A light beam monitoring device

Abstract

A light beam monitoring device comprises a base frame, a position monitoring assembly, an angle monitoring assembly and a plurality of optical elements; the base frame is a one-piece structure and is provided with a light beam incident channel and a monitoring light beam transmission channel; the light beam incident channel is arranged in a main light path, and the monitoring light beam transmission channel is arranged opposite to the light beam incident channel and has an optical axis direction deviating from an optical axis direction of the main light path; the optical elements comprise a coupling beamsplitter, which is arranged in the light beam incident channel and is arranged obliquely towards the monitoring light beam transmission channel to reflect part of the light beam in the main light path into the monitoring light beam transmission channel; the position monitoring assembly and the angle monitoring assembly are arranged opposite to the monitoring light beam transmission channel to monitor the position and the angle of the light beam in the monitoring light beam transmission channel, thereby realizing the position monitoring and the angle monitoring of the light beam in the main light path. The light beam monitoring device provided in the application has the advantages of compact structure, small size, light weight and small space constraint.

Description

A beam monitoring device Technical Field

[0001] This invention relates to the field of lithography machine technology, and more specifically to a beam monitoring device. Background Technology

[0002] In the illumination system of a lithography machine, the position and direction of the output beam of the ArFi excimer laser drift. After long-distance transmission, the position and direction of the laser output beam are also affected by ground vibration, ambient airflow, etc., causing the position and direction of the beam incident on the illumination system to drift over time. Therefore, it is necessary to monitor the position and direction of the beam output by the ArFi excimer laser during the transmission process to ensure that a uniform and stable illumination field with light intensity distribution is obtained on the silicon wafer during the exposure process.

[0003] Existing beam monitoring devices can monitor the position and direction of the beam. However, their structure is a separate design and is bulky. The overall space of the lithography machine's illumination system is limited. If the beam monitoring device is too large, it will easily lead to a bulky overall structure of the lithography machine's illumination system, which in turn will result in a bulky overall structure of the lithography machine, making the overall structure of the lithography machine large and cumbersome. Summary of the Invention

[0004] In view of the structural defects of existing beam monitoring devices, this application provides a beam monitoring device that, by designing an integrated base frame, allows the relevant optical components to be mounted on the integrated base frame, thereby making the overall structure of the beam monitoring device compact, small in size and light in weight.

[0005] The technical solution of this invention is as follows:

[0006] The present invention provides a beam monitoring device, comprising: a base frame, a position monitoring component, an angle monitoring component, and several optical elements;

[0007] The base frame is a one-piece molded structure, and the base frame has a beam incident channel and a monitoring beam transmission channel;

[0008] The beam incident channel is disposed in the main optical path, the monitoring beam transmission channel is disposed relative to the beam incident channel, and the optical axis direction of the monitoring beam transmission channel is deviated from the optical axis direction of the main optical path;

[0009] The optical element includes a coupling beam splitter, which is disposed in the beam incident channel and tilted toward the monitoring beam transmission channel to reflect a portion of the beam in the main optical path into the monitoring beam transmission channel.

[0010] The position monitoring component and the angle monitoring component are arranged relative to the monitoring beam transmission channel to monitor the position and angle of the beam in the monitoring beam transmission channel, thereby realizing the position and angle monitoring of the beam in the main optical path.

[0011] More preferably, the monitoring beam transmission channel includes a first beam transmission channel, a second beam transmission channel, and a beam splitting channel; the optical element further includes a first reflecting mirror and a beam splitter.

[0012] The first beam transmission channel is disposed relative to the beam incident channel, and the optical axis direction of the first beam transmission channel deviates from the optical axis direction of the main optical path;

[0013] The second beam transmission channel is disposed relative to the first beam transmission channel, and the optical axis direction of the second beam transmission channel deviates from the optical axis direction of the first beam transmission channel;

[0014] The first reflector is disposed within the first beam transmission channel and is inclined toward the second beam transmission channel, for reflecting the beam in the first beam transmission channel to the second beam transmission channel;

[0015] The beam splitting channel is positioned relative to the second beam transmission channel, and the beam splitter is positioned within the beam splitting channel and tilted toward the second beam transmission channel. It is used to split and reflect the beam in the second beam transmission channel. The split beam enters the position monitoring component, and the reflected beam enters the angle monitoring component.

