Method for removing fluorine-aluminum polymers generated in an etching process
By forming a sacrificial layer covering the carbon polymer sidewalls during the etching process and performing two etching operations, the problem of difficult removal of fluoroaluminum polymer on aluminum pads was solved, realizing an efficient and simplified removal method and improving the performance of semiconductor devices.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- QINGDAO AUCMA YUNLIAN INFORMATION TECHNOLOGY CO LTD
- Filing Date
- 2024-12-17
- Publication Date
- 2026-06-23
Smart Images
Figure CN122270064A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of semiconductor integrated circuit technology, and in particular to a method for removing fluoroaluminate polymers generated during an etching process. Background Technology
[0002] Dry etching of the dielectric layer on aluminum (Al) pads is an important step in wafer-level packaging (WLP). The dielectric layer on aluminum pads is typically etched using fluorine (F)-based compounds because of their excellent selectivity for the pads.
[0003] However, fluorine groups can cause fluorine-induced defects on aluminum pads. These defects are found to be “crystalline” due to their hexagonal shape and size of about 200 nm. These defects are fluorinated aluminum polymers, whose main component is crystalline AlF3, which are mainly deposited on the sidewalls of the pads rather than on the surface of the pads.
[0004] AlF3 is a non-volatile residue with a melting point as high as 1290°C. Due to its three-dimensional polymer structure, it is difficult to remove from the device structure using post-etching processes such as wet cleaning and plasma stripping (PET). Summary of the Invention
[0005] The purpose of this invention is to provide a method for removing fluoroaluminum polymers generated during an etching process. A sacrificial layer is formed before the fluoroaluminum polymer layer is formed, and the fluoroaluminum polymer layer is formed on the sidewall of the sacrificial layer, making the fluoroaluminum polymer layer easy to remove.
[0006] To address the aforementioned technical problems, this invention provides a method for removing fluoroaluminate polymers generated during an etching process, comprising the following steps:
[0007] A substrate is provided on which an aluminum layer, a dielectric layer and a patterned photoresist layer are sequentially formed.
[0008] The dielectric layer is etched using the patterned photoresist layer as a mask until an aluminum layer is exposed, and the etching stops before the aluminum layer is etched, forming a groove located in the patterned photoresist layer and the dielectric layer. During the etching process, a carbon polymer layer is formed on the sidewall of the groove.
[0009] A sacrificial layer is formed on the sidewall of the groove, the sacrificial layer covering the sidewall of the carbon polymer layer;
[0010] The bottom of the groove is over-etched to completely remove the dielectric layer at the bottom of the groove. During the etching process, a fluoroaluminum polymer layer is formed on the sidewall of the groove, and the fluoroaluminum polymer layer covers the sidewall of the sacrificial layer.
[0011] Remove the patterned photoresist layer; and
[0012] Remove the sacrificial layer, the fluoroaluminum polymer layer, and the carbon polymer layer.
[0013] Optionally, the method for removing the sacrificial layer, the fluoroaluminum polymer layer, and the carbon polymer layer includes:
[0014] Remove the sacrificial layer to allow the fluoroaluminum polymer layer to lie solely on the aluminum layer; and
[0015] Remove the fluoroaluminum polymer layer and the carbon polymer layer.
[0016] Optionally, the sacrificial layer comprises a material that is soluble in water, soluble in an organic solvent, or removed by wet etching; the sacrificial layer is removed by water, organic solvent, or wet etching process.
[0017] Optionally, the sacrificial layer is made of a super tetrahedral SAOT material, and the sacrificial layer is removed using water.
[0018] Optionally, the method for forming the sacrificial layer includes pulsed laser deposition, ion sputtering, or molecular beam epitaxy.
[0019] Optionally, forming a sacrificial layer on the sidewall of the groove, the sacrificial layer covering the sidewall of the carbon polymer layer, includes the following method:
[0020] A sacrificial material layer is formed on the sidewalls, bottom, and surface of the patterned photoresist layer of the groove;
[0021] Remove the sacrificial material layer from the bottom of the groove and the surface of the patterned photoresist layer, and retain the sacrificial material layer on the sidewall of the groove as a sacrificial layer.
[0022] Optionally, a dry etching process can be used to remove the sacrificial layer at the bottom of the groove and on the surface of the patterned photoresist layer.
[0023] Optionally, the patterned photoresist layer is used as a mask to perform dry etching on the dielectric layer; the etching gas in the dry etching includes a fluorine-containing gas.
