Efficient ion beam polishing diaphragm switching device and polishing method

Abstract

The invention provides an efficient ion beam polishing diaphragm switching device and a polishing method. The efficient ion beam polishing diaphragm switching device comprises two diaphragm supports additionally arranged in the wall of a vacuum cavity of ion beam equipment, and further comprises two diaphragms matched with the diaphragm supports for use, namely a working diaphragm and a diaphragm to be used; and the two selected diaphragms are respectively arranged at the ion source process working position and the diaphragm switching device position in the atmospheric environment. The ion source process diaphragm is switched under the vacuum condition, so that high-efficiency processing of a low-frequency surface type is ensured under the condition of one-time vacuum processing, and meanwhile, precise processing of a medium-high-frequency surface type is also ensured. Meanwhile, by using the method, the time of the equipment in a non-vacuum state can be shortened, and the effect of protecting the ion source can be achieved to a certain extent.

Description

Technical Field

[0001] The present invention relates to the technical field of optical processing, and particularly relates to an efficient ion beam polishing aperture switching device and a polishing method. Background Art

[0002] In order to meet the development requirements of large-scale integrated circuits, it is necessary to continuously improve the resolution and production efficiency of lithographic projection objectives. For the lithography machines that are widely used in current commercial production and have an exposure wavelength of 193 nm, the resolution and production efficiency of the lithographic projection objectives are improved by increasing the exposure energy and other means.

[0003] The above lithographic projection objectives often have very high requirements for the surface shape of optical processing. First, it is necessary to meet the requirements that the peak-to-valley value is within a certain range, and at the same time, it is necessary to ensure that its Zernike coefficients meet certain special requirements. Especially for the high-order Zernike coefficients, due to the superposition of multi-order surface shapes, the frequency of the processed peak-to-valley value is already very narrow.

[0004] The conventional processing method for the objective lens is to polish it with a small grinding head to achieve an accuracy of rms 0.05λ or less, and to achieve an accuracy of rms 0.01λ or less through magnetorheological or small grinding head polishing. However, since the magnetorheological or small grinding head numerical control polishing method will leave a lot of intermediate frequency data on the surface shape, it is impossible to achieve higher-precision processing. By introducing ion beam polishing, although the generation of intermediate frequency can be avoided, for the initial surface shape with both low-frequency surface undulations and certain medium-high frequencies in the processed surface shape, aperture switching is required during the ion beam polishing process. Due to the limitation of the working principle of the ion source, the processing needs to be carried out under a vacuum environment, and when switching the ion source aperture in the atmospheric environment, it is necessary to ensure the cooling of the ion source. In actual production, the time for aperture switching cannot generate benefits, so improving the aperture switching efficiency can effectively improve the application of ion beam polishing in actual production. Summary of the Invention

[0005] Aiming at the problems existing in the prior art, the present invention provides an efficient ion beam polishing aperture switching device and a polishing method. By switching the ion source process aperture under vacuum conditions, the high-efficiency processing of the low-frequency surface shape and the precise processing of the medium-high frequency surface shape are ensured under the condition of one-time vacuum processing. At the same time, by using this method, the time in the non-vacuum state of the equipment can be reduced, and to a certain extent, it can play a role in protecting the ion source.

[0006] The technical solution of the present invention is: an efficient ion beam polishing aperture switching device, including two aperture brackets installed in the wall of the vacuum chamber of the ion beam equipment, and a plurality of parallel aperture bracket positioning pins are arranged on the surface of each aperture bracket;

[0007] It includes a diaphragm chuck. The diaphragm chuck is an annular disc with a central opening. Three L-shaped diaphragm claws are evenly arranged on the outer circumferential surface of the diaphragm chuck. One side surface of the diaphragm chuck is fixedly connected to the port of the ion source process component through a turntable connecting piece;

[0008] It also includes two diaphragms for matching with the diaphragm bracket: one working diaphragm and one standby diaphragm;

