Method of coating top anti-reflective coating

Abstract

A method of coating a top anti-reflective coating includes providing a turntable, placing a substrate over the turntable, providing a photoresist layer on the substrate, spraying a deionized water onto the photoresist layer, spraying a top anti-reflective coating liquid onto the deionized water, mixing the top anti-reflective coating liquid with the deionized water and forming a mixed liquid, and coating the top anti-reflective coating with the mixed liquid. And performing a spin coating step to spin-coat and disperse the mixed liquid to form a top anti-reflection coating film on the photoresist layer.

Description

Technical Field

[0001] The invention relates to the field of semiconductors, and in particular to a method for coating a top anti-reflection coating on the surface of a photoresist layer. Background Art

[0002] In semiconductor manufacturing processes, forming a patterned material layer is a very common technique. The patterning steps generally include: coating a photoresist layer on the material layer, exposing and developing the photoresist layer to form a patterned photoresist layer, and then usually using the patterned photoresist layer as a mask and performing an etching step to etch the material layer below that is not blocked by the mask.

[0003] In the above-mentioned patterning step, a photoresist layer needs to be formed on the surface of the material layer. However, during the exposure process, in order to avoid the poor exposure effect caused by the light reflection caused by the photoresist layer, a top anti-reflection coating (TARC) is often formed on the surface of the photoresist layer. The main function of TARC is to reduce the reflection of light and improve the success rate of the exposure process. Therefore, the quality of the formed TARC will also affect the yield of the exposure step in the semiconductor manufacturing process. The current manufacturing process for forming TARC still has some shortcomings that need to be improved, so it is necessary to develop an improved method for forming TARC. Summary of the invention

[0004] The present invention provides a method for coating a top anti-reflection coating, comprising providing a turntable, placing a substrate above the turntable, and having a photoresist layer on the substrate, spraying deionized water onto the photoresist layer, spraying a top anti-reflection coating liquid onto the deionized water, mixing the top anti-reflection coating liquid with the deionized water to form a mixed liquid, and performing a spin coating step to spin-coat and disperse the mixed liquid to form a top anti-reflection coating film located on the photoresist layer.

[0005] The present invention further provides a method for coating a top anti-reflection coating, comprising providing a turntable, placing a substrate above the turntable, and having a photoresist layer on the substrate, spraying deionized water onto the photoresist layer, wherein the spraying position of the deionized water is located at a first offset position, and the first offset position is located at a unit distance next to a center point of the photoresist layer. When the deionized water is sprayed onto the surface of the photoresist layer, the turntable simultaneously performs a momentary rotation step, spraying a top anti-reflection coating liquid onto the deionized water, so that the top anti-reflection coating liquid is mixed with the deionized water to form a mixed liquid, and performing a spin coating step to spin-coat and disperse the mixed liquid to form a top anti-reflection coating film located on the photoresist layer.

[0006] The present invention is characterized in that it provides a method for coating a top anti-reflection coating, wherein deionized water is first sprayed on a photoresist layer, and before the deionized water is spin-coated, the top anti-reflection coating liquid is mixed with the deionized water, and then the mixed liquid is spin-coated. The method provided by the present invention can greatly reduce the amount of the top anti-reflection coating liquid used during the exposure process, thereby reducing costs. In addition, the method provided by the present invention can also solve the problems of tiny bubbles, central area depression, etc. that may be encountered when forming the top anti-reflection coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figures 1 to 4 A schematic diagram of a method for coating a top anti-reflective coating according to a first preferred embodiment of the present invention;

[0008] Figures 5 to 8 A schematic diagram of a method for coating a top anti-reflective coating according to a second preferred embodiment of the present invention;

[0009] Figures 9 to 12 FIG. 4 is a schematic diagram of a method for coating a top anti-reflection coating according to a third preferred embodiment of the present invention.

[0010] Main component symbols

[0011] 10: Turntable

[0012] 12: Base

[0013] 14: Photoresist layer

[0014] 15: Nozzle

[0015] 16: Deionized water

[0016] 17: Mixing liquids

[0017] 18: Top anti-reflective coating liquid

[0018] 20: Top anti-reflective coating film

[0019] E: Edge

[0020] O: Center point DETAILED DESCRIPTION

[0021] In order to enable a person skilled in the art to further understand the present invention, the preferred embodiments of the present invention are listed below, and the components and intended effects of the present invention are described in detail with reference to the accompanying drawings.

