A Kondin method for adjusting ion etching uniformity

Abstract

The present invention discloses a hole for adjusting ion etching uniformity, comprising a cap and a rod, wherein one end of the rod is fixedly connected to the cap, a notch is arranged on the side of the rod, the rod is connected to a position on the cap deviating from the center of the cap, the width of the notch is equal to the thickness of a metal sheet of a grid, a plurality of notches are arranged on the rod, the plurality of notches are evenly distributed along the length direction of the rod, the spacing between two adjacent notches is equal to the spacing between two adjacent metal sheets of the grid, the hole can be conveniently inserted into the hole of the metal sheet on the grid, and a stable structure is formed with the grid, so as to conveniently and quickly adjust the local ion concentration of the ion source grid, and quickly optimize the etching uniformity.

Description

Technical Field

[0001] The invention belongs to the technical field of ion sputtering, and more specifically relates to a hole and method for adjusting the uniformity of ion etching. Background Art

[0002] A grid ion source usually uses a radio frequency power supply and inductively coupled plasma (ICP) to generate argon (Ar) plasma; and accelerates the argon plasma through a metal grid with different voltages to form a plasma beam that is as parallel as possible and has high energy; guides the plasma beam to bombard the surface of the silicon substrate to etch away the material on the surface of the silicon substrate to clean the surface of the silicon substrate; or processes and shapes various micron and nano structures on the silicon substrate.

[0003] In a conventional grid ion source, the grid is composed of a structure of several honeycomb holes. By adjusting the size and layout of the holes, on the one hand, the amount of plasma passing through the holes in different areas can be adjusted to adjust the etching rate in different areas; on the other hand, the trajectory of the plasma can be made more parallel, and the uniformity of the etching rate can also be improved. However, the use of grids also has limitations. The main reason is that the ion source generated by inductive coupling (ICP) is not very uniform in plasma density distribution due to the influence of the non-uniformity of the magnetic field strength generated by the coil, the diffusion of etching gas, the equipment design, the accuracy of parts processing and installation, etc.; at the same time, during the etching process, the RF power supply power, voltage, process gas type, gas pressure, flow rate, etc. of the ion source are not exactly the same for different processes.

[0004] Therefore, in the process of etching process debugging, in many cases, the optimization of process parameters cannot fully meet the process performance requirements (usually the uniformity of etching rate). At this time, the grid structure must be redesigned, manufactured, and tested again. In this way, the process optimization cycle is very long, which seriously reduces the use time and production capacity of the equipment. Summary of the invention

[0005] In view of the deficiencies of the prior art, the present invention provides a device that can be conveniently inserted into the holes of a metal sheet on a grid to form a stable structure with the grid, so as to conveniently and quickly adjust the local ion concentration of the ion source grid and quickly optimize etching uniformity.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a hole for adjusting the uniformity of ion etching, comprising a cap and a rod, one end of the rod is fixedly connected to the cap, and a notch is provided on the side of the rod.

[0007] Further, the rod portion is connected to a position on the cap portion that deviates from the center of the cap portion.

[0008] Furthermore, the width of the notch is equal to the thickness of the metal sheet of the grid.

[0009] Furthermore, the cap has a size capable of covering a hole of one grid or holes of a plurality of adjacent grids.

[0010] Furthermore, the cross section of the cap portion is circular.

[0011] Furthermore, the rod portion is provided with a plurality of notches, the plurality of notches are evenly distributed along the length direction of the rod portion, and the distance between two adjacent notches is equal to the distance between two adjacent metal sheets of the grid.

[0012] Furthermore, the cap and the rod are made of ceramic or quartz.

[0013] A method for adjusting ion etching uniformity comprises the following steps:

[0014] S1: etching the wafer using an ion source grid to obtain ion etching thickness or rate distribution data; S2: preparing an etching thickness or rate T=f(r / R) graph;

[0015] S3: judging whether the etching uniformity requirement is met according to the T=f(r / R) graph;

[0016] S4: If the etching uniformity requirement is met, proceed to step S5; if the etching uniformity requirement is not met, according to the T=f(r / R) diagram, insert a number of holes at the ion source grid position corresponding to the higher etching thickness, and then return to step S1;

[0017] S5: End the adjustment.

[0018] Compared with the prior art, the invention has the following beneficial effects: it can be easily inserted into the metal sheet hole of the grid, and form a stable structure with the metal sheet hole according to its own gravity and geometric shape. In this way, the local ion concentration of the ion source grid can be easily and quickly adjusted, thereby quickly optimizing the etching uniformity and improving the equipment utilization efficiency and production capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the grid explosion;

[0020] Figure 2 A schematic diagram of the metal piece in Forgetfulness;

[0021] Figure 3 A schematic diagram of Embodiment 1 of the present invention for adjusting the uniformity of ion etching using a hole;

[0022] Figure 4 A schematic diagram of Embodiment 2 of the present invention for adjusting the uniformity of ion etching using a hole;

[0023] Figure 5 A flow chart of a method for adjusting ion etching uniformity according to the present invention;

[0024] Figure 6-9 This is a specific test case using the Kongding method to adjust the uniformity of ion etching.