[0024] Optionally, the method for removing the fluoroaluminum polymer layer and the carbon polymer layer includes wet etching.
[0025] Optionally, the etching solution used in the wet etching process includes NE111.
[0026] In the method for removing fluoroaluminate polymer generated during the etching process provided by the present invention, an aluminum layer, a dielectric layer, and a patterned photoresist layer are first formed sequentially on a substrate. Then, the dielectric layer is etched using the patterned photoresist layer as a mask until an aluminum layer is exposed, but before etching the aluminum layer is stopped, forming a groove located within the patterned photoresist layer and the dielectric layer. During the etching process, a carbon polymer layer is formed on the sidewall of the groove, and then a sacrificial layer is formed on the sidewall of the groove, covering the sidewall of the carbon polymer layer. Next, the bottom of the groove is over-etched to completely remove the dielectric layer. During the etching process, a fluoroaluminate polymer layer is formed on the sidewall of the groove, covering the sidewall of the sacrificial layer. Then, the patterned photoresist layer is removed, followed by the removal of the sacrificial layer, the fluoroaluminate polymer layer, and the carbon polymer layer. This invention involves two etching processes for the dielectric layer. The first etching is stopped before the aluminum layer is completely etched, as no fluoroaluminum polymer layer is generated at this point since the aluminum layer is not etched. Then, a sacrificial layer is formed on the sidewall of the groove. Next, the aluminum layer at the bottom of the groove is over-etched to completely remove the dielectric layer. The fluoroaluminum polymer layer generated by etching the aluminum layer is formed on the sidewall of the sacrificial layer, making the fluoroaluminum polymer layer easy to remove.
[0027] Furthermore, the sacrificial layer is first removed to allow the fluoroaluminum polymer layer to stand alone on the aluminum layer, and then the fluoroaluminum polymer layer and the carbon polymer layer are removed. After the sacrificial layer is removed, the isolated fluoroaluminum polymer layer is easier to remove.
[0028] In addition, this invention uses tetragonal SAOT as a sacrificial layer. The tetragonal SAOT dissolves in water and is removed, thereby simplifying the removal process. Attached Figure Description
[0029] Figures 1 to 3 This is a schematic diagram of the steps involved in etching the dielectric layer on the aluminum layer.
[0030] Figure 4 This is a schematic flowchart of a method for removing fluoroaluminum polymer generated during an etching process according to an embodiment of the present invention.
[0031] Figures 5 to 11 This is a schematic diagram of the steps of a method for removing fluoroaluminate polymer generated in an etching process according to an embodiment of the present invention.
[0032] Explanation of reference numerals in the attached figures:
[0033] 10-Aluminum layer; 20-Dielectric layer; 21-Silicon oxide layer; 22-Silicon nitride layer; 30-Patterned photoresist layer; 41-Carbon polymer layer; 42-Fluoroaluminum polymer layer; 50-Groove; 61-Sacrificial material layer; 62-Sacrificial layer. Detailed Implementation
[0034] Figures 1 to 3 This is a schematic diagram illustrating the steps involved in etching the dielectric layer on the aluminum layer. Please refer to it. Figure 1 As shown, a dielectric layer 20 is formed on an aluminum layer 10. The dielectric layer 20 includes a silicon oxide layer 21 and a silicon nitride layer 22 sequentially formed on the aluminum layer 10. A patterned photoresist layer 30 is formed on the dielectric layer 20. Then, the dielectric layer 20 is etched using the patterned photoresist layer 30 as a mask until the aluminum layer 10 is exposed. For example, CF4 is used to perform dry etching on the dielectric layer 20. During the etching process, a carbon polymer layer 41 is formed on the sidewalls of the dielectric layer 20 and the patterned photoresist layer 30. Since the dielectric layer 20 needs to be completely removed, over-etching is inevitably required to completely remove the dielectric layer 20. Therefore, the aluminum layer 10 is etched, thereby forming a fluoroaluminum polymer layer 42 (e.g., AlFx). The fluoroaluminum polymer layer 42 is also formed on the sidewalls of the dielectric layer 20 and the patterned photoresist layer 30, covering the carbon polymer layer 41.
