Method for removing photoresist on semiconductor substrate and method for patterning photoresist

Abstract

The invention provides a method for removing photoresist on a semiconductor substrate and a method for patterning the photoresist. The removing method comprises the following steps: coating the photoresist on the surface of the semiconductor substrate; the photoresist is dried, and the photoresist is converted into a semi-solid state from a gel state; and removing the photoresist in the marginal area of the semiconductor substrate by adopting a chemical method. According to the removing method, the problem that photoresist is easy to remain when the edge of the thick-edge photoresist is removed in the prior art is solved.

Description

Technical Field

[0001] The present application relates to the field of semiconductor manufacturing technology, and in particular to a method for removing photoresist from a semiconductor substrate and a method for patterning the photoresist. Background Art

[0002] In the existing technology, the methods of coating semiconductor substrates are generally divided into: dip-coating, spin-coating, spraying, etc. Among them, the dip-coating method is suitable for photoresists with thin concentrations, has slow production efficiency and is prone to causing the film thickness to be thin at the top and thick at the bottom; the spraying method is suitable for thick glue with low resolution, and the machine must be cleaned regularly, resulting in a decrease in equipment production capacity, and it is difficult to apply to large-scale mass production; polyimide photoresist is a representative of thick glue, and spin coating is a more commonly used coating method, which is widely used in mass production. As the name suggests, its principle is: drop the photoresist in the center of the semiconductor substrate and spread it evenly on the surface through the action of centrifugal force. The photoresist spin-coated in this way is thin in the middle and thicker at the edge. Therefore, the photoresist accumulated at the edge will cause immeasurable pollution to the semiconductor substrate box, crystal boat, equipment, etc. and greatly affect the product yield. However, the existing process currently has the problem of photoresist residue when removing the thick-edge photoresist, and the removal is not clean.

[0003] The above information disclosed in the background technology section is only used to enhance the understanding of the background technology of the technology described in this article. Therefore, the background technology may contain certain information that does not form the prior art known in this country to those skilled in the art. Summary of the Invention

[0004] The main purpose of the present application is to provide a method for removing photoresist from a semiconductor substrate and a method for patterning photoresist, so as to solve the problem in the prior art that photoresist residue is easily left when removing the edge of thick-edge photoresist.

[0005] In order to achieve the above-mentioned purpose, according to one aspect of the present application, a method for removing photoresist from a semiconductor substrate is provided, comprising: coating photoresist on the surface of the semiconductor substrate; drying the photoresist so that the photoresist is transformed from a gel state to a semi-solid state; and removing the photoresist located in the edge area of ​​the semiconductor substrate by a chemical method.

[0006] Optionally, after the step of drying the photoresist, the removal method further comprises: placing the semiconductor substrate on a cold plate for cooling to cool the temperature of the semiconductor substrate to room temperature, the temperature of the cold plate being 20-25° C., and the cooling time being 30-60 s.

[0007] Optionally, the viscosity of the photoresist coated on the surface of the semiconductor substrate is 1500-2500 CP.

[0008] Optionally, the drying temperature of the drying treatment is 110-125° C., and the drying time is 2.5-3.5 minutes.

[0009] Optionally, after the drying process, the organic solvent in the photoresist is 80-90% of that before the drying process.

[0010] Optionally, the de-edging agent used in the chemical method includes: propylene glycol methyl ether acetate and propylene glycol monomethyl ether, wherein the volume content of the propylene glycol methyl ether acetate in the de-edging agent is 25% to 35%, and the volume content of the propylene glycol monomethyl ether is 65% to 75%.

[0011] Optionally, during the chemical method, the flow rate of the edge removal agent is 10 to 16 ml / min, and the edge removal time is 100 to 120 s.

[0012] Optionally, the photoresist comprises: r-butyrolactone, a polyimide precursor, ethyl lactate, an additive, a naphthoquinone diazide derivative and N-methylpyrrolidone.

[0013] Optionally, the volume content of the r-butyrolactone is 35-40%, the volume content of the polyimide precursor is 25-30%, the volume content of the ethyl lactate is 20-25%, the volume content of the additive is 2-12%, the volume content of the naphthoquinone diazide derivative is 3-8%, and the volume content of the N-methylpyrrolidone is less than 2%.