[0016] More preferably, the optical axis direction of the first beam transmission channel is perpendicular to the optical axis direction of the main optical path, and the optical axis direction of the second beam transmission channel is perpendicular to the optical axis direction of the first beam transmission channel.

[0017] More preferably, the beam splitting channel is provided with a position monitoring channel and an angle monitoring channel; the position monitoring component is disposed relative to the position monitoring channel, the angle monitoring component is disposed relative to the angle monitoring channel, and the optical element further includes a first lens, a second lens, and a second reflector;

[0018] The first lens is disposed in the position monitoring channel and is used to focus the beam of the beam splitter onto the position monitoring component so that the position monitoring component can monitor the position of the beam.

[0019] The second lens and the second reflector are respectively disposed in the angle monitoring channel. The second lens is used to focus the reflected beam of the beam splitter, and the second reflector is used to reflect the focused reflected beam back to the angle monitoring component so that the angle monitoring component can monitor the beam angle.

[0020] More preferably, the optical axis of the position monitoring channel is coaxial with the optical axis of the second beam transmission channel, and the optical axis of the angle monitoring channel is parallel to the optical axis of the second beam transmission channel.

[0021] More preferably, the coupling beam splitter, the first reflector, the beam splitter, and the second reflector are all mounted on the base frame from the outside in.

[0022] More preferably, the coupling beam splitter, the first reflector, the beam splitter, and the second reflector are respectively inclined toward the interior of the base frame.

[0023] More preferably, the optical element further includes a third lens, which is disposed within the first beam transmission channel.

[0024] More preferably, the coupling beam splitter is adjustable, while the third lens, the first reflector, the beam splitter, the first lens, the second lens, and the second reflector are fixed.

[0025] More preferably, the third lens and the first lens form a dual telecentric measurement optical path to image the light spot onto the position monitoring component, and the third lens and the second lens form a secondary focusing optical path to image the light spot onto the angle monitoring component.

[0026] According to the above embodiment of the beam monitoring device, due to the design of an integrated base frame, the base frame is provided with a beam incident channel and a monitoring beam transmission channel. A portion of the beam in the main optical path is reflected into the monitoring beam transmission channel by a coupling beam splitter. The position and angle of the beam are monitored by a position monitoring component and an angle monitoring component. The relevant optical components are embedded in the base frame, which makes the overall structure of the beam monitoring device small, simple, lightweight and with little space constraint. Attached Figure Description

[0027] Figure 1 is the optical path diagram of the lighting system;

[0028] Figure 2 is the optical path diagram of the beam monitoring device;

[0029] Figure 3 is a structural diagram of the beam monitoring device;

[0030] Figure 4 is a structural diagram of the base frame;

[0031] Figure 5 shows the structural diagram of the base frame from another orientation.

[0032] Figure 6 shows the structural diagram of the base frame from another orientation.

[0033] Figure 7 shows the optical path diagram for beam position measurement;

[0034] Figure 8 shows the optical path diagram for beam angle measurement. Detailed Implementation

[0035] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings.

[0036] This application provides a beam monitoring device for monitoring the position and angle of the beam in a lithography machine illumination system to ensure a uniform and stable illumination field on the silicon wafer surface during exposure. Considering the structural complexity and space constraints of the lithography machine illumination system, the beam monitoring device of this application uses an integrated frame as support, reducing structural complexity. Simultaneously, relevant optical components are embedded within the internal space of the frame to reduce the size and weight of the beam monitoring device, thereby achieving the goal of reducing the overall structural volume of the lithography machine illumination system.

[0037] First, it should be noted that the structural design of the beam monitoring device is based on the optical path diagram of the beam monitoring device, and the optical path of the lithography machine illumination system is shown in Figure 1. The position of the optical path of the beam monitoring device in the optical path of the lithography machine illumination system is shown as A in Figure 1.

[0038] As shown in Figure 2, the optical components in the optical path of the beam monitoring device include a coupling beam splitter, a lens, a reflector, and a beam splitter. This application designs an integrated base frame and embeds the coupling beam splitter, lens, reflector, and beam splitter inside the base frame, thereby making the overall structure of the beam monitoring device simple, the size small, and the space constraints small.

