Design method of a reticle for dry etching, reticle and dry etching method

Abstract

The present disclosure provides a design method of a correction plate for dry etching, a correction plate and a high-uniformity dry etching method, the design method comprising: S1, obtaining a projection shape of the correction plate on a surface of a sample to be etched according to an etching depth distribution H(r i ) or an etching speed distribution V(r i ) of the surface of the sample to be etched; and S2, obtaining a first shape of the correction plate according to the projection shape of the correction plate on the surface of the sample to be etched and a position of the correction plate between the sample to be etched and an ion source. By designing the first shape of the correction plate between the ion source and the sample to be etched, the shape of an etching surface on the sample to be etched is adjusted, the etching speed of each point on the etching surface is controlled, and the uniformity of dry etching, especially dry etching of a large-aperture device, is improved.

Description

Technical Field

[0001] This invention belongs to the field of micro-nano structure fabrication, specifically relating to a design method for a correction plate for dry etching, the correction plate, and the dry etching method. Background Technology

[0002] In fields such as deep space exploration, Earth observation, and civilian imaging displays, the increasing demands on key system performance indicators (swath width, resolution, etc.) have placed higher requirements on core structural components. For example, meter-level aperture planar imaging systems require not only a single-screen swath width of meters, but also micrometer-level or even submicrometer and nanometer-level structures etched on the surface.

[0003] Currently, the main methods for fabricating micro- and nanostructures in the meter-scale aperture range include semiconductor-based projection exposure and laser direct writing, as well as laser engraving technology. Laser engraving can fabricate microstructures with meter-scale apertures, but the size of the fabricated microstructures is typically larger than 5 μm, and the surface roughness is high, making it difficult to meet the requirements of optical-grade applications. In comparison, projection exposure and laser direct writing can fabricate micron-scale photoresist patterns with meter-scale apertures, offering advantages such as high processing precision and low surface roughness. However, the photoresist pattern still needs to be transferred to the substrate surface to achieve the final fabrication of the micro- and nanostructures.

[0004] There are two methods for photoresist pattern transfer: wet etching and dry etching. Wet etching is isotropic, making it difficult to control the shape of microstructures. Dry etching, on the other hand, allows for control of the lateral and longitudinal etching rates by adjusting parameters such as the type and flow rate of the etching atmosphere, RF power, and cavity pressure, thereby controlling the aspect ratio and cross-sectional shape of the microstructure. It is the most widely used pattern transfer method. However, as apertures increase to the meter level and above, the radial uniformity of the ion source deteriorates, making it difficult to meet application requirements for the uniformity of pattern transfer depth to the substrate surface. Furthermore, increased aperture also leads to more pronounced edge effects, meaning the etching uniformity differs most significantly between the sample edges and the center. Currently, there are no commercially available meter-level aperture high-uniformity pattern transfer technologies in China. Therefore, there is an urgent need to reduce the depth error and improve the uniformity of meter-level aperture pattern transfer, which can provide a technological foundation and support for large-aperture optoelectronic products.

[0005] To address the aforementioned problems, this invention proposes a design method for a correction plate for dry etching, a correction plate, and a dry etching method. This is a highly uniform dry etching method that solves the problem of uneven etching depth of micro-nano structures caused by dry etching over a large range, such as the meter-scale aperture range. It improves etching uniformity and reduces the fabrication cost of meter-scale aperture microstructures. Summary of the Invention

[0006] This disclosure provides a design method for a correction plate for dry etching, a correction plate, and a dry etching method, which at least partially solves the problem of uneven etching depth on the surface of the processed sample and poor device processing quality caused by large differences in the uniformity of the ion source in the prior art.

[0007] Based on this, this disclosure provides a design method for a correction plate for dry etching, including: S1, according to the etching depth distribution H(r) on the surface of the sample to be etched. i or etching rate distribution V(r) i S1) Obtain the projection shape of the correction plate on the surface of the etched sample; S2) Obtain the first shape of the correction plate based on the projection shape of the correction plate on the surface of the etched sample and the position of the correction plate between the etched sample and the ion source.

[0008] According to embodiments of this disclosure, the design method for a correction plate for dry etching further includes: S3, placing the correction plate designed in S2 in the first shape of the design correction plate, at the position of the correction plate between the etched sample and the ion source, and collecting the etching depth distribution H(r) on the surface of the etched sample after etching. i or etching rate distribution V(r) i ), calculate the etching uniformity parameter. If the etching uniformity parameter does not meet the set value, repeat S1 and S2; if the etching uniformity parameter meets the set value, stop the optimization process of the first shape of the correction plate.

[0009] According to an embodiment of this disclosure, S1, based on the etching depth distribution H(r) on the surface of the etched sample... i or etching rate distribution V(r) i The process involves obtaining the projection shape of the correction plate onto the surface of the etched sample, including: S11, based on the etching depth distribution H(r) on the surface of the etched sample. i The mean distribution of etching depth on the surface of the etched sample was obtained. Or the average distribution of etching rates

[0010]

[0011]

[0012] In the formula, n represents the radius r i n etching depth test points on the circumference; t represents the etching time;

[0013] S12, find the minimum average etching depth. or the average minimum etching rate The included angle θ of the ion source to be corrected is obtained from the circumference C. C ;

[0014] S13, the projection shape of the correction plate on the surface of the etched sample is:

[0015] According to an embodiment of this disclosure, S2, obtaining the first shape of the correction plate based on the projection shape of the correction plate on the surface of the etched sample and the position of the correction plate between the etched sample and the ion source includes: when the correction plate is parallel to the etched sample and the ion source, obtaining the first shape formula S'(x,y) of the correction plate based on the relative positional relationship between the correction plate and the etched sample and the ion source is as follows:

[0016]

[0017] Where h is the distance between the correction plate and the ion source; H is the distance between the etched sample and the ion source; and h' is the distance between the ion source and the vertices of a group of similar triangles with the radius R of the etched sample and the ion source as sides, respectively.