[0014] According to another aspect of the present application, a method for patterning a photoresist is provided, the patterning method comprising: pre-treating a semiconductor substrate using a method for removing photoresist from a semiconductor substrate; exposing the photoresist on the pre-treated semiconductor substrate using an exposure machine and a mask plate to expose the photoresist on the photoresist that is not covered by the mask plate; and developing the exposed photoresist to transfer the pattern of the mask plate to the photoresist.

[0015] By applying the technical solution of the present application, the photoresist is first coated on the surface of the semiconductor substrate and then dried to change the physical properties of the photoresist, making it stronger, and the state of the photoresist is changed from a gel state to a more stable semi-solid state. Since the semi-solid state has a higher hardness, it is less likely to deform and shift than the photoresist in the gel state, is less likely to splash, and is easier to be completely removed, thereby enhancing the accuracy and controllability of the subsequent chemical removal of the photoresist, and solving the problem of residual photoresist when removing the edge of thick-edged photoresist in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings that constitute part of this application are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute an improper limitation on this application. In the drawings:

[0017] Figure 1 A schematic flow chart of a method for removing photoresist from a semiconductor substrate according to an embodiment of the present application is shown;

[0018] Figure 2 A schematic diagram of the cross-sectional structure of a substrate after spin coating photoresist on a semiconductor substrate in a method for removing photoresist from a semiconductor substrate according to an embodiment of the present application is shown;

[0019] Figure 3 The edge removal method of this application is used to illustrate the Figure 2 A schematic cross-sectional structure diagram of a semiconductor substrate and a photoresist prepared by removing the edge of the photoresist in FIG.

[0020] Figure 4 A schematic diagram of the structure of chemically removing photoresist from the edge area of ​​a semiconductor substrate is shown;

[0021] Figure 5 Shown Figure 3 A schematic diagram of the structure of a semiconductor substrate and a photoresist after the edges are removed;

[0022] Figure 6 Shown Figure 3 Another schematic diagram of the structure of the semiconductor substrate and photoresist after the edges are removed;

[0023] Figure 7 A schematic diagram of the structure of a semiconductor substrate and a photoresist obtained by removing the photoresist from a semiconductor substrate in the prior art is shown;

[0024] Figure 8 Shown Figure 7 A schematic diagram of the structure of a semiconductor substrate and a photoresist after the edges are removed;

[0025] Figure 9 A schematic flow chart of a photoresist patterning method according to an embodiment of the present application is shown.

[0026] The above drawings include the following reference numerals:

[0027] 10. Semiconductor substrate; 20. Photoresist; 30. Edge region; 40. Storage container; 41. Nozzle; 50. Rotating platform. DETAILED DESCRIPTION

[0028] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present application belongs.

[0029] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0030] It should be noted that the terms "first," "second," and the like in the specification and claims of the present invention and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a particular order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate for the embodiments of the present invention described herein. In addition, the terms "including," "having," and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to these processes, methods, products, or apparatuses.

[0031] It should be understood that when an element (such as a layer, film, region, or substrate) is described as being "on" another element, the element may be directly on the other element or intervening elements may be present. Moreover, in the specification and claims, when it is described that an element is "connected to" another element, the element may be "directly connected to" the other element or "connected to" the other element through a third element.

[0032] As introduced in the background technology, polyimide photoresist in the prior art is a representative of thick photoresist, and spin coating is a more commonly used coating method, which is widely used in mass production. As the name suggests, its principle is: drop the photoresist in the center of the semiconductor substrate, and spread it evenly on the surface through the action of centrifugal force. The photoresist spin-coated in this way is thin in the middle and thicker in the edge area. Therefore, the photoresist accumulated on the edge will cause immeasurable pollution to the semiconductor substrate box, crystal boat, equipment, etc. and greatly affect the product yield. However, the existing process currently has the problem of residual photoresist when removing the thick-edge photoresist, and the removal is not clean. In order to solve the problem of residual photoresist when removing the edge of the thick-edge photoresist in the prior art, the embodiments of the present application provide a method for removing semiconductor substrate photoresist and a method for patterning photoresist.