[0039] The specific structure of the beam monitoring device provided in this application will be described in detail below.

[0040] The overall structure of the beam monitoring device of this application is shown in Figure 3, which includes a base frame 100, a position monitoring component 200, an angle monitoring component 300, and several optical elements.

[0041] The basic structural layout and working principle of the beam monitoring device of this application are as follows: The base frame 100 is an integrally formed structure, and the base frame 100 has a beam incident channel and a monitoring beam transmission channel; the beam incident channel is set in the main optical path, and the monitoring beam transmission channel is set relative to the beam incident channel, and the optical axis direction of the monitoring beam transmission channel is deviated from the optical axis direction of the main optical path; the optical element includes a coupling beam splitter 401, which is set in the beam incident channel and tilted towards the monitoring beam transmission channel to reflect part of the beam in the main optical path into the monitoring beam transmission channel; the position monitoring component and the angle monitoring component 300 are set relative to the monitoring beam transmission channel to monitor the position and angle of the beam in the monitoring beam transmission channel, thereby realizing the position and angle monitoring of the beam in the main optical path.

[0042] The monitoring beam transmission channel includes a first beam transmission channel, a second beam transmission channel, and a beam splitting channel; the optical elements also include a first reflector 402 and a beam splitter 403; the first beam transmission channel is disposed relative to the beam incident channel, and the optical axis of the first beam transmission channel deviates from the optical axis of the main optical path; the second beam transmission channel is disposed relative to the first beam transmission channel, and the optical axis of the second beam transmission channel deviates from the optical axis of the first beam transmission channel; the first reflector 402 is disposed within the first beam transmission channel and tilted toward the second beam transmission channel, for reflecting the beam in the first beam transmission channel to the second beam transmission channel; the beam splitting channel is disposed relative to the second beam transmission channel, and the beam splitter 403 is disposed within the beam splitting channel and tilted toward the second beam transmission channel, for splitting and reflecting the beam in the second beam transmission channel, wherein the split beam enters the position monitoring component 200, and the reflected beam enters the angle monitoring component 300.

[0043] Preferably, the optical axis of the first beam transmission channel is perpendicular to the optical axis of the main optical path, and the optical axis of the second beam transmission channel is perpendicular to the optical axis of the first beam transmission channel.

[0044] Preferably, the beam splitting channel includes a position monitoring channel and an angle monitoring channel; the position monitoring component 200 is positioned relative to the position monitoring channel, and the angle monitoring component 300 is positioned relative to the angle monitoring channel. The optical elements also include a first lens 404, a second lens 405, and a second reflector 406. The first lens 404 is positioned in the position monitoring channel and is used to focus the beam splitter beam of the beam splitter 403 onto the position monitoring component 200, so that the position monitoring component 200 can monitor the beam position. The second lens 405 and the second reflector 406 are respectively positioned in the angle monitoring channel. The second lens 405 is used to focus the reflected beam of the beam splitter 403, and the second reflector 406 is used to reflect the focused reflected beam back to the angle monitoring component 300, so that the angle monitoring component 300 can monitor the beam angle.

[0045] Preferably, the optical axis of the position monitoring channel is coaxial with the optical axis of the second beam transmission channel, and the optical axis of the angle monitoring channel is parallel to the optical axis of the second beam transmission channel.

[0046] Preferably, the optical element further includes a third lens 407, and the second lens 407 is disposed within the first beam transmission channel.

[0047] The following describes in detail the mounting methods of the base 100 and various optical components in this application, taking into account the optical path design of the beam incident channel 500, the first beam transmission channel, the second beam transmission channel, and the beam splitting channel.

[0048] The structural diagram of the base frame 100 is shown in Figure 4-6. The base frame 100 includes a horizontal part 101, an inclined part 102 and a vertical part 103. The horizontal part 101, the inclined part 102 and the vertical part 103 are integrally formed and are generally in the shape of ┌.

[0049] The transverse portion 101 includes a hollow portion 1011 and a non-hollow portion 1012. The hollow portion 1011 is disposed through the main optical path, and the non-hollow portion 1012 is located outside the main optical path. The hollow portion 1011 has a beam inlet hole and a beam outlet hole along the direction of the main optical path, and a beam inlet channel is formed between the beam inlet hole and the beam outlet hole.

