A photomask repair method and apparatus

Abstract

The present application relates to the field of photomask production, in particular to a photomask repairing method and device, the method comprising the following steps: scanning a photomask to be processed to obtain photomask image information; determining risk particle defects according to the photomask image information; determining etching areas corresponding to each of the risk particle defects according to a preset addressing rule; the etching areas are located in adjacent filling material patterns of the risk particle defects; etching the etching areas to obtain accommodation gaps; scraping the risk particle defects into the accommodation gaps by using a probe assembly; repairing the accommodation gaps to obtain a repaired photomask. The present application digs an accommodation gap in the filling material near the risk particle defects, and transfers the risk particle defects to the accommodation gap for filling, thereby avoiding destructive impact on the risk particle defects, and having strong controllability, good integrity of the filling material pattern, and greatly improved repairing efficiency and yield of the photomask.

Description

Technical Field

[0001] This invention relates to the field of photomask production, and in particular to a photomask repair method and apparatus. Background Technology

[0002] During the photomask production process, many granular defects often appear on the photomask. These defects may be particles left over from the early stages of the process or foreign dust. These defects will cover the pattern on the photomask that has been initially patterned, thus leading to a decrease in the quality of the photomask. Therefore, it is necessary to remove the above-mentioned granular defects through subsequent technical means.

[0003] As photomask manufacturing processes advance, the critical dimensions of photomasks decrease, but the size of particle defects does not decrease with process advancements. Therefore, on more advanced photomasks, particle defects become larger relative to the photomask pattern, and their boundaries become closer to, or even overlap with, the filler material pattern. Currently, particle defects at the edges of the filler material pattern on photomasks are typically repaired using focused electron beams combined with xenon difluoride etching (the etching repair refers to repairing the photomask, specifically removing particle defects). However, during etching removal, the closer the particle defects are to the filler material pattern, the more easily the edges of the filler material pattern are sputtered by the particle stream during the etching process. This often damages the normal pattern during particle defect repair, significantly increasing the repair difficulty. Furthermore, as the particle defect size approaches the minimum linewidth, hole-type particle repair will inevitably damage the normal pattern.

[0004] Therefore, how to develop a photomask repair method that does not damage the filling material pattern and is highly efficient is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to provide a photomask repair method and apparatus to solve the problems in the prior art of low repair efficiency for particle defects near the filling material pattern in photomasks, and damage to the filling material pattern.

[0006] To solve the above-mentioned technical problems, the present invention provides a photomask repair method, comprising:

[0007] Scan the photomask to be processed to obtain photomask image information;

[0008] Based on the photomask image information, risk particle defects are identified;

[0009] According to the preset addressing rules, the etching region corresponding to each of the risk particle defects is determined; the etching region is located in the filling material pattern adjacent to the risk particle defect;

[0010] The etched area is etched to obtain a receiving notch;

[0011] The risky particle defect is scraped into the containment opening using a probe assembly;

[0012] The reception gap is repaired to obtain a repaired photomask.

[0013] Optionally, in the photomask repair method, before etching the etched area to obtain the receiving notch, the method further includes:

[0014] Determine whether the width of the etched area in the direction of the line connecting the risk particle defect and the midpoint of the etched area does not exceed the first multiple of the width of the filling material pattern where the etched area is located in the direction of the line after removing the etched area;

[0015] Accordingly, the etched area is etched to obtain a receiving notch;

[0016] When the width of the etched area in the connecting direction does not exceed a first multiple of the width of the filling material pattern in the connecting direction after removing the etched area, the etched area is etched to obtain a receiving notch.

[0017] Optionally, in the photomask repair method, the first multiple ranges from 3 to 4 times, including the endpoint value.

[0018] Optionally, in the photomask repair method, determining the etching region corresponding to each of the risk particle defects according to a preset addressing rule includes:

[0019] Based on preset reference directions, determine the candidate filling material pattern that is closest to the risk particle defect in each of the preset reference directions;

[0020] Determine the width of each of the candidate filling material patterns in the corresponding reference direction;

[0021] The candidate fill material pattern with the largest width in the corresponding reference direction is determined as the fill material pattern to be etched;

[0022] The etching region corresponding to the risk particle defect is determined on the pattern of the filler material to be etched.