[0018] According to an embodiment of this disclosure, S2, obtaining a first shape of the correction plate based on the projection shape of the correction plate on the surface of the etched sample and the position of the correction plate between the etched sample and the ion source includes: when the correction plate has an angle in the direction parallel to the ion source, obtaining a second shape formula S" (x,y) of the projection of the correction plate in the direction parallel to the ion source based on the relative positional relationship between the correction plate and the etched sample and the ion source.

[0019]

[0020] Where h is the distance between the correction plate and the ion source on the plane parallel to the ion source; H is the distance between the etched sample and the ion source; and h' is the distance between the ion source and the vertices of a group of similar triangles with the radius R of the etched sample and the ion source as sides, respectively.

[0021] This disclosure also provides a high-uniformity dry etching method, comprising: S20, etching a sample to be etched; S21, designing a first shape of a correction plate using any of the correction plate design methods for dry etching described above; S22, placing the designed correction plate in the position between the sample to be etched and the ion source when the correction plate is in the first shape or a second shape projected in a direction parallel to the ion source, and etching the sample to be etched.

[0022] According to embodiments of this disclosure, the high-uniformity dry etching method further includes: S23, after placing a correction plate, collecting the etching depth distribution H(r) on the surface of the etched sample. i or etching rate distribution V(r) i), calculate the etching uniformity parameter. If the etching uniformity parameter does not meet the set value, repeat S21 and S22. If the etching uniformity parameter meets the set value, stop the optimization process of the first shape of the correction plate or the second shape projected in the direction parallel to the ion source.

[0023] According to an embodiment of this disclosure, the etched sample in S22 is a new etched sample with the same position and initial size as the etched sample in S20.

[0024] According to embodiments of this disclosure, the first shape of the correction plate or the second shape projected in a direction parallel to the ion source is designed using any of the correction plate design methods for dry etching described above.

[0025] According to embodiments of this disclosure, the correction plate is processed using a laser engraving method.

[0026] The design method for a correction board, the correction board, and the high-uniformity dry etching method provided in the embodiments of this disclosure have at least the following beneficial effects:

[0027] This invention addresses the issue of uneven etching depth in micro / nano structures caused by dry etching, particularly improving etching uniformity for large-aperture micro / nano structures. Furthermore, since there are currently no commercially available large-aperture, high-uniformity pattern transfer technologies in China, this invention improves etching uniformity by adding a correction plate to a traditional etching apparatus, reducing the need for high-cost pattern transfer technologies and lowering the cost of micro / nano structure fabrication. Attached Figure Description

[0028] The above and other objects, features and advantages of this disclosure will become clearer from the following description of embodiments with reference to the accompanying drawings, in which:

[0029] Figure 1 A schematic diagram of conventional dry etching provided in an embodiment of this disclosure is shown.

[0030] Figure 2 The schematic diagram illustrates the etched surface on the sample being etched in a conventional dry etching process according to the embodiments of this disclosure; wherein, (a) is a schematic diagram of a minimum etched surface, (b) is a schematic diagram of a conventional etched surface, and (c) is a schematic diagram of a circular etched surface.

[0031] Figure 3 A flowchart illustrating a design method for a correction plate for improving the uniformity of dry etching, provided in an embodiment of this disclosure, is shown schematically.

[0032] Figure 4 The schematic diagram illustrates the principle of improving the uniformity of dry etching provided by the embodiments of this disclosure.

[0033] Figure 5 The diagram illustrates the projected shape (the portion of the etched surface that is obscured) of the correction plate provided in the embodiments of this disclosure on the surface of the etched sample.

[0034] Figure 6 The schematic diagram illustrates the principle of dry etching projection relationship provided in Embodiment 1 of this disclosure.

[0035] Figure 7 The schematic diagram illustrates the principle of dry etching projection relationship provided in Embodiment 2 of this disclosure; wherein, (a) is a schematic diagram of the modified version at a certain height, and (b) is a schematic diagram of the modified version at another height.

[0036] Figure 8 A flowchart illustrating a design method for a correction plate for improving the uniformity of dry etching, provided in another embodiment of this disclosure, is shown.

[0037] Figure 9 A flowchart illustrating the high uniformity dry etching method provided in the embodiments of this disclosure is shown.

[0038] Figure 10 A flowchart illustrating a high-uniformity dry etching method provided in another embodiment of this disclosure is shown.

[0039] Figure 11 The illustration schematically shows the etching depth distribution of the etched sample in the conventional dry etching process provided in Embodiment 3 of this disclosure.

[0040] Figure 12 The diagram illustrates the shape of the correction plate provided in Embodiment 3 of this disclosure.

[0041] Figure 13 The illustration schematically shows the etching depth distribution of the etched sample after the addition of a correction plate, as provided in Embodiment 3 of this disclosure.

[0042] In the figure, 1-ion source, 2-correction plate, 3-etched sample, 4-etched surface, 5-plane parallel to the ion source. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with specific embodiments and accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without inventive effort are within the scope of protection of this disclosure.

