Method for removing residual Cr layer on photomask surface

Abstract

The present application provides a method for removing the residual Cr layer on the surface of a photomask, which relates to the technical field of photomask surface treatment. The method adopts a repairing machine, and includes the following steps: S1, placing the photomask on the repairing machine; S2, performing ESB signal detection on the surface of the photomask to obtain the ESB signal value; S3, reading the signal value of the Cr layer according to the difference in the ESB signal value of different metal layers; S4, obtaining the corresponding position of the Cr layer according to the signal value of the Cr layer; S5, etching the corresponding position of the Cr layer, repairing the surface of the photomask, and removing the residual Cr layer on the surface of the photomask. Through the above steps, the residual Cr layer of the photomask can be removed on the repairing machine, eliminating the secondary exposure process of the photomask, and reducing the loading time of the exposure machine and the process machine.

Description

Technical Field

[0001] The present application relates to the technical field of photomask surface treatment, and in particular to a method for removing residual Cr layer on the surface of a photomask. Background Art

[0002] During the photomask production process, the photomask must first be exposed on a photosensitive quartz substrate through an exposure machine, and then developed and etched to form extremely fine patterns of light-transmitting and opaque patterns on the surface of the photomask. The opaque patterns are the remaining metal layers.

[0003] Current production methods are likely to leave a Cr layer on the photomask surface. If this Cr layer remains in key locations, it can cause CD variations in those patterns, impacting the CD on the wafer. However, there's currently no effective treatment for this Cr layer on the photomask surface. This typically requires a secondary exposure process, which results in long loading times for both the exposure and processing equipment.

[0004] Therefore, a new method for removing the Cr layer on the surface of the photomask is needed, which can remove the residual Cr layer on the surface of the photomask on other machines, eliminating the secondary exposure process of the photomask and reducing the loading time of the exposure machine and the process machine. Summary of the Invention

[0005] In view of this, an embodiment of this specification provides a method for removing the residual Cr layer on the surface of a photomask, which can remove the residual Cr layer on a repair machine, eliminating the secondary exposure process of the photomask and reducing the loading time of the exposure machine and the process machine.

[0006] The embodiments of this specification provide the following technical solutions:

[0007] The embodiment of this specification provides a method for removing Cr layer residue on the surface of a photomask, using a repair machine, including the following steps:

[0008] S1, placing the photomask on the repair machine;

[0009] S2, performing ESB signal detection on the photomask surface to obtain an ESB signal value;

[0010] S3, reading the signal value of the Cr layer according to the difference in ESB signal values ​​of different metal layers;

[0011] S4, obtaining the corresponding position of the Cr layer according to the signal value of the Cr layer;

[0012] S5, etching the corresponding position of the Cr layer, repairing the surface of the photomask, and removing the residual Cr layer on the surface of the photomask.

[0013] Through the above technical solution, a repair machine is used to detect the surface of the photomask to obtain the ESB signal value. According to the difference in the ESB signal value of each metal layer, the signal value of the Cr layer is obtained. According to the acquisition position of the Cr layer signal value, the corresponding position of the residual Cr layer on the photomask surface is obtained, and the residual Cr layer is removed by etching, thereby eliminating the secondary exposure process. The entire Cr layer removal process is carried out on the repair machine, does not occupy the exposure machine and the process machine, reduces the loading time of the exposure machine and the process machine, and at the same time improves the utilization rate of different machines and improves the production efficiency of the photomask.

[0014] Preferably, between step S1 and step S2, there is further provided step S100:

[0015] The standard signal value of each metal layer is set so that the standard signal value of each metal layer is greater than 10.

[0016] Through the above technical solution, the standard signal value of each metal layer is amplified, and the difference in ESB signal value of each metal layer is increased. Therefore, by reading the ESB signal value, the ESB signal value of the Cr layer can be quickly obtained according to the large fluctuations in the ESB signal value, thereby quickly determining the position of the Cr layer and improving the efficiency of confirming the position of the Cr layer.

[0017] Preferably, step S5 further includes:

[0018] During the etching process, the change of the ESB signal value is observed, and etching is stopped once a sudden change in the ESB signal value occurs.

