An exposure system and a lithographic apparatus with self-compensation of illumination uniformity

Abstract

The utility model discloses an exposure system and photoetching equipment of illumination uniformity self -compensation, and exposure system includes laser light source, illumination system, spatial light modulator and projection objective system, and laser light source enters spatial light modulator after homogenization through illumination system, and spatial light modulator will be modulated after the incident light and be imaged in target place through projection objective system. Exposure system includes still setting up including energy detector, data processor and modulation driver's homogenization compensation system, and the light of guaranteeing output has good uniformity through setting up the illumination system of homogenization, shaping function, and through setting up homogenization compensation system, can improve the illumination uniformity of exposure system when not needing to open the shell and debug lens in factory end manufacturing, in production scene, through homogenization compensation system periodicity detection and correction exposure system's uniformity, need not to replace lens or light source and so on core spare, has saved the maintenance time of customer, and the cost of replacement device.

Description

Technical Field

[0001] This utility model relates to the field of DLP exposure technology, and in particular to an exposure system and lithography equipment with self-compensating illumination uniformity. Background Technology

[0002] Currently, DLP exposure systems are developing towards higher precision (such as submicron lithography) and larger format (such as G10 panels), and the illumination uniformity of the exposure system has become the core bottleneck restricting yield and performance.

[0003] For semiconductor lithography exposures with a linewidth ≤ 5μm, illumination uniformity > 98% is required; otherwise, wafer yield will decrease. However, current exposure systems typically only achieve 90% illumination uniformity. While 95% might be achievable through time-consuming and laborious adjustments, illumination uniformity deteriorates with product use due to varying attenuation levels of individual dies within the light source or changes in the lens. Currently, uniformity issues caused by variations in die attenuation or minor lens changes are usually addressed by replacing the light source or lens. This approach is costly and may disrupt production. Utility Model Content

[0004] To address the aforementioned problems, this invention provides an exposure system with self-compensating illumination uniformity. The system dynamically adjusts the light energy based on the light energy data of the exposure system, effectively solving the illumination uniformity problem of the exposure system.

[0005] To achieve the above-mentioned utility model objectives, this utility model discloses an exposure system with self-compensating illumination uniformity. The exposure system includes a laser source, an illumination system, a spatial light modulator, and a projection lens system arranged sequentially along the optical path. The laser source enters the spatial light modulator after being homogenized by the illumination system. The spatial light modulator modulates the incident light and projects it onto the imaging surface through the projection lens system. The exposure system is further provided with a uniform light compensation system, which includes: An energy detector is located in the outgoing light path of the projection lens system in the exposure system and is used to detect the light energy data of the projection area of ​​the projection lens system. A data processor, connected to the energy detector, is used to receive and process the light energy data transmitted by the energy detector and generate a phase compensation signal. A modulation driver is signal-connected to the data processor and coupled to the spatial light modulator. The modulation driver is used to receive a phase compensation signal and adjust the voltage of the pixel to be compensated in the spatial light modulator according to the phase compensation signal.

[0006] Preferably, the lighting system includes a light-diffusing element and a light-shaping component arranged sequentially along the light propagation direction.

[0007] Preferably, the lighting system includes two sets of shaping components with mutually perpendicular optical axes, and a reflector located between the two sets of shaping components.

[0008] Preferably, the two shaping components include a first shaping component located on the light-incident side of the reflector and a second shaping component located on the light-outceasing side of the reflector, with an aperture between the reflector and the second shaping component.

[0009] Preferably, the energy detector is configured to detect light energy data at different positions in the x and y directions of the projection area of ​​the projection lens system.

[0010] Preferably, the energy detector is an energy detection board that includes an optical power meter.

[0011] Preferably, the data processor is an FPGA system.

[0012] Preferably, the data processor includes a Gigabit Ethernet interface.

[0013] Preferably, the modulation driver is integrated into the spatial light modulator, which is a PLM-type digital micromirror device.

[0014] In another aspect, this utility model provides a photolithography apparatus, including an exposure platform that carries a substrate to be exposed. The photolithography apparatus includes the exposure system with self-compensating illumination uniformity as described in any of the above technical solutions. The exposure platform is located on the outgoing light path of the projection lens system, and the energy detector is disposed on the exposure platform.