[0035] Next, please refer to Figure 2 As shown, the patterned photoresist layer 30 is removed by an ashing process. During the removal of the patterned photoresist layer 30, the carbon polymer layer 41 on the sidewalls of the patterned photoresist layer 30 is also removed simultaneously, forming a layer as shown... Figure 2 The structure shown, wherein the fluoroaluminum polymer layer 42 (on the sidewall of the photoresist layer 30) Figure 2 The fluoroaluminum polymer layer 42 located above the dotted line breaks off due to the removal of the patterned photoresist layer 30 on the sidewall.
[0036] Then, please refer to Figure 3 As shown, the carbon polymer layer 41 and the fluoroaluminum polymer layer 42 are also retained on the sidewalls of the dielectric layer 20. The fluoroaluminum polymer layer 42 is difficult to remove due to its structural characteristics.
[0037] Current process practices use biased argon sputtering to reduce the fluorine concentration after photoresist removal. This method inhibits the formation of fluoroaluminum polymer layers by eliminating fluorine in the chamber. However, this method requires an additional treatment chamber to manage exhaust gas treatment.
[0038] To address the aforementioned problems, this invention provides a method for removing fluoroaluminate polymers generated during an etching process, comprising: providing a substrate, and sequentially forming an aluminum layer, a dielectric layer, and a patterned photoresist layer on the substrate; etching the dielectric layer using the patterned photoresist layer as a mask until an aluminum layer is exposed but before etching the aluminum layer is stopped, forming a groove located within the patterned photoresist layer and the dielectric layer, wherein a carbon polymer layer is formed on the sidewall of the groove during the etching process; forming a sacrificial layer on the sidewall of the groove, the sacrificial layer covering the sidewall of the carbon polymer layer; over-etching the bottom of the groove to completely remove the dielectric layer at the bottom of the groove, wherein a fluoroaluminate polymer layer is formed on the sidewall of the sacrificial layer during the etching process, the fluoroaluminate polymer layer covering the sidewall of the sacrificial layer; removing the patterned photoresist layer; and removing the sacrificial layer, the fluoroaluminate polymer layer, and the carbon polymer layer.
[0039] This invention involves two etching processes for the dielectric layer. The first etching is stopped before the aluminum layer is completely etched, as no fluoroaluminum polymer layer is generated at this point since the aluminum layer is not etched. Then, a sacrificial layer is formed on the sidewall of the groove. Next, the aluminum layer at the bottom of the groove is over-etched to completely remove the dielectric layer. The fluoroaluminum polymer generated during the etching of the aluminum layer is formed on the sidewall of the sacrificial layer, making the fluoroaluminum polymer layer easy to remove.
[0040] To make the objectives, advantages, and features of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that the drawings are all in a very simplified form and are not drawn to scale, and are only used to facilitate and clarify the explanation of the embodiments of this invention. Furthermore, the structures shown in the drawings are often part of the actual structures. In particular, different figures may emphasize different aspects and may sometimes use different scales.
[0041] As used herein, the singular forms “a,” “an,” and “the” include plural objects unless otherwise expressly indicated. As used herein, the term “or” is generally used to mean “and / or” unless otherwise expressly indicated. As used herein, the term “a number” is generally used to mean “at least one” unless otherwise expressly indicated. As used herein, the term “at least two” is generally used to mean “two or more” unless otherwise expressly indicated. Furthermore, the terms “first,” “second,” and “third” are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as “first,” “second,” or “third” may explicitly or implicitly include one or at least two of that feature, unless otherwise expressly indicated.
[0042] Figure 4 This is a schematic flowchart illustrating a method for removing fluoroaluminate polymers generated during an etching process according to an embodiment of the present invention. Figure 4 As shown, the method for removing the fluoroaluminate polymer generated during the etching process includes the following steps:
[0043] S1: Provide a substrate on which an aluminum layer, a dielectric layer, and a patterned photoresist layer are sequentially formed;
[0044] S2: Using the patterned photoresist layer as a mask, the dielectric layer is etched until an aluminum layer is exposed and before the aluminum layer is etched, forming a groove located in the patterned photoresist layer and the dielectric layer. During the etching process, a carbon polymer layer is formed on the sidewall of the groove.
[0045] S3: A sacrificial layer is formed on the sidewall of the groove, the sacrificial layer covering the sidewall of the carbon polymer layer;
[0046] S4: The bottom of the groove is over-etched to completely remove the dielectric layer at the bottom of the groove. During the etching process, a fluoroaluminum polymer layer is formed on the sidewall of the sacrificial layer, and the fluoroaluminum polymer layer covers the sidewall of the sacrificial layer.