[0050] The cavity structure of the non-cavity portion 1012 forms a first beam transmission channel. The cavity portion 1011 has a first window on one side relative to the non-cavity portion 1012. The coupling beam splitter 401 is installed in the cavity portion 1011 from the outside to the inside through the first window, and the coupling beam splitter 401 is tilted toward the first beam transmission channel. The center of the coupling beam splitter 401 is on a straight line with the center of the beam entrance aperture and the beam exit aperture provided in the cavity portion 1011. Thus, the coupling beam splitter 401 reflects part of the beam from the main optical path to the first beam transmission channel, and transmits another part of the beam to the beam exit aperture.

[0051] The third lens 407 is disposed in the cavity of the non-cavity portion 1012, and the optical axis of the third lens 407 is coaxial with the reflected optical axis of the coupling beam splitter 401.

[0052] The inclined portion 102 is inclined between the non-void portion 1012 and the vertical portion 103. A second window is provided on the side of the inclined portion 102 near the outer side. The first reflector 402 is installed in the inclined portion 102 from the outside to the inside through the second window. The non-void portion 1012 is provided with a light-transmitting hole relative to the light transmission direction of the first reflector 402, so that the reflected light of the first reflector 402 can reach the beam splitting channel through the light-transmitting hole. The reflection direction of the first reflector 402 is the second beam transmission channel.

[0053] The vertical section 103 is located below the non-void section 1012. The vertical section 103 has a third window. The beam splitter 403 is installed in the vertical section 103 at an angle from the outside to the inside through the third window. The bottom of the vertical section 103 has a position light monitoring through hole relative to the installation position of the beam splitter. The reflection optical axis of the first reflector 402, the center of the light-transmitting hole provided on the non-void section 1012, the beam splitting optical axis of the beam splitter 403, and the center of the position light monitoring through hole provided at the bottom of the vertical section 103 are all on a straight line. The beam splitting direction of the beam splitter 403 is the position monitoring channel.

[0054] The first lens 404 is positioned relative to the optical monitoring through hole, and the optical axis of the first lens 404 is on a straight line with the center of the optical monitoring through hole.

[0055] A fourth window is provided on the side of the vertical part 103 opposite to the third window. The second reflector 406 is installed in the vertical part 103 at an incline from the outside to the inside through the fourth window. The incline direction of the second reflector 406 and the beam splitter 403 is parallel, and the center of the second reflector 406 and the center of the beam splitter 403 are coaxial or on the same straight line. An angle light monitoring through hole is provided at the bottom of the vertical part 103 relative to the installation position of the second reflector 406. The reflected light axis of the second reflector 402 and the center of the angle light monitoring through hole at the bottom of the vertical part 103 are on the same straight line. The reflected light direction of the second reflector 406 is the angle monitoring channel.

[0056] Furthermore, in order to physically separate the position monitoring channel and the angle monitoring channel and avoid interference between the beams, the angle monitoring channel is provided with a blocking surface relative to the position monitoring channel. In addition, a fifth window is provided on the blocking surface between the beam splitter 403 and the second reflector 406. The second lens 405 is installed opposite to the fifth window. The second lens 405 focuses the reflected beam from the beam splitter and transmits it to the second reflector 406. The second reflector 406 then reflects the focused reflected light back to the angle light monitoring through hole.

[0057] After all the optical components are installed on the base frame 100, the position monitoring component 200 is installed in the position monitoring through hole and the angle monitoring component 300 is installed in the angle monitoring through hole according to the setting positions of the position monitoring through hole and the angle monitoring through hole, so that the corresponding beam position and angle can be monitored.

[0058] Regarding the installation methods of the aforementioned optical components, in this application, the coupling beam splitter 401 adopts an adjustable installation method. The vertical installation height of the coupling beam splitter 401 can be adjusted according to specific optical path requirements to meet the optical path needs. The third lens 407, the first reflector 402, the beam splitter 403, the first lens 404, the second lens 405, and the second reflector 406 are all installed in a fixed manner. It should be noted that since the third lens 407, the first reflector 402, the beam splitter 403, the first lens 404, the second lens 405, and the second reflector 406 are fixedly installed, their installation positions, installation directions, and installation distances between adjacent optical components are all determined through simulation design. After they are fixedly installed, they will not change. When the requirements are not met, only the coupling beam splitter 401 needs to be adjusted. Compared with adjusting the installation direction and position of multiple optical components, this installation method greatly simplifies the installation and adjustment difficulty of optical components.

