An excimer laser and its line width narrowing module

Abstract

The present invention relates to the field of laser line width adjustment technology, and discloses an excimer laser and a line width narrowing module thereof, wherein the line width narrowing module comprises: a housing, a housing is formed inside the housing, a light hole is provided on the housing for light to enter the housing; a prism, the prism is arranged in the housing and is arranged opposite to the light hole; a grating, the grating is also arranged in the housing, and the light hole, the prism and the grating are arranged in sequence in the incident direction of the light; a purge mechanism, the purge mechanism comprises a plurality of gas flow equalization devices arranged on one side of the prism and the grating, and the gas flow equalization device is purged toward the prism and the grating. It can effectively isolate water molecules and other factors that cause the degradation of optical components, and extend the service life of optical components; a large amount of heat is taken away by convection heat dissipation, so that the heat dissipation of the light-passing surface is better, and it is less likely to have thermal instability, and it is easier to ensure the stability of excimer laser wavelength screening.

Description

Technical Field

[0001] The invention relates to the technical field of laser line width adjustment, and in particular to an excimer laser and a line width narrowing module thereof. Background Art

[0002] Excimer laser refers to the laser emitted when the molecules formed by the mixed gas of inert gas and halogen gas excited by electron beam transition to their ground state. Since excimer laser is in the ultraviolet band, it has the characteristics of large single photon energy, large single pulse energy, high power, uniform spot, good beam quality, and single pulse coordination. It is widely used in many fields such as semiconductor lithography, panel annealing, medical treatment and scientific research. In order to make the laser line width generated by the excimer laser meet the needs of semiconductor lithography, it is necessary to select its spectrum, that is, to narrow the line width. The line width narrowing module is separately encapsulated in a sealed cavity. After the excimer laser enters from the light entrance of the line width narrowing module, it is expanded and collimated by prism, prism, prism, and prism respectively, and then irradiated onto a Littrow structure grating. The grating selects the spectrum of the excimer laser through the diffraction effect, that is, the line width is narrowed. The selected spectrum incident light path returns to the discharge cavity of the excimer laser.

[0003] Since the wavelength of excimer laser is very short and in the ultraviolet band, it is a cold laser with no thermal effect. It is a pulsed laser with strong directionality, high wavelength purity and high output power. Since the wavelength of excimer laser is short and the energy of single photon is large, and materials usually have strong absorption of high-energy photons, excimer laser is highly destructive to materials. Therefore, it is necessary to use materials with good optical properties for ultraviolet light, such as CaF2, as optical lenses. However, CaF2 crystals are prone to deliquesce with water molecules, which reduces the optical performance. Prisms and gratings are prone to adsorb dust particles during operation. Due to the strong absorption of ultraviolet light, it will cause local temperature rise, resulting in lens effect, further damaging the performance of optical lenses and accelerating the degradation of optical lenses. In addition, the absorption of ultraviolet light by prisms and gratings causes local temperature rise and deformation, which will also affect the quality of excimer laser beams. Summary of the invention

[0004] The purpose of the present invention is to provide an excimer laser and a line width narrowing module thereof, which can effectively isolate water molecules and other factors that cause optical components to deteriorate, thereby extending the life of the optical components; a large amount of heat can be taken away by convection heat dissipation, so that the heat dissipation of the light-transmitting surface is better, and thermal instability is less likely to occur, making it easier to ensure the stability of excimer laser wavelength screening.

[0005] In order to achieve the above object, the present invention provides a line width narrowing module, comprising:

[0006] A housing, wherein a receiving cavity is formed inside the housing, and a light-through hole is opened on the housing for light to enter the receiving cavity;

[0007] A prism, wherein the prism is disposed in the accommodating cavity and is arranged opposite to the light-through hole;

[0008] A grating, the grating is also arranged in the accommodating cavity, and the light-through hole, the prism and the grating are arranged in sequence in the incident direction of the light;

[0009] The purge mechanism includes a plurality of gas flow-uniform devices arranged on one side of the prism and the grating, and the gas flow-uniform devices purge toward the prism and the grating.