[0047] S5: Remove the patterned photoresist layer; and
[0048] S6: Remove the sacrificial layer, the fluoroaluminum polymer layer, and the carbon polymer layer.
[0049] Figures 5 to 11 This is a schematic diagram of the steps in a method for removing fluoroaluminate polymer generated during an etching process according to an embodiment of the present invention. Next, we will combine... Figure 4 , Figures 5 to 11 The method for removing fluoroaluminate polymers generated in the etching process provided in the embodiments of the present invention will be described in detail.
[0050] In step S1, please refer to Figure 5 As shown, a substrate is provided, on which an aluminum layer 10, a dielectric layer 20 and a patterned photoresist layer 30 are sequentially formed.
[0051] The substrate can be made of silicon, germanium, silicon germanide, silicon carbide, gallium arsenide, or indium gallium arsenide, or it can be silicon-on-insulator or germanium-on-insulator; or it can be other materials, such as gallium arsenide or other III-V compounds. In this embodiment, the substrate is a silicon substrate. Semiconductor devices and metal interconnect structures can be formed on the substrate.
[0052] In this embodiment, the aluminum layer 10 is formed on the uppermost interlayer dielectric layer of the metal interconnect structure and is electrically connected to the metal interconnect structure as an aluminum pad. The aluminum layer 10 can typically be formed on the substrate using physical vapor deposition, chemical vapor deposition, or metal sputtering deposition processes. The thickness of the aluminum layer 10 can be determined based on the actual thickness requirements of the aluminum pad.
[0053] Then, a dielectric layer 20 is formed on the aluminum layer 10, covering the aluminum layer 10. The material of the dielectric layer 20 can be silicon nitride, silicon oxide, silicon oxynitride, silicon carbide, silicon oxycarbonide, or other materials suitable for use as a dielectric layer. The dielectric layer 20 may include at least one layer selected from silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, and silicon oxycarbonide. That is, the dielectric layer 20 in this embodiment of the invention can be a single-layer structure or a multilayer composite structure. In this embodiment, the dielectric layer 20 includes a silicon oxide layer 21 and a silicon nitride layer 22 sequentially located on the substrate 10. The silicon oxide layer 21 and the silicon nitride layer 22 can be formed using any suitable process known to those skilled in the art, such as atomic layer deposition, chemical vapor deposition, or physical vapor deposition.
[0054] Next, a photoresist layer is formed on the dielectric layer 20, and the photoresist layer is exposed and developed to form a patterned photoresist layer 30.
[0055] In step S2, please continue to refer to Figure 5 As shown, the patterned photoresist layer 30 is used as a mask to etch the dielectric layer 20 until the aluminum layer 10 is exposed and before etching the aluminum layer 10 is stopped, forming a groove 50 located in the patterned photoresist layer 30 and the dielectric layer 20. During the etching process, a carbon polymer layer 41 is formed on the sidewall of the groove 50.
[0056] In this embodiment, the patterned photoresist layer 30 is used as a mask to etch the dielectric layer 20 until the aluminum layer 10 is exposed, but before etching the aluminum layer 10, i.e., until the silicon oxide layer 21 is just opened and a portion of the bottom area of the groove 50 is just exposed to expose the aluminum layer 10. At this point, the dielectric layer 20 (specifically the silicon oxide layer 21) still exists at the bottom of the groove 50 and has not been etched. Since the aluminum layer 10 is not etched, no fluoroaluminum polymer layer is formed.
[0057] The dielectric layer 20 is etched to form grooves 50 located within the patterned photoresist layer 30 and the dielectric layer 20. Specifically, the grooves 50 include grooves formed within the patterned photoresist layer 30 (i.e., grooves formed when the photoresist is patterned to form the patterned photoresist layer) and grooves formed by etching the dielectric layer 20. During the etching process, carbon polymer 41 is formed on the sidewalls of the grooves 50, and the carbon polymer 41 covers the sidewalls of the dielectric layer 20 and the patterned photoresist layer 30.
[0058] In one embodiment of the present invention, the patterned photoresist layer 30 is used as a mask to perform dry etching on the dielectric layer 20. The etching gas used in the dry etching includes a fluorine-containing gas, which may include at least one gas selected from carbon tetrafluoride, trifluoromethane, and sulfur hexafluoride. For example, the fluorine-containing gas may be carbon tetrafluoride, trifluoromethane, or sulfur hexafluoride, or it may be a mixture of these gases, but it is not limited to these. In this embodiment, the etching gas is carbon tetrafluoride.