[0019] Through the above technical solution, etching is stopped once a sudden change in the ESB signal value occurs, which can ensure that the main pattern on the photomask is not affected by etching and ensure the yield rate of the photomask during the repair process.

[0020] Preferably, the Cr layer is etched using plasma gas.

[0021] The present invention also provides a method for removing the residual Cr layer on the surface of a PSM photomask. The surface of the PSM photomask includes a MoSi layer and a Cr layer. A repair machine is used. The steps are as follows:

[0022] S101, placing the PSM photomask on a repair machine;

[0023] S201, performing ESB signal detection on the PSM photomask surface, ESB signal value;

[0024] S301, based on the difference in ESB signal values ​​between the Mosi layer and the Cr layer, read the signal value of the Cr layer;

[0025] S401, determining a corresponding position of the Cr layer according to a signal value related to the Cr layer;

[0026] S501 , etching the corresponding position of the Cr layer, repairing the surface of the PSM photomask, and removing the residual Cr layer on the surface of the PSM photomask.

[0027] Through the above technical solution, a repair machine is used to detect the surface of the PSM photomask to obtain an ESB signal value. According to the difference in the ESB signal value between the Mosi layer and the Cr layer, the signal value of the Cr layer is obtained. According to the acquisition position of the Cr layer signal value, the corresponding position of the residual Cr layer on the surface of the PSM photomask is obtained, and the residual Cr layer is removed by etching, thereby eliminating the secondary exposure process. The entire Cr layer removal process is carried out on the repair machine, does not occupy the exposure machine and the process machine, reduces the loading time of the exposure machine and the process machine, and at the same time improves the utilization rate of different machines, thereby improving the production efficiency of the PSM photomask.

[0028] Preferably, between step S101 and step S201, there is further provided step S1001:

[0029] Set the standard signal values ​​of the Mosi layer and the Cr layer so that the standard signal values ​​of the Mosi layer and the Cr layer are both greater than 10.

[0030] Preferably, step S501 further includes:

[0031] During the etching process, the changes in the ESB signal value of the repair machine are observed. Once a sudden change in the ESB signal value occurs, etching is stopped.

[0032] Preferably, the Cr layer is etched using fluorine-containing plasma gas.

[0033] Compared with the prior art, the at least one technical solution adopted in the embodiments of this specification can achieve the following beneficial effects:

[0034] The surface of the photomask is detected by a repair machine to obtain an ESB signal value. Based on the differences in the ESB signal values ​​of each metal layer, the signal value of the Cr layer is obtained. Based on the acquisition position of the Cr layer signal value, the corresponding position of the residual Cr layer on the photomask surface is obtained. The residual Cr layer is removed by etching, thereby eliminating the need for a secondary exposure process. The entire Cr layer removal process is carried out on the repair machine, without occupying the exposure machine and the process machine, reducing the loading time of the exposure machine and the process machine, while improving the utilization rate of different machines and enhancing the production efficiency of the photomask. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0036] Figure 1 This is a flow chart of a method for removing residual Cr layer on the surface of a photomask in this application;

[0037] Figure 2 This is a graph showing changes in the ESB signal obtained by performing ESB signal detection on the photomask repair machine in this application;

[0038] Figure 3 This is a flow chart of a method for removing residual Cr layer on the surface of a PSM photomask in this application. DETAILED DESCRIPTION

[0039] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0040] The following describes the embodiments of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, in the absence of conflict, the features in the following embodiments and embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of this application.

[0041] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on this application, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number and aspect described herein can be used to implement an apparatus and / or practice a method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this apparatus and / or practice this method.

[0042] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present application. The illustrations only show components related to the present application and are not drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component can be changed at will, and the component layout type may also be more complicated.

[0043] Additionally, in the following description, specific details are provided to provide a thorough understanding of the examples, however, one skilled in the art will appreciate that the examples can be practiced without these specific details.

[0044] During the photomask production process, the photomask must first be exposed on a photosensitive quartz substrate through an exposure machine, and then developed and etched to form extremely fine patterns of light-transmitting and opaque patterns on the surface of the photomask. The opaque patterns are the remaining metal layers.