[0023] Optionally, in the photomask repair method, repairing the receiving gap includes:

[0024] The containment opening is filled with deposits to bury the risky particle defects.

[0025] Optionally, in the photomask repair method, the deposition of the receiving opening includes:

[0026] The receiving opening is deposited using a material identical to the filling material pattern.

[0027] Optionally, in the photomask repair method, etching the etched area to obtain the receiving notch includes:

[0028] The etched area is etched to completely remove the filling material pattern within the etched area, resulting in a receiving notch.

[0029] Optionally, in the photomask repair method, scraping the risky particle defect into the receiving opening using a probe assembly includes:

[0030] The risk particle defect is scraped into the containment opening by using a probe assembly that scrapes in the same direction.

[0031] Optionally, in the photomask repair method, the size of the receiving notch is at least 20% larger than the size of the corresponding risk particle defect.

[0032] A photomask repair apparatus is provided for performing the steps of any of the photomask repair methods described above.

[0033] The photomask repair method provided by this invention involves scanning the photomask to be processed to obtain photomask image information; identifying risk particle defects based on the photomask image information; determining the etching region corresponding to each risk particle defect according to a preset addressing rule; the etching region being located in the filling material pattern adjacent to the risk particle defect; etching the etching region to obtain a receiving notch; scraping the risk particle defect into the receiving notch using a probe assembly; and repairing the receiving notch to obtain a repaired photomask. This invention creates a receiving notch in the filling material near the risk particle defect and transfers the risk particle defect into the receiving notch for burial, avoiding destructive impacts on the risk particle defect. It offers strong controllability, effectively maintains the integrity of the filling material pattern on the photomask, and significantly improves the repair efficiency and product yield of the photomask. This invention also provides a photomask repair device with the above-mentioned beneficial effects. Attached Figure Description

[0034] To more clearly illustrate the technical solutions of the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 A flowchart illustrating a specific embodiment of the photomask repair method provided by the present invention;

[0036] Figures 2(a) and 2(b) are microscopic scans of risky particle defects in the photomask repair method provided by the present invention;

[0037] Figure 3 A schematic flowchart illustrating another specific embodiment of the photomask repair method provided by the present invention;

[0038] Figure 4 A process structure diagram of a specific embodiment of the photomask repair method provided by the present invention;

[0039] Figure 5 This is a flowchart illustrating another specific embodiment of the photomask repair method provided by the present invention.

[0040] The diagram includes 01 - risk particle defects, 02 - etched areas, and 03 - filling material pattern. Detailed Implementation

[0041] To enable those skilled in the art to better understand the present invention, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] The core of this invention is to provide a photomask repair method, the flowchart of one specific implementation of which is shown below. Figure 1 As shown, this is referred to as Specific Implementation Method One, which includes:

[0043] S101: Scan the photomask to be processed to obtain photomask image information.

[0044] The photomask image information, also known as the surface image of the photomask to be processed, includes the location information of the particle defects.

[0045] S102: Determine the risk particle defect based on the photomask image information.

[0046] The risk particle defect refers to a particle defect that is close to or near the filling material pattern, as shown in Figure 2(a). The particle defect in Figure 2(a) coincides with or even overlaps with the edge of the filling material pattern, as shown in Figure 2(b).

[0047] S103: Determine the etching region corresponding to each of the risk particle defects according to the preset addressing rules; the etching region is located in the filling material pattern adjacent to the risk particle defect.

[0048] The etching region is located near the risk particle defect, and the etching region is located in the filler material pattern adjacent to the risk particle defect, that is, the risk particle defect can reach the etching region without any obstruction.

[0049] The structure of the photomask is to set an opaque filling material pattern on a transparent substrate, thereby forming various light-transmitting shapes and realizing the function of a mask.

[0050] S104: Etch the etched area to obtain a receiving notch.

[0051] The etched area should completely overlap with the containment opening, and the containment opening should face the risk particle defect.

[0052] S105: Use the probe assembly to scrape the risk particle defect into the containment opening.

[0053] The probe assembly can be a probe-type repair device or other equipment. In this step, the probe assembly is used to poke, scrape, or push the risk particle defect into the containment opening one by one.