[0059] In step S3, please refer to Figure 7 As shown, a sacrificial layer 62 is formed on the sidewall of the groove 50, and the sacrificial layer 62 covers the sidewall of the carbon polymer layer 41.
[0060] In one embodiment of the present invention, please refer to... Figure 6 As shown, a sacrificial material layer 61 is formed on the sidewalls, bottom, and surface of the patterned photoresist layer 30 of the groove 50. Then, the sacrificial material layer 61 on the bottom of the groove 50 and the surface of the patterned photoresist layer 30 is removed, leaving the sacrificial material layer 61 on the sidewalls of the groove 50 as a sacrificial layer 62, forming... Figure 7 The structure shown.
[0061] In this embodiment, the sacrificial layer 62 comprises any material that is soluble in water, soluble in organic solvents, or can be removed by wet etching. The sacrificial layer 62 can be removed using water, organic solvents, or wet etching processes. In one embodiment of the present invention, the material of the sacrificial layer 62 includes supertetragonal SAOT (Sr4Al2O7), and the sacrificial layer 62 can be removed by water dissolution.
[0062] Super tetragonal SAOT is a water-soluble thin film with high water solubility, which simplifies the subsequent removal process of the sacrificial layer. It also has a wide and stable growth window, can be grown using pulsed laser deposition (PLD) technology, and is compatible with the growth of most perovskite oxides.
[0063] In one embodiment of the present invention, the sacrificial material layer 61 can be formed using pulsed laser deposition, ion sputtering, or molecular beam epitaxy. The sacrificial material layer 61 covers the sidewalls and bottom of the trench 50 and the surface of the patterned photoresist layer 30. Subsequently, dry etching is performed to remove the horizontally oriented sacrificial material layer 61 (i.e., the sacrificial material layer 61 at the bottom of the trench 60 and on the surface of the patterned photoresist layer 30), retaining the vertically oriented sacrificial material layer 61 (i.e., the sacrificial material layer 61 on the sidewalls of the trench 50) as the sacrificial layer 62. The sacrificial layer 62 covers the sidewalls of the carbon polymer layer 41.
[0064] In step S4, please refer to Figure 8 As shown, the bottom of the groove 50 is over-etched to completely remove the dielectric layer 20 at the bottom of the groove 50. During the etching process, a fluoroaluminum polymer layer 42 is formed on the sidewall of the groove 50, and the fluoroaluminum polymer layer 42 covers the sidewall of the sacrificial layer 62.
[0065] In this embodiment, the dielectric layer 20 at the bottom of the groove 50 is etched. In order to remove all of the dielectric layer 20, over-etching is required. Therefore, the aluminum layer 10 exposed at the bottom of the groove 50 is inevitably etched. During the etching process, a fluoroaluminum polymer layer 42 is formed on the sidewall of the groove 50. The fluoroaluminum polymer layer 42 covers the sidewall of the sacrificial layer 62. In this embodiment, the fluoroaluminum polymer layer 42 includes aluminum fluoride (AlFx).
[0066] In this embodiment, the carbon polymer layer 41 covers the sidewalls of the patterned photoresist layer 30 and the sidewalls of the dielectric layer 20, the sacrificial layer 62 covers the sidewalls of the carbon polymer layer 41, and the fluoroaluminum polymer layer 42 covers the sidewalls of the sacrificial layer 62.
[0067] In step S5, please refer to Figure 9 As shown, the patterned photoresist layer 30 is removed. In this embodiment, an ashing process can be used to remove the patterned photoresist layer 30, or any suitable process such as wet etching can be used to remove the patterned photoresist layer 30.
[0068] During the removal of the patterned photoresist layer 30, the carbon polymer layer 41 on the sidewalls of the patterned photoresist layer 30 is also removed simultaneously, forming a structure as shown in the image. Figure 9 The structure shown. After removing the patterned photoresist layer 30, the sacrificial layer 62 and the fluoroaluminum polymer layer 42 remaining on the sidewalls of the patterned photoresist layer 30, due to the lack of sidewall support, the sacrificial layer 62 and the fluoroaluminum polymer layer 42 on the sidewalls of the patterned photoresist layer 30 ( Figure 9The sacrificial layer 62 and the fluoroaluminum polymer layer 42 above the dashed line break off and fall off.