[0022] For the convenience of explanation, the drawings of the present invention are only for illustration to make it easier to understand the present invention, and the detailed proportions can be adjusted according to the design requirements. The upper and lower relationships of the relative elements in the drawings described in the text should be understood by those skilled in the art to refer to the relative positions of the objects, so they can be flipped to present the same components, which should all fall within the scope of the disclosure of this specification, and will be explained here first.

[0023] Figures 1 to 4 A schematic diagram of a method for coating a top anti-reflection coating according to a first preferred embodiment of the present invention is shown. Figure 1 As shown, a turntable 10 is first provided, a substrate 12 is placed on the turntable 10, and a photoresist layer 14 is coated on the substrate 12. The turntable 10 described here is, for example, a turntable used for spin coating in a semiconductor manufacturing process, the substrate 12 is, for example, a wafer (chip) or other suitable material layer, and the photoresist layer 14 is a photoresist material suitable for use in a semiconductor manufacturing process.

[0024] Next, in order to reduce the reflectivity of the photoresist layer 14 itself, a top anti-reflection coating (TARC) needs to be coated on the surface of the photoresist layer 14. The anti-reflection coating (TARC) described here is the same or similar to the TARC material used in the existing semiconductor manufacturing process, and its material, for example, includes a mixture of cross-linkable resins, thermal acid generators, surfactants, and solvents. However, the applicant has found that the TARC material is usually water-soluble and therefore highly hydrophilic, while the photoresist layer 14 itself is a non-aqueous solution. Therefore, when TARC is directly coated on the photoresist layer 14, a large amount of TARC solution will be consumed to form a sufficient TARC layer on the surface of the photoresist layer 14, thereby increasing the cost.

[0025] In order to solve the above problems, please refer to the first embodiment of the present invention. Figure 1 , a deionized water 16 is sprayed from the nozzle 15 onto the surface of the photoresist layer 14. After the deionized water 16 is sprayed, the turntable 10 rotates and drives the substrate 12 above, so that the deionized water 16 diffuses outward from the center of the photoresist layer 14 by centrifugal force and is evenly distributed on the surface of the photoresist layer 14. In this embodiment, the rotation speed is 400 rpm and the rotation time is 0.2 seconds, but it is not limited to this. Then, as shown in FIG. Figure 2As shown, TARC liquid 18 is sprayed onto the surface of deionized water 16. It is worth noting that in this embodiment, when the TARC liquid 18 is sprayed, the deionized water 16 is evenly distributed on the surface of the photoresist layer 14 and forms a thin water film. This method of forming a thin water film with deionized water 16 can also be regarded as a pre-wet method. Since the TARC liquid 18 can be dissolved in the deionized water 16, first forming a thin water film of deionized water 16 on the photoresist layer 16 and then spraying the TARC liquid 18 can effectively improve the adhesion of the TARC liquid 18 and greatly reduce the amount of sprayed TARC liquid 18. According to the applicant's observation, the amount of each wafer can be reduced by more than half (the original TARC liquid required to spray each wafer is about 2.0cc, and the method of the present invention can be reduced to less than 1.0cc).

[0026] When spraying the TARC liquid 18, the TARC liquid 18 can be spread and coated on the entire surface of the photoresist layer 14 by rotating at high and low speeds alternately. In this embodiment, for example, a medium speed of 700 rpm is used for 0.3 seconds, followed by a low speed of 100 rpm for 0.5 seconds, and then a high speed of 3200 rpm for 0.3 seconds, but the present invention is not limited thereto. However, the applicant has found that the first embodiment of the present invention still has some problems, such as Figure 3 As shown, the TARC liquid 18 is mixed with the thin water film of the deionized water 16 to form a mixed liquid 17. During the rotation process, the thin water film formed by the deionized water 16 at the edge portion E of the photoresist layer 14 may fly away, resulting in insufficient TARC liquid being attached to the edge portion E of the photoresist layer 14. Figure 4 As shown, after the subsequent baking step, the TARC liquid 18 is dried to form a TARC film 20. The applicant found that the TARC film 20 at the edge of the photoresist layer 14 is not completely formed and is prone to produce tiny bubbles. In addition, voids 22 may also be generated in the central part of the photoresist layer 14, which will affect the quality of subsequent exposure.