[0010] Compared with the prior art, a line width narrowing module according to an embodiment of the present invention has the following beneficial effects: a light-through hole is provided on a shell, a prism and a grating arranged in a line with the light-through hole are arranged in the shell, a purge mechanism is provided on one side of the prism and the grating, and the purge mechanism includes a plurality of gas flow-uniform devices for performing a purge operation on the light-through surfaces of the grating and the prism, and the formation of an air film can effectively prevent pollutants from contacting the surface of optical components, and the protective gas flow field can well immerse the grating and the prism in the protective gas, effectively isolating water molecules and other factors that cause the degradation of optical components, and the high-speed airflow can also more easily flush out the particulate matter normally consumed when the excimer laser passes through the surface of the optical component, thereby extending the life of the optical component; on the other hand, by utilizing the characteristic that the gas convection heat transfer efficiency is much greater than the gas conduction heat transfer efficiency, the high-speed flowing protective gas flow field quickly blows through the light-through surfaces of the grating and the prism, and takes away a large amount of heat through convection heat dissipation, so that the heat dissipation of the light-through surfaces is better, and the phenomenon of thermal instability is less likely to occur, and the stability of the excimer laser wavelength screening is more easily ensured.

[0011] In the line width narrowing module of the embodiment of the present invention, the purge mechanism further includes a gas supply pipeline extending from the outside of the shell to the accommodating cavity, and the plurality of gas flow equalization devices are all fixed on the gas supply pipeline.

[0012] In the line width narrowing module of the embodiment of the present invention, a guide air duct is arranged on the other side of the prism and the grating facing away from the purge mechanism, and the guide air duct includes guide holes corresponding to the multiple gas flow equalization devices, and the multiple guide holes are also connected to the guide air duct.

[0013] In the linewidth narrowing module of the embodiment of the present invention, the end surface of one side of the guide hole close to the grating or the prism is staggered with the light-transmitting surface of the grating or the prism.

[0014] In the line width narrowing module of the embodiment of the present invention, an air outlet is provided on the shell, the end of the air guide duct is connected to the air outlet, and a one-way valve is provided in the air outlet.

[0015] In the linewidth narrowing module of the embodiment of the present invention, a gas flow channel is provided inside the gas flow uniformity device, and two ends of the gas flow channel include an air inlet and an air outlet, and the air outlet is arranged toward the grating and the prism.

[0016] In the line width narrowing module of the embodiment of the present invention, the gas flow channel includes a first chamber connected to the gas inlet, the first chamber is connected to the second chamber, and a plurality of deceleration holes are arranged between the first chamber and the second chamber.

[0017] In the line width narrowing module of the embodiment of the present invention, the second chamber includes a deceleration chamber and a long chamber connected to each other, the deceleration chamber is connected to the deceleration hole, the long chamber is connected to the air outlet, and a plurality of parallel guide plates are arranged in the long chamber.

[0018] In the line width narrowing module of the embodiment of the present invention, the gas flow equalization device is provided on both sides of the prism, and one gas flow equalization device is provided on the side of the grating facing the prism.

[0019] The present invention further provides an excimer laser, comprising the line width narrowing module described in any one of the above embodiments.

[0020] Compared with the prior art, an excimer laser according to an embodiment of the present invention has the following beneficial effects: a line width narrowing module is arranged in the excimer laser, and the generation process of the excimer laser passes through the line width narrowing module; the line width narrowing module comprises a shell, a light through hole is opened on the shell, a prism and a grating arranged in line with the light through hole are arranged in the shell, a purge mechanism is arranged on one side of the prism and the grating, and the purge mechanism comprises a plurality of gas uniform flow devices for performing a purge operation on the light-passing surfaces of the grating and the prism, and the formation of an air film can effectively prevent pollutants from contacting the surface of optical components, and the protective gas flow field can well separate the grating and the prism. The mirror is immersed in the protective gas, which effectively isolates water molecules and other factors that cause the degradation of optical components. The high-speed airflow also makes it easier to promptly wash away the particulate matter normally consumed when the excimer laser passes through the surface of the optical component, thereby extending the life of the optical component. On the other hand, by utilizing the characteristic that the gas convection heat transfer efficiency is much greater than the gas conduction heat transfer efficiency, the high-speed flowing protective gas flow field quickly blows through the light-transmitting surfaces of the grating and prism, and takes away a large amount of heat through convection heat dissipation, making the light-transmitting surface dissipate heat better, making it less likely to experience thermal instability, and making it easier to ensure the stability of the excimer laser wavelength screening.