[0015] The exposure system of this invention ensures excellent uniformity of output light through an illumination system equipped with functions such as light equalization and shaping. By incorporating a light equalization compensation system, the illumination uniformity of the exposure system can be improved during factory manufacturing without disassembling the housing to adjust the lens. In production settings, the light equalization compensation system periodically detects and corrects the uniformity of the exposure system, eliminating the need to replace core components such as lenses or light sources, thus saving customers maintenance time and replacement costs. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the exposure system with self-compensating illumination uniformity in this utility model; Figure 2 This is a schematic diagram of the lighting system in one specific embodiment of the present invention; Figure 3 This is a schematic diagram of the exposure system in a specific embodiment of the present invention; Figure 4 This is a schematic diagram illustrating the principle of phase modulation in a PLM-type DMD. Figure 5 This is a schematic diagram of the detection path for the energy detector. Detailed Implementation

[0017] To facilitate understanding of this utility model, a more comprehensive description of it will be provided below in conjunction with specific embodiments. Preferred embodiments of this utility model are given in the specific embodiments. However, this utility model can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this utility model.

[0018] The terms "optional" and similar expressions used in this invention refer to embodiments of the invention that may provide certain beneficial effects under certain circumstances. However, other embodiments may also be optional in the same or other circumstances. Furthermore, the description of one or more optional embodiments does not imply that other embodiments are unavailable, nor is it intended to exclude other embodiments from the scope of this invention.

[0019] This invention provides an exposure system with self-compensating illumination uniformity, which is used in photolithography equipment. (See reference...) Figures 1 to 3 As shown, the exposure system includes a laser source 1, an illumination system 2, a spatial light modulator 3, and a projection lens system 4. These components are arranged sequentially along the optical path. The laser source 1, after being homogenized by the illumination system 2, enters the spatial light modulator 3. The spatial light modulator 3 modulates the incident light into patterned light. This patterned light is then magnified or reduced by a certain factor by the projection lens system 4 and projected onto the imaging surface. The imaging surface can be the surface of the substrate to be exposed, such as a PCB board or a wafer. The spatial light modulator 3 can be a liquid crystal spatial light modulator (LC-SLM) or a PLM-type digital micromirror device (DMD). It is understood that, in addition to the above structure, the lithography equipment also includes other structures found in existing lithography equipment, which will not be elaborated upon here.

[0020] The exposure system also includes a uniform light compensation system 5, which comprises an energy detector 51, a data processor 52, and a modulation driver 53. Specifically, the energy detector 51 is located on the outgoing light path of the projection lens system 4 in the exposure system and is used to detect the light energy data of the projection area of ​​the projection lens system 4. The projection area of ​​the projection lens system 4 can be understood as the area where the exposure system can form an exposure pattern. The energy detector 51 and the data processor 52 are signal-connected. The data processor 52 is used to receive and process the light energy data transmitted by the energy detector 51 and generate a phase compensation signal. The modulation driver 53 is signal-connected to the data processor 52 and is coupled to the spatial light modulator 3. The modulation driver 53 is used to receive the phase compensation signal and adjust the voltage of the pixel to be compensated in the spatial light modulator 3 according to the phase compensation signal. By precisely controlling the voltage on each pixel, the phase delay of the outgoing light of that pixel relative to the incident light can be independently controlled, thereby realizing dynamic uniform adjustment of light energy based on the light energy data of the exposure system.

[0021] The illumination uniformity self-compensating exposure system of this invention detects the light energy data of the projection area of ​​the projection lens system 4 using an energy detector 51. A data processor 52 then processes the light energy data to generate a phase compensation signal. A modulation driver 53 adjusts the voltage of the pixel to be compensated in the spatial light modulator based on the phase compensation signal. This achieves dynamic uniformity adjustment of the light energy according to the light energy data of the exposure system, improving the illumination uniformity of the exposure system and solving the illumination uniformity problem of the illumination system 2. By setting a uniform light compensation system 5 in the exposure system, the illumination uniformity of the exposure system can be improved without disassembling the housing to adjust the lens during factory manufacturing. In production scenarios, the uniformity of the exposure system is periodically detected and corrected by the uniform light compensation system 5, eliminating the need to replace core components such as lenses or light sources, saving customers maintenance time and replacement costs.

[0022] Furthermore, such as Figure 2As shown, the illumination system 2 includes a light homogenizer 21 and a shaping component 22 arranged sequentially along the light propagation direction. The light homogenizer 21 transforms the incident non-uniformly distributed laser beam into a parallel beam with highly uniform intensity, achieving light homogenization. Then, the shaping component 22 precisely converts the homogenized uniform light spot into an illumination light field with a specific shape, size, and angle distribution to meet the needs of different photolithography processes. Specifically, the light homogenizer 21 can be a light homogenizer bar, a microlens array, etc. The exposure system in this invention ensures good uniformity of the output light by setting the illumination system 2 with functions such as light homogenization and shaping. At the same time, the light homogenization compensation system 5 can improve the illumination uniformity of the exposure system without disassembling the housing to adjust the lens during factory manufacturing. In the production scenario, the light homogenization compensation system 5 periodically detects and corrects the uniformity of the exposure system without replacing core components such as lenses or light sources, saving customers maintenance time and replacement costs.