[0069] In step S6, please refer to Figure 11 As shown, the sacrificial layer 62, the fluoroaluminum polymer layer 42, and the carbon polymer layer 41 are removed.
[0070] In one embodiment of the present invention, please refer to Figure 10 As shown, the sacrificial layer 62 is first removed so that the fluoroaluminum polymer layer 42 is located alone on the aluminum layer 10.
[0071] In this embodiment, the sacrificial layer 62 is removed. In the direction perpendicular to the aluminum layer 10, the sacrificial layer 62 is located between the fluoroaluminum polymer layer 42 and the carbon polymer layer 41. After removing the sacrificial layer 62, the fluoroaluminum polymer layer 42 is located solely on the aluminum layer 10, with a gap between it and the carbon polymer layer 41. Furthermore, because the fluoroaluminum polymer layer 42 is strip-shaped in the direction perpendicular to the aluminum layer 10 (since the fluoroaluminum polymer layer 42 is formed on the sidewall of the sacrificial layer 62, after removing the sacrificial layer 62, the fluoroaluminum polymer layer 42 is strip-shaped, which may be irregular), it is easier to remove.
[0072] In one embodiment, the sacrificial layer 62 can be removed by any suitable method such as water, organic solvents, or wet etching.
[0073] Please refer to Figure 11 As shown, the fluoroaluminum polymer layer 42 and the carbon polymer layer 41 are then removed.
[0074] In this embodiment, wet etching can be used to remove the fluoroaluminum polymer layer 42 and the carbon polymer layer 41. The etching solution used for wet etching may include NE111, but is not limited to this. After removing the fluoroaluminum polymer layer 42 and the carbon polymer layer 41, only the etched dielectric layer 20 and the aluminum layer 10 remain. A groove 50 is formed in the dielectric layer 20 to expose the aluminum layer 10, and there is no polymer residue on the sidewalls of the groove 50.
[0075] In another embodiment of the present invention, the fluoroaluminum polymer layer 42 and the carbon polymer layer 41 can be removed simultaneously with the removal of the sacrificial layer 62. For example, the sacrificial layer 62 can be removed by any suitable method such as wet etching, while the fluoroaluminum polymer layer 42 and the carbon polymer layer 41 are removed at the same time. Of course, the fluoroaluminum polymer layer 42 can also be removed simultaneously with the removal of the sacrificial layer 62, and then the carbon polymer layer 41 can be removed. The present invention does not limit this to this method.
[0076] This invention involves two etching processes for the dielectric layer 20. The first etching stops before further etching of the aluminum layer 10, as the aluminum layer 10 remains unetched and no fluoroaluminum polymer layer 42 is formed. A sacrificial layer 62 is then formed on the sidewall of the groove 50. Next, the aluminum layer 10 at the bottom of the groove 50 is over-etched to completely remove the dielectric layer 20. The fluoroaluminum polymer layer 42 formed during the etching of the aluminum layer 10 is located on the sidewall of the sacrificial layer 62, making it easier to remove. Furthermore, the sacrificial layer 62 is first removed to isolate the fluoroaluminum polymer layer 42 on the aluminum layer 10. Then, the fluoroaluminum polymer layer 42 and the carbon polymer layer 41 are removed. After the sacrificial layer 62 is removed, the isolated fluoroaluminum polymer layer 42 is even easier to remove. Additionally, this invention uses tetragonal SAOT as the sacrificial layer 62, which is water-soluble and easily removed, thus simplifying the removal process.
[0077] In summary, the method for removing the fluoroaluminate polymer generated during the etching process provided by this invention involves firstly forming an aluminum layer, a dielectric layer, and a patterned photoresist layer sequentially on a substrate. Then, using the patterned photoresist layer as a mask, the dielectric layer is etched until an aluminum layer is exposed, but before further etching of the aluminum layer is completed, forming a groove within the patterned photoresist layer and the dielectric layer. During the etching process, a carbon polymer layer is formed on the sidewall of the groove. Then, a sacrificial layer is formed on the sidewall of the groove, covering the sidewall of the carbon polymer layer. Next, the bottom of the groove is over-etched to completely remove the dielectric layer. During the etching process, a fluoroaluminate polymer layer is formed on the sidewall of the groove, covering the sidewall of the sacrificial layer. Afterward, the patterned photoresist layer is removed, followed by the removal of the sacrificial layer, the fluoroaluminate polymer layer, and the carbon polymer layer. This invention involves two etching processes for the dielectric layer. The first etching is stopped before the aluminum layer is completely etched, as no fluoroaluminum polymer layer is generated at this point since the aluminum layer is not etched. Then, a sacrificial layer is formed on the sidewall of the groove. Next, the aluminum layer at the bottom of the groove is over-etched to completely remove the dielectric layer. The fluoroaluminum polymer layer generated by etching the aluminum layer is formed on the sidewall of the sacrificial layer, making the fluoroaluminum polymer layer easy to remove.
