A hybrid illumination system with multiple bands and multiple light sources and a maskless lithography apparatus

Abstract

The present invention relates to the field of maskless lithography illumination technology, and particularly to a hybrid illumination system with multiple bands and multiple light sources and a maskless lithography apparatus. A hybrid illumination system with multiple bands and multiple light sources includes a first light source having a first optical axis; a first lens group arranged along the first optical axis and adjacent to the first light source; a first light bar arranged along the first optical axis and adjacent to the first lens group; a second lens group arranged along the first optical axis and adjacent to the first light bar; a second and a third light source having a second optical axis, and the second optical axis is perpendicular to the first optical axis. The hybrid illumination system with multiple bands and multiple light sources of the present invention can completely eliminate the axial chromatic aberration on the image plane of the digital micromirror device to ensure the lithography effect of the maskless lithography apparatus on the premise that the hybrid light source can fully cover the 350-440 nm band.

Description

Technical Field

[0001] The present invention relates to the technical field of maskless lithography illumination, and specifically to a hybrid illumination system with multiple bands and multiple light sources and a maskless lithography apparatus. Background Art

[0002] Maskless lithography apparatuses are applicable to the production and manufacturing of integrated circuits. Among them, the illumination system is a key component for exposure in the lithography apparatus, which directly affects the lithography effect of the maskless lithography apparatus. Most of the existing illumination systems use a single light source, for example, only an LED light source or only an LD light source is used. The LD light source has a small divergence angle and strong collimation, but the wavelength range of the LD light source is relatively narrow (400 - 440 nm), making the process coverage of the maskless lithography apparatus relatively incomplete. The LED light source has a relatively wide wavelength range (350 - 440 nm), but the light source divergence angle of the LED light source is relatively large in many wavelength bands, resulting in a not very good lithography effect of the maskless lithography apparatus.

[0003] Therefore, the prior art proposes to couple the LED light source and the LD light source. For example, the patent with the application number CN202110858433.0 discloses a dual - band illumination system and a maskless direct - writing lithography apparatus having the same, including a first light source, a first light bar, a second light source, a second light bar, a first lens group, a second lens group, a diaphragm, a coupling lens suitable for coupling light rays, a third lens group, and a digital micromirror device. This dual - band illumination system couples an LD light source with a wavelength range of 400 - 405 nm and an LED light source with a wavelength range of 360 - 365 nm to form a new illumination system to provide illumination for the maskless lithography apparatus, which can both increase the process coverage of the maskless lithography apparatus to a certain extent and ensure the lithography effect of the maskless lithography apparatus to a certain extent.

[0004] However, during the implementation of the above - mentioned technical solution by the inventors of the present application, it is found that the following defects exist in this technical solution: when the wavelength range of the LD light source or the LED light source increases, the axial chromatic aberration on the image plane of the digital micromirror device will increase significantly, resulting in inconsistent object planes entering the imaging system later, and further greatly affecting the lithography effect of the maskless lithography apparatus. Therefore, the process coverage of this illumination system is still relatively narrow. In addition, even if only an LD light source with a wavelength range of 400 - 405 nm and an LED light source with a wavelength range of 360 - 365 nm are used, there will still be a certain amount of axial chromatic aberration on the image plane of the digital micromirror device. Summary of the Invention

[0005] In view of the problems existing in the prior art, the present invention provides a hybrid illumination system with multiple bands and multiple light sources and a maskless lithography apparatus. On the premise that the hybrid light source can fully cover the 350 - 440 nm band, it can also completely eliminate the axial chromatic aberration on the image plane of the digital micromirror device to ensure the lithography effect of the maskless lithography apparatus.