[0054] S106: Repair the receiving gap to obtain a repaired photomask.

[0055] The repair in this step refers to the restoration of the filling material pattern where the receiving gap is located, and the reset of the part of the filling material pattern that was lost in the previous steps, so that the filling material pattern is restored to the preset shape.

[0056] In a preferred embodiment, repairing the receiving gap includes:

[0057] The containment opening is filled with deposits to bury the risky particle defects.

[0058] In this preferred embodiment, deposition technology is used to fill the risky particle defects that enter the containment gap. The deposition uniformity is high, the operation is easy, and the cost is low. Of course, other methods can also be used to repair the containment gap, and the present invention does not limit them.

[0059] Additionally, the deposition of material into the containment opening includes:

[0060] The receiving opening is deposited using a material identical to the filling material pattern.

[0061] In this preferred embodiment, the material used to fill the receiving gap is further specified to be the same as the original material of the filling material pattern, which improves the structural strength and shape preservation ability of the repaired filling material pattern, that is, improves the working stability of the photomask.

[0062] In addition, etching the etched area to obtain the receiving notch includes:

[0063] The etched area is etched to completely remove the filling material pattern within the etched area, resulting in a receiving notch.

[0064] In this preferred embodiment, the opening of the receiving notch is further defined, and the filling material pattern in the etched area is completely etched away. After the filling material pattern in the etched area is completely etched away, the bottom surface inside the receiving notch exposes the transparent substrate of the photomask. This allows risk particle defects located directly on the transparent substrate to roll into the receiving notch without any height difference, making it easier to scrape the risk particle defects subsequently, thus improving the repair success rate and ultimately improving repair efficiency and repair success rate.

[0065] Furthermore, the step of scraping the risky particle defect into the containment opening using the probe assembly includes:

[0066] The risk particle defect is scraped into the containment opening by using a probe assembly that scrapes in the same direction.

[0067] In this preferred embodiment, the probe assembly is limited to scraping the risk particle defect in only one direction, which can prevent the probe assembly from accidentally scraping in a direction outside the design and causing damage to the filling material pattern, thereby improving the yield of finished products.

[0068] In one specific implementation, the size of the containment notch is at least 20% larger than the size of the corresponding risk particle defect.

[0069] If the risk particle defect is approximately circular with a diameter of 20 nanometers, then the size of its corresponding receiving notch should be at least 24 nanometers. Preferably, the receiving notch is rectangular, as this significantly reduces production difficulty. Designing the receiving notch to be slightly larger than the risk particle defect provides greater tolerance for its transfer, improving yield and repair efficiency. The above parameter ranges are optimized ranges based on extensive theoretical calculations and practical testing. Of course, adjustments can be made according to actual circumstances, and this invention does not impose limitations on them.

[0070] The photomask repair method provided by this invention involves scanning the photomask to be processed to obtain photomask image information; identifying risk particle defects based on the photomask image information; determining the etching region corresponding to each risk particle defect according to a preset addressing rule; the etching region being located in the filling material pattern adjacent to the risk particle defect; etching the etching region to obtain a receiving notch; scraping the risk particle defect into the receiving notch using a probe assembly; and repairing the receiving notch to obtain a repaired photomask. This invention creates a receiving notch in the filling material near the risk particle defect and transfers the risk particle defect into the receiving notch for burial, avoiding destructive impacts on the risk particle defect. It offers strong controllability, effectively maintains the integrity of the filling material pattern on the photomask, and significantly improves the repair efficiency and product yield of the photomask.

[0071] Based on Specific Implementation Method 1, the method for determining the location of the receiving opening is further specified, resulting in Specific Implementation Method 2, the corresponding flowchart of which is shown below. Figure 3 As shown, it includes:

[0072] S201: Scan the photomask to be processed to obtain photomask image information.

[0073] S202: Determine the risk particle defect based on the photomask image information.

[0074] S203: Determine the etching region corresponding to each of the risk particle defects according to the preset addressing rules; the etching region is located in the filling material pattern adjacent to the risk particle defect.