[0025] Figure numerals: 1, cap; 2, rod; 21, notch; 3, metal sheet; 31, hole; 4, isolation ceramic. DETAILED DESCRIPTION

[0026] Reference Figures 1 to 9 The embodiments of the present invention are further described.

[0027] In the description of the present invention, it should be noted that directional words, such as the terms "center", "lateral (X)", "longitudinal (Y)", "vertical (Z)", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc., indicating directions and positional relationships are based on the directions or positional relationships shown in the accompanying drawings, which are only for the convenience of narrating the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and cannot be understood as limiting the specific scope of protection of the present invention.

[0028] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features. Therefore, the definition of "first" and "second" features can explicitly or implicitly include one or more of the features. In the description of the present invention, "several" and "a number" mean two or more, unless otherwise clearly and specifically defined.

[0029] The ion source is mainly composed of a grid, a radio frequency (RF) power coil, a quartz cavity, an airflow guide structure, etc.

[0030] 1. The gas flow guiding structure introduces etching gas, such as argon, and evenly distributes it in the vacuum quartz chamber;

[0031] 2. Radio frequency (RF) power supply provides energy to ionize the gas in the vacuum quartz chamber;

[0032] 3. The grid is usually composed of 3 to 5 metal sheets 3 with identical structures, mutual insulation and different voltages. The ion flow is accelerated by the grid with different electric fields and passes through the grid to form a nearly parallel plasma beam with high energy. Usually, the substrate is placed on the substrate stage. The substrate stage can be rotated to help improve the uniformity of the etching rate. The ion beam continuously hits the substrate, bombarding the material on the substrate to form etching.

[0033] like Figure 1 As shown, in this embodiment, the grid is composed of three metal sheets 3 (thickness d) as an example. The metal sheets 3 are usually high-temperature resistant metal Mo. There are ceramic components (length t) between the metal sheets 3 to insulate them from each other; each metal sheet is connected to a different voltage potential.

[0034] Each metal sheet 3 has a densely packed honeycomb-shaped hole 31 in the middle; its size, arrangement, layout, etc. can be different, and a common structure is equal diameter and densely packed in the area, such as Figure 2 shown.

[0035] The ions accelerated by the grid of this structure can form a nearly parallel plasma beam with high energy for etching the wafer surface.

[0036] Embodiment 1:

[0037] A hole for adjusting the uniformity of ion etching comprises a cap portion 1 and a rod portion 2, one end of the rod portion 2 is fixedly connected to the cap portion 1, and a notch 21 is arranged on a side surface of the rod portion 2.

[0038] In this embodiment, the preferred hole is made of insulating and high temperature resistant materials, such as ceramics, quartz, etc.

[0039] In order to facilitate the cooperation with the grid, the preferred width of the slot 21 is d and the height is X. At the same time, the size of the upper rod 2 of the hole is smaller than the size of the hole 31 of the metal sheet 3, so that the hole can be easily inserted into the hole 31, and the hole can be firmly fixed on the grid by relying on the gravity of the hole and the coupling of the slot 21 and the thickness of the metal sheet 3, thereby reducing the ion concentration here and around.

[0040] The cross section of the rod 2 is preferably circular, that is, the rod 2 is cylindrical as a whole, so that the radius of the rod 2 is smaller than the radius of the hole 31 of the metal sheet 3.

[0041] like Figure 3 and 4 As shown, the hole is a non-axisymmetric structure, that is, the rod 2 is connected to the cap 1 at a position deviating from the center. The cross-section of the cap 1 is preferably circular, that is, the rod 2 is connected to the cap 1 at a non-center position. More preferably, the rod 2 is connected to the edge of the cap 1. The radius of the cap 1 is R, which is larger than the radius r of the hole 31 of the metal sheet 3 to ensure that the corresponding hole 31 can be covered.

[0042] Of course, the cap portion 1 may also be in other shapes, such as a triangle, a quadrilateral, an irregular shape, etc.

[0043] The size of the cap 1 in this embodiment can cover the holes 31 of one grid or the holes 31 of a plurality of adjacent grids.

[0044] Embodiment 2:

[0045] like Figure 4 As shown, in this embodiment, the rod 2 has a plurality of slots 21, which are evenly distributed along the length direction of the rod 2, and the spacing between two adjacent slots 21 is equal to the spacing between two adjacent metal sheets 3 of the grid, that is, the spacing t between two adjacent slots 21 is equal to the length of the isolating ceramic 4 between the metal sheets 3.