[0044] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0045] In this disclosure, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances.

[0046] In the description of this disclosure, it should be understood that the terms "longitudinal", "length", "circumferential", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this disclosure and simplifying the description, and do not indicate or imply that the subsystem or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this disclosure.

[0047] Throughout the accompanying drawings, identical elements are represented by the same or similar reference numerals. Conventional structures or constructions have been omitted where they may cause confusion in understanding this disclosure. Furthermore, the shapes, dimensions, and positional relationships of the components in the drawings do not reflect actual size, scale, or actual positional relationships. Additionally, any reference numerals placed between parentheses in the claims should not be construed as limiting the claims.

[0048] Similarly, to simplify this disclosure and aid in understanding one or more of the various aspects of the disclosure, in the above description of exemplary embodiments of the present disclosure, various features of the present disclosure are sometimes grouped together in a single embodiment, figure, or description thereof. The use of terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refers to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the present disclosure. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0049] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this disclosure, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0050] Figure 1 A schematic diagram of conventional dry etching provided in an embodiment of this disclosure is shown. Figure 2 The schematic diagram illustrates the etched surface on the sample being etched in a conventional dry etching process according to an embodiment of the present disclosure. Figure 1 The radius of the etched sample 3 is R, the length of the ion source 1 is A, H is the distance between the etched sample 3 and the ion source 1; h' is... Figure 1 The distance between the midpoint O" and the ion source 1, where the midpoint O" is the vertex of a group of similar triangles with the radius R of the etched sample 3 and the ion source 1 as sides respectively.

[0051] like Figure 2 As shown, during the etching process, the sample 3 being etched rotates around its center O. The ion source 1 generates highly reactive ions or electrons from the etching gas, which physically bombard and chemically react with the sample 3 to remove the areas requiring etching. To ensure the steepness of the etched micro / nano structures, the ion source 1 is usually parallel to the sample 3. Due to the limited area of ​​the ion source 1, at any given moment, the etched surface 4 on the sample 3 is only a portion of the sample 3, such as... Figure 2 As shown. Figure 2 As shown in (a), when the ion source 1 is located to the right of the center O, in order to ensure that every part of the surface of the etched sample 3 can be etched, the etch surface 4 of the ion source 1 acting on the etched sample 3 is the shortest in the radial direction, which requires the left side to be tangent to the center O and the right side to be tangent to the edge of the etched sample 3; when the ion source 1 is located to the left of the center O, the etch surface 4 is the shortest in the radial direction, which requires the right side to be tangent to the center O and the left side to be tangent to the edge of the etched sample 3. Figure 2 Figure (a) schematically illustrates the minimum radial requirement for the etching area (etching surface 4) of the ion source 1 to ensure that all locations on the etched sample 3 are etched; in actual etching, the etching area (etching surface 4) of the ion source 1 can also be as follows: Figure 2 As shown in (b), the length in the radial direction of the etched sample 3 is greater than the radius R of the etched sample 3. Furthermore, Figure 2 (a) and Figure 2 The elliptical etched surface 4 in (b) is just one common etched surface shape. Besides this, there are other shapes such as... Figure 2Other etching surface shapes, such as circular or irregular shapes, as shown in (c), are not limited here.

[0052] During etching, the radial uniformity of the ion source 1 deteriorates, and the increased aperture of the etched sample 3 leads to a greater difference in etching depth between the edge and center of the etched sample 3, resulting in poor etching depth uniformity. To improve the uniformity of etching depth on the etched sample 3, this invention employs a correction plate 2 added between the ion source 1 and the etched sample 3. This correction plate 2 has a first shape, and through its shielding effect, it selectively changes the shape of the etched surface 4 on the etched sample 3, thereby controlling the uniformity of etching depth. That is, in areas not covered by the correction plate, highly reactive ions and electrons generated by the etching gas reach the surface of the etched sample 3 for etching, while the plate body of the correction plate blocks these ions and electrons, preventing them from reaching the surface of the etched sample 3 and thus preventing them from participating in the etching process. Based on this, the first shape of the correction plate is particularly important for controlling the uniformity of etching depth. The design process of the first shape of the correction plate is explained below with reference to specific embodiments.

[0053] The purpose of this disclosure is to provide a design method for a correction plate to improve the uniformity of dry etching. By designing a first shape for the correction plate 2 located between the ion source 1 and the etched sample 3, the projection shape of the correction plate 2 onto the etched sample 3 represents the portion of the etched surface 4 that is obscured. This adjusts the shape of the etched surface 4 on the etched sample 3, controlling the etching rate at each point within the etched surface 4 at a given time, thereby improving the uniformity of dry etching, especially for large-diameter devices. Specifically, this involves controlling the etching depth or etching rate on the circumference of other radii based on the etching depth distribution (or etching rate distribution) on the surface of the etched sample 3, using the minimum etching depth or minimum etching rate as a reference. Specifically, this is achieved by adjusting the shape of the obscured portion of the etched surface 4 on the etched sample 3, and using the projection principle to deduce the first shape of the correction plate 2 from the adjusted shape of the obscured portion of the etched surface 4. The correction plate 2 is then placed at a designated position between the etched sample 3 and the ion source 1 to improve the uniformity of dry etching.

[0054] Figure 3 A flowchart illustrating a design method for a correction plate for improving the uniformity of dry etching, provided in an embodiment of this disclosure, is shown schematically.

[0055] like Figure 3 As shown, this design method may include, for example, operations S1 to S2.

