Semiconductor wet etching process improvement method and device
By adjusting the spray angle and local spraying method, the wet etching process was improved, the problem of etching non-uniformity was solved, and the uniformity of the wafer surface mask and the stability of device performance were achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-08
- Publication Date
- 2026-04-14
AI Technical Summary
In traditional wet etching processes, the isotropic nature of wet etching leads to edge geometric effects, causing residual stress at the edges of mask layer lines and uneven diffusion of etchant. This results in a lower etching rate in the middle of the wafer surface compared to the edges, affecting device performance consistency and yield.
By adjusting the spray angle of the spray nozzle array, a local spraying method is used to pre-process the mask to be patterned on the wafer surface, forming surface trenches, adjusting the thickness of the edge region, balancing the etching rate, and improving the mask uniformity.
Effectively controlling the etching rate of the mask center and edge regions improves the uniformity of the mask after patterning the wafer surface, reduces performance fluctuations, and enhances device consistency and yield.
Smart Images
Figure CN121865862A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of wet etching technology, specifically relating to a method and apparatus for improving semiconductor wet etching processes. Background Technology
[0002] Wet etching technology involves coating a wafer with a pre-coated mask layer using photolithography to cover it with a photoresist protective film, then immersing it in a wet chemical solution. The chemical reaction removes unwanted mask portions, yielding the desired morphology. In traditional wet etching processes, due to the isotropic nature of wet etching and the presence of edge geometry effects, the mask layer edges exhibit a "edge structure" with a high surface area / volume ratio. Furthermore, residual stress at these edges after photoresist development creates preferential etching sites. Additionally, the etchant exhibits diffusion differences; the wet etchant flows more smoothly and is replenished faster at the edges, while a diffusion boundary layer easily forms in the center, reducing the etchant concentration. These factors result in a lower etching rate in the center of the wafer surface compared to the edges during the process.
[0003] For semiconductor devices, edge etching of the gate or source / drain metals alters the contact area between the electrode and the semiconductor, leading to threshold voltage drift and deteriorated switching characteristics. The irregular morphology of the etched edges affects subsequent processes (such as dielectric deposition and photolithography alignment), increasing process deviations and further amplifying performance fluctuations. The randomness of edge effects results in poor performance consistency within the same batch of devices, leading to decreased yield. Summary of the Invention
[0004] To address the aforementioned problems in the prior art, the present invention provides a method and apparatus for improving semiconductor wet etching processes.
[0005] The technical problem to be solved by this invention is achieved through the following technical solution: In a first aspect, the present invention provides a method for improving semiconductor wet etching processes, the method comprising: After adjusting the spray angle of the spray nozzle array to be perpendicular to the mask to be patterned on the upper surface of the wafer, the etchant is sprayed onto the central area of the first preset size of the mask to be patterned to obtain the mask after preliminary spraying. After adjusting the spray angle of the spray nozzle array to a preset angle, an etchant is sprayed onto the edge areas of the mask surface after the initial spraying, excluding the central area, to obtain the mask after the second spraying. After adjusting the spray angle of the spray nozzle array to be perpendicular to the mask to be patterned on the upper surface of the wafer, an etchant is sprayed onto the upper surface of the mask to be patterned to obtain a mask with complete etching.
[0006] Optionally, after adjusting the spray angle of the spray nozzle array to be perpendicular to the mask to be patterned on the upper surface of the wafer, spraying etchant onto the upper surface of the mask to be patterned to obtain the etched mask includes: After adjusting the spray angle of the spray nozzle array to be perpendicular to the mask to be patterned on the upper surface of the wafer, the wafer is rotated at a preset speed and an etchant is sprayed onto the upper surface of the mask to be patterned to obtain a mask with complete etching.
[0007] Optionally, the material of the mask to be patterned is a metal, silicon dioxide, or silicon nitride.
[0008] Optionally, the central region of the mask after the initial spraying is a circular groove.
[0009] Optionally, before spraying an etchant onto the central region of a first preset size of the patterned mask after adjusting the spray angle of the spray nozzle array to be perpendicular to the upper surface of the wafer, and before obtaining the initially sprayed mask, the method further includes: The wafer is placed parallel to the reaction tank.
[0010] Optionally, when spraying the etchant onto the edge region, a spraying direction from the edge to the center may be adopted.
[0011] Optionally, the etchant is determined based on the material of the mask to be patterned.
[0012] In a second aspect, the present invention provides an apparatus for improving semiconductor wet etching processes, the apparatus comprising: The first spray module is used to adjust the spray angle of the spray nozzle array to be perpendicular to the mask to be patterned on the upper surface of the wafer, and then spray etchant on the central area of the mask of a first preset size to obtain the mask after preliminary spraying. The second spray module is used to adjust the spray angle of the spray nozzle array to a preset angle and then spray an etchant onto the edge areas of the mask surface after the initial spraying, excluding the central area, to obtain the mask after the second spraying. The third spray module is used to adjust the spray angle of the spray nozzle array to be perpendicular to the mask to be patterned on the upper surface of the wafer, and then spray etchant onto the upper surface of the mask to be patterned to obtain a mask with complete etching.
