to the groove 41 and the chamfered portion BV. The separation surface 34 has a shape with the chamfered portion BV as one side and four vertices. For example, the separation surface 34 is a rectangle.

[0062] 12, A to D are imaginary points located at the ends of the outer edge 30a of the electrically insulating plate 11. As in the comparative example, triangle BCE corresponds to the cut-off portion K described above. Imaginary point A is located at the end of the outer edge 30a in the Z direction and is located farther from imaginary point E than imaginary point B. Imaginary point D is located at the end of the outer edge 30a in the X direction and is located farther from imaginary point E than imaginary point C.

[0063] In this embodiment, the area surrounded by imaginary points A to D is the separation surface 34. The positions of imaginary points A and D are selected so that line segment AD does not contact the outermost end of groove 41. In this embodiment, line segment BC and line segment AD are parallel. Therefore, separation surface 34 is a trapezoid. Furthermore, the angle θ1 between line segment BC and line segment CE and the angle θ2 between line segment AD and line segment DE are equal, each being 45°.

[0064] In this embodiment, the line segments AD and BC are parallel to each other, but they may be non-parallel. That is, the separation surface 34 is not limited to a trapezoid and may be a quadrilateral other than a trapezoid. For example, the separation surface 34 may be an area surrounded by imaginary points A', B, C, and D. In this case, the positions of the imaginary points A' and D are selected so that the line segment A'D does not contact the outermost end of the groove 41. The separation surface 34 may also be an area surrounded by imaginary points A, B, C, and D'. In this case, the positions of the imaginary points A and D' are selected so that the line segment AD' does not contact the outermost end of the groove 41.

[0065] 2.2 Function and Effect In this embodiment, since the separation surface 34 is formed on the electrical insulating plate 11, the longest distance from the boundary portion 32 to the end of the contact surface 33 in the Z direction is the distance L from the intersection point F1 to the imaginary point B. Ｆ１Ｂ From the above, the distance L from the intersection point F2 to the virtual point A Ｆ２ＡThe same can be said for the relationship between imaginary point D and imaginary point C. In this way, in this embodiment, by providing separation surface 34, the distance from boundary portion 32 to the end of contact surface 33 is reduced, thereby reducing the bending moment generated at boundary portion 32. This suppresses the occurrence of cracks and extends the life of electrical insulating plate 11.

[0066] In addition, when the separation surface 34 is an area surrounded by the imaginary points A′, B, C, and D, the longest distance from the boundary portion 32 to the end of the contact surface 33 in the Z direction is the distance L from the intersection point F3 to the imaginary point A′. Ｆ３Ａ’ , and the distance from the boundary portion 32 to the end of the contact surface 33 becomes even smaller. The same applies to the case where the separation surface 34 is an area surrounded by the imaginary points A, B, C, and D'.

[0067] FIG. 13 shows the dependence of the maximum value of stress applied to boundary portion 32 on the length of line segment AE. The stress applied to boundary portion 32 is a bending stress corresponding to the bending moment. FIG. 13 shows the simulation results when θ1 = θ2 = 45° and the depth of cutout portion 50 in the Y direction is 0.6 mm. The length of line segment AE is equal to the length of line segment DE. The horizontal axis represents the maximum length of line segment AE when line segment AD does not contact the outermost end of groove 41, with 100% as the value. The vertical axis represents the maximum value of stress applied to boundary portion 32 in the comparative example, with 100% as the value.

[0068] In the comparative example, i.e., when the line segment AE overlaps with the line segment BC, the length of the line segment AE is 48% of the maximum length. The maximum value of the stress applied to the boundary portion 32 decreases as the length of the line segment AE increases. When the length of the line segment AE is 100%, i.e., when the area of ​​the separation surface 34 is maximum, the maximum value of the stress applied to the boundary portion 32 is suppressed to approximately 50%.