[0006] The technical solution adopted by the present invention to solve its technical problems is: a hybrid illumination system with multiple bands and multiple light sources, including

[0007] A first light source having a first optical axis;

[0008] A first lens group arranged along the first optical axis, and the first lens group is arranged adjacent to the first light source;

[0009] A first light bar arranged along the first optical axis, and the first light bar is arranged adjacent to the first lens group;

[0010] A second lens group arranged along the first optical axis, and the second lens group is arranged adjacent to the first light bar;

[0011] A second and a third light source having a second optical axis, and the second optical axis is perpendicular to the first optical axis;

[0012] A third lens group arranged along the second optical axis, and the third lens group is arranged adjacent to the second and third light sources;

[0013] A second light bar arranged along the second optical axis, and the second light bar is arranged adjacent to the third lens group;

[0014] A fourth lens group arranged along the second optical axis, and the fourth lens group is arranged adjacent to the second light bar;

[0015] A band - pass filter is arranged at the intersection of the optical axes of the first optical axis and the second optical axis, and couples the first light ray emitted from the second lens group and the second light ray emitted from the fourth lens group to obtain a mixed light ray;

[0016] A reflecting mirror is arranged in cooperation with the band - pass filter and the digital micromirror device, and reflects the mixed light ray emitted from the band - pass filter onto the digital micromirror device.

[0017] Preferably, the first lens group includes a first lens one and a first lens two, and the first lens one is a meniscus positive lens, and the first lens two is a biconvex lens.

[0018] Preferably, the second lens group includes a second lens one and a second lens two, and the second lens one is a meniscus positive lens, and the second lens two is a biconvex lens.

[0019] Preferably, the third lens group includes a first third lens and a second third lens, the first third lens being a plano-convex lens and the second third lens being a bi-convex lens.

[0020] Preferably, the fourth lens group includes a first fourth lens and a second fourth lens, the first fourth lens being a plano-convex lens and the second fourth lens being a bi-convex lens.

[0021] Preferably, the first light bar is a conical light bar; the second light bar is a trapezoidal light bar.

[0022] Preferably, the first light source includes an LED light source with a wavelength band of 360 - 390 nm; the second and third light sources include an LD light source with a wavelength band of 400 - 440 nm and a solid laser light source with a wavelength band of 350 - 355 nm.

[0023] Preferably, the band-pass filter is a band-pass filter that is highly transmissive to light sources in the 360 - 390 nm wavelength band and highly reflective to light sources in the 350 - 355 nm and 400 - 440 nm wavelength bands.

[0024] Preferably, the LED light source has peaks at 360 - 370 nm and 380 - 390 nm; the LD light source has peaks at 400 - 410 nm and 420 - 440 nm.

[0025] A maskless lithography apparatus includes the above-described hybrid illumination system.

[0026] Advantageous Effects

[0027] In the hybrid illumination system according to the embodiment of the present invention, the common lens group in the prior art is removed, and by adding a first lens group and a third lens group and simultaneously improving the second lens group and the fourth lens group, the hybrid illumination system can still generate an illumination spot with a required size aperture and uniformity. Moreover, on the premise that the hybrid light source can fully cover the 350 - 440 nm wavelength band, the hybrid illumination system can completely eliminate the axial chromatic aberration on the image plane of the digital micromirror device to ensure the lithography effect of the maskless lithography apparatus. Description of the Drawings

[0028] Figure 1 It is a schematic structural diagram of a hybrid illumination system with multiple wavelength bands and multiple light sources in the embodiment of the present invention. Detailed Embodiments

[0029] The technical solution of the present invention will be further described below with reference to the drawings and through specific embodiments.

[0030] The inventors of the present application have found through research that in the prior art, axial chromatic aberration occurs on the image plane of the digital micromirror device 700 because in the existing dual-band illumination system, the LD light source and the LED light source share a lens group, and the wider the bandwidth of the mixed light source, the more obvious the axial chromatic aberration on the image plane of the digital micromirror device 700. Therefore, the present application has improved the existing dual-band illumination system so that, on the premise that the mixed light source can fully cover the 350-440 nm band, it can completely eliminate the axial chromatic aberration on the image plane of the digital micromirror device 700 to ensure the lithography effect of the maskless lithography equipment.