[0021] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1is a schematic structural diagram of a line width narrowing module according to an embodiment of the present invention;

[0023] Figure 2 is a schematic cross-sectional structural diagram of a gas flow uniforming device of a line width narrowing module according to an embodiment of the present invention;

[0024] Figure 3 is a schematic cross-sectional structure diagram of another direction of the gas uniform flow device of the line width narrowing module according to an embodiment of the present invention;

[0025] In the figure, 1, shell; 11, accommodating cavity; 12, light hole; 14, one-way valve; 15, shell air outlet; 2, prism; 3, grating; 4, purge mechanism; 41, gas uniform flow device; 411, air inlet; 412, air outlet; 413, first chamber; 414, second chamber; 415, deceleration hole; 416, deceleration chamber; 417, long chamber; 418, guide plate; 42, air supply pipeline; 421, air outlet; 5, guide air duct; 51, guide hole. DETAILED DESCRIPTION

[0026] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0027] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., and orientations or positional relationships indicated are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0028] In the description of the present invention, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed" etc. are understood as not including the number itself, and "above", "below", "within" etc. are understood as including the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0029] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0030] like Figure 1As shown, a line width narrowing module according to a preferred embodiment of the present invention comprises: a shell 1, a closed accommodating cavity 11 is formed inside the shell 1, a light through hole 12 is opened on the side wall of the shell 1, and the excimer laser is emitted from the discharge cavity of the excimer laser and enters the accommodating cavity 11 through the light through hole 12 to perform the line width narrowing operation.

[0031] A prism 2 and a grating 3 are arranged in the accommodating cavity 11, and an optical fixing platform 13 is arranged in the accommodating cavity 11. The prism 2 and the grating 3 are fixed in the accommodating cavity 11 through the optical fixing platform 13; the prism 2 is arranged in the accommodating cavity 11 at a position directly opposite to the light through hole 12, and the light directly enters the accommodating cavity 11 through the light through hole 12 and then directly enters the prism 2; the grating 3 is arranged on the other side of the prism 2 facing away from the light through hole 12, and the light through hole 12, the prism 2 and the grating 3 are arranged in sequence in the incident direction of the light, and the grating 3 selects the spectrum of the excimer laser through the diffraction effect, that is, the line width is narrowed, and the selected spectrum returns to the discharge cavity of the excimer laser along the original path of the incident light.

[0032] A purge mechanism 4 is provided in the accommodating cavity 11 for purging the grating 3 and the prism 2 with protective gas; the purge mechanism 4 includes a plurality of gas flow equalizers 41 provided on one side of the prism 2 and the grating 3, and the gas flow equalizers 41 purge toward the prism 2 and the grating 3. The gas film formed by the protective gas can effectively prevent pollutants from contacting the surface of the optical components, and the protective gas flow field can well immerse the grating 3 and the prism 2 in the protective gas, effectively isolating water molecules and other factors that cause the degradation of the optical components, and the high-speed airflow can also more easily flush out the particulate matter normally consumed when the excimer laser passes through the surface of the optical components, thereby extending the life of the optical components; on the other hand, by utilizing the characteristic that the gas convection heat transfer efficiency is much greater than the gas conduction heat transfer efficiency, the high-speed flowing protective gas flow field quickly blows through the light-transmitting surface of the grating 3 and the prism 2, and takes away a large amount of heat through convection heat dissipation, so that the light-transmitting surface has better heat dissipation, is less likely to have thermal instability, and is more likely to ensure the stability of the excimer laser wavelength screening.

[0033] In some embodiments of the present invention, the purge mechanism 4 further includes a gas supply pipeline 42 extending from the outside of the shell 1 to the accommodating chamber 11, the gas supply pipeline 42 is horizontally arranged, and the gas supply pipeline 42 is provided with a plurality of evenly distributed gas outlets 421, each gas outlet 421 corresponds to a gas flow equalizer 41, and the positions of the gas outlets 421 corresponding to the gas flow equalizers 41 are fixed on the gas supply pipeline 42. The gas supply pipeline 42 supplies the protective gas to the gas flow equalizer 41, thereby ensuring a stable supply of the protective gas.

[0034] In some embodiments of the present invention, a guide air duct 5 is provided on the other side of the prism 2 and the grating 3 facing away from the purging mechanism 4, and the guide air duct 5 is used to deliver the purged protective gas to the outside of the shell 1; the guide air duct 5 includes guide holes 51 corresponding to multiple gas flow equalization devices 41, the guide holes 51 are opened on one side of the optical fixed platform 13, and each guide hole 51 is connected to the guide air duct 5. The guide holes 51 are used to collect the protective gas after the light-transmitting surface of the prism 2 or the grating 3 is purged, and the guide holes 51 are arranged directly below the gas flow equalization device 41, and each guide hole 51 corresponds to a gas flow equalization device 41, so as to realize the complete recovery of the purged protective gas.