[0027] Therefore, in order to solve the above-mentioned problems, the present invention provides a second preferred embodiment of a method for coating a top anti-reflection coating. Figures 5 to 8 A schematic diagram of a method for coating a top anti-reflection coating according to a second preferred embodiment of the present invention is shown. Figure 5 As shown, this embodiment also provides a turntable 10, a substrate 12 located on the turntable 10, and a photoresist layer 14 located on the substrate 12. The main difference between this embodiment and the first embodiment is that when spraying deionized water 16, no rotation is performed first or only a short-term low-speed rotation (e.g., 0.1 second of 50 rpm rotation, or no rotation) is performed, so that the deionized water 16 is still located in the central area of ​​the photoresist layer 14. Then, as shown in FIG. Figure 6 and Figure 7As shown, when the deionized water 16 has not yet been spin-coated, the TARC liquid 18 is directly sprayed onto the deionized water 16 to mix with the deionized water 16, and a mixed liquid 17 is generated, and a spinning step is performed at the same time (for example, a low-speed rotation of 200 rpm for 1 second followed by a high-speed rotation of 3200 rpm for 0.5 second, but not limited thereto), and the mixed liquid 17 of the deionized water 16 and the TARC liquid 18 is spin-coated from the central portion of the photoresist layer 14 to the entire surface of the photoresist layer 14, and then a baking step is performed to form a TARC film (as shown in FIG. Figure 8 That is, in this embodiment, the TARC liquid 18 and the deionized water 16 are first mixed in the central part of the photoresist layer 14, and then the mixture is applied to the periphery of the photoresist layer 14 in a rotational manner. Different from the first embodiment, since a thin water film of the deionized water 16 is not formed first, unlike the pre-wet step, there is no thin water film scattered at the edge of the photoresist layer 14, thereby avoiding the problem of tiny bubbles generated in the TARC film 20 at the edge described in the first embodiment.

[0028] However, if Figure 8 As shown, the applicant found that although the present embodiment has solved the problem of tiny bubbles in the surrounding area of ​​the TARC film, a void 22 may still be generated in the central part of the photoresist layer 14. The applicant observed that the reason for the central void 22 is that when the deionized water 16 is sprayed on the surface of the photoresist layer 14, the water column has a strong force when it first impacts the surface of the photoresist layer 14 (please note that the applicant found that only the force of the first impact of the water column is relatively strong, and the force of the water column in the subsequent continuous spraying process is relatively weak), so a groove is generated on the surface of the central part of the photoresist layer 14, and the groove will become as shown after the baking step. Figure 8 The cavity 22 is shown.

[0029] Therefore, in order to solve the above-mentioned problems, the present invention provides a third preferred embodiment of a method for coating a top anti-reflection coating. Figures 9 to 12 A schematic diagram of a method for coating a top anti-reflection coating according to a third preferred embodiment of the present invention is shown. Fig. 9As shown, the present embodiment also provides a turntable 10, a substrate 12 located on the turntable 10, and a photoresist layer 14 located on the substrate 12. The main difference between the present embodiment and the first or second embodiment is that, in the above embodiments, the water column is aimed at the central part of the photoresist layer (or the center of the corresponding wafer) when spraying deionized water, while in the present embodiment, the nozzle 15 for spraying deionized water 16 is aimed at a unit distance to the side of the center point of the photoresist layer 14, for example, a position 7mm away from the center point O, but not limited to this. It is also worth noting that while the nozzle 15 sprays the deionized water 16 and contacts the photoresist layer 14, the turntable 10 performs an instantaneous rotation, for example, a momentary rotation of 400rpm for 0.3 seconds (but the actual value is not limited to this), so as to disperse the vertical downward impact force of the water column by centrifugal force, so as to avoid the problem of holes and depressions in the middle of the photoresist layer 14 caused by too strong impact force of the water column as described in the above other embodiments.

[0030] Follow-up Fig.10 and Fig.11 As shown, after the turntable 10 stops rotating, the deionized water 16 is continuously sprayed for a period of time to accumulate a sufficient amount of deionized water 16 on the photoresist layer 14. Then, since the nozzle 15 is not located at the center of the photoresist layer 14, the position of the nozzle 15 needs to be adjusted, for example, to move it to 7 mm away from another center point O. In more detail, if Fig. 9 The position of the middle nozzle 15 is 7 mm away from the center point O in the -X direction. Fig.10 The position of the nozzle 15 is 7 mm away from the center point O in the +X direction. Subsequently, the nozzle 15 is moved to the center point O to continue spraying a sufficient amount of deionized water 16. In this embodiment, the nozzle 15 is Fig. 9 The time for spraying deionized water 16 at the position is preferably equal to Fig. 9 The time for spraying the deionized water 16 at the positions is, for example, 3 seconds, and the time for the nozzle 15 to spray the deionized water 16 at the center point O is about 6 seconds (e.g. Fig.11 It is also worth noting that, except for the momentary rotation of the turntable 10 at the beginning, the rest of the Fig.10 and Fig.11 In the steps shown, the turntable 10 does not rotate.