[0031] Example 1: As Figure 1 , a multi-band and multi-light-source hybrid illumination system, comprising a first light source 100, a first lens group 200, a first light bar 300, a second lens group 400, second and third light sources 800, a third lens group 900, a second light bar 1000, a fourth lens group 1100, a band-pass filter 500, and a mirror 600.

[0032] The first light source 100 has a first optical axis. The first light source 100 includes an LED light source with a wavelength band of 360-390 nm, and its wave peaks are at 360-370 nm and 380-390 nm. The lithography effect of the LED light source in this wavelength band is the best.

[0033] The first lens group 200 is arranged along the first optical axis, and the first lens group 200 is adjacent to the first light source 100. The first lens group 200 is used to couple all the light emitted by the first light source 100 to the entrance end of the first light bar 300 and to improve the uniformity of the first light source 100. Specifically, the first lens group 200 includes a first lens one 201 and a first lens two 202 that are spaced apart along the first optical axis. The first lens one 201 is arranged close to the first light source 100, and the first lens two 202 is arranged close to the first light bar 300. Among them, the first lens one 201 is a meniscus positive lens, and the first lens two 202 is a biconvex lens.

[0034] The first light bar 300 is arranged along the first optical axis, and the first light bar 300 is adjacent to the first lens group 200. The first light bar 300 is used to cause the light entering the first light bar 300 to undergo multiple total internal reflections to form a uniform illumination beam. Specifically, the first light bar 300 can be a solid or hollow conical light bar, and the material used can be ultraviolet fused silica. The conical first light bar 300 can reduce the divergence angle of the light.

[0035] The second lens group 400 is arranged along the first optical axis, and the second lens group 400 is arranged adjacent to the first light bar 300. On the one hand, the second lens group 400 is used to couple and collimate the light emitted from the exit end of the first light bar 300, and on the other hand, it is used to form an illumination spot with a required size aperture and uniformity. Specifically, the second lens group 400 includes a first second lens 401 and a second second lens 402 arranged at intervals along the first optical axis. The first second lens 401 is arranged close to the first light bar 300, and the second second lens 402 is arranged close to the band-pass filter 500. Among them, the first second lens 401 is a meniscus positive lens, and the second second lens 402 is a biconvex lens. Although the first second lens 401 has the same type as the first first lens 201, their thicknesses and curvature radii are different. The same is true for the second second lens 402 and the second first lens 202, so that the second lens group 400 and the first lens group 200 have different functions. In addition, the specific thicknesses and curvature radii of the first first lens 201, the second first lens 202, the first second lens 401, and the second second lens 402 are not limited, as long as the first lens group 200 and the second lens group 400 can achieve the above functions according to the actual use situation.

[0036] The second and third light sources 800 have a second optical axis, and the second optical axis is perpendicular to the first optical axis. The second and third light sources 800 include two light sources, specifically including an LD light source with a wavelength band of 400-440nm and a solid laser light source with a wavelength band of 350-355nm. The wave peaks of the wavelength band of the LD light source are 400-410nm and 420-440nm, and the lithography effects of the LD light source and the solid laser light source in this wavelength band are both good.

[0037] The second and third light sources 800 cooperate with the first light source 100, so that the formed hybrid light source can comprehensively cover the wavelength band of 350-440nm (including the solid laser light source of 350-355nm, the LED light source of 360-390nm, and the LD light source of 400-440nm), so that the hybrid lighting system of the embodiment of the present invention has a wide process coverage. The LD light source and the solid laser light source are arranged together by means of optical fiber bundling. After the LD light source and the solid laser light source are turned on at the same time, the light generated by the two light sources can be located in the same light beam. In addition, according to the use requirements, only one of the LD light source or the solid laser light source can also be turned on.