[0045] Current production methods are likely to leave a Cr layer on the photomask surface. If this Cr layer remains in key locations, it can cause CD variations in those patterns, impacting the CD on the wafer. However, there's currently no effective treatment for this Cr layer on the photomask surface. This typically requires a secondary exposure process, which results in long loading times for both the exposure and processing equipment.

[0046] Based on this, the embodiment of this specification proposes a method for removing the residual Cr layer on the surface of the photomask, which can remove the residual Cr layer on a repair machine, eliminating the secondary exposure process of the photomask and reducing the loading time of the exposure machine and the process machine.

[0047] The following describes the technical solutions provided by various embodiments of the present application in conjunction with the accompanying drawings.

[0048] like Figure 1 As shown, the embodiment of this specification provides a method for removing the Cr layer residue on the surface of a photomask, using a repair machine, including the following steps:

[0049] S1, placing the photomask on the repair machine.

[0050] S2, performing ESB signal detection on the surface of the photomask to obtain an ESB signal value.

[0051] S3, reading the signal value of the Cr layer according to the difference in ESB signal values ​​of different metal layers.

[0052] S4, obtaining the corresponding position of the Cr layer according to the signal value of the Cr layer.

[0053] S5, etching the corresponding position of the Cr layer to repair the surface of the photomask and remove the residual Cr layer on the surface of the photomask. The Cr layer is etched using plasma gas.

[0054] like Figure 2 As shown, in actual application, the repair machine is used to read the ESB signal value on the surface of the photomask, and the signal value of the Cr layer is obtained according to the difference in the ESB signal value of each metal layer. According to the acquisition position of the Cr layer signal value, the corresponding position of the residual Cr layer on the photomask surface is obtained, and the residual Cr layer is removed by etching, thereby eliminating the secondary exposure process. The entire Cr layer removal process is carried out on the repair machine, and does not occupy the exposure machine and the process machine, reducing the loading time of the exposure machine and the process machine, while improving the utilization rate of different machines and improving the production efficiency of the photomask.

[0055] Furthermore, between step S1 and step S2, there is a step S100:

[0056] The standard signal value of each metal layer is set so that the standard signal value of each metal layer is greater than 10.

[0057] Specifically, by amplifying the standard signal value of each metal layer, the difference in the ESB signal value of each metal layer can be increased. Therefore, in the process of reading the ESB signal value, the ESB signal value corresponding to the Cr layer can be quickly obtained according to the large fluctuations in the ESB signal value, thereby quickly determining the position of the Cr layer, improving the efficiency of confirming the position of the Cr layer, and facilitating the subsequent etching of the Cr layer.

[0058] Wherein, S100 may also be set before step S1.

[0059] Furthermore, step S5 further includes:

[0060] During the etching process, the change of the ESB signal value is observed, and etching is stopped once a sudden change in the ESB signal value occurs.

[0061] Among them, the sudden change of the ESB signal value indicates that the Cr layer at the current position has been basically etched. Stopping the etching in time can effectively prevent the etching of the main pattern on the photomask and maintain the integrity of the main pattern.

[0062] The embodiment of this specification also proposes a method for removing the residual Cr layer on the surface of the PSM photomask, such as Figure 3 As shown, the surface of the PSM photomask includes a MoSi layer and a Cr layer. A repair machine is used, and the steps are as follows:

[0063] S101, placing the PSM photomask on a repair machine.

[0064] S201, performing ESB signal detection on the surface of the PSM photomask, and obtaining an ESB signal value.

[0065] S301 : Reading the signal value of the Cr layer according to the difference in ESB signal values ​​between the Mosi layer and the Cr layer.

[0066] S401 : Determine a corresponding position of the Cr layer according to a signal value related to the Cr layer.

[0067] S501, etching the corresponding position of the Cr layer to repair the surface of the PSM photomask and remove the residual Cr layer on the surface of the PSM photomask. The Cr layer is etched using fluorine-containing plasma gas.