[0009] A plurality of diaphragm positioning holes corresponding one by one to the positioning inserting rods of the diaphragm bracket are opened on the diaphragm. The standby diaphragm can be fixed on the corresponding diaphragm bracket by inserting the diaphragm positioning holes one by one onto the positioning inserting rods of the diaphragm bracket; Three diaphragm buckles corresponding one by one to the three L-shaped diaphragm claws on the diaphragm chuck are also arranged on the diaphragm. The working diaphragm can be fixed on the diaphragm chuck by correspondingly rotating and clamping the diaphragm claws and the diaphragm buckles;

[0010] When the diaphragm needs to be replaced, the main shaft moves the working diaphragm to the position of the vacant diaphragm bracket, and the diaphragm positioning holes on the end face of the working diaphragm pass through the positioning inserting rods of the diaphragm bracket on the diaphragm bracket one by one for diaphragm positioning. At this time, the main shaft is rotated by a preset angle, and the working diaphragm is separated from the diaphragm chuck through the torsion between the positioning inserting rods of the diaphragm bracket on the diaphragm bracket and the diaphragm; Then the main shaft moves to the standby diaphragm, and the standby diaphragm is fixed on the diaphragm chuck for standby by correspondingly rotating and clamping the diaphragm claws and the diaphragm buckles.

[0011] Furthermore, there are three positioning inserting rods of the diaphragm bracket, which are located at three equidistant points on the surface of the diaphragm bracket.

[0012] The present invention also provides an efficient ion beam polishing method implemented according to the described efficient ion beam polishing diaphragm switching device, and the specific steps are as follows:

[0013] Step 1: Decompose the low-frequency surface shape and high-frequency surface shape before ion beam processing;

[0014] According to the product size and surface shape frequency, the original surface shape is extracted with a suitable low-frequency frequency to mark D1, so as to match the removal function of the large-aperture diaphragm GL1 of the ion beam; Then the medium-high frequency surface shape in the original surface shape is extracted and marked G1. According to the extracted medium-high frequency characteristic, the removal function of the corresponding diaphragm aperture GL2 is selected and matched;

[0015] Step 2: Diaphragm assembly;

[0016] Under the atmospheric environment, the selected diaphragm GL2 is installed at the working position of the port of the ion source process component, and the diaphragm GL1 is fixed at the diaphragm switching position inside the wall of the vacuum cavity of the ion beam equipment;

[0017] The installation method of the aperture GL2 is as follows: Rotate and snap the aperture buckle of the aperture GL2 with the aperture claws on the aperture chuck, and then fix it to the port of the ion source process component;

[0018] The installation method of the aperture GL1 is as follows: Align the aperture positioning holes of the aperture GL1 one by one with the aperture support positioning pins on the aperture support for switching the aperture position inside the wall of the vacuum chamber of the ion beam equipment, and then install it inside the vacuum chamber of the ion beam equipment;

[0019] Locate the coordinate positions of the two aperture supports through the three coordinates inside the ion beam equipment;

[0020] Step Three: Medium and high-frequency surface machining;

[0021] After reaching the vacuum condition for the ion source to start up, trigger the ion source, and in the process software, import the medium and high-frequency surface G1 for calculation to obtain the dwell time required for machining and then perform machining;

[0022] Step Four: Ion beam aperture switching;

[0023] After completing the medium and high-frequency surface machining, use the ion beam polishing aperture switching device to remove GL2 and switch to GL1; The specific switching method is as follows: The main shaft moves the GL2 aperture to the position of the vacant aperture support, and aligns the aperture positioning holes on the end face of the GL2 aperture with the aperture support positioning pins on the aperture support one by one for aperture positioning. At this time, rotate the main shaft by a preset angle so that the GL2 aperture is separated from the aperture chuck through the torsion between the aperture support positioning pins on the aperture support and the aperture; Then the main shaft moves to the GL1 aperture, and fixes the GL1 aperture to the aperture chuck by corresponding rotation and snapping of the aperture claws and the aperture buckle for standby;

[0024] Step Five: Low-frequency surface machining;

[0025] Import the low-frequency surface into the process software for calculation to obtain the required dwell time for machining. After completing the machining, the final surface can achieve the machining effect of high-precision surface.

[0026] Furthermore, the low-frequency frequency described in Step One is a frequency greater than 4 mm; the medium and high-frequency is a frequency less than 4 mm.