[0031] Afterwards Fig.12As shown, when the deionized water 16 has not yet been spin-coated, the TARC liquid 18 is directly sprayed onto the deionized water 16 to mix with the deionized water 16, and a mixed liquid 17 is generated. The subsequent steps are the same as those of the second preferred embodiment of the present invention, where the mixed liquid 17 of the deionized water 16 and the TARC liquid 18 is spin-coated from the central portion of the photoresist layer 14 to the entire surface of the photoresist layer 14, and then a baking step is performed to form a TARC film. These steps can be referred to in Figures 6 to 8 , I will not elaborate on this.

[0032] Compared with the above-mentioned embodiments, this embodiment can solve the problem of tiny bubbles around the photoresist layer 14 and the problem of depression in the center of the photoresist layer 14 caused by the impact of the water column, so the overall manufacturing process quality can be effectively improved.

[0033] In summary, the present invention provides a method for coating a top anti-reflective coating, comprising providing a turntable 10, placing a substrate 12 above the turntable 10, and having a photoresist layer 14 on the substrate 12, spraying a deionized water 16 onto the photoresist layer 14, spraying a top anti-reflective coating (TARC) liquid 18 onto the deionized water 16, mixing the top anti-reflective coating liquid 18 with the deionized water 16 to form a mixed liquid 17, and performing a spin coating step to spin-coat and disperse the mixed liquid 17 to form a top anti-reflective coating film 20 located on the photoresist layer 14.

[0034] In some embodiments of the present invention, after spraying deionized water 16 onto the photoresist layer 14, a water film is formed concentrated on the central portion of the photoresist layer 14 (eg, Figure 6 shown).

[0035] In some embodiments of the present invention, the concentrated water film is only located in a central area of ​​the photoresist layer 14, and is not located in a peripheral area of ​​the photoresist layer 14 (eg, Figure 6 shown).

[0036] In some embodiments of the present invention, before forming the mixed liquid 17, the turntable does not rotate or rotates slowly at a low speed (e.g. Figure 6 and Figure 7 ).

[0037] In some embodiments of the present invention, after spraying the top anti-reflection coating liquid 18 onto the deionized water 16 to form the mixed liquid 17, the top anti-reflection coating liquid 18 is continuously sprayed without stopping until a baking step is performed.

[0038] In some embodiments of the present invention, after coating the mixed liquid 17 onto the surface of the photoresist layer 14 , a baking step is further performed.

[0039] In some embodiments of the present invention, after the baking step, a central region of the photoresist layer 14 includes a cavity 22 therein, and the cavity 22 is located below the top anti-reflective coating film 20 (eg, Figure 8 shown).

[0040] The present invention further provides a method for coating a top anti-reflection coating, comprising providing a turntable 10, placing a substrate 12 on the turntable 10, and having a photoresist layer 14 on the substrate 12, spraying a deionized water 16 onto the photoresist layer 14, wherein the spraying position of the deionized water 16 is located at a first offset position (such as Fig. 9 The first offset position is located at a unit distance next to a center point O of the photoresist layer 14, and when the deionized water 16 is sprayed onto the surface of the photoresist layer 14, the turntable 10 simultaneously performs a momentary rotation step to spray a top anti-reflective coating liquid 18 onto the deionized water 16 to mix the top anti-reflective coating liquid 18 with the deionized water 16 to form a mixed liquid 17, and performs a spin coating step to spin-coat and disperse the mixed liquid 17 to form a top anti-reflective coating film 20 located on the photoresist layer.

[0041] In some embodiments of the present invention, after the deionized water 16 is sprayed onto the surface of the photoresist layer 14 , the rotating step is stopped, and the deionized water 16 is continuously sprayed to the first offset position.

[0042] In some embodiments of the present invention, the deionized water 16 is sprayed at the first offset position for a period of time and then sprayed at a second offset position (eg, Fig.10 The deionized water 16 is continued to be sprayed at the second offset position, wherein the second offset position is located at a unit distance next to a center point O of the photoresist layer 14.

[0043] In some embodiments of the present invention, the second offset position and the first offset position are located at two opposite directions of the center point O.

[0044] In some embodiments of the present invention, after the deionized water is sprayed at the second offset position for a period of time, the deionized water 16 is continuously sprayed to the center point O of the photoresist layer 14 .

