Optical fiber type projection exposure photoetching device

Abstract

The utility model provides an optical fiber type projection exposure photoetching device. The optical fiber type projection exposure photoetching device comprises a light source system, a collimation beam expander, a mask and a workbench which are arranged according to a light beam path, the collimation beam expander is used for expanding or reducing the diameter of an incident light beam to a certain multiple, an input end divergence angle fine adjustment structure can be fixed after debugging and collimation, collimation and stability of an output light spot are guaranteed, and light is guided to the mask plate; the mask plate is used for engraving a processing image and forming the processing image when light passes through the mask plate; the projection objective lens is used for scaling down the image light beam on the mask plate according to a proportion and mapping the image light beam to the silicon wafer coated with the photoresist; and a homogenizing optical fiber is arranged in the light source system and is used for uniformly distributing the energy of the incident laser beam on a horizontal plane. A large number of reflectors and lens elements are omitted, the probability that light beams are affected by dust and equipment precision is reduced, and the quality of the light beams is improved. Due to the fact that parts are greatly reduced, a uniform, stable and reliable laser light source for photoetching exposure can be provided.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of photoetching machine light source especially a kind of optical fiber type projection exposure photoetching device. BACKGROUND

[0002] The structure of the photoetching device of prior art is shown in Figure 5 Two key technical problems exist in the existing projection exposure technology: 1 is the transmission problem of ultraviolet laser; 2 is the homogenization and shaping problem of ultraviolet laser. Regarding laser transmission, the existing technology uses multiple mirrors to reflect and transmit laser, wherein each mirror has fixed loss to laser, and the overall power loss of laser is large after the superposition of the loss of multiple mirrors. In addition, the mirror surface has a certain roughness, and the surface roughness of the mirror will affect the spatial transmission phase of laser every time the laser passes through a mirror. The superposition of multiple reflecting mirrors and lenses will complicate the final spatial energy distribution of laser. Regarding the homogenization and shaping of ultraviolet laser, the current main method is to use a lens group or a diffraction element to homogenize the energy distribution of laser. However, increasing the lens will increase the loss of laser, and the homogenization degree is low. As a laser transmission medium, the homogenization optical fiber can realize extremely low transmission loss, extremely high laser homogenization degree, and can realize the replacement of the transmission light path from the laser to the mask in photoetching, greatly simplifying the design difficulty of the photoetching light path. For example, a special optical fiber for realizing flat-top energy distribution and controlling beam quality is described in CN114859459A. However, with the progress of materials, the corresponding photoetching device has not been optimized, and the existing system still has many redundant components, which affects the production efficiency of chips, power consumption and equipment cost. For example, the structures described in JPH0897125A and CN110431487A. SUMMARY

[0003] The technical problem to be solved by the utility model is to provide an optical fiber type projection exposure photoetching device, which can greatly reduce the redundant elements of the exposure photoetching device, improve the utilization efficiency of laser, improve the homogenization degree of light source, and reduce the control difficulty, power consumption and manufacturing cost.

[0004] To solve the above technical problems, the utility model adopts the technical scheme of: an optical fiber type projection exposure photoetching device, comprising a light source system arranged according to a light beam path, a collimating beam expander, a mask and a workbench.

[0005] The collimating beam expander is used to expand or reduce the diameter of incident light beam to a certain multiple, and the input end divergence angle fine adjustment structure is fixed after collimation adjustment to ensure the collimation and stability of the output light spot and guide the light to the mask.

[0006] The mask is used for engraving an image, and the image is formed when the light passes through.

[0007] A projection objective for reducing an image beam on a mask to a scale and mapping it onto a silicon wafer coated with photoresist;

[0008] A worktable for carrying and moving the silicon wafer;

[0009] A homogenizing optical fiber is arranged in the light source system for homogenizing the energy of the incident laser beam in a horizontal plane.

[0010] In a preferred embodiment, the light source system comprises a laser light source, an attenuation controller, a beam coupler and a homogenizing optical fiber arranged in sequence;

[0011] The attenuation controller is used for actively controlling the output laser power;

[0012] The beam coupler is used for coupling the light beam to the homogenizing optical fiber.

[0013] In a preferred embodiment, the laser light source comprises an ultraviolet light source, a deep ultraviolet excimer laser light source or an extreme ultraviolet light source.

[0014] In a preferred embodiment, the attenuation controller comprises a mechanical diaphragm, a piezoelectric crystal diaphragm or a rotating wave plate type attenuation controller.

[0015] In a preferred embodiment, the beam coupler is a focusing lens for reducing the light spot to be transmitted into the homogenizing optical fiber;

[0016] Or the beam coupler is a fusion structure, which fuses the laser optical fiber with the homogenizing optical fiber when the laser light source is a laser optical fiber output.