[0013] The technical solutions provided by the embodiments of the present invention may include the following beneficial effects: In the above technical solution, the present invention uses a local spraying method to adjust the spraying angle to preprocess the mask to be patterned on the wafer surface and form surface trenches; the thickness of the mask to be patterned in the edge area is adjusted by adjusting the spraying angle; the present invention can control the thickness of the mask to be patterned in the central area and the edge area of the mask center, balance the problem of excessively fast etching rate in the edge area caused by the boundary layer effect, and effectively improve the uniformity of the mask after patterning the wafer surface.
[0014] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description
[0015] Figure 1 This is a flowchart of an improved semiconductor wet etching process provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of a mask and wafer to be patterned, provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the central region of a patterned mask subjected to spray etching, provided in an embodiment of the present invention. Figure 4 This is a schematic diagram of a spray etching process for the edge region of a mask to be patterned, provided in an embodiment of the present invention. Figure 5 This is a schematic diagram of a spray etching process for the upper surface of a mask to be patterned, provided in an embodiment of the present invention. Figure 6 This is a block diagram of a semiconductor wet etching process improvement device provided in an embodiment of the present invention.
[0016] Explanation of reference numerals in the attached figures 1. Wafer; 2. Mask to be patterned. Detailed Implementation
[0017] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto.
[0018] Figure 1 This is a flowchart of an improved semiconductor wet etching process provided by an embodiment of the present invention, such as... Figure 1 As shown, the method may include the following steps: S101. After adjusting the spray angle of the spray nozzle array to be perpendicular to the patterned mask on the upper surface of the wafer, spray the etchant onto the central area of the first preset size of the patterned mask to obtain the mask after preliminary spraying.
[0019] Example, Figure 2 This is a schematic diagram of the structure of a mask and wafer to be patterned, provided by an embodiment of the present invention. Figure 3This is a schematic diagram of the central region of a patterned mask subjected to spray etching, as provided in an embodiment of the present invention. Figure 2 and Figure 3 As shown, after placing the wafer parallel to the reaction tank, a vertical spray is applied to the central 4-inch area of the mask to be patterned. The spray angle is 90° perpendicular to the wafer surface, and the spray solution is the etching solution corresponding to the mask to be patterned. Spraying enhances the fluidity of the etching solution, preventing it from adhering to the wafer surface and allowing the etchant to quickly contact and react with the mask, thereby removing the mask of the appropriate thickness in the central area.
[0020] Optionally, the material of the mask to be patterned is metal, silicon dioxide, or silicon nitride; the central area of the mask after initial spraying is a circular groove; the etchant is determined according to the material of the mask to be patterned.
[0021] S102. After adjusting the spray angle of the spray nozzle array to the preset angle, spray the etchant onto the edge areas of the mask surface after the initial spraying, except for the central area, to obtain the mask after the second spraying.
[0022] Optionally, when spraying etchant into the edge area, a spraying direction from the edge to the center is adopted.
[0023] Example, Figure 4 This is a schematic diagram of a spray etching process for the edge region of a patterned mask, as provided in an embodiment of the present invention. Figure 4 As shown, after the initial spraying, the arrangement of the spray nozzle array and the spray angle are changed so that the spraying direction is from the wafer edge (cut edge and top) to the center. The spray angle forms a certain angle with the mask to be patterned on the wafer surface. Spray etching is performed on the edge area outside the etching trench of the mask to be patterned on the surface of the 6-inch silicon carbide wafer. The edge area forms a step difference due to the angled spraying. The etching liquids with different flow directions converge in the central area and generate eddies, which can change the flow field direction of the etching liquid, destroy the surface tension of the etching liquid, and accelerate the etching rate of the central area.
[0024] S103. After adjusting the spray angle of the spray nozzle array to be perpendicular to the patterned mask on the upper surface of the wafer, spray etchant onto the upper surface of the patterned mask to obtain the etched mask.
[0025] Optionally, Figure 5 This is a schematic diagram of a spray etching process for the upper surface of a patterned mask provided in an embodiment of the present invention. S103 may include: After adjusting the spray angle of the spray nozzle array to be perpendicular to the mask to be patterned on the upper surface of the wafer, the wafer is rotated at a preset speed and an etchant is sprayed onto the upper surface of the mask to be patterned to obtain the etched mask.