[0075] S204: Determine whether the width of the etched area in the direction of the line connecting the risk particle defect and the midpoint of the etched area does not exceed the first multiple of the width of the filling material pattern where the etched area is located in the direction of the line after removing the etched area.

[0076] You can refer to this. Figure 4 , Figure 4The line connecting the risk particle defect and the midpoint of the etched area is represented by a dashed line. In the figure, 01 represents the risk particle defect, 02 represents the etched area (which has the same position and size as the subsequent containment notch), 03 represents the filling material pattern, A represents the width of the etched area in the direction of the line connecting the midpoint of the risk particle defect and the etched area, and B represents the width of the filling material pattern containing the etched area in the direction of the line after removing the etched area.

[0077] S205: When the width of the etched area in the connecting line direction does not exceed a first multiple of the width of the filling material pattern where the etched area is located in the connecting line direction after removing the etched area, the etched area is etched to obtain a receiving notch.

[0078] S206: Use the probe assembly to scrape the risky particle defect into the containment opening.

[0079] S207: Repair the receiving gap to obtain a repaired photomask.

[0080] The difference between this specific embodiment and the above specific embodiment is that this specific embodiment adds a step to check whether the etched area can be etched. The remaining steps are the same as those in the above specific embodiment, and will not be described in detail here.

[0081] In this preferred embodiment, the etched area was checked. Specifically, since the technical solution provided by this invention requires opening a notch in the filling material pattern, it is necessary to ensure that the filling material pattern remains intact and structurally sound after the notch is opened. In terms of parameters, the remaining filling material pattern after the notch is opened cannot become too thin, resulting in an unstable structure. Therefore, in this specific embodiment, after determining the etched area according to the addressing rules, it first checks whether the width of the remaining part of the material filling pattern after removing the etched area is sufficient. In other words, whether the remaining part satisfies the proportional relationship of the etched area. If the size of the etched area does not exceed the first multiple of the width of the remaining part, it indicates that the remaining part of the filling material pattern can maintain a complete structure, greatly improving the yield of the finished product.

[0082] Specifically, the range of the first multiple is 3 to 4 times, including endpoint values ​​such as 3.0 times, 3.5 times, or 4.0 times. The above range is obtained after extensive theoretical calculations and practical verification. Of course, it can be adjusted according to the actual situation, and this invention does not limit it.

[0083] Based on Implementation Method 1, the addressing rules are further defined to obtain Implementation Method 3, the corresponding flowchart of which is shown below. Figure 5 As shown, it includes:

[0084] S301: Scan the photomask to be processed to obtain photomask image information.

[0085] S302: Determine the risk particle defect based on the photomask image information.

[0086] S303: Based on the preset reference directions, determine the candidate filling material pattern that is closest to the risk particle defect in each of the reference directions.

[0087] The reference direction can be selected according to actual needs. For example, if a rectangular coordinate system is established in the photomask image information, the reference direction is the positive and negative four directions of the x-axis and y-axis. Of course, other reference directions can also be selected according to actual conditions. This invention does not make specific limitations here.

[0088] S304: Determine the width of each of the candidate fill material patterns in the corresponding reference direction.

[0089] The candidate filling material pattern is the first filling material pattern encountered by the risk particle defect in the corresponding reference direction. Therefore, the reference direction should correspond one-to-one with the candidate filling material pattern. The width in this step is the intercept of the candidate filling material pattern in the corresponding reference direction.

[0090] S305: Determine the candidate fill material pattern with the largest width in the corresponding reference direction as the fill material pattern to be etched.

[0091] S306: Determine the etching region corresponding to the risk particle defect on the pattern of the filler material to be etched.

[0092] S307: Etch the etched area to obtain a receiving notch.

[0093] S308: Use the probe assembly to scrape the risky particle defect into the containment opening.

[0094] S309: Repair the receiving gap to obtain a repaired photomask.

[0095] The difference between this specific implementation method and the above specific implementation method is that this specific implementation method provides an addressing rule, while the remaining steps are the same as those in the above specific implementation method, and will not be elaborated here.