[0069] 2.3 Modifications of the First Embodiment Various modifications of the first embodiment will be described below.

[0070] In the above embodiment, the shape of the separating surface 34 is a rectangle, but any shape may be used as long as it is surrounded by lines passing through four imaginary points at the ends of the outer edge portion 30 a. For example, as shown in Figure 14, the line segment AD does not have to be a perfect straight line, and both ends of the straight line segment AD may be curved.

[0071] 15, the line segment AD may be a concave curved line extending toward the center point O. More specifically, the line segment AD may be an arc shape centered on the center point O. In this case, the distance L from the boundary 32 to the line segment AD at the corner 11b is equal at all positions, so that the stress acting on the boundary 32 at the corner 11b is uniform. This suppresses stress concentration, further suppressing damage to the boundary 32.

[0072] 16, the line segment AD may be a curved line that is convex toward the center point O. In this case, the line segment AD may be an arc having the same curvature as the boundary portion 32.

[0073] In the above embodiment, the chamfered portions BV are formed at the corners 11b, but the chamfered portions BV do not necessarily have to be formed. That is, the electrical insulating plate 11 may be rectangular without the chamfered portions BV. In this case, as shown in FIG. 17 , the separating surface 34 has a shape with three vertices. Specifically, the separating surface 34 is a triangle with imaginary points A, D, and E as its vertices. The shape of the separating surface 34 may be a right triangle or a right-angled isosceles triangle. In this case, the separating surface 34 does not have to be a triangle as long as it is surrounded by a line passing through the three imaginary points. The line segment AD can be modified in the same manner as in FIGS. 14 to 16 .

[0074] In the above embodiment, the distance between the separation surface 34 and the receiving surface 43 formed in the cutout 50 is constant, but as shown in Figures 18 to 20, the cutout 50 may be formed so that the distance between the separation surface 34 and the receiving surface 43 increases toward the outside of the outer edge 30a. In this case, the angle of the end of the contact surface 33 increases, making it possible to prevent damage to the end of the contact surface 33.

[0075] Fig. 18 shows an example in which the rate of increase of the gap between the spacing surface 34 and the receiving surface 43 is constant. In this case, the spacing surface 34 is flat. Fig. 19 shows an example in which the rate of increase of the gap between the spacing surface 34 and the receiving surface 43 decreases toward the outer periphery. In this case, the spacing surface 34 is concave. Fig. 20 shows an example in which the rate of increase of the gap between the spacing surface 34 and the receiving surface 43 increases toward the outer periphery. In this case, the spacing surface 34 is convex.

[0076] In the above embodiment, the notch 50 is formed in all four corners 11b, but it is sufficient that the notch 50 is formed in at least one of the four corners 11b. For example, the notch 50 may be formed in two of the four corners 11b, or the notch 50 may be formed in three of the four corners 11b.

[0077] 3. Second Embodiment 3.1 Configuration A gas laser device 2 according to a second embodiment of the present disclosure has the same configuration as the gas laser device 2 according to the first embodiment, except that the configurations of the electrically insulating plate 11 and the housing 10 are different.

[0078] Fig. 21 shows the configuration of the electrically insulating plate 11 and housing 10 according to the second embodiment when viewed from above with the PPM 5 removed. Fig. 22 shows the configuration of the electrically insulating plate 11 and housing 10 according to the second embodiment. Fig. 22(A) shows a cross section taken along line A3-A3 in Fig. 21. Fig. 22(B) shows the configuration of the electrically insulating plate 11 according to the second embodiment when viewed from below.

[0079] The electrically insulating plate 11 according to the second embodiment has the same configuration as the electrically insulating plate 11 according to the comparative example, and does not have the cutouts 50. In this embodiment, cutouts 60 are formed by partially cutting out areas corresponding to the four corners 11 b of the housing 10.