[0026] Figure 6This is a block diagram of a semiconductor wet etching process improvement device provided in an embodiment of the present invention, as shown below. Figure 6 As shown, the device may include: The first spray module 601 is used to adjust the spray angle of the spray nozzle array to be perpendicular to the patterned mask on the upper surface of the wafer, and then spray etchant on the central area of the first preset size of the patterned mask to obtain the mask after preliminary spraying. The second spray module 602 is used to adjust the spray angle of the spray nozzle array to a preset angle and then spray etchant onto the edge areas of the mask surface after the initial spraying, excluding the central area, to obtain the mask after the second spraying. The third spray module 603 is used to adjust the spray angle of the spray nozzle array to be perpendicular to the patterned mask on the upper surface of the wafer, and then spray etchant onto the upper surface of the patterned mask to obtain the etched mask.
[0027] In the above technical solution, the present invention uses a local spraying method to adjust the spraying angle to preprocess the mask to be patterned on the wafer surface and form surface trenches; by adjusting the spraying angle, the thickness of the mask to be patterned in the edge region is adjusted, and an etching liquid vortex is formed in the central region, changing the direction of the etching liquid flow field, thereby promoting the etching rate in the central region; the present invention can control the thickness of the mask to be patterned in the central region and the edge region of the mask center, balance the problem of excessively fast etching rate in the edge region caused by the boundary layer effect, and can effectively improve the uniformity of the mask after patterning the wafer surface.
[0028] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.
[0029] Although the invention has been described herein in conjunction with various embodiments, those skilled in the art will understand and implement other variations of the disclosed embodiments by reviewing the accompanying drawings and the disclosure in carrying out the claimed invention. In the description of the invention, the word "comprising" does not exclude other components or steps, "a" or "an" does not exclude a plurality, and "a plurality" means two or more, unless otherwise explicitly specified. Furthermore, while different embodiments may describe certain measures, this does not mean that these measures cannot be combined to produce good results.
[0030] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.
Claims
1. A method for improving semiconductor wet etching process, characterized in that, The method includes: After adjusting the spray angle of the spray nozzle array to be perpendicular to the mask to be patterned on the upper surface of the wafer, the center area of the mask to be patterned, which is a first preset size, is sprayed with etchant to obtain the mask after preliminary spraying. After adjusting the spray angle of the spray nozzle array to a preset angle, an etchant is sprayed onto the edge areas of the mask surface after the initial spraying, excluding the central area, to obtain the mask after the second spraying. After adjusting the spray angle of the spray nozzle array to be perpendicular to the mask to be patterned on the upper surface of the wafer, an etchant is sprayed onto the upper surface of the mask to be patterned to obtain a mask with complete etching.
2. The method for improving semiconductor wet etching process according to claim 1, characterized in that, The step of adjusting the spray angle of the spray nozzle array to be perpendicular to the patterned mask on the upper surface of the wafer, and then spraying an etchant onto the upper surface of the patterned mask to obtain an etched mask, includes: After adjusting the spray angle of the spray nozzle array to be perpendicular to the mask to be patterned on the upper surface of the wafer, the wafer is rotated at a preset speed and an etchant is sprayed onto the upper surface of the mask to be patterned to obtain a mask with complete etching.
3. The method for improving semiconductor wet etching process according to claim 1, characterized in that, The material of the mask to be patterned is metal, silicon dioxide, or silicon nitride.
4. The method for improving semiconductor wet etching process according to claim 1, characterized in that, The central area of the mask after the initial spraying is a circular groove.
5. The method for improving semiconductor wet etching process according to claim 1, characterized in that, Before spraying an etchant onto the central region of the patterned mask of a first preset size at the center of the patterned mask, after adjusting the spray angle of the spray nozzle array to be perpendicular to the upper surface of the wafer, and before obtaining the initially sprayed mask, the method further includes: The wafer is placed parallel to the reaction tank.
6. The method for improving semiconductor wet etching process according to claim 1, characterized in that, When spraying the etching agent onto the edge region, a spraying direction from the edge to the center is adopted.
7. The method for improving semiconductor wet etching process according to claim 3, characterized in that, The etchant is determined based on the material of the mask to be patterned.
8. An apparatus for improving semiconductor wet etching process, characterized in that, The device includes: The first spray module is used to adjust the spray angle of the spray nozzle array to be perpendicular to the mask to be patterned on the upper surface of the wafer, and then spray etchant on the central area of the first preset size of the mask to be patterned to obtain the mask after preliminary spraying. The second spray module is used to adjust the spray angle of the spray nozzle array to a preset angle and then spray an etchant onto the edge areas of the mask surface after the initial spraying, excluding the central area, to obtain a mask after the second spraying. The third spray module is used to adjust the spray angle of the spray nozzle array to be perpendicular to the mask to be patterned on the upper surface of the wafer, and then spray etchant onto the upper surface of the mask to be patterned to obtain a mask with complete etching.