Mask black spot removing process method

Abstract

The invention discloses a mask black spot removal process method, which comprises the following steps of: determining and marking the position of each black spot on a mask, and determining a pattern around the black spots according to a design pattern of the mask; placing the mask plate on a light table in parallel, coating the pattern around the black spot by using photoresist, and standing for a preset time T1; covering and fixing the mask plate except the photoresist covering area and the black spots in sequence through dust-free cloth and a protective film; the black spots are coated with etching liquid in a dipping mode, standing is conducted for preset time T2, and after the black spots are removed, deionized water is dipped to remove the etching liquid; and after the dust-free cloth and the protective film are removed, photoresist stripping liquid is used for removing photoresist of the mask plate, and the mask plate is washed. The pattern with the large black dot distance removed can reach 1 mm, if an amplification device is used for observation, the pattern control distance can reach within 0.5 mm, the pattern is well protected, wrong patterns cannot occur, and the completion time can be controlled within 2 h.

Description

Technical Field

[0001] The present application relates to the field of semiconductor production technology, and in particular to a process method for removing black spots from a mask. Background Art

[0002] The photolithography mask (also known as the mask, in English, Mask Reticle), referred to as the mask, is a graphic master used in the photolithography process commonly used in micro-nano processing technology. The mask pattern structure is formed on the transparent substrate by an opaque light-shielding film, and then the graphic information is transferred to the product substrate through the exposure process. The mask to be processed is composed of a glass / quartz substrate, a chrome layer and a photoresist layer. Its graphic structure can be obtained through plate making technology, and the commonly used processing equipment is direct writing photolithography equipment, such as laser direct writing photolithography machine, electron beam photolithography machine, etc. Masks are widely used, and masks are needed in fields involving photolithography, such as IC (Integrated Circuit), FPD (Flat Panel Display), PCB (Printed Circuit Boards), MEMS (Micro Electro Mechanical Systems), etc.

[0003] During the manufacturing process of the mask, some large black spots of millimeter scale will be generated due to various reasons or usage requirements, and it is necessary to find a way to remove them. For residual chromium with a relatively large area, the existing process methods are as follows:

[0004] 1. Directly use chromium etching solution to process. This method is more difficult to process for those close to the graphics. It may cause useful graphics to be removed and cause the plate to be scrapped. It can only process large black spots 5mm away from the graphics.

[0005] 2. Use photoresist to coat the entire plate or most of it, then expose, develop and etch. Although this method can remove large black spots that are very close to the pattern, it is time-consuming and difficult to control the uniformity of the coating. It is also difficult to accurately select the exposure energy. The second exposure also requires a rough second alignment, which is time-consuming and may not meet the requirements.

[0006] 3. Use the ZAP function of the repair machine to remove the spots. This method can ensure the removal accuracy, but for large black spots of millimeter level, since the area to be cleared at one time is very small, about 10X10um, and one ZAP takes about 5 seconds, even a 1mm black spot will take about 14 hours to remove. It is inefficient and costly, and cannot meet production requirements. Summary of the invention

[0007] The main purpose of the present invention is to provide a process method for removing black spots from a mask, aiming to solve the technical problem that some large black spots of the millimeter level on the mask cannot be quickly removed.

[0008] In order to solve the above technical problems, the present invention provides a method for removing black spots from a mask, the method comprising:

[0009] Determine and mark the position of each black dot on the mask, and determine the pattern around the black dot by comparing it with the mask design pattern;

[0010] The mask is placed parallel to the optical table, and the pattern around the black spot is coated with photoresist and left to stand for a preset time T1;

[0011] Covering and fixing the mask except the photoresist covered area and the black spots in sequence with a dust-free cloth and a protective film;

[0012] Applying the etching liquid to the black spots by dipping, leaving it for a preset time T2 until the black spots are removed, and then dipping it in deionized water to remove the etching liquid;

[0013] After removing the dust-free cloth and the protective film, the photoresist of the mask is removed by using a photoresist stripping solution and then rinsed.

[0014] Furthermore, the step of determining and marking the positions of the black dots on the mask, and determining the graphics around the black dots by comparing the mask design pattern specifically includes:

[0015] In a darkroom, a spotlight is used to determine and mark the positions of each black dot on the mask, and at the same time, the mask design pattern is opened, and the pattern around the black dot is determined by comparing the mask design pattern.

[0016] Furthermore, the process of coating the pattern around the black spot with photoresist and leaving it for a preset time T1 specifically includes:

[0017] Dip the photoresist to coat the pattern within 5 cm around the black spot and leave it for a preset time T1;

[0018] When the distance between the black spot and the surrounding graphics is less than 0.5 mm from the black spot, the graphics within the surrounding range of the black spot are coated under a magnifying device.

