CN118276399A - Photomask defect repairing method and photomask - Google Patents

Abstract

The invention discloses a photomask defect repairing method and a photomask, wherein the photomask defect repairing method comprises the steps of obtaining defect position coordinate information of a defect part in the photomask; acquiring graphic position information based on the defect position coordinate information, wherein the graphic position information is the position information of an exposure graphic corresponding to the defect position coordinate information in an original design graphic; acquiring and determining a repair area based on the graphic position information, and redesigning an exposure area and an exposure file based on the repair area; spin-coating photoresist on the photomask, and exposing the repair area based on the exposure area and the exposure file; and developing and etching the repair area in sequence. The invention can repair various defects, and solves the problem that the existing chromium residual defect repairing method cannot remove the chromium residual defects caused by various conditions.

Description

Photomask defect repairing method and photomask

Technical Field

The invention relates to the technical field of semiconductor chip manufacturing process, and in particular to a photomask defect repairing method and a photomask.

Background technique

Photomask production is a very important module in the chip manufacturing process. As shown in Figure 1, during the photomask manufacturing process, due to the influence of process, equipment, environment, etc., metal chromium residual defects may be left on the photomask. If this defect is not processed, it will affect the circuit performance of the chip.

In the prior art, the common method of repairing chromium residue defects is to use a special repair machine to repair the photomask, and the application scenario is relatively single. As shown in Figure 2, when the number of chromium residue defects is large and the size is large, the repair machine cannot handle it, and the repair effect of the repair machine for positive film mask (PSM) chromium residue is not good.

Based on this, a new technical solution is needed to remove the chromium residual defects caused by various conditions and ensure the photomask yield.

Summary of the invention

In view of this, an embodiment of the present invention provides a photomask defect repairing method and a photomask, so as to at least solve the problem that the existing chromium residual defect repairing method cannot remove the chromium residual defects caused by various conditions.

The embodiment of the present invention provides the following technical solutions:

An embodiment of the present invention provides a photomask defect repairing method, comprising:

Obtaining defect position coordinate information of defects in the photomask;

Acquiring pattern position information based on the defect position coordinate information, wherein the pattern position information is position information of an exposure pattern corresponding to the defect position coordinate information in an original design pattern;

Acquire and determine a repair area based on the graphic position information, and redesign an exposure area and an exposure file based on the repair area;

Spin-coating photoresist on the photomask, and exposing the repair area based on the exposure area and the exposure file;

The repair area is developed and etched in sequence.

Furthermore, after developing and etching the repairing area in sequence, excess photoresist on the photomask is removed.

Furthermore, the defects in the photosensitive membrane are chromium residual defects.

Further, acquiring the graphic position information based on the defect position coordinate information includes:

Based on the defect position coordinate information, the graphic position information is acquired through a data processing method.

Furthermore, defect position coordinate information of defects in the photomask is obtained based on the inspection machine.

Furthermore, an exposure machine is used to expose the repair area based on the exposure area and the exposure file.

Furthermore, the exposure machine is a photolithography machine.

An embodiment of the present invention further provides a photomask, wherein the photomask is obtained by any of the above-mentioned photomask defect repairing methods.

Compared with the prior art, the at least one technical solution adopted in the embodiment of the present invention can achieve the following beneficial effects:

A photomask defect repairing method of the present invention obtains defect position coordinate information of a defect in a photomask; obtains graphic position information based on the defect position coordinate information, wherein the graphic position information is position information of an exposure graphic corresponding to the defect position coordinate information in an original design graphic; obtains and determines a repairing area based on the graphic position information, and redesigns an exposure area and an exposure file based on the repairing area; spin-coats photoresist on the photomask, and exposes the repairing area based on the exposure area and the exposure file; and sequentially develops and etches the repairing area, thereby being able to repair a variety of defects and solving the problem that the existing chromium residual defect repairing method cannot remove the chromium residual defects caused by a variety of conditions.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. 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 paying creative work.

FIG1 shows a common chromium residual defect in an existing photomask;

FIG2 is an image of a circuit with chromium residual defects in the prior art;

FIG3 is a flow chart of a photomask defect repairing method according to an embodiment of the present invention;

FIG4 is a schematic diagram of the inspection machine locating the chromium residue position in an embodiment of the present invention;

FIG5 is a schematic diagram of repairing chromium residual defects by re-exposure of the defective part by designing the repair area in an embodiment of the present invention;

FIG6 is a schematic flow chart of a photomask defect repairing method according to an embodiment of the present invention;

FIG. 7 is a comparison diagram of the chromium residual defect before and after repair according to an embodiment of the present invention.