[0023] Furthermore, the lighting system 2 includes two sets of shaping components 22 with mutually perpendicular optical axes, and a reflector 23 located between the two sets of shaping components 22. Specifically, the two sets of shaping components 22 include a first shaping component 221 located on the light-incident side of the reflector 23, and a second shaping component 222 located on the light-outceasing side of the reflector 23. By changing the optical path direction through the reflector 23, the output light from the first shaping component 221 is introduced into the second shaping component 222. Through the cooperation of the two sets of shaping components 22, the light field is shaped and controlled multiple times, improving resolution and image quality. Specifically, the shaping component 22 can be selected as a lens group, and the reflector 23 can be selected as a plane mirror.

[0024] Furthermore, an aperture 24 is provided between the reflector 23 and the second shaping component 222. Through the coordinated work of the aperture 24, the light-diffusing component 21 and the shaping component 22 in the illumination system 2, the photolithographic pattern finally projected onto the substrate has high resolution, high contrast and extremely high linewidth uniformity.

[0025] In a specific embodiment, the energy detector 51 can be an energy detection plate disposed on the exposure platform, which is a substrate to be exposed in a photolithography device. The exposure platform is located below the exposure system, specifically in the outgoing light path of the projection lens system. The energy detection plate includes an optical power meter, which is moved by the exposure platform to detect the optical power data of the projection area and obtain the brightness data of various positions in the exposure system. Further, the energy detector 51 is configured to detect the optical energy data at different x and y coordinate positions in the projection area of ​​the projection lens system 4 to obtain the energy distribution of the projection area. The detection path of the energy detection plate can be set as needed, for example, see [reference needed]. Figure 5As shown, after the exposure platform moves to the initial position (x0, y0), it moves slowly along the y-direction while the energy detection board collects optical power data. When the exposure platform moves to the position (x0, yn), it moves to the position (x1, y0) and moves slowly along the y-direction again while the energy detection board collects optical power data. The above steps are repeated to complete the detection of all projection areas, thereby obtaining the energy distribution table of (x, y, energy value).

[0026] Furthermore, the data processor 52 can be an FPGA system. FPGA stands for Field Programmable Gate Array. Specifically, the data processor 52 can be a Xilinx Kintex UltraScale series FPGA system of level KU060 or higher, or a Virtex UltraScale series FPGA system of level XCVU065 or higher. The data processor 52 includes a Gigabit Ethernet interface, which can quickly receive the light energy data transmitted by the energy detector 51. Then, the data processor 52 calculates the light intensity standard deviation and uniformity coefficient based on the light energy data, thereby identifying the locations and energy differences where the light energy is weak in the exposure system, generating corresponding phase compensation signals, and compensating for those areas. This improves the illumination uniformity of the exposure system and solves the illumination uniformity problem of illumination system 2.

[0027] In one embodiment, see Figure 3As shown, the modulation driver 53 is integrated into the spatial light modulator 3. The spatial light modulator 3 is selected as a PLM-type digital micromirror device, or PLM-type DMD for short. A PLM-type DMD is a spatial light modulator 3 based on MEMS micromirror technology that can directly modulate the phase of light waves. Each micromirror in the PLM-type DMD can be understood as a pixel of the spatial light modulator 2. The PLM-type DMD changes the optical path by physically moving the position of the micromirrors, thereby achieving precise phase control. In this embodiment, the energy detector 51 is an energy detection board set on the exposure platform, and the data processor 52 is an FPGA system. The exposure platform drives the energy detection board to detect the light power data at different x and y coordinate positions in the projection area of ​​the projection lens system. The FPGA system receives the light energy data at different positions through a gigabit Ethernet interface, and uses the algorithm pre-stored inside the data processor 52 to calculate the standard deviation of light intensity and the uniformity coefficient, generating a PLM-type DMD phase compensation signal. The phase compensation signal can specifically be a digital signal containing the desired phase distribution. The modulation driver 53 is a driving circuit integrated on the chip of the PLM-type DMD. The modulation driver 53 (driving circuit) receives this digital signal and simultaneously calculates the target displacement required for each micromirror. For example, for 16 levels of displacement, the grayscale value is decoded into an integer level between 0 and 15. Based on the calculated target displacement level, the driving circuit applies a precise voltage to the electrode below the micromirror that needs to be added in the DMD, causing the micromirror to move downwards and stably contact a stop point at a specific height. Changing the voltage level of the driving circuit alters the electrostatic force, pulling the micromirror to different stop points, thus achieving discrete but precise vertical displacement. This changes the optical phase of the micromirror array, i.e., adjusting the optical phase of the spatial light modulator.