[0080] FIG. 23 shows a cross section taken along line B3-B3 in FIG. 21. For the sake of explanation, FIG. 23 shows the electrical insulating plate 11 separated from the housing 10 in the Y direction. A cutout 60 is formed in the housing 10 at the corner 11b by cutting out a portion of the surface facing the end of the outer edge 30a of the electrical insulating plate 11. By forming the cutout 60 in the housing 10, the end of the outer edge 30a is separated from the receiving surface 43 in the Y direction. The portion of the underside of the outer edge 30a facing the cutout 60 functions as the separating surface 34. In this embodiment, the bottom surface of the cutout 60 is also referred to as the receiving surface 43, in addition to the surface in which the groove 41 is formed.

[0081] As in the first embodiment, the separation surface 34 is spaced from the receiving surface 43 on the outer circumferential side of the contact surface 33 and faces the receiving surface 43. In other words, the separation surface 34 is a non-contact surface that does not contact the receiving surface 43. In this embodiment, the distance between the separation surface 34 and the receiving surface 43 is constant. The contact surface 33 contacts the receiving surface 43 so as to cover the groove 41.

[0082] 24 shows a cross section taken along line B3-B3 in FIG. 21 when the housing 10 and the electrical insulating plate 11 are heated by laser gas. In this embodiment, the separating surface 34 is not subjected to stress from the receiving surface 43, and therefore the magnitude of the bending moment with the boundary portion 32 as the fulcrum is smaller than in the comparative example. The depth of the cutout portion 60 in the Y direction is preferably equal to or greater than the amount of thermal deformation of the housing 10, for example, 0.1 mm or greater, so that the separating surface 34 does not come into contact with the receiving surface 43.

[0083] 25 shows the configuration of the housing 10 and the corner 11b of the electrical insulating plate 11 as viewed from below. The separation surface 34 is formed between the area corresponding to the groove 41 and the chamfered portion BV. The separation surface 34 has a shape with four vertices. For example, the separation surface 34 is a rectangle.

[0084] 25, A to D are imaginary points located at the ends of the outer edge 30a of the electrical insulating plate 11. In this embodiment, the area surrounded by imaginary points A to D is the separation surface 34. In this embodiment, line segments AD and BC are parallel, but they may also be non-parallel. The shape of the separation surface 34 can be modified in the same way as in the first embodiment. In other words, the separation surface 34 is not limited to a trapezoid, and may be a quadrilateral other than a trapezoid.

[0085] The points where an extension of line segment AD intersects with the end of receiving portion 40 are defined as A' and D', respectively, the point where an extension of line segment OB intersects with the end of receiving portion 40 is defined as B', and the point where an extension of line segment OC intersects with the end of receiving portion 40 is defined as C'. Cutout portion 60 is the area surrounded by A', B', C', and D'.

[0086] 3.2 Functions and Effects In this embodiment, similarly to the first embodiment, the separation surface 34 is formed on the electrical insulating plate 11. Therefore, the longest distance from the boundary portion 32 to the end of the contact surface 33 in the Z direction is the distance L from the intersection point F1 to the imaginary point B. Ｆ１Ｂ From the above, the distance L from the intersection point F2 to the virtual point A Ｆ２Ａ The same can be said for the relationship between imaginary point D and imaginary point C. In this way, in this embodiment, by providing separation surface 34, the distance from boundary portion 32 to the end of contact surface 33 is reduced, thereby reducing the bending moment generated at boundary portion 32. This suppresses the occurrence of cracks and extends the life of electrical insulating plate 11.

[0087] 3.3 Modifications of the Second Embodiment Various modifications of the second embodiment will be described below.

[0088] In the above embodiment, the line segments AA' and DD', which are part of the planar shape of the cutout portion 60, are each linear, but as shown in FIG. 26, the line segments AA' and DD' may each be curved.