[0033] The technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present invention.

[0034] Figure 1 FIG. 1 is a flow chart of a method for removing photoresist from a semiconductor substrate according to an embodiment of the present application. Figure 1 As shown, the method includes the following steps:

[0035] Step S1, such as Figure 2 As shown, a photoresist 20 is coated on the surface of the semiconductor substrate 10 .

[0036] Particularly, the technology of coating photoresist can be spin coating, semiconductor substrate is placed in glue coating machine, photoresist is spin-coated on the surface of semiconductor substrate, the operating conditions of spin coating can be: rotating speed 900~1300rpm, time 25~35s, utilize spin coating to carry out glue coating, by the effect of centrifugal force, photoresist is evenly spin-coated on the surface of semiconductor substrate, the glue thickness after the spin coating is 12~20 μ m (preferred 16 μ m).In the spin coating process, the composition of solvent accounts for 65% in the liquid photoresist, when spin coating, can correspondingly throw away 60%~80% solvent, and owing to there is surface tension, cause photoresist to be accumulated at the edge, carry out chemical process (ChemicalEBR) de-fringe now and can be difficult to remove the thicker photoresist at the edge, cause edge to occur jagged and rinse uncleanly and cause residual easily.By being set to above-mentioned scope by the spin coating parameter, the content of the solvent in the photoresist is tentatively reduced, for follow-up drying and de-fringe provide good initial conditions, thereby contribute to improving the yield rate and the efficiency of overall process.

[0037] Step S12, drying the photoresist so that the photoresist changes from a gel state to a semi-solid state.

[0038] Specifically, the drying process can be a heat treatment, which can be a pre-baking process. After the photoresist is spin-coated, the semiconductor substrate is placed on a hot plate for drying to fully remove the organic solvent in the photoresist, causing it to transform from a gel state to a semi-solid state. The gel state is a material state between solid and liquid: it has a certain degree of fluidity but can still maintain its shape, unlike pure liquids that flow freely. When applied to photoresists, "gel state" means that after the photoresist is spin-coated onto the semiconductor substrate, the polymer molecules therein are dispersed by the solvent to form a viscous state that can temporarily maintain its shape but still has fluidity. In the gel state, the solvent content in the photoresist is high, which allows the photoresist to be evenly distributed on the surface of the semiconductor substrate during spin coating. However, due to the presence of the solvent, the photoresist still has a certain degree of fluidity, which may cause photoresist accumulation in edge areas. The semi-solid state is a state between the gel state and the fully solid state. It generally refers to a state in which the material becomes more viscous and hard after heating or solvent evaporation, but still has a certain degree of plasticity or can deform under certain conditions. During the photoresist processing process, a pre-bake step evaporates most of the solvent in the photoresist, causing the viscosity of the photoresist to increase significantly, transforming it into a semi-solid state. In this state, the photoresist is more robust and has enhanced adhesion to the semiconductor substrate surface, while maintaining sufficient viscosity for subsequent chemical edge removal. In the semi-solid state, the photoresist structure is more compact and the morphology is more controlled. This helps reduce photoresist sputtering during the edge removal process and avoids jagged or other irregular edges, thereby improving the edge removal effect and the overall yield of the semiconductor substrate.

[0039] This application adopts pre-baking instead of post-baking. The purpose of pre-baking is to dry the organic matter in the photoresist, make the photoresist harder, and increase the adhesion to the substrate; the purpose of post-baking is to reduce the standing wave effect, make the pattern straighter, and have a better morphology.

[0040] Step S3, such as Figure 3 As shown, the photoresist 20 located in the edge region 30 of the semiconductor substrate 10 is removed by a chemical method.

[0041] Specifically, the chemical method can be a chemical method (Chemical, EBR), which adopts a process of drying before chemical edge removal, which significantly improves the removal effect of edge photoresist. The edge photoresist can be basically removed without leaving any traces, making the edge surface flat and smooth.

