CN111906684A - a grinding method - Google Patents

Abstract

The embodiment of the present application provides a grinding method, which includes providing a control sheet, the control sheet has a surface to be polished, the surface to be polished is modified with a polishing pad, and a strong alkaline polishing liquid is arranged between the polishing pad and the surface to be polished. That is to say, a strong alkaline polishing liquid is arranged between the polishing pad and the control sheet. In the process of modifying the surface to be polished, the influence of the chemical reaction on the surface to be polished can be improved, which is beneficial to the polishing of the surface to be polished, thereby improving the The flatness of the surface to be ground can reduce impurities on the surface to be ground, improve the grinding efficiency, reduce the number of grinding times, improve the recovery efficiency of the control sheet, and reduce the recovery cost.

Description

a grinding method

technical field

The present application relates to the field of semiconductor devices and their manufacture, and in particular, to a grinding method.

Background technique

In the manufacturing process of semiconductor devices, the use of control chips is usually included, and the control chips can be used to monitor the semiconductor process. For example, in the deposition process, the same deposition process can be used to form a thin film on the control wafer and the wafer to be processed at the same time, and the monitoring of the processing process can be realized by detecting the control wafer.

The control film can be recycled and reused, that is, the used control film is cleaned, and if the cleaned control film meets the inspection standard, it can be put into use again. Specifically, the recycling process may include: stripping, grinding, acid bath treatment (wet), inspection (inspection), that is, the stripping process can be used to remove the film on the control sheet, and the grinding and acid bath treatment can be used to remove residual impurities on the surface , and then inspect the control film. If there are too many defects and residues on the surface of the control film, the process of grinding and acid tank treatment needs to be repeated until the inspection meets the standard. If the control film cannot meet the standard after multiple inspections, the control film is scrapped. .

At present, in the process of recycling and reusing control tablets, many times of grinding and acid tank treatment are required, the recovery efficiency is low, and the load of grinding and acid tank is increased, so the cost of recycling control tablets is very high.

SUMMARY OF THE INVENTION

In view of this, the purpose of the present application is to provide a grinding method, which can improve the recovery efficiency of the control tablet and reduce the recovery cost.

To achieve the above object, the application has the following technical solutions:

The embodiment of the present application provides a grinding method, comprising:

providing a control sheet having a surface to be ground;

The surface to be polished is modified by a polishing pad; a strong alkaline polishing liquid is arranged between the polishing pad and the surface to be polished.

Optionally, the grinding liquid includes at least one of the following substances: potassium hydroxide, calcium hydroxide, sodium hydroxide, barium hydroxide, and cesium hydroxide.

Optionally, a surfactant is provided between the polishing pad and the surface to be polished.

Optionally, the polishing pad is not activated.

Optionally, the hardness of the surface of the polishing pad is in the range of 53 to 63°; in the process of using the polishing pad to modify the surface to be polished, the rotational speed of the polishing pad is less than or equal to 30 rpm; The pressure is less than or equal to 1 psi, and the modification time ranges from 180 to 300 sec.

Optionally, in the process of using the polishing pad to modify the surface to be polished, the finishing operation on the surface of the polishing pad by using a finisher is not performed.

Optionally, before using a polishing pad to modify the surface to be polished, the method further includes:

Coarse grinding and fine grinding are performed on the surface to be ground by chemical mechanical grinding.

Optionally, before the chemical mechanical grinding method is used to perform rough grinding and fine grinding on the surface to be ground, the method further includes:

The film layer on the surface to be ground is peeled off.

Optionally, after the surface to be polished is modified with a polishing pad, the method further includes:

The control sheet is subjected to acid solution soaking treatment.

Optionally, after the control sheet is subjected to acid solution soaking treatment, the method further includes:

Detecting the surface to be ground of the control sheet to obtain a detection result;

When the detection result is failed, returning to the step of modifying the surface to be polished with a polishing pad.