[0019] Specifically, the coating thickness of the photoresist is 3-6 microns.

[0020] Specifically, the preset time T1 is 0.8-1.5 hours.

[0021] Further, applying the etching liquid to the black spots by dipping, leaving it for a preset time T2 until the black spots are removed, and then dipping it in deionized water to remove the etching liquid comprises:

[0022] When the distance between the black spot and the surrounding patterns is less than 1 mm from the black spot, the etching liquid is applied to the black spot by dipping, and after a preset time T2, the etching liquid is removed by dipping in deionized water.

[0023] Further, applying the etching liquid to the black spots by dipping, leaving it for a preset time T2 until the black spots are removed, and then dipping it with deionized water to remove the etching liquid further comprises:

[0024] When the distance between the black spot and the surrounding patterns is greater than or equal to 1 mm from the black spot, the etching liquid is applied to the black spot by dipping and wiping until the black spot is removed, and then the etching liquid is removed by dipping in deionized water.

[0025] Specifically, the preset time T2 is 8-15 minutes.

[0026] Beneficial effects of the technical solution of the present invention:

[0027] The process method for removing black spots from the mask of the embodiment of the present invention uses photoresist to directly coat around the large black spots. The photoresist can protect the pattern from being removed by the etching solution. The coating time is fast and can be completed in about 0.5 hours. After the photoresist is dried, the time is about 1 hour. The time for removing the large black spots using the etching solution is fast, about 10 minutes. The above-mentioned removal of the large black spots can reach 1mm from the pattern. If a magnifying device is used for observation, the pattern control distance can be within 0.5mm, which has good protection for the pattern, and there will be no error in the pattern removal, and the completion time can be controlled within 2 hours. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a flow chart of a method for removing black spots from a mask provided by an embodiment of the present invention;

[0029] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0030] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0031] Example 1

[0032] like Figure 1 As shown, an embodiment of the present invention provides a method for removing black spots from a mask, the method comprising:

[0033] S101, determining and marking the positions of each black dot on the mask, and determining the pattern around the black dot by comparing the mask design pattern;

[0034] S102, placing the mask plate parallel to the optical table, coating the pattern around the black spot with photoresist and leaving it for a preset time T1;

[0035] S103, covering and fixing the mask except the photoresist covered area and the black spots in sequence with a dust-free cloth and a protective film;

[0036] S104, applying the etching liquid to the black spots by dipping, leaving it for a preset time T2 until the black spots are removed, and then dipping it in deionized water to remove the etching liquid;

[0037] S105 , after removing the dust-free cloth and the protective film, use a photoresist stripping solution to remove the photoresist on the mask and rinse.

[0038] The steps of determining and marking the positions of the black dots on the mask, and determining the patterns around the black dots by comparing the mask design pattern specifically include:

[0039] In a darkroom, a spotlight is used to determine and mark the positions of each black dot on the mask, and at the same time, the mask design pattern is opened, and the pattern around the black dot is determined by comparing the mask design pattern.

[0040] The process of coating the pattern around the black spot with photoresist and leaving it for a preset time T1 specifically includes:

[0041] Dip the photoresist to coat the pattern within 5 cm around the black spot and leave it for a preset time T1;

[0042] When the distance between the black spot and the surrounding graphics is less than 0.5 mm from the black spot, the graphics within the surrounding range of the black spot are coated under a magnifying device.

[0043] During operation, use a cotton swab or a dipping stick to slowly apply photoresist to the pattern around the large black dot. For patterns that are less than 0.5mm away from the large black dot, you can use a 5X or 10X magnifying glass to apply precise positioning.

[0044] Just coat the pattern within 5cm around the big black dot. No bubbles or pinholes should appear. You can coat it thicker. After coating, leave it for 1H.

[0045] After leaving it for 1 hour, cover the other parts of the mask coated with photoresist with a dust-free cloth and add a layer of plastic film. The dust-free cloth and plastic film need to cover 1 cm more into the photoresist area and fix them with tape.

[0046] Specifically, the coating thickness of the photoresist is 3-6 microns.

[0047] Specifically, the preset time T1 is 0.8-1.5 hours.

[0048] The method of applying the etching liquid to the black spots by dipping, leaving the black spots for a preset time T2 until the black spots are removed, and then dipping the etching liquid with deionized water to remove the etching liquid comprises:

[0049] When the distance between the black spot and the surrounding patterns is less than 1 mm from the black spot, the etching liquid is applied to the black spot by dipping, and after a preset time T2, the etching liquid is removed by dipping in deionized water.