[0038] The third lens group 900 is arranged along the second optical axis, and the third lens group 900 is arranged adjacent to the second and third light sources 800. The third lens group 900 is used to couple all the light emitted by the second and third light sources 800 into the entrance end of the second light bar 1000, and is used to improve the uniformity of the second and third light sources 800. Specifically, the third lens group 900 includes a first third lens 901 and a second third lens 902 arranged at intervals along the first optical axis. The first third lens 901 is arranged close to the second and third light sources 800, and the second third lens 902 is arranged close to the second light bar 1000. Among them, the first third lens 901 is a plano-convex lens, and the second third lens 902 is a biconvex lens.

[0039] The second light bar 1000 is arranged along the second optical axis, and the second light bar 1000 is arranged adjacent to the third lens group 900. The second light bar 1000 is used to make the light entering the second light bar 1000 undergo multiple total internal reflections to form a uniform illumination beam. Specifically, the second light bar 1000 can be a solid or hollow trapezoidal light bar, and the material used can be ultraviolet fused silica. The trapezoidal second light bar 1000 can form a more uniform illumination beam.

[0040] The fourth lens group 1100 is arranged along the second optical axis, and the fourth lens group 1100 is arranged adjacent to the second light bar 1000. On the one hand, the fourth lens group 1100 is used to couple and collimate the light emitted from the exit end of the second light bar 1000, and on the other hand, it is used to form an illumination spot with the required size aperture and uniformity. Specifically, the fourth lens group 1100 includes a first fourth lens 1101 and a second fourth lens 1102 arranged at intervals along the second optical axis. The first fourth lens 1101 is arranged close to the second light bar 1000, and the second fourth lens 1102 is arranged close to the band-pass filter 500. Among them, the first fourth lens 1101 is a plano-convex lens, and the second fourth lens 1102 is a biconvex lens. Although the first fourth lens 1101 has the same type as the first third lens 901, their thicknesses and curvature radii are different. The same is true for the second fourth lens 1102 and the second third lens 902, which makes the fourth lens group 1100 and the third lens group 900 have different functions. In addition, the specific thicknesses and curvature radii of the first third lens 901, the second third lens 902, the first fourth lens 1101, and the second fourth lens 1102 are not limited, as long as the third lens group 900 and the fourth lens group 1100 can achieve the above functions according to the actual use situation.

[0041] A band-pass filter 500 is disposed at the optical axis intersection of the first optical axis and the second optical axis to couple the first light beam emitted from the second lens group 400 and the second light beam emitted from the fourth lens group 1100 to obtain a mixed light beam. The band-pass filter 500 is required to allow all of the first light beam emitted from the second lens group 400 to pass through the band-pass filter 500, and is required to reflect all of the second light beam emitted from the fourth lens group 1100. Therefore, in the embodiment of the present invention, a band-pass filter with high transmittance for a light source in the 360-390 nm band and high reflectance for light sources in the 350-355 nm and 400-440 nm bands is used.

[0042] A reflector 600 is cooperatively disposed with the band-pass filter 500 and the digital micromirror device 700 to reflect the mixed light beam emitted from the band-pass filter 500 onto the digital micromirror device 700. The arrangement of the reflector 600 makes the setting position of the entire mixed illumination system relative to the digital micromirror device 700 more reasonable and can shorten the structural length of the entire mixed illumination system.

[0043] In the mixed illumination system of the embodiment of the present invention, the common lens group in the prior art is removed, and by adding a first lens group 200 and a third lens group 900 and simultaneously improving the second lens group 400 and the fourth lens group 1100, the mixed illumination system can still generate an illumination spot with a required size aperture and uniformity. In addition, on the premise that the mixed light source can fully cover the 350-440 nm band, the mixed illumination system of this embodiment can completely eliminate the axial chromatic aberration on the image plane of the digital micromirror device to ensure the lithography effect of the maskless lithography equipment.

[0044] Embodiment 2: A maskless lithography apparatus includes the mixed illumination system in Embodiment 1, so that the process coverage of the maskless lithography apparatus is relatively comprehensive and the lithography effect is very good.