[0042] like Figure 4As shown, a photoresist 20 is spin-coated on the surface of a semiconductor substrate 10. The thickness of the photoresist 20 in the edge region 30 of the semiconductor substrate 10 is relatively thick. A conventional de-edging method is used. First, a storage container 40 filled with a chemical de-edging agent is used to spray the de-edging agent onto the edge region 30 of the semiconductor substrate 10. The storage container 40 has a nozzle 41. During spraying, the nozzle 41 has an inclined angle with the surface of the semiconductor substrate 10. After spraying, the rotating platform 50 where the semiconductor substrate 10 is located is rotated, and the de-edging agent and the dissolved photoresist are thrown out by centrifugal force. Then, the photoresist 20 is dried. However, since the photoresist 20 is not dried before the de-edging rotation in the above process, the liquid photoresist 20 is easily thrown out to the edge of the semiconductor substrate 10 during the de-edging rotation and cannot be completely removed, resulting in a jagged shape, as shown in FIG. Figure 5 and Figure 6 As shown, Figure 6 The clear boundary between the photoresist 20 and the semiconductor substrate cannot be seen. The above removal method can remove the photoresist more cleanly. The top view of the semiconductor substrate 10 after the photoresist 20 is removed is as shown in FIG. Figure 7 and Figure 8 As shown, the edges are neat and smooth, Figure 8 The white edge in the figure is the semiconductor substrate 10 exposed after the photoresist in the edge area is removed.

[0043] Through this embodiment, the photoresist is first coated on the surface of the semiconductor substrate, and then the photoresist is dried to change the physical properties of the photoresist, making it stronger, and changing the state of the photoresist from a gel state to a more stable semi-solid state. Since the semi-solid state has a higher hardness, it is less likely to deform and shift than the photoresist in the gel state, is less likely to splash, and is easier to be completely removed, thereby enhancing the accuracy and controllability of the subsequent chemical removal of the photoresist, and solving the problem of residual photoresist when removing the edge of thick-edged photoresist in the prior art.

[0044] The above removal method is not only applicable to polyimide photoresists, but also includes but is not limited to other types of photoresists, such as phenolic resin-based, epoxy resin-based photoresists, etc., which are prone to produce thick edges (12 to 20 μm) at the edges of semiconductor substrates, showing a wide range of applications.

[0045] In some optional embodiments, after performing step S12, the removal method further includes: placing the semiconductor substrate on a cold plate for cooling to cool the temperature of the semiconductor substrate to room temperature, wherein the temperature of the cold plate is 20-25° C. and the cooling time is 30-60 seconds. After the photoresist is pre-dried, the semiconductor substrate is transferred to the cold plate to reduce the surface temperature of the semiconductor substrate to room temperature. The cold plate temperature of 20-25° C. and the cooling period of 30-60 seconds can quickly and gently cool the semiconductor substrate, thereby avoiding undesirable stress changes in the photoresist when it suddenly drops from high temperature to ambient temperature, which may cause cracking, and maintaining the optimal state of the photoresist for subsequent chemical edge removal and other treatments.

[0046] In some optional embodiments, in step S11, the viscosity of the photoresist coated on the surface of the semiconductor substrate is 1500-2500 CP. The photoresist may be a polyimide photoresist. Photoresists within this viscosity range are neither runny nor too viscous during spin coating, and can form a relatively uniform film layer, which is beneficial for controlling the edge removal during EBR and reducing sputtering and residue.

[0047] In some optional embodiments, the drying temperature in step S12 is 110-125° C. and the drying time is 2.5-3.5 minutes. Such temperature and time settings can ensure that the organic solvent in the photoresist is fully evaporated, causing it to transform from a gel state to a semi-solid state, while preventing overheating and damaging the properties of the photoresist.

[0048] In some optional embodiments, after the drying process in step S12, the organic solvent in the photoresist is 80-90% of the amount before the drying process. This ensures that the photoresist maintains sufficient wettability after drying to prevent it from hardening too quickly. Retaining an appropriate amount of organic solvent is beneficial to the stability and workability of the photoresist in subsequent processing, avoiding cracks or pattern defects caused by premature hardening. At the same time, the reduction of organic solvent also promotes the transformation of the photoresist morphology, making it easier to accurately remove edges.