[0027] The beneficial effect of the present invention is to provide an efficient ion beam polishing aperture switching device and polishing method. By switching the ion source process aperture under vacuum conditions, it ensures the high-efficiency machining of the low-frequency surface and the precise machining of the medium and high-frequency surface under one-time vacuum machining conditions. At the same time, using this method can reduce the time in the non-vacuum state of the equipment, and to a certain extent, it can play a role in protecting the ion source. Description of the Drawings

[0028] Figure 1 It is a flow chart of the ion beam polishing method;

[0029] Figure 2 It is the initial processed surface shape in the embodiment;

[0030] Figure 3 It is the decomposed low-frequency surface shape in the embodiment;

[0031] Figure 4 It is the decomposed high-frequency surface shape in the embodiment;

[0032] Figure 5 It is a schematic diagram of installing the well-matched diaphragm GL2 at the ion source process working position in the atmospheric environment;

[0033] Figure 6 It is a schematic diagram of installing the well-matched diaphragm GL1 at the diaphragm switching device position in the atmospheric environment;

[0034] Figure 7 It is a schematic diagram of the diaphragm chuck structure;

[0035] Figure 8 It is a schematic diagram of the diaphragm structure;

[0036] Figure 9 It is an effect diagram of achieving high-precision surface shape processing.

[0037] In the figure: 101 is the main shaft, 102 is the ion source process component port, 103 is the turntable connecting piece, 104 is the diaphragm, 105 is the diaphragm positioning hole, 106 is the diaphragm buckle, 201 is the diaphragm bracket, 202 is the diaphragm bracket positioning insertion rod, 301 is the diaphragm chuck, and 302 is the diaphragm jaw. Specific implementation manner

[0038] The present invention will be further described below with reference to the accompanying drawings. Figure 1 It is the implementation process of the technical solution.

[0039] S1. Decompose the low-frequency surface shape and high-frequency surface shape before ion beam processing

[0040] According to the product size and surface shape frequency, extract the surface shape with a suitable low-frequency greater than 4 mm from the original surface shape, mark it as D1, to match the removal function of the large-aperture diaphragm GL1 with a diameter of 4 mm to 40 mm of the ion beam. Then extract the medium- and high-frequency surface shape with a frequency less than 4 mm from the original surface shape, mark it as G1, and select the removal function of the corresponding diaphragm aperture GL2 according to the extracted medium- and high-frequency frequency characteristics. Figure 2 Initial processed surface shape. Figure 3 It is the decomposed low-frequency surface shape, Figure 4 It is the decomposed high-frequency surface shape.

[0041] S2. Diaphragm assembly

[0042] Under atmospheric environment, the selected diaphragm GL2 and GL1 are respectively installed at the ion source process working position and the diaphragm switching device position, such as Figure 5 , Figure 6 .

[0043] The traditional diaphragm has a single circular through-hole and is connected to the ion source process component through bolts. Based on the traditional diaphragm, the present invention adds a three-claw diaphragm buckle on the back. It is fixed to the ion source process port through a rotating manner with the chuck adapter.

[0044] The specific structure is: an efficient ion beam polishing diaphragm switching device, including two diaphragm brackets 201 installed in the wall of the vacuum cavity of the ion beam equipment. Each diaphragm bracket 201 is provided with 3 diaphragm bracket positioning insertion rods 202 arranged in parallel on its surface.

[0045] Including the diaphragm chuck 301 as shown in Figure 7 . The diaphragm chuck 301 is an annular disc with a central opening. Three L-shaped diaphragm claws 302 are evenly arranged on the outer circumferential surface of the diaphragm chuck 301. One side surface of the diaphragm chuck 301 is fixedly connected to the ion source process component port 102 through a turntable connector 103.

[0046] As shown in Figure 8 , it also includes 2 diaphragms 104 matching with the diaphragm bracket 201: one working diaphragm and one standby diaphragm.

