Gas showerhead for use in a plasma processing apparatus
Patent Information
- Application Number
- CN202521687597.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-08
- Publication Date
- 2026-10-20
- Estimated Expiration
- 2035-08-08
AI Technical Summary
如果准直性不足发生微小的偏移（称之为global tilting），则容易导致高密度的凹槽在刻蚀的过程中发生倾斜，严重到一定程度则有可能与周边的其它凹槽交错在一起，导致晶圆的功能失效
本发明提供的气体喷淋头中，所述气体喷淋头下表面的厚度沿其径向由其中心向外满足一预设函数，所述预设函数在所述第一下表面区域的二阶导数大于0，在所述第二下表面区域的二阶导数从正转为负，在所述第三下表面区域的二阶导数小于0，有利于改善等离子体的鞘层厚度的均匀性，而等离子体的方向垂直于所述鞘层，使得等离子体能够较均匀的垂直向下，使得在晶圆表面形成的凹槽的垂直度较高，即：有利于提高晶圆的全局刻蚀垂直度。
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Figure CN224870225U_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of semiconductors, and more particularly to a gas spray head for use in plasma processing equipment. Background Technology
[0002] With the advent of the big data era, the demand for storage has increased exponentially. To meet this demand, memory chip technology has transitioned from 2D NAND to 3D NAND, which has higher storage density but a more complex structure. High aspect ratio etching is the most critical step in this process. As the aspect ratio increases, the collimation of ions incident on the wafer surface grooves typically requires increasingly higher levels of precision. Insufficient collimation leading to even slight misalignment (known as global tilting) can easily cause the high-density grooves to tilt during etching. If this tilting becomes severe, the grooves may intersect with surrounding grooves, leading to wafer malfunction. Summary of the Invention
[0003] The purpose of this invention is to provide a gas spray head for use in plasma processing equipment to improve the global etching collimation of wafers.
[0004] To achieve the above objectives, the present invention provides a gas spray head for use in a plasma processing device. The gas spray head is used to deliver reactive gas to the surface of a wafer, the reactive gas being used to form plasma. The gas spray head has a disk-shaped structure and includes: a lower surface facing the plasma, the lower surface being curved, and the lower surface including a first lower surface, a second lower surface, and a third lower surface in sequence from its center outward along the radial direction of the gas spray head. The thickness of the lower surface in the radial direction of the gas spray head from its center outward satisfies a preset function, wherein the second derivative of the preset function is greater than 0 in the region of the first lower surface, the second derivative changes from positive to negative in the region of the second lower surface, and the second derivative is less than 0 in the region of the third lower surface.
[0005] Optionally, the first lower surface is the lower surface of the spray head with a radius of less than 5 mm.
[0006] Optionally, the second lower surface is the lower surface of the gas spray head with a radius greater than 5 mm and less than 20 mm.
[0007] Optionally, the third lower surface is the lower surface of the gas spray head with a radius greater than 20 mm and less than 120 mm.
[0008] Optionally, the lower surface further includes a fourth lower surface located around the third lower surface along the radial direction of the gas spray head; the fourth lower surface is the lower surface of the gas spray head with a radius greater than 120 mm and less than 150 mm; the second derivative of the preset function in the region of the fourth lower surface can be positive, 0, or negative.
[0009] Optionally, the lower surface further includes, along the radial direction of the gas spray head, a fifth lower surface disposed around the fourth lower surface; the fifth lower surface is a lower surface of the gas spray head with a radius greater than 150 mm and less than 160 mm; the second derivative of the preset function in the region of the fifth lower surface is less than 0.
[0010] Optionally, when the second derivative is less than 0, the absolute value of the second derivative is less than 0.005.
[0011] Optionally, the absolute value of the second derivative of the preset function in the region where the radius of the gas spray head is greater than 20 mm and less than 40 mm is greater than 0.0015 and less than 0.005.
[0012] Optionally, the point where the first derivative of the preset function is 0 is located between 90 mm and 110 mm in radius of the gas spray head.
[0013] Optionally, the thickness of the gas spray head is greater than 7.5 mm.
[0014] Optionally, the maximum thickness difference of the gas spray head is greater than 5 mm and less than 15 mm.
[0015] Optionally, the thickness of the gas spray head corresponding to the first lower surface is greater than the thickness of the gas spray head corresponding to the second lower surface.