[0049] In some optional embodiments, the de-edging agent used in the chemical method in step S13 includes: propylene glycol methyl ether acetate and propylene glycol monomethyl ether, wherein the volume content of propylene glycol methyl ether acetate in the de-edging agent is 25% to 35%, and the volume content of propylene glycol monomethyl ether is 65% to 75%. The type of the above-mentioned de-edging agent can effectively dissolve and remove the photoresist at the edge, thereby improving the efficiency and accuracy of de-edging. The ratio of the de-edging agent components can also balance the solubility and stability, ensuring the thorough removal of the photoresist edge while reducing the negative impact on the central area of ​​the semiconductor substrate.

[0050] In some optional embodiments, during the chemical process, the flow rate of the edge remover is 10 to 16 ml / min, and the edge removal time is 100 to 120 seconds. For example, the flow rate of the edge remover is 10 ml / min, and the edge removal time is 100 seconds; the flow rate of the edge remover is 13 ml / min, and the edge removal time is 110 seconds; the flow rate of the edge remover is 16 ml / min, and the edge removal time is 120 seconds. The edge removal width of the photoresist can be 1.5 to 3.0 mm. By adjusting the flow rate and time, the removal of the photoresist edge can be precisely controlled, avoiding excessive edge remover sputtering to the center of the semiconductor substrate, maintaining the integrity of the center pattern and the smoothness of the edge, and minimizing the impact on the photoresist pattern in the center of the semiconductor substrate while removing the photoresist edge.

[0051] In some optional embodiments, the photoresist comprises: r-butyrolactone, a polyimide precursor, ethyl lactate, an additive, a naphthoquinone diazide derivative, and N-methylpyrrolidone. The polyimide precursor, after curing, is a polymer material. Using the aforementioned photoresist materials optimizes the photoresist's performance, improving its stability at high temperatures, chemical reactivity, and development selectivity, ensuring stable and reliable performance during critical steps such as high-temperature pre-bake, chemical EBR edge removal, and subsequent development.

[0052] To ensure the prepared photoresist exhibits improved reactivity and stability, in some optional embodiments, the volume content of r-butyrolactone is 35-40%, the volume content of the polyimide precursor is 25-30%, the volume content of ethyl lactate is 20-25%, the volume content of the additives is 2-12%, the volume content of the naphthoquinone diazide derivative is 3-8%, and the volume content of N-methylpyrrolidone is less than 2%. By adjusting the volume content of each component, the chemical activity of the photoresist during processing is ensured, while maintaining its stability under temperature fluctuations and appropriate solubility in the developer. This avoids problems such as incomplete patterning, photoresist residue, or rough edges caused by excessive hardening that is difficult to remove or insufficient reaction with the edge remover.

[0053] According to another aspect of the present application, a method for patterning a photoresist is provided, such as Figure 9 As shown, the patterning method includes:

[0054] Step S21, pre-treating the semiconductor substrate using a method for removing photoresist from the semiconductor substrate;

[0055] Specifically, the pretreatment involves edge removal of the photoresist on the semiconductor substrate using the aforementioned removal method. This method, which transforms the photoresist from a gel state to a semi-solid state before performing EBR, effectively improves the precision and efficiency of edge photoresist removal, reduces adverse effects on the pattern in the center region of the semiconductor substrate, and improves the overall yield of the semiconductor substrate.

[0056] Step S22, using an exposure machine and a mask to perform exposure processing on the pre-treated photoresist on the semiconductor substrate, so as to expose the photoresist that is not covered by the mask;

[0057] Specifically, the exposure machine can use the NSR8 exposure machine, set the product exposure program of the exposure machine, automatically transfer the semiconductor substrate with the edges removed into the exposure machine, and use a special mask for exposure. Before the operation, the machine needs to automatically identify and align the alignment mark on the semiconductor substrate with the alignment mark on the mask, and then perform exposure. The exposure time can be 10 to 30 seconds. During the exposure process, the photoresist will produce a photochemical reaction with the ultraviolet light source. Therefore, after exposure, the photoresist on the surface of the semiconductor substrate will form the required mask pattern.

[0058] In step S23 , the exposed photoresist is developed to transfer the pattern of the mask into the photoresist.