[0035] In some embodiments of the present invention, the end face of the guide hole 51 close to the grating 3 or prism 2 is staggered with the light-transmitting surface of the grating 3 or prism 2. This setting is to make the flow velocity of the protective gas flow field large enough and not to generate large disturbances that affect the normal operation of the grating 3 or prism 2. There is a certain appropriate staggered setting between the guide hole 51 and the light-transmitting surface of the grating 3 or prism 2. When the protective gas flow field is at a high flow velocity, the protective gas fully exchanges heat with the light-transmitting surface of the grating 3, and will be collected and captured by the guide hole 51 before a large vortex is formed, preventing the formation of vortices, resulting in uneven gas flow field, and the protective gas after heat exchange still stays on one side of the light-transmitting surface, affecting the subsequent heat dissipation efficiency.

[0036] In some embodiments of the present invention, a housing air outlet 15 is provided on the housing 1 to deliver the protective gas to the outside of the housing 1. The end of the guide air duct 5 is connected to the housing air outlet 15 to prevent the protective gas from accumulating in the guide air duct 5. A one-way valve 14 is provided in the housing air outlet 15. The one-way valve 14 has a one-way conduction function to prevent external air from flowing back into the line width narrowing module through the guide air duct 5. The protective gas flowing out of the housing air outlet 15 can be recycled and filtered, and then delivered to the housing 1 again through the air supply pipeline 42 to realize the recycling of the protective gas.

[0037] like Figure 2 and Figure 3 As shown, in some embodiments of the present invention, a gas flow channel is opened inside the gas flow equalization device 41, and the gas flow channel slows down and equalizes the protective gas sent to the gas flow equalization device 41 through the air inlet pipeline, so that the flow rate of the protective gas blown to the prism 2 and the grating 3 is uniform and stable; the two ends of the gas flow channel include an air inlet 411 and an air outlet 412, the air inlet 411 is connected to the air outlet 421 of the air supply pipeline 42, and the air outlet 412 is arranged toward the grating 3 and the prism 2.

[0038] In some embodiments of the present invention, the gas flow channel includes a first chamber 413 connected to the air inlet 411, and the protective gas entering the gas flow channel from the air inlet 411 is filled in the first chamber 413 and is decelerated for the first time through the side wall of the first chamber 413; the first chamber 413 is connected to the second chamber 414, and a plurality of deceleration holes 415 are arranged between the first chamber 413 and the second chamber 414. The aperture of the deceleration holes 415 is small, so that the overall flow rate of the protective gas through the deceleration holes 415 is low, and the pressure of the protective gas reaching the second chamber 414 is also low, so that there is a pressure difference between the first chamber 413 and the second chamber 414, and the protective gas flow entering the second chamber 414 can rotate evenly in the second chamber 414 to form a uniform long strip of airflow filling the second chamber 414, so as to control the flow rate and flow of the protective gas and reduce the turbulence effect.

[0039] In some embodiments of the present invention, the second chamber 414 includes a deceleration chamber 416 and a long chamber 417 connected to each other. The deceleration chamber 416 is connected to the deceleration hole 415. The protective gas forms a relatively low-speed airflow in the deceleration chamber 416 and then enters the long chamber 417. The long chamber 417 is connected to the gas outlet 412. A plurality of parallel guide plates 418 are arranged in the long chamber 417. When the airflow passes through the long chamber 417, it passes through the guide plates 418. The guide plates 418 are all arranged toward the gas outlet 412 to ensure that the gas flows evenly in the direction of the gas outlet 412. The long chamber 417 provided with the guide plates 418 makes the protective airflow blown out of the gas outlet 412 uniform and stable, and the direction is fixed.

[0040] In some embodiments of the present invention, a gas flow-leveling device 41 is provided on both sides of the prism 2. Since the two light-transmitting surfaces of the prism 2 have the excimer laser passing through them, various reactions will occur with the two ends of the prism 2, causing the two sides of the prism 2 to age. Therefore, providing a gas flow-leveling device 41 on both sides can ensure that both ends of the prism 2 are well protected, further improving the overall life of the prism 2. A gas flow-leveling device 41 is provided on the side of the grating 3 facing the prism 2. The grating 3 has light incident and emitted through one side of the light-transmitting surface. Therefore, it is only necessary to provide a gas flow-leveling device 41 on one side for complete protection.