[0045] In summary, the present invention is characterized in that it provides a method for coating a top anti-reflective coating, wherein deionized water is first sprayed on a photoresist layer, and before the deionized water is spin-coated, the top anti-reflective coating liquid is mixed with the deionized water, and then the mixed liquid is spin-coated. The method provided by the present invention can greatly reduce the amount of the top anti-reflective coating liquid used during the exposure process, thereby reducing costs. In addition, the method provided by the present invention can also solve the problems of tiny bubbles, central area depressions, etc. that may be encountered when forming a top anti-reflective coating.

[0046] The above descriptions are only preferred embodiments of the present invention. All equivalent changes and modifications made according to the claims of the present invention should fall within the scope of the present invention.

Claims

1. A method for applying a top anti-reflective coating, comprising: providing a turntable, on which a substrate is placed, and on which a photoresist layer is formed; spraying deionized water onto the photoresist layer; spraying a top anti-reflection coating liquid onto the deionized water to mix the top anti-reflection coating liquid with the deionized water to form a mixed liquid; and A spin coating step is performed to spread the mixed liquid by spin coating to form a top anti-reflective coating film on the photoresist layer.

2. The method for coating a top anti-reflective coating as claimed in claim 1, wherein after spraying the deionized water onto the photoresist layer, a water film is concentrated on a central portion of the photoresist layer.

3. The method for coating a top anti-reflective coating as claimed in claim 2, wherein the concentrated water film is located only in a central area of ​​the photoresist layer, and not in a peripheral area of ​​the photoresist layer.

4. The method for coating a top anti-reflection coating as claimed in claim 1, wherein before forming the mixed liquid, the turntable does not rotate or rotates slowly at a low speed. 5 . The method for coating a top anti-reflective coating as claimed in claim 1 , further comprising a baking step after coating the mixed liquid onto the surface of the photoresist layer.

6. The method for applying a top anti-reflective coating as claimed in claim 5, wherein after the baking step, the central region of the photoresist layer includes a cavity therein, And the cavity is located below the top anti-reflective coating film.

7. The method for coating a top anti-reflection coating as claimed in claim 5, wherein after spraying the top anti-reflection coating liquid onto the deionized water to form the mixed liquid, the top anti-reflection coating liquid is continuously sprayed without stopping until the baking step is performed.

8. A method for applying a top anti-reflective coating, comprising: providing a turntable, on which a substrate is placed, and on which a photoresist layer is formed; Spraying deionized water onto the photoresist layer, wherein the spraying position of the deionized water is located at a first offset position, the first offset position is located at a unit distance next to the center point of the photoresist layer, and when the deionized water is sprayed onto the surface of the photoresist layer, the turntable simultaneously performs a momentary rotation step; spraying a top anti-reflection coating liquid onto the deionized water to mix the top anti-reflection coating liquid with the deionized water to form a mixed liquid; and A spin coating step is performed to spread the mixed liquid by spin coating to form a top anti-reflective coating film on the photoresist layer. 9 . The method for coating a top anti-reflective coating as claimed in claim 8 , wherein after the deionized water is sprayed onto the surface of the photoresist layer, the rotating step is stopped, and the deionized water is continuously sprayed to the first offset position.

10. The method for coating a top anti-reflective coating as described in claim 9, wherein after the deionized water is sprayed at the first offset position for a period of time, the deionized water is continued to be sprayed at a second offset position of the photoresist layer, wherein the second offset position is located at a unit distance next to the center point of the photoresist layer. 11 . The method for coating a top anti-reflection coating as claimed in claim 10 , wherein the second offset position and the first offset position are located at two opposite directions of the center point. 12 . The method for coating a top anti-reflection coating as claimed in claim 10 , wherein after the deionized water is sprayed at the second offset position for a period of time, the deionized water is continuously sprayed to the center point of the photoresist layer. 13 . The method for coating a top anti-reflective coating as claimed in claim 8 , wherein after spraying the deionized water onto the photoresist layer, a water film is concentrated on a central portion of the photoresist layer. 14 . The method for coating a top anti-reflection coating as claimed in claim 13 , wherein the concentrated water film is located only in a central area of ​​the photoresist layer, but not in a peripheral area of ​​the photoresist layer.

15. The method for coating a top anti-reflection coating as claimed in claim 8, wherein after spraying the top anti-reflection coating liquid onto the deionized water to form the mixed liquid, the top anti-reflection coating liquid is continuously sprayed without stopping until a baking step is performed.

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