[0078] Furthermore, the sacrificial layer is first removed to allow the fluoroaluminum polymer layer to stand alone on the aluminum layer, and then the fluoroaluminum polymer layer and the carbon polymer layer are removed. After the sacrificial layer is removed, the isolated fluoroaluminum polymer layer is easier to remove.
[0079] In addition, this invention uses tetragonal SAOT as a sacrificial layer. The tetragonal SAOT dissolves in water and is removed, thereby simplifying the removal process.
[0080] The above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the claims.
Claims
1. A method for removing fluoroaluminate polymers generated during an etching process, characterized in that, Includes the following steps: A substrate is provided on which an aluminum layer, a dielectric layer and a patterned photoresist layer are sequentially formed. The dielectric layer is etched using the patterned photoresist layer as a mask until an aluminum layer is exposed, and the etching stops before the aluminum layer is etched, forming a groove located in the patterned photoresist layer and the dielectric layer. During the etching process, a carbon polymer layer is formed on the sidewall of the groove. A sacrificial layer is formed on the sidewall of the groove, the sacrificial layer covering the sidewall of the carbon polymer layer; The bottom of the groove is over-etched to completely remove the dielectric layer at the bottom of the groove. During the etching process, a fluoroaluminum polymer layer is formed on the sidewall of the groove, and the fluoroaluminum polymer layer covers the sidewall of the sacrificial layer. Remove the patterned photoresist layer; and Remove the sacrificial layer, the fluoroaluminum polymer layer, and the carbon polymer layer.
2. The method for removing the fluoroaluminate polymer generated in the etching process according to claim 1, characterized in that, The method for removing the sacrificial layer, the fluoroaluminum polymer layer, and the carbon polymer layer includes: Remove the sacrificial layer to allow the fluoroaluminum polymer layer to lie solely on the aluminum layer; and Remove the fluoroaluminum polymer layer and the carbon polymer layer.
3. The method for removing the fluoroaluminate polymer generated in the etching process according to claim 1, characterized in that, The sacrificial layer comprises a material that is soluble in water, soluble in an organic solvent, or removed by wet etching; the sacrificial layer is removed by a water, organic solvent, or wet etching process.
4. The method for removing the fluoroaluminate polymer generated in the etching process according to claim 3, characterized in that, The sacrificial layer is made of SAOT (Super Tetragonal), and water is used to remove the sacrificial layer.
5. The method for removing the fluoroaluminate polymer generated in the etching process according to claim 1, characterized in that, The methods for forming the sacrificial layer include pulsed laser deposition, ion sputtering, or molecular beam epitaxy.
6. The method for removing the fluoroaluminate polymer generated in the etching process according to claim 1, characterized in that, A method for forming a sacrificial layer on the sidewall of the groove, the sacrificial layer covering the sidewall of the carbon polymer layer, includes: A sacrificial material layer is formed on the sidewalls, bottom, and surface of the patterned photoresist layer of the groove; Remove the sacrificial material layer from the bottom of the groove and the surface of the patterned photoresist layer, and retain the sacrificial material layer on the sidewall of the groove as a sacrificial layer.
7. The method for removing the fluoroaluminate polymer generated in the etching process according to claim 6, characterized in that, The sacrificial layer between the bottom of the groove and the surface of the patterned photoresist layer is removed using a dry etching process.
8. The method for removing the fluoroaluminate polymer generated in the etching process according to claim 1, characterized in that, The dielectric layer is dry-etched using the patterned photoresist layer as a mask; the etching gas in the dry etching includes a fluorine-containing gas.
9. The method for removing the fluoroaluminate polymer generated in the etching process according to claim 1, characterized in that, The method for removing the fluoroaluminum polymer layer and the carbon polymer layer includes wet etching.
10. The method for removing the fluoroaluminate polymer generated in the etching process according to claim 9, characterized in that, The etching solution used in the wet etching process includes NE111.