[0017] In a preferred embodiment, a homogenizing optical fiber ring is arranged on the homogenizing optical fiber, i.e. the homogenizing optical fiber is wound into multiple ring structures and fixed to increase the degree of laser homogenization.

[0018] In a preferred embodiment, a light splitting coupler is further arranged between the output port of the homogenizing optical fiber and the input port of the collimating beam expander, which is used for splitting the incident light beam into multiple optical fibers, one of which is connected to the input port of the collimating beam expander, and the other is connected to an energy detector.

[0019] The energy detector is used for detecting the fluctuation of the laser energy and feeding back to adjust the laser output intensity of the laser light source.

[0020] In a preferred embodiment, the light spot interface energy of the output light beam of the collimating beam expander is flatly distributed.

[0021] In a preferred embodiment, the top surface shape of the flat top includes a square, a rectangle, a circle, an ellipse, a triangle or a line.

[0022] In a preferred embodiment, the homogenizing optical fiber is provided with a cladding and a core, and the cross-sectional shape of the core includes a square, a rectangle, a circle, an ellipse, a triangle or a line.

[0023] The homogenization structure of the homogenization optical fiber includes a graded-index structure at a fiber core, a partial ring structure, or a spatially asymmetric structure of any one of sharp angles, square angles, and obtuse angles.

[0024] The utility model provides a kind of optical fiber formula projection exposure photoetch device, by adopting homogenization optical fiber, omit a large number of reflector and lens element, especially compound eye lens, slit diffraction element etc., greatly reduce the probability that light beam is influenced by dust and is influenced by equipment precision, improve light beam quality.Due to the substantial reduction of parts, the production cost and control difficulty of entire photoetch system are greatly reduced, can provide uniform stable reliable photoetch exposure laser light source.The homogenization optical fiber ring structure of setting, further improve laser homogenization effect.Adopt the light splitting of coupling mode, compared with splitter in prior art, low loss, less interference, higher precision.The homogenization optical fiber ring of setting reaches balance between homogenization and energy attenuation, and can be customized according to the needs of homogenization compared with prior art, the utility model reduces the amount of use of lens, reduces laser transmission loss;And optical fiber is closed waveguide transmission, is not influenced by dust in environment, conventional optical path lens is greatly influenced after sticking dust, opens new technical route for the development of photoetch machine;And the photoetch machine optical path volume of prior art, after being influenced by environmental vibration, relative displacement is easily generated between lens, and spot stability reduces, and the utility model is influenced by vibration low. BRIEF DESCRIPTION OF DRAWINGS

[0025] The utility model will be further described below in connection with drawings and examples:

[0026] Figure 1 It is the system structure schematic drawing of the utility model.

[0027] Figure 2 It is the preferred system structure schematic drawing of the utility model.

[0028] Figure 3 It is the homogenization optical fiber output laser Gauss energy distribution effect drawing of the utility model.

[0029] Figure 4 It is the energy distribution diagram of the output homogenization laser spot of the utility model.

[0030] Figure 5 It is the typical structure schematic diagram of prior art photoetch machine.

[0031] In the figure, 1 is the laser source, 2 is the attenuation controller, 3 is the beam coupler, 4 is the homogenizing fiber, 41 is the homogenizing fiber ring, 5 is the beam splitter, 6 is the energy detector, 61 is the beam position pointing detector, 7 is the collimator expander, 8 is the mask, 9 is the projection lens, 10 is the silicon wafer, 11 is the displacement stage, 12 is the first-stage beam expander, 121 is the second-stage beam expander, 13 is the beam stabilization system, 14 is the first beam splitter, 15 is the pupil converter, 16 is the zoom beam group, 17 is the second beam splitter, 18 is the conical lens, 19 is the compound eye lens, 20 is the pupil shape adjuster, 21 is the condenser lens, 22 is the homogenization adjuster, 23 is the slit diffractor, and 24 is the coupling lens group. Detailed Implementation

[0032] Example 1:

[0033] like Figure 1 In the present invention, a fiber optic projection exposure lithography apparatus includes a light source system arranged according to the beam path, a collimator and beam expander 7, a mask 8 and a stage 11.

[0034] The collimator beam expander 7 is used to enlarge or reduce the diameter of the incident beam by a certain factor. The divergence angle fine-tuning structure at the input end can be fixed after collimation adjustment to ensure the collimation and stability of the output beam spot and guide the light to the mask plate 8. The collimator beam expander 7 is a lens group, including at least one negative lens to diverge the incident beam and one positive lens to capture and refocus the beam diverged by the negative lens, ultimately forming a magnified and more parallel output beam. The laser source after shaping and homogenization according to this invention is as follows: Figure 3 , 4 As shown in the image.