The embodiment of the present application provides a grinding method, which includes providing a control sheet, the control sheet has a surface to be polished, the surface to be polished is modified with a polishing pad, and a strong alkaline polishing liquid is arranged between the polishing pad and the surface to be polished. That is to say, a strong alkaline polishing liquid is arranged between the polishing pad and the control sheet. In the process of modifying the surface to be polished, the influence of the chemical reaction on the surface to be polished can be improved, which is beneficial to the polishing of the surface to be polished, thereby improving the The flatness of the surface to be ground can reduce impurities on the surface to be ground, improve the grinding efficiency, reduce the number of grinding times, improve the recovery efficiency of the control sheet, and reduce the recovery cost.

Description of drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are For some embodiments of the present application, for those of ordinary skill in the art, other drawings can also be obtained based on these drawings without any creative effort.

Fig. 1 shows the schematic flow chart of a kind of grinding method in the embodiment of the present application;

2 is a schematic diagram of a chemical mechanical polishing device in an embodiment of the application;

FIG. 3 is a schematic diagram of the acid tank in the embodiment of the application.

Detailed ways

In order to make the above objects, features and advantages of the present application more clearly understood, the specific embodiments of the present application will be described in detail below with reference to the accompanying drawings.

Many specific details are set forth in the following description to facilitate a full understanding of the present application, but the present application can also be implemented in other ways different from those described herein, and those skilled in the art can do so without departing from the connotation of the present application. Similar promotion, therefore, the present application is not limited by the specific embodiments disclosed below.

Next, the present application will be described in detail with reference to the schematic diagrams. When describing the embodiments of the present application in detail, for the convenience of explanation, the cross-sectional views showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not be limited here. The scope of protection of this application. In addition, the three-dimensional spatial dimensions of length, width and depth should be included in the actual production.

As described in the background art, the recycling process of the control film can include: peeling, grinding, acid tank treatment, inspection, etc., that is, the film on the control film can be removed by the peeling process, and the residual impurities on the surface can be removed by grinding and acid tank treatment. After that, the control film can be inspected. If there are too many defects and residues on the surface of the control film, the process of grinding and acid tank treatment needs to be repeated until the inspection meets the standard. If the control film cannot meet the standard after multiple inspections, the control film is scrapped. . However, at present, in the process of recycling and reusing control tablets, many times of grinding and acid tank treatment are required, the recovery efficiency is low, and the load of grinding and acid tank is increased, so the cost of recycling control tablets is high.

This is because during the current chemical mechanical polishing process, it is not easy to remove part of the area that appears on the control wafer. This area is called the wafer defect feature area, which may be related to the processing process of the control wafer. The existence of this area will cause The control tablet needs multiple grindings and multiple acid tank treatments during the recycling operation, thereby increasing the load of the grinding and acid tank. Therefore, a grinding method that can effectively remove impurities on the control tablet is required.

Based on the above technical problems, the embodiment of the present application provides a grinding method, including providing a control sheet, the control sheet has a surface to be ground, the surface to be polished is modified by a polishing pad, and a strong alkali property is arranged between the polishing pad and the surface to be polished grinding fluid. That is to say, a strong alkaline polishing liquid is arranged between the polishing pad and the control sheet. In the process of modifying the surface to be polished, the influence of the chemical reaction on the surface to be polished can be improved, which is beneficial to the polishing of the surface to be polished, thereby improving the The flatness of the surface to be ground can reduce impurities on the surface to be ground, improve the grinding efficiency, reduce the number of grinding times, improve the recovery efficiency of the control sheet, and reduce the recovery cost.

In order to better understand the technical solutions and technical effects of the present application, specific embodiments will be described in detail below with reference to the accompanying drawings.

Referring to Fig. 1, which is a flowchart of a grinding method provided in an embodiment of the present application, the method may include the following steps:

S101, providing control films.

In the embodiments of the present application, the control chip can be used for monitoring the semiconductor processing process. For example, in the deposition process, the same deposition process can be used to form a thin film on the control wafer and the wafer to be processed at the same time, so that the thickness of the film on the control wafer and the film on the wafer to be processed are the same, and the quality of the film layer is the same. Wafer inspection enables monitoring of the processing process and thus the thin film on the wafer to be processed. For another example, in the etching process, a consistent film layer can be formed on the control wafer and the wafer to be processed, so that the treatment effect is consistent with the wafer to be processed, so that the control wafer can be used to detect the etching quality of the etching equipment .

