A method for adjusting ion source uniformity

Abstract

The present application provides a method for adjusting the uniformity of an ion source, and the specific steps are as follows: Step 1, install the ion source for testing; Step 2, observe whether the ion beam uniformity is satisfactory based on the ion beam intensity collected by the sensor at the receiving end of the umbrella; Step 3, if the ion beam uniformity is not satisfactory, reversely infer the radial position of the grid corresponding to the strong ion beam; Step 4, remove the grid of the ion source, select the grid hole to install the shielding component; Step 5, repeat Step 1 to Step 4 until the ion beam uniformity reaches a satisfactory level. One or more shielding components are installed on the grid. This method uses ceramic screws to fix the metal sheet to block the lead-out hole corresponding to the strong ion beam. According to the actual situation of the ion source, the shielding grid holes can be adjusted again after the ion source is installed. The operation is convenient and effectively saves the process and cost of re-gridding the grid holes.

Description

Technical Field

[0001] The present application relates to the field of optical coating, to an ion source, and in particular to a method for adjusting the uniformity of an ion source. Background Art

[0002] Ion sources are commonly used in precision machining equipment such as ion beam etching, ion beam sputtering, and ion beam-assisted coating. During operation, plasma forms a plasma beam through the plasma extraction holes on the plasma extraction grid. However, the structure causes uneven density of the extracted plasma, which in turn leads to uneven distribution of the plasma beam, resulting in uneven distribution of ion current density, affecting machining quality.

[0003] In order to adjust the ion beam to achieve uniform distribution, the method that can be used is to shield and weaken the position where the emission is too strong, so as to make the ion beam uniform. The shielding position can be selected to be external to the ion source or internal to the ion source; however, shielding outside the ion source is prone to sputtering, so the best solution is to use a shielding screen to reduce the part with excessive emission.

[0004] The existing improvement method mainly calculates in advance the position of the stronger ion beam on the extraction grid, and leaves the grid at the corresponding position without making through holes during manufacturing, thereby weakening the ion beam at the stronger position. However, in the application of this method, the position of the prefabricated closed hole is often inconsistent with the actual working conditions, and cannot be adjusted and improved, resulting in poor ion beam uniformity. Re-drilling and adjustment operations are difficult and costly.

[0005] After searching, the following patent documents related to the improved structure of the ion source grid were found:

[0006] An ion source grid (CN114864363A) includes a plurality of equally divided regions, each of which has a center of the grid as a starting point. The sector angle formed by each equally divided region from the center of the circle is (360 / n)o, where n is a positive integer between 1 and 12. Each equally divided region is provided with a plurality of closely packed holes, and the holes on the boundary of each equally divided region are shared with its adjacent equally divided regions. The optimized closely packed hole design of the present invention enables a continuous hole area distribution in both radial and axial directions, eliminating the influence of discontinuous boundaries on the uniformity of plasma density distribution. At the same time, the optimized axial hole area distribution is adopted to further improve the uniformity of plasma density distribution.

[0007] A grid (CN106158565B) for use in the ion optical system of an ion source. The grid comprises a grid aperture region with grid holes. Multiple thermal strain grooves are radially formed on the grid from the edges of the grid aperture region, extending through the upper and lower surfaces of the grid. The present invention also provides an ion source using the grid. By providing radial thermal strain grooves on the grid, the present invention completely solves the problem of thermal deformation of a planar refractory metal grid. It also maintains the uniformity and stability of the ion beam current, enabling the ion source to operate in long-term and repeated high-temperature environments, thereby improving the repeatability of ion source performance and the process uniformity of ion beam processing.

[0008] After comparison, the technical means for improving the grid structure in the existing technology are different from the ideas and specific structural methods for solving the problems in this application. Summary of the Invention

[0009] In order to effectively solve the problem of metal head and tail deformation, the present application provides a method for adjusting the uniformity of an ion source with a simple structure, reasonable design, convenient operation, and stable and reliable performance.