[0035] Mask 8 is used to engrave the image; the image is formed when light passes through it.

[0036] Projection lens 9 is used to scale down the image beam on the mask and map it onto the silicon wafer 10 coated with photoresist;

[0037] The worktable 11 is used to support and move the silicon wafer 10;

[0038] The light source system includes a homogenizing fiber 4 to ensure that the energy of the incident laser beam is uniformly distributed on the horizontal plane. Optionally, the homogenizing fiber 4 may be the homogenizing fiber 4 described in CN117434733A of this company.

[0039] In a preferred embodiment, the light source system includes a laser light source 1, an attenuation controller 2, a beam coupler 3, and a homogenizing fiber 4 arranged sequentially.

[0040] Attenuation controller 2 is used to actively control the output laser power;

[0041] Beam coupler 3 is used to couple the beam to the homogenizing fiber 4.

[0042] In a preferred embodiment, the laser light source 1 comprises an ultraviolet light (UV) source, such as g-line: 436 nm, i-line: 365 nm, generated by a high-pressure mercury lamp with a specific emission spectrum selected by optical filtering. Deep ultraviolet (DUV) excimer laser sources, such as KrF excimer laser: 248 nm, ArF excimer laser: 193 nm, F2 excimer laser: 157 nm. Extreme ultraviolet (EUV) light sources: wavelength range between 10 nm and 15 nm, commonly used EUV light source wavelength is 13.5 nm, EUV light source is generated by high-energy laser bombardment of tin droplets to obtain plasma.

[0043] In a preferred embodiment, the attenuation controller 2 comprises a mechanical iris, a piezoelectric crystal iris, or a rotating wave plate attenuation controller.

[0044] In a preferred embodiment, the beam coupler 3 is a focusing lens to reduce the spot size for transmission into the homogenization fiber 4.

[0045] Alternatively, the beam coupler 3 is a fusion structure, which fuses the laser fiber and the homogenization fiber 4 when the laser light source 1 is a laser fiber output. In this case, an integrated optical waveguide coupler is preferred, which uses a multi-branch coupling structure to distribute multiple light beams to a single-core or multi-core homogenization fiber 4.

[0046] Embodiment 2:

[0047] In a preferred embodiment, the homogenization fiber 4 is provided with a homogenization fiber ring 41, which is wound into multiple ring structures and fixed to increase the degree of laser homogenization. The homogenization fiber ring 41 in this case can increase the degree of laser homogenization by increasing the length. Due to the total reflection characteristics of the fiber, the attenuation of laser power is small, and after a sufficient number of reflections, the degree of laser homogenization is greatly improved. The present application achieves the same or even better light source homogenization effect with a more simplified structure compared to the prior art, and obtains a homogenized exposure light source suitable for a photolithography machine.

[0048] In a preferred embodiment, a light splitting coupler 5 is further provided between the output of the homogenization fiber 4 and the input of the collimating beam expander 7. The light splitting coupler 5 is used to split the incident light beam into multiple beams, one of which is connected to the input of the collimating beam expander 7, and the other is connected to the energy detector 6. The energy detector 6 is used to detect the fluctuation of laser energy and feedback adjust the laser output intensity of the laser light source 1 to improve the stability of the laser power. The laser energy detector in this case adopts, for example, the StarBright series of Coherent Company or the Vega series of Ophir Photonics Company.

[0049] In a preferred embodiment, the spot interface energy of the output light beam of the collimating beam expander 7 is flat-topped.

[0050] In a preferred embodiment, the flat top surface shape comprises a square, a rectangle, a circle, an ellipse, a triangle or a line.

[0051] In a preferred embodiment, the homogenizing optical fiber 4 is provided with a cladding and a core, and the cross-sectional shape of the core comprises a square, a rectangle, a circle, an ellipse, a triangle or a line.

[0052] The homogenization structure of the homogenizing optical fiber 4 comprises a graded-index fiber structure at the core, a bias ring structure or a spatial asymmetric structure of any one of an acute angle, a square angle and an obtuse angle. The graded-index fiber structure at the core is that the refractive index of the core is not constant but gradually decreases from the center of the core to the edge, and preferably, the refractive index varies in a parabolic distribution mode. The bias ring structure refers to that the core of the optical fiber is uniformly distributed with a material, and a different refractive index structure, such as a ring structure, is arranged in the core to break the spatial symmetry of the structure as a whole, so that the light beam is uniformly distributed in the transmission of the optical fiber. The circle is an absolute spatial symmetric structure, which has an infinite number of symmetry axes passing through the circle; and the acute angle, the square angle and the obtuse angle are non-absolute spatial symmetric structures which have only a few symmetry axes. The transmission of the laser in the optical fiber is approximately the superposition of infinite diffractions, and because the circle is absolutely symmetric, the diffraction intensity center is distributed at the center of the circle; and the non-symmetric structures of the acute angle, the square angle and the obtuse angle avoid the superposition of the diffraction intensity center to the geometric center of the structure each time, and instead, the intensity is filled in the whole non-symmetric structure, so that the homogenization of the laser spot is realized. The homogenization effect of the present application is shown in Figure 3 4 .