[0068] In actual application, since the surface of the PSM photomask includes MoSi and Cr layers, and the ESB signal values ​​obtained by ESB signal detection on the repair machine differ between the MoSi and Cr layers, this difference in ESB signal values ​​can be exploited to quickly determine whether the current area is a Cr layer based on the ESB signal value when scanning the area where the Cr layer is located. The Cr layer can then be removed by etching. The entire process is carried out on the repair machine, so it does not occupy the exposure machine and process machine, reducing the loading time of the exposure machine and process machine, while improving the utilization rate of different machines and enhancing the production efficiency of PSM photomasks.

[0069] Furthermore, between step S101 and step S201, there is further provided step S1001:

[0070] Set the standard signal values ​​of the Mosi layer and the Cr layer so that the standard signal values ​​of the Mosi layer and the Cr layer are both greater than 10.

[0071] Specifically, by amplifying the standard signal values ​​of the Mosi layer and the Cr layer, the difference in the ESB signal value between the Mosi layer and the Cr layer can be increased. Therefore, in the process of reading the ESB signal value, the ESB signal value corresponding to the Cr layer can be quickly obtained according to the large fluctuations in the ESB signal value, thereby quickly determining the position of the Cr layer, improving the efficiency of confirming the position of the Cr layer, and facilitating subsequent etching of the Cr layer.

[0072] Furthermore, step S501 further includes:

[0073] During the etching process, the changes in the ESB signal value of the repair machine are observed. Once a sudden change in the ESB signal value occurs, etching is stopped.

[0074] Among them, the sudden change of the ESB signal value indicates that the Cr layer at the current position has been basically etched. Stopping the etching in time can effectively prevent the etching of the main pattern on the photomask and maintain the integrity of the main pattern.

[0075] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments.

[0076] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A method for removing residual Cr layer on the surface of a photomask, characterized in that: The repair machine is used, including the following steps: S1, placing the photomask on the repair machine; S2, performing ESB signal detection on the surface of the photomask to obtain an ESB signal value; S3, reading the signal value of the Cr layer according to the difference in ESB signal values ​​of different metal layers; S4, obtaining the corresponding position of the Cr layer according to the signal value of the Cr layer; S5, etching the corresponding position of the Cr layer, repairing the surface of the photomask, and removing the residual Cr layer on the surface of the photomask.

2. The method for removing the residual Cr layer on the surface of the photomask according to claim 1, characterized in that: Between step S1 and step S2, step S100 is further provided: The standard signal value of each metal layer is set so that the standard signal value of each metal layer is greater than 10.

3. The method for removing the residual Cr layer on the surface of the photomask according to claim 2, characterized in that: The step S5 further comprises: During the etching process, the change of the ESB signal value is observed, and once a sudden change in the ESB signal value occurs, etching is stopped.

4. The method for removing the residual Cr layer on the surface of the photomask according to claim 1, characterized in that: The Cr layer is etched using plasma gas.

5. A method for removing the residual Cr layer on the surface of a PSM photomask, characterized in that: The surface of the PSM photomask includes a MoSi layer and a Cr layer. The repair machine is used. The steps are as follows: S101, placing the PSM photomask on a repair machine; S201, performing ESB signal detection on the surface of the PSM photomask to obtain an ESB signal value; S301, according to the difference in ESB signal values ​​between the Mosi layer and the Cr layer, read out the signal value of the Cr layer; S401, determining a corresponding position of the Cr layer according to a signal value related to the Cr layer; S501, etching the corresponding position of the Cr layer, repairing the surface of the PSM photomask, and removing the residual Cr layer on the surface of the PSM photomask.

6. The method for removing the residual Cr layer on the surface of the PSM photomask according to claim 5, characterized in that: Between step S101 and step S201, step S1001 is further provided: Set the standard signal values ​​of the Mosi layer and the Cr layer so that the standard signal values ​​of the Mosi layer and the Cr layer are both greater than 10.

7. The method for removing the residual Cr layer on the surface of the PSM photomask according to claim 5, characterized in that: Step S501 also includes: During the etching process, the changes in the ESB signal value of the repair machine are observed. Once a sudden change in the ESB signal value occurs, etching is stopped.

8. The method for removing the residual Cr layer on the surface of the PSM photomask according to claim 5, characterized in that: The Cr layer is etched using a fluorine-containing plasma gas.

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