[0016] Optionally, the gas spray head further includes: an upper surface opposite to the lower surface; and a gas delivery channel penetrating the upper and lower surfaces, the gas delivery channel being used to deliver the reactive gas to the surface of the wafer, the reactive gas entering the gas delivery channel from the upper surface and exiting from the lower surface.
[0017] Optionally, the gas spray head further includes a peripheral region located outside the fifth lower surface, and the peripheral region further includes an upper grounding ring.
[0018] Optionally, the radius of the wafer is 150 mm.
[0019] Compared with the prior art, the technical solution of the present invention has at least the following beneficial effects: In the gas spray head provided by the present invention, the thickness of the lower surface of the gas spray head satisfies a preset function along its radial direction from its center outward. The second derivative of the preset function is greater than 0 in the first lower surface region, changes from positive to negative in the second lower surface region, and is less than 0 in the third lower surface region. This is beneficial to improving the uniformity of the plasma sheath thickness. The direction of the plasma is perpendicular to the sheath, so that the plasma can be vertically downward more uniformly, resulting in a higher verticality of the grooves formed on the wafer surface, that is, it is beneficial to improve the global etching verticality of the wafer. Attached Figure Description
[0020] Figure 1 This is a schematic diagram of the structure of a plasma processing device according to the present invention. Figure 2 This is a schematic diagram illustrating the principle of a gas spray head used for etching wafers. Figure 3 This is a schematic diagram of the structure of a gas spray head according to the present invention; Figure 4 for Figure 3 A schematic diagram showing the uneven distribution of the lower surface of the gas spray head; Figure 5 This is a schematic diagram illustrating the principle of using the gas spray head of the present invention for etching wafers. Detailed Implementation
[0021] The following will be combined with the appendix in the embodiments of the present invention. Figure 1 ~Attached Figure 5 The technical solutions, structural features, objectives and effects achieved in the embodiments of the present invention will be described in detail.
[0022] It should be noted that the accompanying drawings are in a very simplified form and use non-precise proportions. They are only used to facilitate and clarify the purpose of illustrating the embodiments of the present invention, and are not intended to limit the implementation conditions of the present invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportional relationship, or adjustments to the size should still fall within the scope of the technical content disclosed in the present invention, provided that they do not affect the effects and objectives that the present invention can produce.
[0023] It should be noted that, in this invention, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only the expressly listed elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus.
[0024] As described in the background section, the global etching collimation of wafers is poor. To address this problem, this invention provides a gas spray head. The thickness of the lower surface of the gas spray head, along its radial direction from the center outwards, satisfies a preset function. The second derivative of this preset function is greater than 0 in the first lower surface region, changes from positive to negative in the second lower surface region, and is less than 0 in the third lower surface region, thereby improving the poor global etching collimation of the wafer. A detailed description follows: Figure 1 This is a schematic diagram of the structure of a plasma processing device according to the present invention.
[0025] Please refer to Figure 1In this embodiment, the plasma processing equipment is a capacitively coupled plasma etching (CAPE) device. CAPE is a device that uses a radio frequency power supply applied to an electrode plate to generate plasma within a reaction chamber via capacitive coupling for etching. It includes a vacuum reaction chamber 10, which includes a generally cylindrical reaction chamber sidewall 11 made of metallic material. An opening 12 is provided on the sidewall for accommodating the entry and exit of a substrate. A gas spray head 13 and a base 14 opposite to the gas spray head 13 are disposed within the reaction chamber. The base 14 supports the wafer W. The gas spray head 13 is connected to a gas supply device 15 for supplying reaction gas to the vacuum reaction chamber and also serves as the upper electrode of the vacuum reaction chamber. An electrostatic chuck (not shown in the figure) is disposed above the base and serves as the lower electrode of the vacuum reaction chamber. A reaction region is formed between the upper and lower electrodes. At least one radio frequency (RF) power supply 16 is applied to one of the upper or lower electrodes through a matching network (not shown in the figure), generating an RF electric field between the upper and lower electrodes to dissociate the reaction gas into plasma. The plasma contains a large number of active particles such as electrons, ions, excited-state atoms, molecules, and free radicals. These active particles can undergo various physical and chemical reactions with the surface of the substrate to be treated, thereby changing the morphology of the substrate surface and completing the etching process. An exhaust pump 17 is also provided below the vacuum reaction chamber 10 to discharge reaction byproducts from the reaction chamber and maintain the vacuum environment of the reaction chamber.