Specifically, the material of the control wafer can be the same as that of the substrate of the wafer to be processed. For example, the control wafer can be a silicon substrate, a germanium substrate, a silicon germanium substrate, etc. After the control wafer is used, other surfaces are often formed on its surface. The film layer may be formed by deposition and then inspected, or may be etched.

In order to reduce the cost, the control film can be recycled and reused at present, that is, the used control film is cleaned, and if the cleaned control film meets the inspection standard, it can be put into use again. Specifically, the film on the control sheet can be peeled off first, and then the impurities on the surface can be removed by grinding and acid bath treatment. When the impurities are completely removed and the obtained control sheet has a high surface flatness, it can be considered that the control sheet can be put back into use. The thickness of the substrate of the cleaned control wafer may be less than the thickness before cleaning.

Therefore, in the embodiment of the present application, the control sheet to be recovered is used as the processing object, and the control sheet has a surface to be ground. Specifically, a complete film layer can be formed on the surface to be ground, so the film layer needs to be removed so that the controller can be recycled and reused; impurities remaining after grinding can also be formed on the surface to be ground, so these impurities need to be removed. Therefore, the control sheet can be recycled and reused; the surface to be ground can also have a large roughness, so the surface to be ground needs to be flattened, so that the control sheet can be recycled and reused.

S102, using a polishing pad to modify the surface to be polished.

In the embodiment of the present application, the surface to be polished can be modified to remove impurities on the surface to be polished and to improve the flatness of the surface to be polished, so that the control sheet can be recycled. Before that, the chemical mechanical grinding method can be used for rough grinding and fine grinding on the surface to be ground to remove impurities on the surface to be ground and improve the flatness of the surface to be ground. The film layer on the grinding surface can also be peeled off, so that the surface to be ground is treated with multiple processes, and the controlled film recovery can be achieved with high efficiency.

The surface to be polished can be modified by chemical mechanical polishing (Chemical Mechanical Polishing, CMP). Referring to FIG. 2 , a schematic diagram of a chemical mechanical polishing device provided in the embodiment of the present application, wherein the surface of the polishing pad 100 has With a certain roughness, the surface to be ground of the control sheet 200 faces the surface of the polishing pad 100. After the two are in contact, the material structure of the surface to be ground of the control sheet 200 is destroyed by relative motion, and some protruding particles on the surface to be ground from The surface to be polished falls off, thereby realizing the modification of the surface to be polished.

The polishing pad 100 may be placed on the polishing disc 110 and rotated by the polishing disc 110 , and the material of the polishing pad 100 may be polyurethane (Polyurethane). The control plate 200 can be fixed on the polishing head assembly 210, and the polishing head assembly 210 can fix the control plate 200 by adsorption, and exert a certain downward pressure on the control plate 200 to increase the friction between the control plate 200 and the polishing pad 100. , the polishing head assembly 210 can also drive the control plate 200 to move, so as to realize the relative movement between the control plate 200 and the polishing pad 100 .

Between the polishing pad and the surface to be polished, a polishing liquid with strong alkaline properties may be provided. Specifically, the polishing liquid may include at least one of the following: potassium hydroxide (KOH), calcium hydroxide (Ca(OH) ₂ ), Sodium hydroxide (NaOH), barium hydroxide (Ba(OH) ₂ ), cesium hydroxide (CsOH), etc. In this way, the strong alkaline polishing liquid can chemically react with the surface to be polished to promote the modification of the surface to be polished, and the modification process based on the chemical reaction is easy to obtain a faster modification efficiency and a smoother surface, thus improving the polishing efficiency.