[0045] The above-described embodiments are only used to describe the preferred embodiments of the present invention, and do not limit the concept and scope of the present invention. Without departing from the design concept of the present invention, various modifications and improvements made by those of ordinary skill in the art to the technical solutions of the present invention should fall within the protection scope of the present invention. The technical content claimed by the present invention has been fully recorded in the claims.

Claims

1. A hybrid lighting system with multiple bands and multiple light sources, characterized in that: Comprising A first light source (100) having a first optical axis; A first lens group (200) arranged along the first optical axis, and the first lens group (200) is arranged adjacent to the first light source (100); A first light bar (300) arranged along the first optical axis, and the first light bar (300) is arranged adjacent to the first lens group (200); A second lens group (400) arranged along the first optical axis, and the second lens group (400) is arranged adjacent to the first light bar (300); Second and third light sources (800) having a second optical axis, and the second optical axis is perpendicular to the first optical axis; A third lens group (900) arranged along the second optical axis, and the third lens group (900) is arranged adjacent to the second and third light sources (800); A second light bar (1000) arranged along the second optical axis, and the second light bar (1000) is arranged adjacent to the third lens group (900); A fourth lens group (1100) arranged along the second optical axis, and the fourth lens group (1100) is arranged adjacent to the second light bar (1000); A band-pass filter (500) is disposed at the optical axis intersection of the first optical axis and the second optical axis to couple the first light ray emitted by the second lens group (400) and the second light ray emitted by the fourth lens group (1100) to obtain a mixed light ray; A reflector (600) is cooperatively arranged with the band-pass filter (500) and the digital micromirror device (700) to reflect the mixed light ray emitted by the band-pass filter (500) onto the digital micromirror device (700).

2. The hybrid lighting system with multiple bands and multiple light sources according to claim 1, characterized in that: The first lens group (200) includes a first lens one (201) and a first lens two (202), and the first lens one (201) is a meniscus positive lens, and the first lens two (202) is a biconvex lens.

3. The hybrid lighting system with multiple bands and multiple light sources according to claim 2, characterized in that: The second lens group (400) includes a second lens one (401) and a second lens two (402), and the second lens one (401) is a meniscus positive lens, and the second lens two (402) is a biconvex lens.

4. The hybrid lighting system with multiple bands and multiple light sources according to claim 1, characterized in that: The third lens group (900) includes a third lens one (901) and a third lens two (902), and the third lens one (901) is a plano-convex lens, and the third lens two (902) is a biconvex lens.

5. The hybrid lighting system with multiple bands and multiple light sources according to claim 4, characterized in that: The fourth lens group (1100) includes a fourth lens one (1101) and a fourth lens two (1102), and the fourth lens one (1101) is a plano-convex lens, and the fourth lens two (1102) is a biconvex lens.

6. The hybrid lighting system with multiple bands and multiple light sources according to claim 1, characterized in that: The first light bar (300) is a conical light bar; the second light bar (1000) is a trapezoidal light bar.

7. The hybrid lighting system with multiple bands and multiple light sources according to claim 1, characterized in that: The first light source (100) includes an LED light source with a wavelength band of 360 - 390 nm; the second and third light sources (800) include an LD light source with a wavelength band of 400 - 440 nm and a solid laser light source with a wavelength band of 350 - 355 nm.

8. The hybrid lighting system with multiple bands and multiple light sources according to claim 7, characterized in that: The band-pass filter (500) is a band-pass filter that is highly transmissive to light sources in the 360 - 390 nm band and highly reflective to light sources in the 350 - 355 nm and 400 - 440 nm bands.

9. The hybrid lighting system with multiple bands and multiple light sources according to claim 7, characterized in that: The peak wavelengths of the LED light source are 360 - 370 nm and 380 - 390 nm; the peak wavelengths of the LD light source are 400 - 410 nm and 420 - 440 nm.

10. A maskless lithography apparatus, characterized in that: It includes the hybrid lighting system according to any one of claims 1 to 9.

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