Detailed ways

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

The following describes the implementation methods of the present application through specific 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 implementation methods, 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 following embodiments and the features in the embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present application.

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 the present 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 the device and/or practice the method. In addition, other structures and/or functionalities other than one or more of the aspects described herein can be used to implement this device and/or practice this method.

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 drawings only show components related to the present application rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

Additionally, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, it will be understood by those skilled in the art that the embodiments may be practiced without these specific details.

Photomask production is a very important module in the entire chip manufacturing process, and the cost of manufacturing a photomask is also very expensive. A usable phase-shift mask costs tens of thousands of dollars. During the photomask manufacturing process, due to the influence of process, equipment, environment, etc., metal chromium residual defects may be left on the photomask. If this defect is not treated, it will affect the circuit performance of the chip.

The cycle from exposure to finished product of photomask is relatively long. It takes more than 10 hours for an ordinary binary mask to go from exposure to finished product. The phase-shift mask process is more complicated and requires longer production time. If it is not repaired, it will be scrapped, which not only increases production costs but also affects product delivery time.

As shown in FIG1 , FIG1 shows the chromium residual defects that may be generated in the photomask manufacturing process. In FIG1 , Disconnect is a line break defect, which means that there is no effective connection point between two parts that should be connected in the mask group, resulting in a missing connection; Intrusion is an intrusion defect, which means that the excess part or impurities that should not exist in the mask pattern enter the interior of the pattern; Short is a short circuit defect, which means that there is an erroneous connection between two parts that should not be connected in the mask pattern, resulting in an unexpected short circuit; Pinhole is a pinhole defect, which refers to a tiny hole in the mask pattern, which may cause incomplete light transmission during the photolithography process, resulting in an incomplete or unclear pattern; Pin dot is a pin point defect, which refers to a tiny dot defect in the mask pattern; Protrusion is a protrusion defect, which refers to a convex part that should not exist on the mask pattern; Missing is a missing defect, which refers to a part that should exist in the mask pattern but is missing for some reason; Missing size is a size missing defect, which means that the size of some parts in the mask pattern does not meet the design requirements due to manufacturing or processing problems; Rough Edge is a rough edge defect, which means that the edge of the mask pattern is rough or uneven; Jog is a defect in which the material is not completely removed.

At present, the common chromium residue repair method has low processing efficiency and is applied in a single scenario. For example, the repair effect of the repair machine on PSM mask chromium residue (positive mask chromium residue) is not good. Therefore, a simple and efficient chromium residue removal method is needed to remove the chromium residue defects caused by various conditions, ensure the photomask yield and production efficiency, and improve chip quality.

Based on this, an embodiment of the present invention proposes a processing scheme: as shown in Figures 4 to 6, a photomask defect repair method of the present invention locates the defect coordinates of the defect on the photomask, finds the exposure pattern corresponding to the defect on the original design pattern, and calculates a reasonable repair area based on the exposure pattern, and then redesigns the exposure area and exposure file, and uses a secondary exposure machine to re-expose the repair area in the photomask. After reading the redesigned exposure file, the photolithography machine exposes the specified exposure area of the repair area, and the excess chromium residue is removed through development, etching and other process flows, while the defect-free areas on the original design pattern will be protected by the photoresist spin-coated during exposure, thereby achieving effective removal of chromium residual defects without affecting the original design pattern, and is suitable for a variety of chromium residual defects.

The technical solutions provided by various embodiments of the present application are described below in conjunction with the accompanying drawings.

As shown in FIGS. 3 to 7 , an embodiment of the present invention provides a method for repairing photomask defects, comprising:

Step S102: Obtain defect position coordinate information of a defect in the photomask.

When there are defects in the photomask, the defect position coordinate information of the defect in the photomask can be obtained through the inspection machine.

Specifically, when there are defects in the photomask, the inspection machine detects the defects on the photomask and then obtains defect position coordinate information of the defects to ensure that subsequent operations are directed to the correct position.

Wherein, the defect is a chromium residue defect or other similar defects.

In the present invention, the chromium residual defect is described in detail.

Step S104: acquiring pattern position information based on the defect position coordinate information, wherein the pattern position information is position information of an exposure pattern corresponding to the defect position coordinate information in an original design pattern.

After obtaining the defect position coordinate information of the defect position, by retrieving the position information of the exposure pattern corresponding to the defect position coordinate information in the original design pattern, it can be ensured that the repair work can accurately correspond to the specific defect pattern.

Among them, based on the defect position coordinate information, the graphic position information can be obtained through a data processing method.

In one embodiment of the present invention, a software processing tool can be used to extract the position information of the corresponding exposure pattern from the database of the original data design pattern according to the defect position coordinate information, which includes the specific pattern position and size of the defect and the relationship with other design elements.