[0056] S1, based on the etching depth distribution H(r) on the surface of the etched sample 3 i or etching rate distribution V(r) i), thus obtaining the projection shape of the correction plate 2 on the surface of the etched sample 3;

[0057] S2, based on the projection shape of the correction plate 2 on the surface of the etched sample 3 and the position of the correction plate 2 between the etched sample 3 and the ion source 1, the first shape of the correction plate 2 is obtained.

[0058] Figure 4 The schematic diagram illustrates the principle of improving the uniformity of dry etching provided by the embodiments of this disclosure.

[0059] like Figure 4 As shown, during the etching process, the sample 3 being etched rotates around its center O to complete the etching of the entire circumference. Due to factors such as the inhomogeneity of the ion source 1, the etching rate v(r) may differ between circumferences with different radii r, i.e., the radii in the figure are r... i and r j Etching speed v(r) on the circumference i ) and v(r j The etching depths (H(r) and etching rates (V(r)) are not the same. In this embodiment of the invention, the minimum etching depth H(r) is found by first measuring the etching depth H(r) or etching rate V(r) on circles with different radii r. min or minimum etching rate V(r) min The circle C containing the digit ) has a radius of r. C Typically, the circumference C is located at the edge of the etched sample 3, i.e., r. C =R, but in some cases, due to the inhomogeneity of ion source 1, the circumferential C may appear in a radius of r. i At any position. At the etching rate V(r) on that circumference C. min Based on this, the etching speed V on other circumferences is adjusted.

[0060] Figure 4 When the etched sample 3 rotates clockwise, its angular velocity is w and its radius is r. i A point B on the circumference is etched from the moment it enters the etching surface 4 until it leaves the etching surface 4, that is, the etching time in one etching cycle is t. i The central angle θ corresponding to the arc of point B's movement within the etched surface 4. i This is called the etching angle. The etching depth h(r) on this circumference within one etching cycle... i This can be represented as:

[0061]

[0062] Assumption Figure 4 With a mid-radius of r j The circumference is circumference C, and the etching depth on circumference C is H(r). min), etching rate is V(r) min The etching depth h(r) on the circumference within one etching cycle min ), etching rate is v(r) min The angle between the two points where the etched surface 4 intersects the circumference C and the center of the circle is θ. C This is referred to as the ion source angle to be corrected. The etching depth h(r) on the circumferential C is... min This can be represented as:

[0063]

[0064] Radius r i The etching depth on the circumference is h(r) i ) and the etching depth h(r) on the circumference C min The difference is:

[0065]

[0066] The difference in etching depth can be eliminated by placing a correction plate 2 between the etched sample 3 and the ion source 1, that is:

[0067]

[0068]

[0069] Where θ′ is the angle between the parts of the etched surface 4 that are obscured, such as Figure 5 As shown in the image.

[0070] The above formula applies to any radius r. i This derivation is based on the assumption that the etching rate remains constant along the circumference. In reality, the etching rate v(r) varies at different positions and at different times along the same circumference. i There may also be differences, so the angle θ′ of the part of the etched surface 4 that is blocked can be calculated using the integral form in the following formulas (6) and (7).

[0071]

[0072]

[0073] That is, if we want the radius r to be i If the etching rate or depth on the circumference is the same as the etching rate or depth on the circumference C, then the radius r needs to be set to... i The etching angle θ′ on the circumference is blocked, which can be achieved by adding a correction plate 2 between the ion source 1 and the etched sample 3.

[0074] After obtaining the adjusted etching angle, to facilitate differentiation, different radii r iThe included angle of the obscured portion on the circumference is θ' i This indicates that the shape formula S(x,y) of the projection of the correction plate 2 onto the etched surface 4 is:

[0075]

[0076] Figure 6 The schematic diagram illustrates the principle of dry etching projection relationship provided in Embodiment 1 of this disclosure.

[0077] Formula (8) gives the shape of the correction plate 2 projected onto the etched surface 4. This shape is formed by controlling the projection of the first shape of the correction plate 2, such as... Figure 6 As shown, when the correction plate 2 is parallel to both the etched sample 3 and the ion source 1, based on the relative positional relationship between the correction plate 2 and the etched sample 3 and the ion source 1, and according to the projection principle, the first shape formula S'(x,y) of the correction plate 2 can be obtained as follows:

[0078]

[0079] Where h is the distance between correction plate 2 and ion source 1; H is the distance between the etched sample 3 and ion source 1; h' is... Figure 6 The distance between the midpoint O" and the ion source 1, where the midpoint O" is the vertex of a group of similar triangles with the radius R of the etched sample 3 and the ion source 1 as sides respectively.

[0080] According to the projection principle, after the ions and electrons generated by the ion source 1 pass through the correction plate 2, the plate body of the correction plate 2 blocks the particles. At this time, the blocked part of the etching surface 4 with the shape formula S(x,y) is formed on the etched sample 3. At this time, different radii r i The etching rate on the circumference tends to be consistent, ensuring the uniformity of the etching depth.

[0081] like Figure 6 As shown, when designing the first shape, the correction plate 2 can be located at any position between the ion source 1 and the etched sample 3. As shown, the correction plate 2 at two different positions can form the same part of the etched surface 4 that is blocked on the etched sample 3. That is, the position of the correction plate 2 in the height direction is not unique.

[0082] Figure 7 The schematic diagram illustrates the principle of dry etching projection relationship provided in Embodiment 2 of this disclosure. It is applicable to etching apparatuses where, due to space constraints, the correction plate 2 cannot be mounted in parallel.