[0010] A method for adjusting the uniformity of an ion source, characterized in that the specific steps are as follows:

[0011] Step 1: Install the ion source for testing. The umbrella receiving end is spaced apart from the upper and lower ends of the ion source. During the test, the ion source and the umbrella receiving end rotate coaxially relative to each other, and sensors are evenly arranged on the umbrella receiving end.

[0012] Step 2: Based on the ion beam intensity collected by the sensor at the receiving end of the umbrella, a beam distribution diagram is formed to observe whether the ion beam uniformity is satisfactory;

[0013] Step 3: If the ion beam uniformity is satisfactory, the adjustment is ended;

[0014] If the ion beam uniformity is not satisfactory, the position of the strong ion beam is determined according to the beam current distribution diagram, and the radial position of the grid corresponding to the strong ion beam is inferred inversely;

[0015] Step 4: Remove the grid of the ion source, select the grid holes on the circumference of the radial position as shielding holes according to the radial position obtained in the previous step, install the shielding assembly at the selected shielding hole position, and then reinstall the grid;

[0016] Step 5: Repeat steps 1 to 4 until the ion beam uniformity reaches a satisfactory level.

[0017] A method for adjusting the uniformity of an ion source, characterized in that the specific steps are as follows:

[0018] Step 1: Predict the intensity of the ion beam using estimated data and pre-install a shielding component in the grid;

[0019] Step 2: Install the ion source for testing. The umbrella receiving end is spaced apart from the upper and lower ends of the ion source. During the test, the ion source and the umbrella receiving end rotate coaxially relative to each other, and sensors are evenly arranged on the umbrella receiving end.

[0020] Step 3: Based on the ion beam intensity collected by the sensor at the receiving end of the umbrella, a beam distribution diagram is formed to observe whether the ion beam uniformity is satisfactory;

[0021] Step 4: If the ion beam uniformity is satisfactory, the adjustment is ended;

[0022] If the ion beam uniformity is not satisfactory, the strong ion beam position or the weak ion beam position is determined according to the beam current distribution diagram, and the radial position of the grid corresponding to the strong ion beam or the weak ion beam is inferred inversely;

[0023] Step 5: Remove the grid of the ion source and select grid holes at corresponding radial positions as shielding holes for strong ion beams.

[0024] For a weak ion beam, the shielding assembly installed on the annular circumference at the radial position is selected for removal;

[0025] Step 6: Repeat steps 1 to 5 until the ion beam uniformity reaches a satisfactory level.

[0026] Moreover, the reverse process:

[0027] d=D·L / R

[0028] Among them, d is the distance from the grid hole to the center of the grid, L is the distance from the center of the grid hole area to the edge of the grid hole area, D is the distance from the center point of the strong ion beam to the center point of the umbrella receiving end, and R is the distance from the center of the ion projection area of ​​the umbrella receiving end to the edge of the ion projection area of ​​the umbrella receiving end.

[0029] An ion source grid is provided with a circular grid hole area in the middle of the grid, and grid holes are evenly arranged in a ring array in the grid hole area. The characteristic is that one or more shielding components are installed on the grid.

[0030] Moreover, the shielding assembly includes a ceramic bolt, a baffle and an insulating nut. The baffle is attached to the lower end of the grid. The baffle is provided with a positioning hole corresponding to the grid hole. The ceramic bolt passes through the corresponding positioning hole of the baffle and the corresponding grid hole from top to bottom. An insulating nut is installed on the ceramic bolt at the lower end of the baffle.

[0031] Moreover, a ceramic gasket is installed between the insulating nut and the blocking piece.

[0032] Moreover, the ceramic bolt is a countersunk screw structure.

[0033] Moreover, the blocking piece is made of the same material as the grid.

[0034] Moreover, the grid has a multi-layer structure at the top and bottom, and the shielding components are all installed on the grid at the bottom.