[0050] Wherein, applying the etching liquid to the black spots by dipping, leaving it for a preset time T2 until the black spots are removed, and then dipping it with deionized water to remove the etching liquid further comprises:

[0051] When the distance between the black spot and the surrounding patterns is greater than or equal to 1 mm from the black spot, the etching liquid is applied to the black spot by dipping and wiping until the black spot is removed, and then the etching liquid is removed by dipping in deionized water.

[0052] Specifically, the preset time T2 is 8-15 minutes.

[0053] When using, use a cotton swab dipped in etching solution to apply it to the large black spots, leave it for 10 minutes, and observe whether the large black spots have disappeared. If you want to speed up the removal time, you can use a cotton swab dipped in etching solution to gently wipe the large black spots. If it is less than 1mm away from the pattern, you can only soak it and cannot use a cotton swab to wipe it, so as not to scratch the photoresist and remove the pattern.

[0054] After the removal of the big black spots is completed, use a dust-free cloth dipped in deionized water (DI water) to carefully remove the etching solution. After the removal is completed, remove the dust-free cloth and plastic film covering it. Remove the mask and rinse it with water, and use photoresist stripping liquid or other methods to remove the photoresist. The removal of the big black spots is complete.

[0055] The process method for removing black spots from the mask of the embodiment of the present invention uses photoresist to directly coat around the large black spots. The photoresist can protect the pattern from being removed by the etching solution. The coating time is fast and can be completed in about 0.5 hours. After the photoresist is dried, the time is about 1 hour. The time for removing the large black spots using the etching solution is fast, about 10 minutes. The above-mentioned removal of the large black spots can reach 1mm from the pattern. If a magnifying device is used for observation, the pattern control distance can be within 0.5mm, which has good protection for the pattern, and there will be no error in the pattern removal, and the completion time can be controlled within 2 hours.

[0056] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0057] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0058] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, a magnetic disk, or an optical disk), and includes a number of instructions for enabling a terminal device (which can be a mobile phone, a computer, a server, an air conditioner, or a network device, etc.) to execute the methods described in each embodiment of the present invention.

[0059] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for removing black spots from a mask, characterized in that: The method comprises: Determine and mark the position of each black dot on the mask, and determine the pattern around the black dot by comparing it with the mask design pattern; The mask is placed parallel to the optical table, and the pattern around the black spot is coated with photoresist and left to stand for a preset time T1; Covering and fixing the mask except the photoresist covered area and the black spots in sequence with a dust-free cloth and a protective film; Applying the etching liquid to the black spots by dipping, leaving it for a preset time T2 until the black spots are removed, and then dipping it in deionized water to remove the etching liquid; After removing the dust-free cloth and the protective film, the photoresist of the mask is removed by using a photoresist stripping solution and then rinsed.

2. The method for removing black spots from a mask according to claim 1, characterized in that: The step of determining and marking the positions of the black dots on the mask, and determining the patterns around the black dots by comparing the mask design pattern specifically includes: In a darkroom, a spotlight is used to determine and mark the positions of each black dot on the mask, and at the same time, the mask design pattern is opened, and the pattern around the black dot is determined by comparing the mask design pattern.

3. The method for removing black spots from a mask according to claim 1, characterized in that: The process of coating the pattern around the black spot with photoresist and leaving it for a preset time T1 specifically includes: Dip the photoresist to coat the pattern within 5 cm around the black spot and leave it for a preset time T1; When the distance between the black spot and the surrounding graphics is less than 0.5 mm from the black spot, the graphics within the surrounding range of the black spot are coated under a magnifying device.

4. The method for removing black spots from a mask according to claim 3, characterized in that: The coating thickness of the photoresist is 3-6 microns.

5. The method for removing black spots from a mask according to claim 3, characterized in that: The preset time T1 is 0.8-1.5 hours.

6. The method for removing black spots from a mask according to claim 1, characterized in that: Applying the etching liquid to the black spots by dipping, leaving it for a preset time T2 until the black spots are removed, and then dipping it in deionized water to remove the etching liquid comprises: When the distance between the black spot and the surrounding patterns is less than 1 mm from the black spot, the etching liquid is applied to the black spot by dipping, and after a preset time T2, the etching liquid is removed by dipping in deionized water.

7. The method for removing black spots from a mask according to claim 1, characterized in that: Applying the etching liquid to the black spots by dipping, leaving it for a preset time T2 until the black spots are removed, and removing the etching liquid by dipping it in deionized water further comprises: When the distance between the black spot and the surrounding patterns is greater than or equal to 1 mm from the black spot, the etching liquid is applied to the black spot by dipping and wiping until the black spot is removed, and then the etching liquid is removed by dipping in deionized water.

8. The method for removing black spots from a mask according to claim 1, characterized in that: The preset time T2 is 8-15 minutes.

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