[0047] Three diaphragm positioning holes 105 corresponding to the diaphragm bracket positioning insertion rods 202 are opened on the diaphragm. By inserting the diaphragm positioning holes 105 one by one onto the diaphragm bracket positioning insertion rods, the standby diaphragm can be fixed to the corresponding diaphragm bracket 201. Three diaphragm buckles 106 corresponding to the three L-shaped diaphragm claws 302 on the diaphragm chuck 301 are also provided on the diaphragm 104. By rotating and clamping the diaphragm claws 302 and the diaphragm buckles 106 correspondingly, the working diaphragm can be fixed to the diaphragm chuck 301.

[0048] When the diaphragm needs to be replaced, the main shaft 101 moves to move the working diaphragm to the vacant diaphragm bracket position, and the diaphragm positioning holes on the end face of the working diaphragm pass through the diaphragm bracket positioning insertion rods on the diaphragm bracket one by one for diaphragm positioning. At this time, the main shaft is rotated by a preset angle, and the working diaphragm is separated from the diaphragm chuck through the torsion force between the diaphragm bracket positioning insertion rods on the diaphragm bracket and the diaphragm. Then the main shaft moves to the standby diaphragm, and the standby diaphragm is fixed to the diaphragm chuck through the corresponding rotation and clamping of the diaphragm claws and the diaphragm buckles for standby.

[0049] In this embodiment, the installation method of the aperture GL2 is as follows: Rotate and snap the aperture clip of the aperture GL2 with the aperture claws on the aperture chuck, and then fix it to the port of the ion source process component.

[0050] The installation method of the aperture GL1 is as follows: Align the aperture positioning holes of the aperture GL1 one by one with the aperture support positioning pins on the aperture support for switching the position of the aperture inside the wall of the vacuum chamber of the ion beam equipment, and then install it inside the vacuum chamber of the ion beam equipment.

[0051] Locate the coordinate positions of the two aperture supports through three-dimensional coordinates inside the ion beam machine tool.

[0052] S3. Medium and high-frequency surface machining

[0053] After reaching the vacuum condition for the ion source to start discharging, trigger the ion source, and in the process software, import the medium and high-frequency surface G1 for calculation to obtain the dwell time required for machining and perform machining.

[0054] S4. Ion beam aperture switching

[0055] After completing the medium and high-frequency surface machining, use the ion beam aperture quick switching device to remove GL2. First, through the movement of the main shaft, move the ion source process port with GL2 to the position of the vacant aperture support, and make the three small holes on the end face of the aperture pass through the three positioning sockets on the aperture support for aperture positioning. At this time, rotate the main shaft by a preset angle so that the aperture is separated from the aperture chuck through the torsion between the aperture support positioning pin on the aperture support and the aperture. Method of main shaft movement: First, locate the position of the aperture support through the three-dimensional coordinate structure available on the equipment, and use the located coordinates as the target coordinates for the main shaft movement to achieve precise movement of the main shaft.

[0056] Then use the same positioning method to install GL1.

[0057] S5. Low-frequency surface machining

[0058] Import the low-frequency surface into the process software for calculation to obtain the required dwell time for machining. After completing the machining, the final surface can achieve a high-precision surface machining effect as Figure 9 .

[0059] The significance of the present invention is that by switching the ion source process aperture under vacuum conditions, high-efficiency machining of the low-frequency surface is ensured under the condition of one-time vacuum machining, and at the same time, precise machining of the medium and high-frequency surface is ensured. At the same time, using this method can reduce the time in the non-vacuum state of the equipment, and to a certain extent, it can play a role in protecting the ion source.