[0035] An ion source, characterized in that it is equipped with an ion source grid as claimed in any one of claims 4 to 9.

[0036] In summary, this application includes at least one of the following beneficial technical effects:

[0037] 1. This method uses ceramic screws to fix metal sheets to block the extraction holes corresponding to the strong ion beam. The shielding grid holes can be adjusted again after the ion source is installed according to the actual situation of the ion source. The operation is convenient and effectively saves the process and cost of re-gridding the grid holes.

[0038] 2. The ion beam grid used in this method is pre-installed with a shielding component before leaving the factory. The initial uniformity of the ion beam extracted by the grid is adjusted according to the budget data. After installation, the shielding component is added or removed according to the actual situation. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a bottom view of the grid structure.

[0040] Figure 2 yes Figure 1 Enlarged view of part A in .

[0041] Figure 3 It is a side view of a single-layer grid structure.

[0042] Figure 4 yes Figure 3 A partial enlarged view of part B in FIG.

[0043] Figure 5 It is a side view of a single-layer grid structure.

[0044] Figure 6 yes Figure 5 A partial enlarged view of part C in FIG.

[0045] Figure 7 This is the beam distribution diagram of the current emission measured using a Faraday cup.

[0046] Figure 8 This is the distribution diagram of the emitted beam after adjustment using this method, measured using a Faraday cup.

[0047] Explanation of the accompanying reference numerals: 1. Ceramic bolt; 2. Grid; 3. Blocking piece; 4. Ceramic gasket; 5. Insulating nut. DETAILED DESCRIPTION

[0048] The following is a further detailed description of the present application in conjunction with the accompanying drawings. In this embodiment, the default ion source

[0049] A method for adjusting the uniformity of an ion source, comprising the following steps:

[0050] Step 1: Install the ion source for testing. The umbrella receiving end is spaced apart from the upper and lower ends of the ion source. During the test, the ion source and the umbrella receiving end rotate coaxially relative to each other, and sensors are evenly arranged on the umbrella receiving end.

[0051] Step 2: Based on the ion beam intensity collected by the sensor at the receiving end of the umbrella, a beam distribution diagram is formed to observe whether the ion beam uniformity is satisfactory;

[0052] Step 3: If the ion beam uniformity is satisfactory, the adjustment is ended;

[0053] If the ion beam uniformity is not satisfactory, the position of the strong ion beam is determined according to the beam current distribution diagram, and the radial position of the grid corresponding to the strong ion beam is inferred inversely;

[0054] Reverse process: d = D·L / R

[0055] d is the distance from the grid hole to the center of the grid, L is the distance from the center of the grid hole area to the edge of the grid hole area, D is the distance from the center point of the strong ion beam to the center point of the umbrella receiving end, and R is the distance from the center of the ion projection area of ​​the umbrella receiving end to the edge of the ion projection area of ​​the umbrella receiving end;

[0056] In step 4, the engineer removes the ion source grid and, based on the radial position obtained in the previous step, selects a grid hole on the circumference of the radial position as a shielding hole. The engineer then installs the shielding assembly at the selected shielding hole position and reinstalls the grid.

[0057] Step 5: Repeat steps 1 to 4 until the ion beam uniformity reaches a satisfactory level and the ion beam density is balanced.

[0058] Based on accumulated test data, the relationship between the beam intensity produced by the ion source and the position of the grid can be predicted. A variety of methods exist for calculating ion beam intensity, and the method selected depends on the specific specifications of the ion source. Generally, the intensity is greatest at the center of the grid, with the intensity gradually decreasing from the center toward the periphery. A shielding assembly can be pre-installed on the grid before it leaves the factory.

[0059] For a grid with a pre-installed shielding assembly, the method for adjusting the uniformity of the ion source is as follows:

[0060] Step 1: Predicting the intensity of the ion beam and the radiation of an ion source of the same specification based on existing test data, and pre-installing one or more shielding components in the grid;

[0061] Usually the ion beam is strongest at the center and gradually weakens towards the edge. Therefore, more barrier metal sheets are installed at annular intervals near the center of the grid.