[0046] Taking the grid having three metal sheets 3 as an example, there can be three slots 21 to couple with the three metal sheets 3 at the same time so that the holes are firmly fixed on the grid. The other technical features are the same as those in the first embodiment.

[0047] like Figure 5 As shown, a method for adjusting ion etching uniformity includes the following steps:

[0048] S1: etching the wafer using an ion source grid to obtain ion etching thickness or rate distribution data; S2: preparing an etching thickness or rate T=f(r / R) graph;

[0049] S3: judging whether the etching uniformity requirement is met according to the T=f(r / R) graph;

[0050] S4: If the etching uniformity requirement is met, proceed to step S5; if the etching uniformity requirement is not met, according to the T=f(r / R) diagram, insert a number of holes at the ion source grid position corresponding to the higher etching thickness, and then return to step S1;

[0051] S5: End the adjustment.

[0052] Figure 6-9 This is a specific test case using the above method.

[0053] Figure 6 In the figure, A is the change of normalized etching thickness with the distance from the center of the wafer to the edge of the wafer without any hole, that is, T = f (r / R). As can be seen from the figure, the etching thickness of the wafer starts to increase at r / R = ~ 0.32, reaches the maximum at r / R = ~ 0.63, and then slowly decreases. The uniformity of the etching thickness is StdD% = 3.17%, as shown in Figure 1. Figure 7 This shows that starting from r / R = 0.32, the etching ion concentration increases rapidly and then slowly decreases.

[0054] Based on this situation, in the ion source grid,

[0055] 1. Insert a ceramic hole at a radius of about 0.50 from the center;

[0056] 2. Insert three ceramic holes at a radius of about 0.63 from the center;

[0057] 3. Insert two ceramic holes at a radius of about 0.95 from the center;

[0058] In this way, the inserted ceramic hole effectively reduces the ion concentration and the corresponding etching speed at that location and the surrounding area, so that the etching thickness of the corresponding area is reduced, which greatly improves the uniformity of the etching thickness. Figure 6 As shown in the middle curve B. The uniformity of etching thickness reaches StdD% = 1.05%, as shown in Figure 8 shown.

[0059] Further, in the ion source grid,

[0060] 1.2.3.4. Insert another ceramic hole at a radius of about 0.50 from the center;

[0061] 5. Insert another ceramic hole at a radius of about 0.63 from the center;

[0062] 6. Insert another ceramic hole at a radius of about 0.95 from the center;

[0063] In this way, the inserted ceramic hole effectively reduces the ion concentration and the corresponding etching speed at that location and the surrounding area, so that the etching thickness of the corresponding area is reduced, which greatly improves the uniformity of the etching thickness. Figure 6 As shown in the middle curve C. The uniformity of etching thickness reaches StdD% = 0.20%, as shown in Fig. 9 shown.

[0064] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A method for adjusting the uniformity of ion etching, characterized in that: It comprises a cap part and a rod part, one end of the rod part is fixedly connected to the cap part, and a notch is arranged on the side of the rod part; The method for adjusting the uniformity of ion etching by using the hole is characterized by comprising the following steps: S1: Etching the wafer using an ion source grid to obtain ion etching thickness or rate distribution data; S2: Prepare an etching thickness or rate T = f (r / R) graph; S3: judging whether the etching uniformity requirement is met according to the T=f(r / R) graph; S4: If the etching uniformity requirement is met, proceed to step S5; if the etching uniformity requirement is not met, according to the T=f(r / R) diagram, insert a number of holes at the ion source grid position corresponding to the higher etching thickness, and then return to step S1; S5: End the adjustment.

2. A method for adjusting ion etching uniformity according to claim 1, characterized in that: The rod portion is connected to a position on the cap portion that deviates from the center of the cap portion.

3. The method for adjusting ion etching uniformity according to claim 2, characterized in that: The width of the notch is equal to the thickness of the metal sheet of the grid.

4. The method for adjusting ion etching uniformity according to claim 3, characterized in that: The cap has a size capable of covering a hole of one grid or holes of a plurality of adjacent grids.

5. The method for adjusting ion etching uniformity according to claim 4, characterized in that: The cross section of the cap portion is circular.

6. A method for adjusting ion etching uniformity according to any one of claims 1 to 5, characterized in that: The rod portion is provided with a plurality of notches, which are evenly distributed along the length direction of the rod portion, and the distance between two adjacent notches is equal to the distance between two adjacent metal sheets of the grid.

7. The method for adjusting ion etching uniformity according to claim 6, characterized in that: The cap part and the rod part are made of ceramic or quartz.

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