[0053] The above-mentioned embodiments are only preferred technical solutions of the present application, and should not be regarded as limitations of the present application. The embodiments in the present application and the features in the embodiments can be combined with each other as long as there is no conflict. The protection scope of the present application should be based on the technical solutions of the claims, including the equivalent replacement solutions of the technical features of the technical solutions of the claims. That is, the equivalent replacement improvement within this range is also within the protection scope of the present application.​

Claims

1. A fiber-optic projection exposure photolithography apparatus, characterized by: The light source system comprises a collimating expander (7), a mask (8) and a worktable (11) arranged along the light beam path; The collimating expander (7) is used to expand or reduce the diameter of the incident light beam to a certain multiple, and the input end is provided with a divergence angle fine adjustment structure which can be fixed after collimation adjustment, so as to ensure the collimation and stability of the output light spot and guide the light to the mask (8); The mask (8) is used to engrave the image, and the processing image is formed when the light passes through; The projection objective (9) is used to reduce the image light beam on the mask in proportion and map it to the silicon wafer (10) coated with photoresist; The worktable (11) is used to carry and move the silicon wafer (10); The homogenization optical fiber (4) is arranged in the light source system and is used to distribute the energy of the incident laser light beam uniformly in the horizontal plane.

2. A fiber-optic projection exposure photolithography apparatus according to claim 1, characterized in that: The light source system comprises a laser light source (1), an attenuation controller (2), a beam coupler (3) and a homogenization optical fiber (4) arranged in sequence; The attenuation controller (2) is used to actively control the output laser power; The beam coupler (3) is used to couple the light beam to the homogenization optical fiber (4).

3. A fiber-optic projection exposure photolithography apparatus according to claim 2, characterized in that: The laser light source (1) comprises an ultraviolet light source, a deep ultraviolet light excimer laser light source or an extreme ultraviolet light source.

4. A fiber-optic projection exposure photolithography apparatus according to claim 2, characterized by: The attenuation controller (2) comprises a mechanical diaphragm, a piezoelectric crystal diaphragm or a rotating wave plate type attenuation controller.

5. A fiber-optic projection exposure photolithography apparatus according to claim 2, characterized by: The beam coupler (3) is a focusing lens to reduce the light spot to be transmitted into the homogenization optical fiber (4); Or the beam coupler (3) is a fusion structure, and when the laser light source (1) is a laser optical fiber output, the laser optical fiber is fused with the homogenization optical fiber (4).

6. A fiber-optic projection exposure photolithography apparatus according to any one of claims 1 to 5, characterized in that: A homogenization optical fiber ring (41) is arranged on the homogenization optical fiber (4), that is, the homogenization optical fiber (4) is wound into multiple ring structures and fixed to increase the homogenization degree of the laser.

7. A fiber-optic projection exposure photolithography apparatus according to claim 1, characterized by: A light splitting coupler (5) is further arranged between the output port of the homogenization optical fiber (4) and the input port of the collimating expander (7), and the light splitting coupler (5) is used to split the incident light beam into multiple optical fibers, one of which is connected with the input port of the collimating expander (7), and the other of which is connected with an energy detector (6); The energy detector (6) is used to detect the fluctuation of the laser energy and feedback adjust the laser output intensity of the laser light source (1).

8. A fiber-optic projection exposure photolithography apparatus according to claim 1, characterized by: The light spot interface energy of the output light beam of the collimating expander (7) is flat top distribution.

9. A fiber-optic projection exposure photolithography apparatus according to claim 8, characterized by: The flat top surface shape comprises a square, a rectangle, a circle, an ellipse, a triangle or a line.

10. A fiber-optic projection exposure photolithography apparatus according to claim 9, characterized by: The homogenization optical fiber (4) is provided with a cladding and a core, and the cross-sectional shape of the core comprises a square, a rectangle, a circle, an ellipse, a triangle or a line; The homogenization structure of the homogenization optical fiber (4) comprises a graded refractive index structure at the core, a bias ring structure or a spatial asymmetric structure of any one of sharp angle, square angle and obtuse angle.

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