Step S106: acquiring and determining a repair area based on the graphic position information, and redesigning an exposure area and an exposure file based on the repair area.

The exposure area refers to the specific area on the silicon wafer or photomask where the light source is irradiated in the photolithography machine. In this area, ultraviolet light (or other types of light sources, such as electron beam, extreme ultraviolet light, etc.) passes through the mask (if mask-patterned exposure is used) or is directly written (in maskless direct write lithography) to form the desired pattern on the substrate coated with photoresist.

Among them, the exposure file is a data file that contains all the necessary information to guide the lithography machine for precise exposure. The exposure file defines which areas should be irradiated (exposed) with light and which should not be irradiated, thereby ensuring the correct transfer of the pattern. The exposure file is usually generated by the design stage of the lithography process, including key parameters such as the pattern layout data, exposure intensity, and exposure time. In electron beam lithography (E-beam lithography), the exposure file also specifies the scanning path and focal size of the electron beam in detail.

Specifically, after determining the graphic position information, it is necessary to calculate the area range that needs to be repaired, and redesign the exposure area and corresponding exposure file according to the area range that needs to be repaired to ensure that the repair operation is limited to the defective area and does not affect other graphics on the mask.

Step S108, spin-coating photoresist on the photomask, and exposing the repair area based on the exposure area and the exposure file;

In the embodiment of the present invention, an exposure machine may be used to expose the repair area based on the exposure area and the exposure file.

For example, a photolithography machine may be used to expose the repaired area.

A new layer of photoresist is applied to the repaired area and then accurately exposed according to the redesigned exposure file to ensure that the corrected pattern is correctly transferred to the photomask.

Step S110, developing and etching the repair area in sequence.

After exposing the repaired area, it is also necessary to develop the repaired area to show the new pattern of the repaired area, and then etch to remove excess material so that the repaired area is consistent with the original design pattern and contains no defects.

Step S112: After developing and etching the repaired area in sequence, removing the excess photoresist on the photomask.

After the photomask is repaired, the excess photoresist on the photomask needs to be removed to make it a complete photomask.

The photomask defect repairing method of the present invention is described in detail below with reference to the accompanying drawings using a chromium residual defect:

As shown in FIG6 , the inspection machine is positioned on the photomask to the location of the chromium residual defect;

Using data processing methods to find the corresponding exposure pattern at the specified coordinate position of the original design pattern;

Regenerate the exposure file and generate exposure areas only for defective locations;

The exposure machine performs partial exposure on the regenerated defects;

After the processes of developing, etching, resist removal, etc., a photomask without chromium residue is obtained.

As shown in FIG. 7 , the present invention provides a method for repairing photomask defects. The pattern of the defect exposure area of the photomask is reasonably designed by a data processing method, and the repair area is re-exposed using a photolithography machine to repair the chromium residue defects on the photomask. This repair method will not affect the circuit pattern, and can efficiently and accurately remove the chromium residue on the photomask, greatly reducing the chromium residue removal time and the scrap rate of the photomask.

An embodiment of the present invention further provides a photomask, wherein the photomask is obtained by any of the above-mentioned photomask defect repairing methods.

In this specification, the same or similar parts between the various embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the product embodiment described later, since it corresponds to the method, the description is relatively simple, and the relevant parts can be referred to the partial description of the system embodiment.

The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims (8)

1. A photomask defect repair method, comprising:

acquiring defect position coordinate information of a defect in a photomask;

Acquiring graphic position information based on the defect position coordinate information, wherein the graphic position information is the position information of an exposure graphic corresponding to the defect position coordinate information in an original design graphic;

acquiring and determining a repair area based on the graphic position information, and redesigning an exposure area and an exposure file based on the repair area;

spin-coating photoresist on the photomask, and exposing the repair area based on the exposure area and the exposure file;

and developing and etching the repair area in sequence.

2. The method of claim 1, wherein the photoresist is removed after the repair areas are sequentially subjected to development etching.

3. The method of claim 1, wherein the defect in the photo-mask is a chromium residual defect.

4. The photomask defect repair method of claim 1, wherein acquiring pattern position information based on the defect position coordinate information comprises:

And acquiring the graphic position information by a data processing method based on the defect position coordinate information.

5. The method according to claim 1, wherein the defect position coordinate information of the defect in the photomask is obtained based on an inspection machine.

6. The method according to claim 1, wherein the repair area is exposed based on the exposure area and the exposure file using an exposure tool.

7. The method of claim 6, wherein the exposure tool is a lithography tool.

8. A photomask, characterized in that the photomask is obtained by the photomask defect repairing method according to any one of claims 1 to 7.