[0083] The shape of the portion of the etched surface 4 that is obscured is formed by controlling the projection of the first shape of the correction plate 2, such as... Figure 7As shown, when the correction plate 2 is not parallel to the etched sample 3 and the ion source 1, and when the correction plate 2 has an angle α in the direction parallel to the ion source 1, according to the relative positional relationship between the correction plate 2 and the etched sample 3 and the ion source 1, and according to the projection principle, the second shape formula S"(x,y) of the projection of the correction plate 2 onto the plane 5 parallel to the ion source 1 can be obtained as follows:

[0084]

[0085] Where h is the distance between plane 5 and ion source 1; H is the distance between the etched sample 3 and ion source 1; h' is... Figure 7 The distance between the midpoint O" and the ion source 1, where point O" is the vertex of a group of similar triangles with the radius R of the etched sample 3 and the ion source 1 as sides, respectively. Figure 7 (a) Figure 7 As shown in Figure (b), when designing the first shape, the correction plate 2 can be located at any position between the ion source 1 and the etched sample 3. As shown in the figure, the correction plate 2 at two different positions can form the same part of the etched surface 4 that is blocked on the etched sample 3. That is, the position of the correction plate 2 in the height direction is not unique.

[0086] Because in Figure 7 In the XOZ coordinate system shown, there is an angle α between the correction plate 2 and the plane 5 in the X direction. After obtaining the second shape formula S(x,y), the first shape formula of the correction plate 2 can be derived by using geometric theorems. Figure 7 (a) For example:

[0087]

[0088] To facilitate differentiation from the first embodiment, the horizontal and vertical coordinates in the first shape formula in formula (11) are represented by x” and y”, respectively. z” represents the height of the correction plate 2 deviating from the plane 5.

[0089] In addition, there may be other positional relationships between the correction plate 2 and the plane 5. For example, there may be angles (α, β, γ) between the normal of the correction plate 2 and the normal of the plane 5 on the X, Y, and Z axes, respectively. In this case, the first shape formula can be derived by using the second shape formula S (x, y) on the plane 5 according to geometric principles. This will not be elaborated here.

[0090] Furthermore, as the above analysis shows, as long as the shape formula of the etching surface 4 of the correction plate 2 on the etched sample 3 is S(x,y), the etching uniformity of the etched sample can be adjusted. Therefore, the correction plate 2 can also be a curved plate. Since flat plates are easier to design and manufacture, the correction plate 2 will be described as a flat plate here.

[0091] According to the projection principle, after the ions and electrons generated by the ion source 1 pass through the correction plate 2, the plate body of the correction plate 2 blocks the particles. At this time, the blocked part of the etching surface 4 with the shape formula S(x,y) is formed on the etched sample 3. At this time, different radii r i The etching rate on the circumference tends to be consistent, ensuring the uniformity of the etching depth.

[0092] For ease of understanding, the above uses the etching depth distribution h(r) within one etching cycle as an example. i or etching velocity distribution v(r) i Taking t as an example, in actual design, the etching depth distribution H(r) corresponding to the entire etching process (etching time t) can also be used. i or etching rate distribution V(r) i The first shape of the correction plate 2 is designed. As can be seen from the above explanation, the use of etching depth distribution or etching rate distribution is to obtain the circumference C with the minimum etching rate, and to adjust the etching angle of other radii circumferences based on this minimum etching rate. Therefore, the etching depth distribution h(r) within a single etching cycle is selected. i or etching velocity distribution v(r) i Alternatively, select the etching depth distribution H(r) corresponding to the entire etching process (etching time t). i or etching rate distribution V(r) i This does not affect the final design result.

[0093] Figure 8 A flowchart illustrating a design method for a correction plate for improving the uniformity of dry etching, provided in another embodiment of this disclosure, is shown.

[0094] like Figure 8 As shown, this design method includes operation S3 after operation S2.

[0095] S3, Place the correction plate 2 designed in S2 into the first shape of the design, at the position of the correction plate 2 between the etched sample 3 and the ion source 1, and collect the etching depth distribution H(r) on the surface of the etched sample 3 after etching. i or etching rate distribution V(r) i ), calculate the etching uniformity parameter. If the etching uniformity parameter does not meet the set value, repeat S1 and S2; if the etching uniformity parameter meets the set value, stop the optimization process of the first shape of the correction plate.

[0096] To verify the effect of the correction plate 2 in improving the uniformity of dry etching, the correction plate 2 designed in S1 and S2 can be placed between the etched sample 3 and the ion source 1 when the first shape of the correction plate 2 is designed. At this time, the projection of the correction plate on the etched sample 3 is the shape of the part of the etched surface 4 that is blocked. After etching for a period of time, the etching depth distribution H(r) of the etched sample 3 is measured. i ), calculate the etching uniformity parameters. Commonly used uniformity parameters can be expressed as:

[0097]

[0098] Wherein, H(r) max ) represents the maximum etching depth value, r max H(r) represents the radius value corresponding to the maximum etching depth. min ) represents the minimum etching depth value, r min This is the radius value corresponding to the minimum etching depth.

[0099] When the uniformity parameter meets the design expectation, it means that the designed correction board meets the requirements for improving the uniformity of dry etching and can be put into mass production. If the uniformity parameter cannot reach the set value, it is necessary to combine the newly obtained etching depth distribution or etching rate distribution to carry out iterative optimization design of the first shape of the correction board.