[0089] In the above embodiment, the line segment AD, which is part of the planar shape of the cutout portion 60, is linear, but as shown in Fig. 27, the line segment AD may be entirely curved and convex toward the center point O. In this case, the line segment AD may be an arc with the same curvature as the boundary portion 32. Furthermore, as in Fig. 26, the line segment AA' and the line segment DD' may each be curved.

[0090] 28, the line segment AD may be a concave curved line extending toward the center point O. More specifically, the line segment AD may be an arc-shaped line centered on the center point O. In this case, the distance L from the boundary 32 to the line segment AD at the corner 11b is equal at all positions, so that the stress acting on the boundary 32 at the corner 11b is uniform. This suppresses stress concentration, further suppressing damage to the boundary 32. Furthermore, as in FIG. 26, the line segments AA' and DD' may each be curved.

[0091] In addition, in the above embodiment, the cutout portions 60 are formed in all of the areas corresponding to the four corner portions 11b, but it is sufficient that the cutout portion 60 is formed in the area corresponding to at least one corner portion 11b.

[0092] 29 shows a schematic configuration example of an exposure apparatus 100. The exposure apparatus 100 includes an illumination optical system 104 and a projection optical system 106. The illumination optical system 104 illuminates a reticle pattern of a reticle (not shown) placed on a reticle stage RT with, for example, pulsed laser light PL generated by a gas laser apparatus 2 and incident from the gas laser apparatus 2. The projection optical system 106 reduces and projects the pulsed laser light PL that has passed through the reticle, forming an image on a workpiece (not shown) placed on a workpiece table WT. The workpiece is a photosensitive substrate such as a semiconductor wafer coated with photoresist.

[0093] The exposure apparatus 100 exposes the workpiece with pulsed laser light PL reflecting a reticle pattern by synchronously translating the reticle stage RT and the workpiece table WT. After the reticle pattern is transferred to the semiconductor wafer through the exposure process described above, a semiconductor device can be manufactured through multiple processes. A semiconductor device is an example of an "electronic device" in this disclosure.

[0094] The gas laser device 2 is not limited to use in the manufacture of electronic devices, but can also be used for laser processing such as drilling.

[0095] The above description is intended to be illustrative rather than limiting. Thus, it will be apparent to those skilled in the art that modifications may be made to the embodiments of the present disclosure without departing from the scope of the appended claims.

[0096] Terms used throughout this specification and the appended claims should be interpreted as "open-ended" terms. For example, the terms "include" or "including" should be interpreted as "not limited to what is stated as including." The term "having" should be interpreted as "not limited to what is stated as having." Additionally, the modifier "a" used in this specification and the appended claims should be interpreted as "at least one" or "one or more." Additionally, the term "at least one of A, B, and C" should be interpreted as "A," "B," "C," "A+B," "A+C," "B+C," or "A+B+C," and should also be interpreted as including combinations other than "A," "B," and "C."

Claims

1. A chamber device comprising: a metal casing having an opening for accommodating laser gas and a discharge electrode, the edge of the opening being stepped around its entire circumference; a ceramic electrically insulating plate having a planar shape surrounded by two sets of opposing straight edges and four corners, the plate having stepped edges that fit with the edges of the opening around its entire circumference so as to cover the opening; a pressing member that presses the two sets of opposing straight edges against the edge of the opening while leaving the four corners open; a groove formed in a receiving surface that receives the edge of the electrically insulating plate at the edge of the opening, the groove surrounding the opening; and an O-ring disposed in the groove, wherein at least one of the four corners, a surface of the edge of the electrically insulating plate that faces the receiving surface includes a contact surface that contacts the receiving surface and covers the groove, and a separation surface that is spaced from the receiving surface on the outer circumferential side of the contact surface.

2. A chamber apparatus according to claim 1, wherein at all of the four corners, the surface of the end of the electrically insulating plate facing the receiving surface includes the contact surface and the separation surface.

3. A chamber apparatus as claimed in claim 1, wherein the contact surface and the separation surface are each flat, and the distance between the contact surface and the separation surface is constant.