[0041] A preferred embodiment of the present invention is an excimer laser, comprising the linewidth narrowing module of any one of the above embodiments. The linewidth narrowing module is provided in the excimer laser, and the generation process of the excimer laser will pass through the linewidth narrowing module; and the linewidth narrowing module comprises a shell 1, on which a light through hole 12 is provided, and in which a prism 2 and a grating 3 arranged in line with the light through hole 12 are provided, and a purge mechanism 4 is provided on one side of the prism 2 and the grating 3, and the purge mechanism 4 comprises a plurality of gas uniform flow devices 41, which are used to purge the light-passing surfaces of the grating 3 and the prism 2, and the formation of an air film can effectively prevent pollutants from contacting the surface of optical components, and the protective gas flow field can well immerse the grating 3 and the prism 2 in the protective gas. In the air, water molecules and other factors that cause the degradation of optical components are effectively isolated. The high-speed airflow can also more easily wash away the particulate matter normally consumed when the excimer laser passes through the surface of the optical component, thereby extending the life of the optical component. On the other hand, by utilizing the characteristic that the gas convection heat transfer efficiency is much greater than the gas conduction heat transfer efficiency, the high-speed flowing protective airflow field quickly blows through the light-transmitting surfaces of the grating 3 and the prism 2, and takes away a large amount of heat through convection heat dissipation, so that the light-transmitting surfaces dissipate heat better, are less likely to experience thermal instability, and are more likely to ensure the stability of the excimer laser wavelength screening.

[0042] The working process of the present invention is as follows: a light-through hole 12 is opened on the shell 1, and a prism 2 and a grating 3 arranged in line with the light-through hole 12 are arranged in the shell 1. A purge mechanism 4 is arranged on one side of the prism 2 and the grating 3. The purge mechanism 4 includes a plurality of gas flow-leveling devices 41. The gas flow-leveling devices 41 supply gas through a gas supply pipeline 42, and then the light-through surfaces of the grating 3 and the prism 2 are purged with protective gas. The purged gas enters the guide air duct 5 through the guide hole 51, and finally reaches the outside of the shell 1 through the air outlet 421.

[0043] In summary, the embodiment of the present invention provides an excimer laser and a line width narrowing module thereof, which form an air film that can effectively prevent pollutants from contacting the surface of optical components. The protective gas flow field can well immerse the grating 3 and the prism 2 in the protective gas, effectively isolating water molecules and other factors that cause the degradation of optical components. The high-speed airflow can also more easily flush out the particulate matter normally consumed when the excimer laser passes through the surface of the optical component, thereby extending the life of the optical component. On the other hand, by utilizing the characteristic that the gas convection heat transfer efficiency is much greater than the gas conduction heat transfer efficiency, the high-speed flowing protective gas flow field quickly blows through the light-transmitting surfaces of the grating 3 and the prism 2, and takes away a large amount of heat through convection heat dissipation, so that the light-transmitting surfaces have better heat dissipation, are less likely to have thermal instability, and are more likely to ensure the stability of the excimer laser wavelength screening.

[0044] The above are only preferred embodiments of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A line width narrowing module, characterized in that: include: A housing, wherein a receiving cavity is formed inside the housing, and a light-through hole is opened on the housing for light to enter the receiving cavity; A prism, wherein the prism is disposed in the accommodating cavity and is arranged opposite to the light-through hole; A grating, the grating is also arranged in the accommodating cavity, and the light-through hole, the prism and the grating are arranged in sequence in the incident direction of the light; A purge mechanism, the purge mechanism comprising a plurality of gas flow equalizers arranged on one side of the prism and the grating, the gas flow equalizers purge toward the prism and the grating, a guide air duct is arranged on the other side of the prism and the grating facing away from the purge mechanism, the guide air duct comprises guide holes corresponding to the plurality of gas flow equalizers, the plurality of guide holes are further connected to the guide air duct, and the end surface of the guide hole close to the grating or the prism is staggered with the light-transmitting surface of the grating or the prism; Wherein, a gas flow channel is provided inside the gas flow uniformity device, and two ends of the gas flow channel include a gas inlet and a gas outlet, and the gas outlet is arranged toward the grating and the prism; The gas flow channel includes a first chamber connected to the gas inlet, the first chamber is connected to the second chamber, and a plurality of deceleration holes are arranged between the first chamber and the second chamber; The second chamber includes a deceleration chamber and a long chamber connected to each other, the deceleration chamber is connected to the deceleration hole, the long chamber is connected to the air outlet, and a plurality of guide plates arranged in parallel are arranged in the long chamber.

2. The line width narrowing module according to claim 1, characterized in that: The purge mechanism also includes a gas supply pipeline extending from the outside of the shell to the accommodating cavity, and the plurality of gas flow equalization devices are all fixed on the gas supply pipeline.

3. The line width narrowing module according to claim 1, characterized in that: An air outlet is provided on the shell, the end of the air guide channel is connected to the air outlet, and a one-way valve is arranged in the air outlet.

4. The line width narrowing module according to claim 1, characterized in that: The gas flow-uniform device is disposed on both sides of the prism, and one gas flow-uniform device is disposed on the side of the grating facing the prism.

5. An excimer laser, characterized in that: It comprises the line width narrowing module as described in any one of claims 1 to 4.

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