[0026] During the etching process of wafer W, the distribution of plasma affects the collimation of the overall etching. The distribution of plasma is influenced by many factors, such as the area of the upper electrode and process parameters. Studies have found that the morphology of the lower surface of the gas spray head 13 also has a significant impact on the distribution of plasma.
[0027] Please refer to Figure 2 In this embodiment, the lower surface 23a of the gas spray head 23 is a plane, and the plasma concentration P gradually decreases from the center point of the wafer W to the outside (arrow direction in the figure). This causes the sheath S on the entire wafer surface to gradually tilt from the center point outward from the vertical. The direction of the plasma is perpendicular to the sheath S, which makes the direction of the plasma also gradually tilt from the center outward. This will cause the collimation of the groove 20 formed on the surface of the wafer W to gradually tilt from the center outward, that is, the global etching collimation of the wafer is poor.
[0028] Figure 3 This is a schematic diagram of the structure of a gas spray head according to the present invention.
[0029] Please refer to Figure 3The gas spray head 33 includes a lower surface 33a for facing the plasma, wherein the lower surface 33a is a curved surface along the radial direction r of the gas spray head 33. For a clearer illustration of the convexity and concavity of this curved surface, please refer to [reference needed]. Figure 4 Please provide a detailed explanation.
[0030] Because the lower surface of the gas spray head is uneven along its radial direction, the thickness of the lower surface varies at different locations. Figure 4 (1) illustrates the thickness of the lower surface at various locations along the radial direction. Figure 4 The curve in (1) represents the shape of the thickness of the lower surface of the gas spray head along its radial direction from its center outward, and this shape satisfies a preset function. Figure 4 In equation (2), the horizontal axis represents the radius of the gas spray head, and the vertical axis represents the slope of the tangent at various positions on the lower surface of the gas spray head, i.e.: for Figure 4 The first derivative of the preset function in (1) is obtained by taking the first derivative. Figure 4 The curve in (2) is shown. Figure 4 In (3), the horizontal axis still represents the radius of the gas spray head, and the vertical axis represents the rate of change of the slope at various positions on the lower surface of the gas spray head, that is: for Figure 4 The curve obtained by taking the second derivative of the preset function in (1).
[0031] The lower surface of the gas spray head includes, radially outward from its center, a first lower surface, a second lower surface, a third lower surface, a fourth lower surface, and a fifth lower surface. The first lower surface has a radius less than 5 mm, and the second derivative of the preset function in the region of the first lower surface is greater than 0. The second lower surface has a radius greater than 5 mm but less than 20 mm, and the second derivative of the preset function in the region of the second lower surface changes from positive to negative. The third lower surface has a radius greater than 20 mm but less than 120 mm, and the second derivative of the preset function in the region of the third lower surface is less than 0. The thickness of the gas spray head corresponding to the first lower surface is greater than the thickness of the gas spray head corresponding to the second lower surface. The fourth lower surface is the lower surface of the gas spray head with a radius greater than 120 mm and less than 150 mm. The second derivative of the preset function in the region of the fourth lower surface can be positive, 0, or negative. Here, it is illustrated that the second derivative of the preset function in the region of the fourth lower surface is less than 0. The fifth lower surface is the lower surface of the gas spray head with a radius greater than 150 mm and less than 160 mm, and the second derivative of the thickness of the fifth lower surface is less than 0. Furthermore, when the second derivative is less than 0, the absolute value of the second derivative is less than 0.005. And the absolute value of the second derivative of the preset function in the region of the gas spray head with a radius greater than 20 mm and less than 40 mm is greater than 0.0015 and less than 0.005.
[0032] In addition, from Figure 4 As can be seen in (2), the point where the first derivative of the preset function is 0 is located between 90 mm and 110 mm in radius of the gas spray head. Here it is shown that the point where the first derivative of the preset function is 0 is located at the position where the radius of the gas spray head is 100 mm.
[0033] Furthermore, the thickness of the gas spray head designed above is greater than 7.5 mm, and the maximum thickness difference of the gas spray head is greater than 5 mm and less than 15 mm.
[0034] The gas spray head has a disc-shaped structure and is used to process the surface of a wafer with a diameter of 300 mm. The gas spray head also includes: an upper surface opposite the lower surface; and a gas delivery channel penetrating the upper and lower surfaces, the gas delivery channel for delivering the reactive gas to the surface of the wafer, the reactive gas entering the gas delivery channel from the upper surface and exiting from the lower surface. The gas spray head also includes a peripheral region located outside the fifth lower surface, the peripheral region further including: an upper grounding ring.