[0059] The position monitoring component 200 and the angle monitoring component 300 of this application have the same components, both including a conversion plate, a filter, a doublet lens, and a PSD sensor. Please refer to Figure 2 for the optical path diagram. The optical path diagram for beam position measurement is shown in Figure 7, and the optical path diagram for beam angle measurement is shown in Figure 8.

[0060] In the optical path for beam position measurement, the beam reflected by the coupling beam splitter 401 enters the third lens 407 and is then reflected by the first reflecting mirror 402. It is then split and transmitted at the beam splitter 403 at a 1:1 ratio. The third lens 407 and the first lens 404 form a dual telecentric measurement optical path, imaging the spot at the equivalent position of the DOE (Optical Diffraction Element) onto the conversion plate. The fluorescence generated by the conversion plate is filtered and imaged onto the position-sensitive detector (PSD) by a 1* imaging mirror composed of two cemented doublet lenses. The beam reduction ratio of the beam position measurement optical path is 0.125.

[0061] The beam size at the incident end of the base is 22mm × 22mm, and the divergence angle is less than 2mrad. Therefore, the spot size on the position measurement PSD is 2.75mm × 2.75mm. The photosensitive surface of the PSD is 10mm × 10mm. Due to the nonlinear effect of the photosensitive edge, the actual utilized area is 8mm × 8mm. Considering the limitation of the aperture in the optical system, the beam position measurement range is 22.9mm. Taking into account the influence of optical aberrations and circuit errors, the positioning accuracy of the PSD can reach 10μnm. Therefore, the beam position measurement accuracy is 0.08nm, which meets the design requirement of ±0.4mm.

[0062] In the optical path for beam angle measurement, the beam reflected by the coupling beam splitter 401 enters the third lens 407 and is then reflected by the first mirror 402. It is then split and transmitted at the beam splitter 403 at a 1:1 ratio. The third lens 407 and the second lens 405 form a secondary focusing optical path, imaging the spot at the equivalent position of the DOE (Optical Diffraction Element) onto the conversion plate. The fluorescence generated by the conversion plate is filtered and imaged onto the position-sensitive detector (PSD) by a 1* imaging mirror composed of two cemented doublet lenses. The equivalent focal length of the secondary focusing optical path in the beam angle measurement optical path is 800mm, the beam divergence angle is calculated as 2mrad, and the spot size on the PSD is Φ1.6mm. The actual usable area of ​​the PSD is 8mm×8mm, therefore the measurement range of the beam angle is (8-1.6)mm / 0.8m=8mrad. Taking into account the effects of optical aberrations and circuit errors, the positioning accuracy of the PSD can reach 10μnm, and the measurement accuracy of the beam angle is 0.013mrad, which meets the design requirement of ±0.075mrad.

[0063] The above verification analysis shows that, under the condition of meeting the design requirements, the beam monitoring device provided in this application adopts an integrated structure for the base frame 100, and the third lens 407, the first reflector 402, the beam splitter 403, the first lens 404, the second lens 405, and the second reflector 406 are fixedly installed on the base frame 100. This reduces the installation difficulty of the beam monitoring device and the adjustment difficulty of the optical components. Furthermore, through reasonable design, each optical component is installed from the outside to the inside of the base frame 100, making the structure of each optical component and the base frame 100 compact. This achieves the effect of making the beam monitoring device small in size and light in weight, with little space constraint and a wide range of applications.

[0064] The above examples illustrate the present invention only to aid in understanding it and are not intended to limit the scope of the invention. Those skilled in the art can make various simple deductions, modifications, or substitutions based on the principles of this invention.