[0062] Step 2: Install the ion source for testing. The umbrella receiving end is spaced apart from the upper and lower ends of the ion source. During the test, the ion source and the umbrella receiving end rotate coaxially relative to each other, and sensors are evenly arranged on the umbrella receiving end.

[0063] Step 3: Based on the ion beam intensity collected by the sensor at the receiving end of the umbrella, a beam distribution diagram is formed to observe whether the ion beam uniformity is satisfactory;

[0064] Step 4: If the ion beam uniformity is satisfactory, the adjustment is ended;

[0065] If the ion beam uniformity is not satisfactory, the strong ion beam position or the weak ion beam position is determined according to the beam current distribution diagram, and the radial position of the grid corresponding to the strong ion beam or the weak ion beam is inferred inversely;

[0066] Step 5: For a strong ion beam, select a grid hole at a corresponding radial position as a shielding hole;

[0067] For a weak ion beam, the shielding assembly installed on the annular circumference at the radial position is selected for removal;

[0068] Step 6: Repeat steps 1 to 5 until the ion beam uniformity reaches a satisfactory level.

[0069] An ion source grid is provided with a circular grid hole area in the middle of the grid, and grid holes are arranged evenly in a circular array in the grid hole area. The grid holes have the same size, and one or more shielding components are installed in the grid holes.

[0070] See attached Figure 3 、 4 As shown in the figure, a schematic diagram of a single-layer grid structure is shown. The shielding component is fixed on the grid. The shielding component includes a ceramic bolt 1, a baffle 3, a ceramic gasket 4 and an insulating nut 5. The baffle is attached to the lower end of the grid. The baffle is provided with a positioning hole corresponding to the grid hole. The ceramic bolt passes through the corresponding positioning hole of the baffle and the corresponding grid hole from top to bottom. An insulating nut 5 is installed on the ceramic bolt at the lower end of the baffle. The ceramic bolt and the insulating nut lock the installation position of the baffle on the grid.

[0071] In order to ensure a firm and reliable installation, a ceramic gasket 4 is installed between the insulating nut and the baffle.

[0072] The ceramic bolt is a countersunk screw structure, and the nail cap of the ceramic bolt is above the grid.

[0073] The baffle is made of the same material as the grid. In this embodiment, the grid is made of metal tungsten.

[0074] The baffles shown in the attached drawings are fixed by two ceramic bolts. Depending on the actual size of the baffle, multiple ceramic bolts can be installed.

[0075] See attached Figure 6 、7 The figure shows a schematic diagram of a three-layer grid structure. For a multi-layer grid structure, the shielding components are all installed on the bottom grid.

[0076] An ion source includes a grid, wherein the grid is provided with one or more shielding components.

[0077] See also Figure 7 The figure shows the distribution of the emitted beam current obtained by measuring the ion source beam current using a Faraday cup. A three-dimensional analysis of the test data reveals the protruding points that cause the beam current to be uneven. Block the protruding points with a certain area. For example, point A in the center of the figure has the strongest emission, so point A can be blocked with a small circular area. If there is excessive strip emission at some places on the edge, a strip of metal can be designed to block it, thereby eliminating the excessive strip emission at the edge. After multiple adjustments, the retest data has been significantly improved, see Figure 8 The data retested after adjustment using this method showed significantly improved uniformity.