[0059] Specifically, the exposed semiconductor substrate is transferred to a developer for development. The developer program is set, using 2.38% TMAH. The development time can be 100 to 150 seconds, with options of 100, 120, 130, or 140 seconds depending on process requirements. The developer temperature can be controlled between 20 and 25°C. The developer operates automatically. During the development process, the developer dissolves the chemically reacted photoresist, while leaving unexposed portions undissolved. Furthermore, the developer removes any remaining photoresist on flat edges, ultimately resulting in the desired pattern.

[0060] By using the above-mentioned removal method, photoresist is first coated on the surface of the semiconductor substrate, and then dried, the physical properties of the photoresist are changed, making it more solid, and the state of the photoresist is transformed from a gel state to a more stable semi-solid state. Due to the higher hardness of the semi-solid state, compared with the photoresist in the gel state, it is less likely to deform and shift, less likely to splash, and easier to completely remove. This enhances the accuracy and controllability of the subsequent chemical removal of the photoresist, and solves the problem of residual photoresist when removing thick-edged photoresist edges in the prior art. The prepared semiconductor substrate is then subjected to the above-mentioned patterning method, improving the quality of the resulting photoresist with the specific pattern of the mask.

[0061] The semiconductor substrate may include a silicon wafer and an epitaxial layer thereon. After the photoresist is fabricated into a specific shape, the photoresist is used as a mask to pattern the epitaxial layer to form a pattern on the silicon wafer for subsequent process preparation.

[0062] In order to enable those skilled in the art to more clearly understand the technical solution of the present application, the implementation process of the method for removing photoresist from a semiconductor substrate of the present application will be described in detail below with reference to specific embodiments.

[0063] The method for removing the semiconductor substrate photoresist of the present application will be described in detail below with reference to specific embodiments and comparative examples.

[0064] Example 1

[0065] This embodiment provides a method for removing photoresist from a semiconductor substrate, comprising:

[0066] Step S11: Spin-coating a photoresist on the surface of a semiconductor substrate. The photoresist has a viscosity of 1500 cp, is spun at a speed of 900 rpm, and is applied for 2 seconds to a thickness of 12 μm. The photoresist comprises r-butyrolactone, a polyimide precursor, ethyl lactate, an additive, a naphthoquinone diazide derivative, and N-methylpyrrolidone. The polyimide precursor, after curing, is a polymer material. The volume content of r-butyrolactone is 35%, the volume content of the polyimide precursor is 25%, the volume content of ethyl lactate is 20%, the volume content of the additive is 2%, the volume content of the naphthoquinone diazide derivative is 3%, and the volume content of N-methylpyrrolidone is 2%. The semiconductor substrate is a silicon wafer and a silicon carbide epitaxial layer thereon.

[0067] Step S12: drying the photoresist so that the photoresist changes from a gel state to a semi-solid state. The drying temperature is 110° C. and the drying time is 3.5 minutes. The organic solvent in the photoresist after drying is 80% of that before drying.

[0068] Step S121: placing the semiconductor substrate on a cold plate for cooling to cool the semiconductor substrate to room temperature. The temperature of the cold plate is 20° C., and the cooling time is 30 seconds.

[0069] Step S13: removing the photoresist located in the edge area of ​​the semiconductor substrate by a chemical method, wherein the edge remover includes propylene glycol methyl ether acetate and propylene glycol monomethyl ether, wherein the volume content of propylene glycol methyl ether acetate in the edge remover is 25%, and the volume content of propylene glycol monomethyl ether is 75%.

[0070] Example 2

[0071] This embodiment provides a method for removing photoresist from a semiconductor substrate, which differs from Embodiment 1 in that the temperature of the cold plate is 23° C. and the cooling time is 50 seconds.

[0072] Example 3

[0073] This embodiment provides a method for removing photoresist from a semiconductor substrate, which differs from Embodiment 1 in that the temperature of the cold plate is 25° C. and the cooling time is 60 seconds.

[0074] Example 4

[0075] This embodiment provides a method for removing photoresist from a semiconductor substrate, which differs from Embodiment 1 in that the temperature of the cold plate is 28° C. and the cooling time is 80 seconds.