Claims

1. A beam monitoring device, characterized in that, include: The system comprises a base frame, a position monitoring component, an angle monitoring component, and several optical elements. The base frame is a one-piece molded structure and includes a beam input channel and a monitoring beam transmission channel. The monitoring beam transmission channel includes a first beam transmission channel, a second beam transmission channel, and a beam splitting channel. The base frame includes a horizontal section, an inclined section, and a vertical section, all of which are integrally molded. The optical elements include a coupling beam splitter, a first reflecting mirror, and a beam splitter. The horizontal section includes an open section and a non-open section, wherein the open section is disposed through the main optical path, and the non-open section is located outside the main optical path. The open section has a beam input aperture and a beam output aperture along the direction of the main optical path. A beam incident channel is formed between the beam entrance aperture and the beam exit aperture, and the beam incident channel is disposed in the main optical path. The cavity structure of the non-cavitary part forms a first beam transmission channel. A first window is opened on one side of the non-cavitary part relative to the non-cavitary part. The coupling beam splitter is installed obliquely from the outside to the inside of the cavity through the first window, and the coupling beam splitter is tilted toward the first beam transmission channel. The center of the coupling beam splitter is on a straight line with the center of the beam entrance aperture and the beam exit aperture disposed in the cavity, so that the coupling beam splitter reflects part of the beam from the main optical path to the first beam transmission channel, and transmits another part of the beam to the beam exit aperture. A perforation is provided; the inclined portion is inclinedly disposed between the non-void portion and the vertical portion, and a second window is provided on the outer side of the inclined portion. The first reflector is installed inclinedly from the outside to the inside of the inclined portion through the second window. A light-transmitting hole is provided in the non-void portion relative to the light transmission direction of the first reflector, so that the reflected light from the first reflector reaches the beam splitting channel through the light-transmitting hole, wherein the reflection direction of the first reflector is the second beam transmission channel; the beam splitting channel is disposed relative to the second beam transmission channel, and the beam splitter is disposed in the beam splitting channel and inclined toward the second beam transmission channel for splitting the second beam. The light beam within the transmission channel is split and reflected. The beam split by the beam splitter enters the position monitoring component, and the beam reflected by the beam splitter enters the angle monitoring component. Specifically, the vertical section is located below the non-open section, and the vertical section has a third window. The beam splitter is installed obliquely from the outside to the inside of the vertical section through the third window, so that the beam splitter is tilted towards the second light beam transmission channel. The position monitoring component and the angle monitoring component are arranged relative to the monitored light beam transmission channel to monitor the position and angle of the light beam within the monitored light beam transmission channel, thereby realizing position and angle monitoring of the light beam in the main optical path.

2. The beam monitoring device as described in claim 1, characterized in that, The beam splitting channel includes a position monitoring channel and an angle monitoring channel. The position monitoring component is positioned relative to the position monitoring channel, and the angle monitoring component is positioned relative to the angle monitoring channel. The optical element further includes a first lens, a second lens, and a second reflector. The first lens is positioned in the position monitoring channel and is used to focus the beam splitter beam from the beam splitter onto the position monitoring component, so that the position monitoring component can monitor the beam position. The second lens and the second reflector are respectively positioned in the angle monitoring channel. The second lens is used to focus the reflected beam from the beam splitter, and the second reflector is used to reflect the focused reflected beam back to the angle monitoring component, so that the angle monitoring component can monitor the beam angle.

3. The beam monitoring device as described in claim 2, characterized in that, The optical axis of the position monitoring channel is coaxial with the optical axis of the second beam transmission channel, and the optical axis of the angle monitoring channel is parallel to the optical axis of the second beam transmission channel.

4. The beam monitoring device as described in claim 2, characterized in that, The coupling beam splitter, the first reflector, the beam splitter, and the second reflector are all mounted on the base frame from the outside in.

5. The beam monitoring device as described in claim 2, characterized in that, The coupling beam splitter, the first reflector, the beam splitter, and the second reflector are respectively inclined inwards towards the base frame.

6. The beam monitoring device as described in claim 2, characterized in that, The optical element further includes a third lens, which is disposed within the first beam transmission channel.

7. The beam monitoring device as described in claim 6, characterized in that, The third lens, the first reflector, the beam splitter, the first lens, the second lens, and the second reflector are all fixedly installed.

8. The beam monitoring device as described in claim 7, characterized in that, The third lens and the first lens form a dual telecentric measurement optical path to image the light spot onto the position monitoring component, and the third lens and the second lens form a secondary focusing optical path to image the light spot onto the angle monitoring component.

Images