[0078] The above are all preferred embodiments of the present application, and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A method for adjusting ion source uniformity, characterized in that: The specific steps are as follows: Step 1: Install the ion source for testing. The umbrella receiving end is spaced apart from the upper and lower ends of the ion source. During the test, the ion source and the umbrella receiving end rotate coaxially relative to each other, and sensors are evenly arranged on the umbrella receiving end. Step 2: Based on the ion beam intensity collected by the sensor at the receiving end of the umbrella, a beam distribution diagram is formed to observe whether the ion beam uniformity is satisfactory; Step 3: If the ion beam uniformity is satisfactory, the adjustment is ended; If the ion beam uniformity is not satisfactory, the position of the strong ion beam is determined according to the beam current distribution diagram, and the radial position of the grid corresponding to the strong ion beam is inferred inversely; Step 4: Remove the grid of the ion source, select the grid holes on the circumference of the radial position as shielding holes according to the radial position obtained in the previous step, install the shielding assembly at the selected shielding hole position, and then reinstall the grid; Step 5, repeat steps 1 to 4 until the ion beam uniformity reaches a satisfactory level; The reverse process: d=D·L / R Among them, d is the distance from the grid hole to the center of the grid, L is the distance from the center of the grid hole area to the edge of the grid hole area, D is the distance from the center point of the strong ion beam to the center point of the umbrella receiving end, and R is the distance from the center of the ion projection area of ​​the umbrella receiving end to the edge of the ion projection area of ​​the umbrella receiving end.

2. A method for adjusting ion source uniformity, characterized in that: The specific steps are as follows: Step 1: Predict the intensity of the ion beam using estimated data and pre-install a shielding component in the grid; Step 2: Install the ion source for testing. The umbrella receiving end is spaced apart from the upper and lower ends of the ion source. During the test, the ion source and the umbrella receiving end rotate coaxially relative to each other, and sensors are evenly arranged on the umbrella receiving end. Step 3: Based on the ion beam intensity collected by the sensor at the receiving end of the umbrella, a beam distribution diagram is formed to observe whether the ion beam uniformity is satisfactory; Step 4: If the ion beam uniformity is satisfactory, the adjustment is ended; If the ion beam uniformity is not satisfactory, the strong ion beam position or the weak ion beam position is determined according to the beam current distribution diagram, and the radial position of the grid corresponding to the strong ion beam or the weak ion beam is inferred inversely; Step 5: Remove the grid of the ion source and select grid holes at corresponding radial positions as shielding holes for strong ion beams. For a weak ion beam, the shielding assembly installed on the annular circumference at the radial position is selected for removal; Step 6, repeat steps 1 to 5 until the ion beam uniformity reaches a satisfactory level; The reverse process: d=D·L / R Among them, d is the distance from the grid hole to the center of the grid, L is the distance from the center of the grid hole area to the edge of the grid hole area, D is the distance from the center point of the strong ion beam to the center point of the umbrella receiving end, and R is the distance from the center of the ion projection area of ​​the umbrella receiving end to the edge of the ion projection area of ​​the umbrella receiving end.

3. An ion source grid, wherein a circular grid hole region is provided in the middle of the grid, and grid holes are uniformly arranged in a circular array in the grid hole region, characterized in that: In the method for adjusting the uniformity of an ion source as claimed in claim 1 or 2, one or more shielding components are installed on the grid.

4. The ion source grid according to claim 3, characterized in that: The shielding assembly includes a ceramic bolt, a baffle and an insulating nut. The baffle is attached to the lower end of the grid. The baffle is provided with positioning holes corresponding to the grid holes. The ceramic bolt passes through the corresponding positioning holes of the baffle and the corresponding grid holes from top to bottom. An insulating nut is installed on the ceramic bolt at the lower end of the baffle.

5. The ion source grid according to claim 4, characterized in that: A ceramic gasket is installed between the insulating nut and the blocking piece.

6. The ion source grid according to claim 4, characterized in that: The ceramic bolt is a countersunk screw structure.

7. The ion source grid according to claim 4, characterized in that: The blocking piece is made of the same material as the grid.

8. The ion source grid according to claim 4, characterized in that: The grid has a multi-layer structure at the top and bottom, and the shielding components are all installed on the grid at the bottom.

9. An ion source, characterized in that: An ion source grid as claimed in any one of claims 3 to 8 is installed.

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