[0076] Example 5

[0077] This embodiment provides a method for removing photoresist from a semiconductor substrate, which differs from Embodiment 1 in that the temperature of the cold plate is 18° C. and the cooling time is 20 seconds.

[0078] Example 6

[0079] This embodiment provides a method for removing photoresist from a semiconductor substrate, which differs from Embodiment 1 in that the drying temperature of the drying process is 120° C. and the drying time is 3 minutes.

[0080] Example 7

[0081] This embodiment provides a method for removing photoresist from a semiconductor substrate, which differs from Embodiment 1 in that the drying temperature of the drying process is 125° C. and the drying time is 2.5 minutes.

[0082] Example 8

[0083] This embodiment provides a method for removing photoresist from a semiconductor substrate, which differs from Embodiment 1 in that the drying temperature of the drying process is 135° C. and the drying time is 1.5 minutes.

[0084] Example 9

[0085] This embodiment provides a method for removing photoresist from a semiconductor substrate, which differs from Embodiment 1 in that the drying temperature of the drying process is 100° C. and the drying time is 4.5 minutes.

[0086] Example 10

[0087] This embodiment provides a method for removing photoresist from a semiconductor substrate, which differs from Embodiment 1 in that the organic solvent in the photoresist is 85% of that before the drying process.

[0088] Example 11

[0089] This embodiment provides a method for removing photoresist from a semiconductor substrate, which differs from Embodiment 1 in that the organic solvent in the photoresist is 90% of that before the drying process.

[0090] Example 12

[0091] This embodiment provides a method for removing photoresist from a semiconductor substrate, which differs from Embodiment 1 in that the organic solvent in the photoresist is 95% of that before the drying process.

[0092] Example 13

[0093] This embodiment provides a method for removing photoresist from a semiconductor substrate, which differs from Embodiment 1 in that the organic solvent in the photoresist is 70% of that before the drying process.

[0094] Example 14

[0095] This embodiment provides a method for removing photoresist from a semiconductor substrate, which differs from Embodiment 1 in that the volume content of propylene glycol methyl ether acetate in the edge remover is 30%, and the volume content of propylene glycol monomethyl ether is 70%.

[0096] Example 15

[0097] This embodiment provides a method for removing photoresist from a semiconductor substrate, which differs from Embodiment 1 in that the volume content of propylene glycol methyl ether acetate in the edge remover is 35%, and the volume content of propylene glycol monomethyl ether is 65%.

[0098] Example 16

[0099] This embodiment provides a method for removing photoresist from a semiconductor substrate, which differs from Embodiment 1 in that the volume content of propylene glycol methyl ether acetate in the edge remover is 20%, and the volume content of propylene glycol monomethyl ether is 80%.

[0100] Example 17

[0101] This embodiment provides a method for removing photoresist from a semiconductor substrate, which differs from Embodiment 1 in that the volume content of propylene glycol methyl ether acetate in the edge remover is 45%, and the volume content of propylene glycol monomethyl ether is 55%.

[0102] Example 18

[0103] This embodiment provides a method for removing photoresist from a semiconductor substrate, which differs from Embodiment 1 in that the flow rate of the edge remover is 13 ml / min and the edge removal time is 110 s.

[0104] Example 19

[0105] This embodiment provides a method for removing photoresist from a semiconductor substrate, which differs from Embodiment 1 in that the flow rate of the edge remover is 16 ml / min and the edge removal time is 120 s.

[0106] Example 20

[0107] This embodiment provides a method for removing photoresist from a semiconductor substrate, which differs from Embodiment 1 in that the flow rate of the edge remover is 8 ml / min and the edge removal time is 80 s.

[0108] Example 21

[0109] This embodiment provides a method for removing photoresist from a semiconductor substrate, which differs from Embodiment 1 in that the flow rate of the edge remover is 20 ml / min and the edge removal time is 130 s.

[0110] Comparative Example 1

[0111] This comparative example provides a method for removing photoresist from a semiconductor substrate, which differs from Example 1 in that step S13 is performed first, and then step S12 is performed.