[0100] It should be noted that the above uniformity parameters are only one example, and other expressions can also be used, such as the maximum etching depth H(r). max Minimum etching depth H(r) min ), average etching depth H(r) mean The relationships between them are expressed.

[0101] In this embodiment of the disclosure, S1, based on the etching depth distribution H(r) on the surface of the etched sample 3... i or etching rate distribution V(r) i The projection shape of the correction plate 25 on the surface of the etched sample 3 is obtained, including:

[0102] S11, based on the etching depth distribution H(r) on the surface of the etched sample 3 i The mean distribution of etching depth on the surface of etched sample 3 was obtained. Or the average distribution of etching rates

[0103]

[0104]

[0105] In the formula, n represents the radius r in etching depth test points on the circumference; t represents the etching time;

[0106] S12, find the minimum average etching depth. or the average minimum etching rate The included angle θ of the ion source to be corrected is obtained from the circumference C. C ;

[0107] S13, the projection shape of the correction plate 2 on the surface of the etched sample 3 is:

[0108]

[0109] In S11, instead of using the etching depth value of a single point, a radius of r is used. i The average of n etching depths on the circumference is used as the etching depth value for that circumference to eliminate the influence of a few sudden etching anomalies on the design results of the correction board. Alternatively, a radius of r can be used. i The median value of the many etching depths on the circumference is taken as the etching depth value of the circumference.

[0110] In this embodiment of the disclosure, S2, based on the projection shape of the correction plate 2 on the surface of the etched sample 3 (i.e., the shape of the portion of the etched surface 4 that is obscured) and the position of the correction plate 2 between the etched sample 3 and the ion source 1, a first shape of the correction plate 2 is obtained, including:

[0111] When the correction plate 2 is parallel to the etched sample 3 and the ion source 1, the first shape formula S'(x,y) is obtained based on the relative positional relationship between the correction plate 2, the etched sample 1, and the ion source 1:

[0112]

[0113] Where h is the distance between the correction plate 2 and the ion source 1; H is the distance between the etched sample 3 and the ion source 1; and h' is the distance between the ion source 1 and the vertices of a group of similar triangles with the radius R of the etched sample 3 and the ion source 1 as sides, respectively.

[0114] In embodiments of this disclosure, S2 further includes:

[0115] When the correction plate 2 forms an angle with the ion source 1 in the direction parallel to it, i.e., the correction plate 2 and the ion source 1 are not parallel, the second shape formula S(x,y) of the projection of the correction plate 2 in the direction parallel to the ion source 1 is obtained based on the relative positional relationship between the correction plate 2, the etched sample 3, and the ion source 1:

[0116]

[0117] Where h is the distance between plane 5 and ion source 1; H is the distance between the etched sample 3 and ion source 1; and h' is the distance between ion source 1 and the vertices of a group of similar triangles with the radius R of the etched sample 3 and ion source 1 as sides, respectively.

[0118] The first shape formula can be derived by using geometric theorems, based on the second shape formula S(x,y) of the projection of the correction plate 2 in the direction parallel to the ion source 1 and the angle between the correction plate 2 and the plane 5. The specific operation process will not be described here.

[0119] Based on the same inventive concept, this disclosure provides a correction plate that can improve the uniformity of dry etching.

[0120] The first shape of the correction plate 2 or the second shape projected in a direction parallel to the ion source 1 is designed using the above-described design method for correction plates used in dry etching.

[0121] To ensure processing accuracy, the correction plate 2 is processed using laser engraving. Of course, other processing methods can also be used.

[0122] Since the correction plate 2 is attacked by highly reactive ions or electrons, it is usually made of corrosion-resistant metal plate in order to extend its service life.

[0123] Based on the same inventive concept, this disclosure provides a high-uniformity dry etching method using the above-mentioned correction plate.

[0124] Figure 9 A flowchart illustrating the high uniformity dry etching method provided in the embodiments of this disclosure is shown.

[0125] like Figure 9 As shown, the high-uniformity dry etching method includes:

[0126] S20, etching sample 2;

[0127] S21, the first shape of the correction plate 2 is designed using the above-described design method for the correction plate 2 used in dry etching;

[0128] S22, when the designed correction plate 2 is placed in the first shape of the design correction plate 2 or the second shape projected in the direction parallel to the ion source 1, the correction plate 2 is positioned between the etched sample 3 and the ion source 1, and the etched sample 3 is etched.

[0129] Figure 10 A flowchart illustrating a high-uniformity dry etching method provided in another embodiment of this disclosure is shown.

[0130] like Figure 10As shown, the etching method further includes operation S23 after operation S22.

[0131] S23, after placing the revised version 2, collect the etching depth distribution H(r) on the surface of the etched sample 3. i or etching rate distribution V(r) i ), calculate the etching uniformity parameter. If the etching uniformity parameter does not meet the set value, repeat S21 and S22. If the etching uniformity parameter meets the set value, stop the optimization process of the first shape of the correction plate 2 or the second shape projected in the direction parallel to the ion source 1.