[0035] Figure 5 for Figure 3A schematic diagram illustrating the principle of using a gas spray head for etching wafers.
[0036] Please refer to Figure 5 ,use Figure 3 The gas spray head 33, wherein the lower surface 33a of the gas spray head 33 is Figure 4 The curved surface described in the text is beneficial for improving the uniformity of the sheath thickness, and the direction of the plasma is perpendicular to the sheath, so that the plasma can be vertically downward more uniformly, resulting in a higher verticality of the grooves formed on the wafer surface, that is, it is beneficial for improving the global etching verticality of the wafer.
[0037] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.
Claims
1. A gas spray head for use in a plasma processing device, the gas spray head being used to deliver reactive gases to the surface of a wafer, the reactive gases being used to form plasma, the gas spray head having a disk-shaped structure, characterized in that, include: The lower surface, facing the plasma, is a curved surface. Along the radial direction of the gas spray head, from its center outwards, the lower surface includes a first lower surface, a second lower surface, and a third lower surface. The thickness of the lower surface along the radial direction of the gas spray head from its center outwards satisfies a preset function. The second derivative of this preset function is greater than 0 in the region of the first lower surface, changes from positive to negative in the region of the second lower surface, and is less than 0 in the region of the third lower surface.
2. The gas spray head for plasma processing equipment as described in claim 1, characterized in that, The first lower surface is the lower surface of the spray head with a radius of less than 5 mm.
3. The gas spray head for plasma processing equipment as described in claim 2, characterized in that, The second lower surface is the lower surface of the gas spray head with a radius greater than 5 mm and less than 20 mm.
4. The gas spray head for plasma processing equipment as described in claim 3, characterized in that, The third lower surface is the lower surface of the gas spray head with a radius greater than 20 mm and less than 120 mm.
5. The gas spray head for plasma processing equipment as described in claim 4, characterized in that, The lower surface further includes, along the radial direction of the gas spray head, a fourth lower surface located on the periphery of the third lower surface; the fourth lower surface is the lower surface of the gas spray head with a radius greater than 120 mm and less than 150 mm; the second derivative of the preset function in the region of the fourth lower surface can be positive, 0, or negative.
6. The gas spray head for plasma processing equipment as described in claim 5, characterized in that, The lower surface further includes, along the radial direction of the gas spray head, a fifth lower surface located on the periphery of the fourth lower surface; the fifth lower surface is a lower surface of the gas spray head with a radius greater than 150 mm and less than 160 mm; the second derivative of the preset function in the region of the fifth lower surface is less than 0.
7. The gas spray head for plasma processing equipment as described in claim 1, characterized in that, When the second derivative is less than 0, the absolute value of the second derivative is less than 0.
005.
8. The gas spray head for use in a plasma processing device as described in claim 7, characterized in that, The absolute value of the second derivative of the preset function in the region where the radius of the gas spray head is greater than 20 mm and less than 40 mm is greater than 0.0015 and less than 0.
005.
9. The gas spray head for plasma processing equipment as described in claim 3, characterized in that, The point where the first derivative of the preset function is 0 is located between 90 mm and 110 mm in radius of the gas spray head.
10. The gas spray head for a plasma processing device as described in claim 1, characterized in that, The thickness of the gas spray head is greater than 7.5 mm.
11. The gas spray head for use in a plasma processing device as described in claim 1, characterized in that, The maximum thickness difference of the gas spray head is greater than 5 mm and less than 15 mm.
12. The gas spray head for plasma processing equipment as described in claim 1, characterized in that, The thickness of the gas spray head corresponding to the first lower surface is greater than the thickness of the gas spray head corresponding to the second lower surface.
13. The gas spray head for plasma processing equipment as described in claim 1, characterized in that, The gas spray head further includes: an upper surface opposite to the lower surface; and a gas delivery channel penetrating the upper and lower surfaces, the gas delivery channel being used to deliver the reactive gas to the surface of the wafer, the reactive gas entering the gas delivery channel from the upper surface and exiting from the lower surface.
14. The gas spray head for use in a plasma processing device as described in claim 6, characterized in that, The gas spray head also includes a peripheral region located outside the fifth lower surface, and the peripheral region also includes an upper grounding ring.
15. The gas spray head for use in a plasma processing device as described in claim 1, characterized in that, The wafer has a radius of 150 millimeters.