[0060] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. An efficient ion beam polishing aperture switching device, characterized in that: It includes two aperture supports (201) installed in the wall of the vacuum chamber of the ion beam device. Multiple aperture support positioning pins (202) arranged in parallel are provided on the surface of each aperture support (201); It includes an aperture chuck (301). The aperture chuck (301) is an annular disc with a central opening. Three L-shaped aperture claws (302) are evenly arranged on the outer circumferential surface of the aperture chuck (301). One side surface of the aperture chuck (301) is fixedly connected to the ion source process component port (102) through a turntable connecting piece (103); It further includes two apertures (104) for matching with the aperture supports (201): one working aperture and one standby aperture; A plurality of aperture positioning holes (105) corresponding to the aperture support positioning pins (202) one by one are provided on the aperture. The standby aperture can be fixed to the corresponding aperture support (201) by inserting the aperture positioning holes (105) onto the aperture support positioning pins (202) one by one; Three aperture buckles (106) corresponding to the three L-shaped aperture claws (302) on the aperture chuck (301) are further provided on the aperture (104). The working aperture can be fixed to the aperture chuck (301) by rotatably clamping the aperture claws (302) and the aperture buckles (106) correspondingly; When the aperture needs to be replaced, the main shaft (101) moves to move the working aperture to the vacant aperture support position, and the aperture positioning holes on the end face of the working aperture pass through the aperture support positioning pins on the aperture support one by one for aperture positioning. At this time, the main shaft is rotated by a preset angle, and the working aperture is separated from the aperture chuck through the torsion between the aperture support positioning pins on the aperture support and the aperture; Then the main shaft moves to the standby aperture, and the standby aperture is fixed to the aperture chuck for standby by rotatably clamping the aperture claws and the aperture buckles correspondingly.

2. An efficient ion beam polishing aperture switching device according to claim 1, characterized in that: There are three aperture support positioning pins (202), which are located at three equidistant points on the surface of the aperture support (201).

3. An efficient ion beam polishing method implemented by an efficient ion beam polishing aperture switching device according to claim 1 or 2, characterized in that, The specific steps are as follows: Step 1: Decompose the low-frequency surface shape and high-frequency surface shape before ion beam processing; According to the product size and surface shape frequency, the original surface shape is extracted with a suitable low-frequency frequency to mark D1, so as to match the removal function of the large-aperture aperture GL1 of the ion beam; Then the medium-high frequency surface shape in the original surface shape is extracted and marked G1. According to the extracted medium-high frequency characteristic, the removal function of the corresponding aperture diameter GL2 is selected; Step 2: Aperture assembly; Under the atmospheric environment, the selected aperture GL2 is installed at the working position of the ion source process component port, and the aperture GL1 is fixed at the aperture switching position in the wall of the vacuum chamber of the ion beam device; The installation method of the aperture GL2 is: the aperture buckles of the aperture GL2 are rotatably clamped with the aperture claws on the aperture chuck and then fixed to the ion source process component port; The installation method of the aperture GL1 is: the aperture positioning holes of the aperture GL1 pass through the aperture support positioning pins on the aperture support at the aperture switching position in the wall of the vacuum chamber of the ion beam device one by one and then installed in the vacuum chamber of the ion beam device; Locate the coordinate positions of two diaphragm brackets through three - coordinate inside the ion beam equipment; Step 3: Medium - high frequency surface machining; After reaching the starting vacuum condition of the ion source, trigger the ion source, and in the process software, import the medium - high frequency surface G1 for calculation to obtain the dwell time required for machining and then perform machining; Step 4: Ion beam diaphragm switching; After completing the medium - high frequency surface machining, use the ion beam polishing diaphragm switching device to remove GL2 and switch to GL1. The specific switching method is as follows: The main shaft moves to position the GL2 diaphragm at the vacant diaphragm bracket position, and makes the diaphragm positioning holes on the end face of the GL2 diaphragm pass through the diaphragm bracket positioning pins on the diaphragm bracket one by one for diaphragm positioning. At this time, rotate the main shaft by a preset angle so that the GL2 diaphragm is separated from the diaphragm chuck through the torsion between the diaphragm bracket positioning pins on the diaphragm bracket and the diaphragm. Then the main shaft moves to the GL1 diaphragm, and fixes the GL1 diaphragm on the diaphragm chuck through the corresponding rotational clamping of the diaphragm jaws and the diaphragm buckle for standby; Step 5: Low - frequency surface machining; Import the low - frequency surface in the process software for calculation to obtain the required dwell time for machining. After completion of machining, a high - precision surface machining effect can be achieved for the final surface.

4. The ion beam polishing method according to claim 3, wherein: The low - frequency in Step 1 refers to a frequency greater than 4 mm; the medium - high frequency refers to a frequency less than 4 mm.

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