[0132] In the embodiments of this disclosure, the etched sample 3 in S22 is a new etched sample 3 with the same position and initial size as the etched sample 3 in S20. This ensures that the designed correction plate achieves the best effect in improving the etching uniformity of the etched sample 3. It should also be noted that this correction plate can also be used for etching etched samples 3 with radii smaller or larger than those in S20, although its processing efficiency will be reduced. This is because when the radius R1 of the etched sample 3 in S22 is smaller than the radius R of the etched sample 3 in S20, under the same ion source 1 and the same correction plate 2, theoretically, without the correction plate, the minimum etching depth H(r) is... min or minimum etching rate V(r) min The radius of the circumference C where the sample 3 is located will not change. The correction plates designed by S1 and S2 can also improve the etching uniformity of the etched sample 3. However, the radius R1 of the processed etched sample 3 is smaller than the radius R used in the design, which reduces the processing economy. When the radius R2 of the etched sample 3 in S22 is greater than the radius R of the etched sample 3 in S20, under the same ion source 1 and the same correction plate 2, in principle, without the correction plate, the minimum etching depth H(r) is... min or minimum etching rate V(r) min The radius of the circumference C will not change, but since the area of ​​the adjusted etching surface 4 is limited, it cannot cover the part of the new etched sample 3 with a radius greater than R. Therefore, it can only improve the etching uniformity within the radius R range, and the processing economy is also reduced.

[0133] The present disclosure will be further described below through specific embodiments. The high-uniformity dry etching method described above will be specifically illustrated in the following embodiments. However, the following embodiments are merely illustrative of the present disclosure, and the scope of the present disclosure is not limited thereto.

[0134] The high-uniformity dry etching method disclosed herein includes performing the following steps sequentially:

[0135] Step 1: Fix the sample 3 to be etched into the etching equipment, evacuate, introduce etching gas and control the flow rate, set the power of ion source 1 to W and the etching time to t, and etch the sample 3 to be etched.

[0136] Step 2: Test different radii r on the surface of the etched sample 3 i Etching depth distribution H(r) i The calculation radius is r. i The etching depth or etching rate value on the circumference;

[0137] Step 3: Calculate the radio frequency angle θ to be corrected based on the circumference C containing the minimum etching depth or minimum etching rate. C The shape formula S(x,y) for the occluded portion of the adjusted etched surface 4 is as follows:

[0138]

[0139] Step 4: Based on the relative positions of the correction plate 2, the etched sample 3, and the ion source 1, and according to the projection principle, the first shape formula S'(x,y) of the correction plate can be obtained as follows:

[0140]

[0141] Where h is the distance between correction plate 2 and ion source 1; H is the distance between the etched sample 3 and ion source 1; h' is... Figure 5 The distance between the midpoint O" and the ion source 1, where the midpoint O" is the vertex of a group of similar triangles with the radius R of the etched sample 3 and the ion source 1 as sides respectively.

[0142] Step 5: Process the correction plate 2 with the first shape, and place the correction plate 2 in the position between the etched sample 3 and the ion source 1 when the first shape of the correction plate 2 is designed.

[0143] Step 6: Use a new etched sample 3 with the same initial size, place it in the same position as the etched sample 3 in the design process, and re-etch to verify the effectiveness of the improved etching uniformity.

[0144] Step 7: Collect the etching depth distribution H(r) on the surface of the etched sample 3 after etching. i or etching rate distribution V(r) i ), calculate the etching uniformity parameter. If the etching uniformity parameter does not meet the set value, repeat steps 1-6; if the etching uniformity parameter meets the set value, stop the optimization process of the first shape of the correction plate.

[0145] The etching gases used in the etching process include SF6, CHF3, NF3, Ar, O2, etc.; the etching rate is adjusted by adjusting parameters such as ion source energy, type and flow rate of etching gas, target distance, and cavity pressure; the etched sample 3 can rotate, and the rotational angular velocity is continuously adjustable.

[0146] Based on steps 1 to 7 above, the following is a specific embodiment.

[0147] Example 1:

[0148] The implementation steps of the high-uniformity dry etching method in this embodiment are as follows:

[0149] Step 11: Fix the sample to be etched, sample 3 (K9 glass, with a 500nm thick AZ1500 photoresist spin-coated on the surface), into the etching equipment and evacuate to 10°C. -3 Below Pa, etching gas is introduced and the flow rate is controlled. The plate voltage is set to 700V, the beam current is 260mA, and the etching time is 20min. The workpiece is rotated at a speed of 10r / min. O2 is selected as the etching gas to etch sample 3.

[0150] Step 12: After etching is completed, use a film thickness gauge to measure the different radii r on the surface of the etched sample 3. i Etching depth distribution H(r) i The calculation radius is r. i The etching depth or etching rate value on the circumference, at this time, the uniformity is approximately ±44%, such as Figure 11 As shown, the numbers in the boxes represent the etching depth values ​​at that location;

[0151] Step 13: Calculate the radio frequency angle θ to be corrected based on the circumference C containing the minimum etching depth or minimum etching rate. C The shape formula S(x,y) for the adjusted etched surface 4 is as follows:

[0152]

[0153] Step 14: Based on the relative positions of the correction plate 2, the etched sample 3, and the ion source 1, and according to the projection principle, the first shape formula S'(x,y) of the correction plate can be obtained as follows:

[0154]

[0155] Where h is the distance between correction plate 2 and ion source 1; H is the distance between the etched sample 3 and ion source 1; h' is... Figure 5 The distance between the midpoint O" and the ion source 1, where the midpoint O" is the vertex of a group of similar triangles with the radius R of the etched sample 3 and the ion source 1 as sides respectively.

[0156] In this embodiment, the shape of the designed correction plate 2 is as follows: Figure 12 As shown.

[0157] Step 15: Process the correction plate 2 with the first shape using laser engraving method, and place the correction plate 2 in the position between the etched sample 3 and the ion source 1 when the first shape of the correction plate 2 is designed.