[0096] In this preferred embodiment, the candidate filler material pattern with the largest width in the reference direction is selected as the filler material pattern to be etched, and the etching area is set on the filler material pattern to be etched. This ensures that after the receiving notch is opened, the remaining width of the filler material pattern to be etched is maximized, making it least likely to break or be damaged, thereby further improving the yield of the finished product. Of course, specific embodiments two and three of the present invention can be used in combination, and will not be elaborated further here.

[0097] This invention also provides a photomask repair apparatus for performing the steps of any of the photomask repair methods described above. The photomask repair method provided by this invention involves scanning the photomask to be processed to obtain photomask image information; identifying risk particle defects based on the photomask image information; determining the etching region corresponding to each risk particle defect according to a preset addressing rule; the etching region being located in the filling material pattern adjacent to the risk particle defect; etching the etching region to obtain a receiving notch; scraping the risk particle defect into the receiving notch using a probe assembly; and repairing the receiving notch to obtain a repaired photomask. This invention creates a receiving notch in the filling material near the risk particle defect and transfers the risk particle defect into the receiving notch for burial, avoiding destructive impacts on the risk particle defect, providing strong controllability, and effectively maintaining the integrity of the filling material pattern on the photomask, greatly improving the repair efficiency and product yield of the photomask.

[0098] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to in the method section.

[0099] It should be noted that, in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0100] The photomask repair method and apparatus provided by this invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the embodiments above are merely for the purpose of helping to understand the method and core ideas of this invention. It should be noted that those skilled in the art can make various improvements and modifications to this invention without departing from its principles, and these improvements and modifications also fall within the protection scope of the claims of this invention.

Claims

1. A method for repairing photomasks, characterized in that, include: Scan the photomask to be processed to obtain photomask image information; Based on the photomask image information, risk particle defects are identified; According to the preset addressing rules, the etching area corresponding to each of the risk particle defects is determined; The etched area is located in the filler material pattern adjacent to the risk particle defect; The etched area is etched to obtain a receiving notch; The risky particle defect is scraped into the containment opening using a probe assembly; The reception gap is repaired to obtain a repaired photomask.

2. The photomask repair method as described in claim 1, characterized in that, Before etching the etched area to obtain the receiving notch, the process further includes: Determine whether the width of the etched area in the direction of the line connecting the risk particle defect and the midpoint of the etched area does not exceed the first multiple of the width of the filling material pattern where the etched area is located in the direction of the line after removing the etched area; Accordingly, the etched area is etched to obtain a receiving notch; When the width of the etched area in the connecting direction does not exceed a first multiple of the width of the filling material pattern in the connecting direction after removing the etched area, the etched area is etched to obtain a receiving notch.

3. The photomask repair method as described in claim 2, characterized in that, The first multiple ranges from 3 to 4 times, including the endpoint values.

4. The photomask repair method as described in claim 1, characterized in that, The step of determining the etching region corresponding to each of the risk particle defects according to the preset addressing rules includes: Based on preset reference directions, determine the candidate filling material pattern that is closest to the risk particle defect in each of the preset reference directions; Determine the width of each of the candidate filling material patterns in the corresponding reference direction; The candidate fill material pattern with the largest width in the corresponding reference direction is determined as the fill material pattern to be etched; The etching region corresponding to the risk particle defect is determined on the pattern of the filler material to be etched.

5. The photomask repair method as described in claim 1, characterized in that, The repair of the containment gap includes: The containment opening is filled with deposits to bury the risky particle defects.

6. The photomask repair method as described in claim 5, characterized in that, The deposition of the containment opening includes: The receiving opening is deposited using a material identical to the filling material pattern.

7. The photomask repair method as described in claim 1, characterized in that, The etching of the etched area to obtain the receiving notch includes: The etched area is etched to completely remove the filling material pattern within the etched area, resulting in a receiving notch.

8. The photomask repair method as described in claim 1, characterized in that, The step of scraping the risky particle defect into the containment opening using a probe assembly includes: The risk particle defect is scraped into the containment opening by using a probe assembly that scrapes in the same direction.

9. The photomask repair method as described in claim 1, characterized in that, The size of the containment opening is at least 20% larger than the size of the corresponding risk particle defect.

10. A photomask repair device, characterized in that, The photomask repair apparatus is used to perform the steps of the photomask repair method as described in any one of claims 1 to 9.

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