[0112] The semiconductor substrates prepared by the methods for removing the semiconductor substrate photoresist in the above-mentioned Examples 1 to 20 and Comparative Example 1 were tested, and the test results are shown in Table 1:

[0113] Table 1

[0114]

[0115]

[0116] It can be seen from the data in Table 1 above that the flatness of the photoresist edge, the number of particles sputtered to the center defect of the semiconductor substrate and the amount of photoresist residue in Comparative Example 1 are the worst among the data in the above table; the probability of photoresist cracking after drying in Examples 1 to 3 is less than that in Examples 4 to 5; the flatness of the photoresist edge of Examples 1, 6 and 7 is better than that of Examples 8 to 9; the flatness of the photoresist edge of Examples 1, 10 and 11 is better than that of Examples 12 to 13, and the number of particles sputtered to the center defect of the semiconductor substrate is also less; the amount of photoresist residue in Examples 1, 14 and 15 is less than that in Examples 16 and 17; the amount of photoresist residue in Examples 1, 18 and 19 is less than that in Examples 20 and 21, and the flatness of the photoresist edge is also better than that in Examples 20 and 21.

[0117] The above experimental data demonstrates that, compared to gel-state photoresist, the present method for removing semiconductor substrate photoresist is less likely to deform and shift, less likely to cause splashing, and more easily removed. This method addresses the existing issue of photoresist residue when removing thick-edged photoresist edges. Furthermore, it improves the smoothness of the photoresist edge, reduces the number of defects sputtered to the center of the semiconductor substrate, the probability of photoresist cracking after drying, and the amount of photoresist residue.

[0118] The foregoing description is merely a preferred embodiment of the present application and is not intended to limit the present application. Persons skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A method for removing photoresist from a semiconductor substrate, characterized in that: include: coating a photoresist on the surface of a semiconductor substrate; Drying the photoresist so that the photoresist changes from a gel state to a semi-solid state; The photoresist located in the edge area of ​​the semiconductor substrate is removed by a chemical method.

2. The removal method according to claim 1, characterized in that After the step of drying the photoresist, the removal method further comprises: The semiconductor substrate is placed on a cold plate for cooling to cool the temperature of the semiconductor substrate to room temperature. The temperature of the cold plate is 20-25° C. and the cooling time is 30-60 seconds.

3. The removal method according to claim 1, characterized in that The viscosity of the photoresist coated on the surface of the semiconductor substrate is 1500-2500 CP.

4. The removal method according to claim 1, characterized in that The drying temperature of the drying process is 110-125° C., and the drying time is 2.5-3.5 minutes.

5. The removal method according to claim 1, characterized in that: After the drying process, the organic solvent in the photoresist is 80-90% of that before the drying process.

6. The removal method according to claim 1, characterized in that: The de-edging agent used in the chemical method includes propylene glycol methyl ether acetate and propylene glycol monomethyl ether, wherein the volume content of the propylene glycol methyl ether acetate in the de-edging agent is 25% to 35%, and the volume content of the propylene glycol monomethyl ether is 65% to 75%.

7. The removal method according to claim 6, characterized in that: During the chemical method, the flow rate of the edge removal agent is 10 to 16 ml / min, and the edge removal time is 100 to 120 seconds.

8. The removal method according to claim 1, characterized in that: The photoresist comprises: r-butyrolactone, a polyimide precursor, ethyl lactate, an additive, a naphthoquinone diazide derivative and N-methyl pyrrolidone.

9. The removal method according to claim 8, characterized in that: The volume content of the r-butyrolactone is 35-40%, the volume content of the polyimide precursor is 25-30%, the volume content of the ethyl lactate is 20-25%, the volume content of the additive is 2-12%, the volume content of the naphthoquinone diazide derivative is 3-8%, and the volume content of the N-methylpyrrolidone is less than 2%.

10. A method for patterning a photoresist, characterized in that: The patterning method comprises: Pre-treating a semiconductor substrate using the method for removing photoresist from a semiconductor substrate according to any one of claims 1 to 9; Performing an exposure process on the pre-treated photoresist on the semiconductor substrate using an exposure machine and a mask plate, so as to expose the photoresist on the photoresist that is not covered by the mask plate; The exposed photoresist is developed to transfer the pattern of the mask into the photoresist.

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