[0158] Step 16: Using a new etched sample 3 with the same initial dimensions, place it at the same position as the etched sample 3 in the design process, and re-etch to obtain the corrected etching depth. The uniformity is better than ±6%. Figure 13 As shown.

[0159] In summary, this disclosure improves the uniformity of dry etching, especially dry etching of micro-nano structures of large-aperture devices, and reduces the cost of high-uniformity etching by designing a correction plate and placing it at a designated position between the ion source and the etched sample on a conventional etching apparatus.

[0160] The specific embodiments described above further illustrate the purpose, technical solutions, and beneficial effects of this disclosure. It should be understood that the above descriptions are merely specific embodiments of this disclosure and are not intended to limit this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the protection scope of this disclosure.

Claims

1. A method for designing a correction board for dry etching, characterized in that, include: S1, based on the etching depth distribution H(r) on the surface of the etched sample (3) i or etching rate distribution V(r) i The projection shape of the correction plate (2) on the surface of the etched sample (3) is obtained, including: S11, based on the etching depth distribution H(r) on the surface of the etched sample (3) i The mean distribution of etching depth on the surface of the etched sample (3) was obtained. Or the average distribution of etching rates , ； ； In the formula, n represents the radius r i n etching depth test points on the circumference; t represents the etching time; S12, find the minimum average etching depth. or the average minimum etching rate The included angle θ of the ion source to be corrected is obtained from the circumference C. C ; S13, the projection shape of the correction plate (2) on the surface of the etched sample (3) is as follows: ； Where, θ' i This indicates that after obtaining the adjusted etching angle, different radii r i The included angle of the obscured portion on the circumference; θ is the angle between the etched surfaces and the portion that is obscured. i For etching angle; S2, based on the projection shape of the correction plate (2) on the surface of the etched sample (3) and the position of the correction plate (2) between the etched sample (3) and the ion source (1), the first shape of the correction plate (2) is obtained.

2. The design method for a correction board for dry etching according to claim 1, characterized in that, The design method for the correction board used in dry etching also includes: S3, when the correction plate designed in S2 is placed in the first shape of the correction plate, the position of the correction plate (2) between the etched sample (3) and the ion source (1) is such that the etching depth distribution H(r) on the surface of the etched sample (3) after etching is collected. i or etching rate distribution V(r) i ), calculate etching uniformity parameters; If the etching uniformity parameter does not meet the set value, repeat steps S1 and S2; if the etching uniformity parameter meets the set value, stop the optimization process of the first shape of the correction plate.

3. The design method for a correction board for dry etching according to claim 1, characterized in that, S2, based on the projection shape of the correction plate (2) on the surface of the etched sample (3) and the position of the correction plate (2) between the etched sample (3) and the ion source (1), obtains a first shape of the correction plate (2), including: When the correction plate (2) is parallel to the etched sample (3) and the ion source (1), the first shape formula S' (x,y) of the correction plate is obtained according to the relative positional relationship between the correction plate (2), the etched sample (3), and the ion source (1): ； Where h is the distance between the correction plate (2) and the ion source (1); H is the distance between the etched sample (3) and the ion source (1); and h' is the distance between the ion source (1) and the vertices of a group of similar triangles with the radius R of the etched sample (3) and the ion source (1) as sides, respectively.

4. The design method for a correction board for dry etching according to claim 1, characterized in that, S2, based on the projection shape of the correction plate (2) on the surface of the etched sample (3) and the position of the correction plate (2) between the etched sample (3) and the ion source (1), obtains a first shape of the correction plate (2), including: When the correction plate (2) forms an angle with the ion source (1) in a direction parallel to it, the second shape formula S'' (x,y) of the projection of the correction plate (2) in the direction parallel to the ion source (1) is obtained based on the relative positional relationship between the correction plate (2), the etched sample (3), and the ion source (1): ； Where h is the distance between the correction plate (2) and the ion source (1) in a plane parallel to the ion source (1); H is the distance between the etched sample (3) and the ion source (1); and h' is the distance between the ion source (1) and the vertices of a group of similar triangles with the radius R of the etched sample (3) and the ion source (1) as sides, respectively.

5. A high-uniformity dry etching method, characterized in that, include: S20, etching the sample (3) to be etched; S21, the first shape of the correction plate is designed using the correction plate design method for dry etching as described in any one of claims 1-4; S22, when the designed correction plate is placed in the first shape or the second shape projected in the direction parallel to the ion source (1), the correction plate (2) is positioned between the etched sample (3) and the ion source (1) and etches the etched sample (3).

6. The high-uniformity dry etching method according to claim 5, characterized in that, The high-uniformity dry etching method also includes: S23, after placing the correction plate, collect the etching depth distribution H(r) on the surface of the etched sample (3) after etching. i or etching rate distribution V(r) i ), calculate the etching uniformity parameter, if the etching uniformity parameter does not meet the set value, repeat S21 and S22; if the etching uniformity parameter meets the set value, stop the optimization process of the first shape of the correction plate or the second shape projected in the direction parallel to the ion source.

7. The high-uniformity dry etching method according to claim 5, characterized in that, The etched sample (3) in S22 is a new etched sample (3) with the same position and initial size as the etched sample (3) in S20.

8. A correction plate for improving the uniformity of dry etching, characterized in that, The first shape of the correction plate or the second shape projected in a direction parallel to the ion source (1) is designed using the design method for a correction plate for dry etching as described in any one of claims 1-4.

9. The correction plate for improving the uniformity of dry etching according to claim 8, characterized in that, The correction plate (2) is processed by laser engraving.

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