4. A chamber apparatus according to claim 1, wherein at least one of said four corners is chamfered by cutting off an edge of said electrically insulating plate.

5. A chamber apparatus according to claim 4, wherein the separating surface has a shape with the chamfered portion as one side and four vertices.

6. A chamber apparatus according to claim 5, wherein the separating surface is rectangular.

7. A chamber apparatus as claimed in claim 6, wherein said spacing surface is trapezoidal.

8. A chamber apparatus according to claim 1, wherein the electrically insulating plate is rectangular with no chamfered edges.

9. A chamber apparatus according to claim 8, wherein the separation surface has a shape having three vertices.

10. The chamber apparatus according to claim 9, wherein the separating surface is a right triangle or a right isosceles triangle.

11. A chamber apparatus according to claim 1, wherein the distance between the contact surface and the separation surface increases toward the outer periphery.

12. A chamber apparatus as claimed in claim 1, wherein the separation surface is formed by partially cutting out an area of ​​the housing corresponding to at least one of the four corners.

13. A chamber apparatus as described in claim 1, wherein the electrically insulating plate is composed of a base portion and an electrode fixing portion having a smaller planar shape than the base portion, and the electrode fixing portion is positioned further inside the housing than the base portion.

14. A chamber apparatus as set forth in claim 13, wherein the contact surface and the separation surface are formed on an outer edge of the base portion that protrudes outward beyond the electrode fixing portion.

15. A chamber apparatus according to claim 14, wherein the housing is formed with a receiving portion that protrudes inward from an inner wall, and the receiving surface is formed on the receiving portion.

16. A chamber apparatus comprising: a metal housing having an opening for accommodating laser gas and a discharge electrode therein, the edge of the opening being stepped around its entire periphery; a ceramic electrically insulating plate having a planar shape surrounded by two sets of opposing straight edges and four corners, the planar shape being a stepped edge that fits around the edge of the opening around its entire periphery so as to cover the opening; a pressing member that presses the two sets of opposing straight edges against the edge of the opening while leaving the four corners open; a groove that is formed in a receiving surface that receives the edge of the electrically insulating plate at the edge of the opening so as to surround the opening; and an O-ring disposed in the groove; and at least one of the four corners, a surface of the edge of the electrically insulating plate that faces the receiving surface includes a contact surface that contacts the receiving surface and covers the groove, and a separation surface that is spaced from the receiving surface on the outer circumferential side of the contact surface; a pulse power module connected to the discharge electrode via a plurality of feedthroughs embedded in the electrically insulating plate; and a charger that supplies a voltage to the pulse power module. A gas laser device comprising:

17. A method for manufacturing an electronic device, comprising: a metal casing having an opening for accommodating laser gas and a discharge electrode therein, the edge of the opening having a stepped shape around its entire periphery; a ceramic electrically insulating plate having a planar shape surrounded by two sets of opposing straight edges and four corners, the planar shape being such that the stepped edge fits with the edge of the opening around its entire periphery so as to cover the opening; a pressing member for pressing the two sets of opposing straight edges against the edge of the opening while leaving the four corners open; a groove formed in a receiving surface that receives the edge of the electrically insulating plate at the edge of the opening so as to surround the opening; and an O-ring disposed in the groove; and at least one of the four corners, a surface of the edge of the electrically insulating plate that faces the receiving surface includes a contact surface that contacts the receiving surface and covers the groove, and a separation surface that is spaced from the receiving surface on the outer circumferential side of the contact surface; and a pulse power module connected to the discharge electrode via a plurality of feedthroughs embedded in the electrically insulating plate. a charger that supplies a charging voltage to the pulse power module; generating a laser beam by a gas laser apparatus including the gas laser apparatus; outputting the laser beam to an exposure apparatus; and exposing a photosensitive substrate to the laser beam in the exposure apparatus to manufacture an electronic device.

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