[0028] Preferably, the PLM-type DMD has 16 levels of micromirror displacement. (See also...) Figure 4 The schematic diagram of the phase modulation principle of the PLM-type DMD is shown. The PLM-type DMD dynamically adjusts the optical phase through 16 levels of micromirror displacement (resolution 250nm) to achieve submicron-level optical field reconstruction. A controllable diffraction pattern is generated through the coordinated motion of the micromirror array in the PLM-type DMD, with a phase modulation depth λ=405nm, to compensate for optical uniformity.

[0029] This utility model also discloses a photolithography apparatus, which includes an exposure system with self-compensating illumination uniformity. The specific structure of the exposure system with self-compensating illumination uniformity is as described above and will not be repeated here. The photolithography apparatus also includes an exposure platform that carries the substrate to be exposed. The exposure platform is disposed below the exposure system and located in the output light path of the projection lens system 4. An energy detector 51 in the exposure system with self-compensating illumination uniformity is disposed on the exposure platform. The exposure platform drives the energy detector 51 to move in order to detect the light energy data of the projection area of ​​the projection lens system 4.

[0030] The illumination uniformity self-compensation exposure system of this invention ensures good uniformity of output light by incorporating functions such as light homogenization and shaping in the illumination system. The energy detector 51 in the light homogenization compensation system 5 detects the light energy data of the projection area of ​​the projection lens system. The data processor 52 then processes the light energy data to generate a phase compensation signal. The modulation driver 53 adjusts the voltage of the pixel to be compensated in the spatial light modulator according to the phase compensation signal, thereby dynamically homogenizing and adjusting the light energy based on the light energy data of the exposure system, improving the illumination uniformity of the exposure system and solving the illumination uniformity problem of the illumination system 2. By setting up the light homogenization compensation system 5, the illumination uniformity of the exposure system can be improved without disassembling the housing to adjust the lens during factory manufacturing. In production scenarios, the light homogenization compensation system 5 periodically detects and corrects the uniformity of the exposure system, eliminating the need to replace core components such as lenses or light sources, saving customers maintenance time and replacement costs.

[0031] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. An exposure system with self-compensating illumination uniformity, the exposure system comprising a laser source, an illumination system, a spatial light modulator, and a projection lens system arranged sequentially along the optical path, characterized in that, The laser light source enters the spatial light modulator after being homogenized by the illumination system. The spatial light modulator modulates the incident light and projects it onto the imaging surface through the projection lens system. The exposure system is further provided with a uniform light compensation system, which includes: An energy detector is located in the outgoing light path of the projection lens system in the exposure system and is used to detect the light energy data of the projection area of ​​the projection lens system. A data processor, connected to the energy detector, is used to receive and process the light energy data transmitted by the energy detector and generate a phase compensation signal. A modulation driver is signal-connected to the data processor and coupled to the spatial light modulator. The modulation driver is used to receive a phase compensation signal and adjust the voltage of the pixel to be compensated in the spatial light modulator according to the phase compensation signal.

2. The exposure system with self-compensating illumination uniformity according to claim 1, characterized in that, The lighting system includes a light-diffusing element and a light-shaping component arranged sequentially along the direction of light propagation.

3. The exposure system with self-compensating illumination uniformity according to claim 2, characterized in that, The lighting system includes two sets of shaping components with their optical axes perpendicular to each other, and a reflector located between the two sets of shaping components.

4. The exposure system with self-compensating illumination uniformity according to claim 3, characterized in that, The two shaping components include a first shaping component located on the light-incident side of the reflector and a second shaping component located on the light-outceasing side of the reflector, with an aperture between the reflector and the second shaping component.

5. The exposure system with self-compensating illumination uniformity according to claim 1, characterized in that, The energy detector is configured to detect light energy data at different positions in the x and y directions within the projection area of ​​the projection lens system.

6. The exposure system with self-compensating illumination uniformity according to claim 1, characterized in that, The energy detector is an energy detection board that includes an optical power meter.

7. The exposure system with self-compensating illumination uniformity according to claim 1, characterized in that, The data processor is an FPGA system.

8. The exposure system with self-compensating illumination uniformity according to claim 1, characterized in that, The data processor includes a gigabit Ethernet interface.

9. The exposure system with self-compensating illumination uniformity according to claim 1, characterized in that, The modulation driver is integrated into the spatial light modulator, which is a PLM-type digital micromirror device.

10. A photolithography apparatus, comprising an exposure platform supporting a substrate to be exposed, characterized in that, The photolithography apparatus includes the illumination uniformity self-compensating exposure system as described in any one of claims 1-9, wherein the exposure platform is located on the outgoing light path of the projection lens system, and the energy detector is disposed on the exposure platform.

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