When using the polishing pad to modify the surface to be polished, a surfactant may be provided between the polishing pad and the surface to be polished to promote the chemical reaction between the polishing liquid and the surface to be polished and improve the modification efficiency of the surface to be polished. Among them, the surface of the polishing pad may not be activated, so that the physical polishing effect of the polishing pad on the surface to be polished can be suppressed to a certain extent, so that the chemical polishing effect is dominant.

In the modification process, the finisher 300 can be used to remove the used slurry on the polishing pad, including used polishing liquid and waste particles generated during the polishing process, etc., to improve the surface roughness of the polishing pad, and the present application implements For example, in the modification process, the surface of the polishing pad may not be cleaned by the finisher 300, which prevents the use of the finisher 300 to improve the roughness of the surface of the polishing pad, so that the physical polishing effect of the polishing pad on the surface to be polished is suppressed to a certain extent. Make the chemical grinding action predominant.

In the embodiment of the present application, the physical polishing effect of the polishing pad on the surface to be polished can be controlled by adjusting the polishing parameters. Downforce, etc., thereby reducing the rate of physical grinding. Specifically, the hardness of the polishing pad is in the range of 53 to 63° (Shore hardness), the rotational speed of the polishing pad is less than or equal to 30 revolutions per minute (rpm), and the pressure applied on the control plate is less than or equal to 1 pound force per minute Pounds per square inch (psi). In this way, by adjusting the polishing parameters, the physical polishing effect of the polishing pad on the surface to be polished can be restrained to a certain extent, and the relative movement of physical polishing can also promote the chemical reaction, and the chemical reaction can obtain a faster modification rate. , while obtaining a flat interface.

In the examples of the present application, since the physical polishing effect of the polishing pad on the surface to be polished is suppressed, the modification rate of the polishing pad is relatively limited. Therefore, a better polishing effect can be obtained by extending the polishing time. Specifically, using The time range for the polishing pad to modify the surface to be polished can be 180-300 seconds (second, sec). In this way, the entire modification and grinding step is equivalent to the grinding and cleaning tank. This design has the dual benefits of chemical mechanical grinding and acid tank. The chemical reaction of the control film is used to match the minimum physical grinding amount, and the grinding seconds are increased to improve the flatness of the surface at the same time. , which can reduce the number of switching between grinding and acid tanks, and reduce the cost of control chip recovery.

After using the polishing pad to modify the surface to be polished, the control sheet can also be treated with acid solution soaking, that is, acid tank treatment, to further remove impurities on the control sheet to be polished and smooth the surface to be polished, as shown in Figure 3, This is a schematic diagram of an acid tank in the embodiment of the present application. The acid tank 400 includes an acid solution and a wafer holder 500 . The wafer 200 can be placed on the wafer holder 500 to contact the acid solution to generate a chemical reaction. After the control sheet is soaked in acid solution, the surface to be ground of the control sheet can also be tested to obtain a test result. The test result can include the roughness and composition of the surface to be ground. If the roughness is less than the preset roughness threshold, And if the proportion of impurities is less than the preset proportion, it can be considered that the test is passed, and the control film can be used again, otherwise, the test is considered to fail. When the test result is not passed, it can be considered that the control film needs further treatment, and the surface to be polished can be modified by using the polishing pad again, that is, returning to the modification step. Of course, after modification, the acid solution immersion treatment can be performed again. .

If the number of modification and acid solution soaking exceeds the preset number of times, and the test result is still not passed, the recovery cost of the control film is too high, and at this time, it is discarded.

The embodiment of the present application provides a grinding method, which includes providing a control sheet, the control sheet has a surface to be polished, the surface to be polished is modified with a polishing pad, and a strong alkaline polishing liquid is arranged between the polishing pad and the surface to be polished. That is to say, a strong alkaline polishing liquid is arranged between the polishing pad and the control sheet. In the process of modifying the surface to be polished, the influence of the chemical reaction on the surface to be polished can be improved, which is beneficial to the polishing of the surface to be polished, thereby improving the The flatness of the surface to be ground can reduce impurities on the surface to be ground, improve the grinding efficiency, reduce the number of grinding times, improve the recovery efficiency of the control sheet, and reduce the recovery cost.

The above descriptions are only the preferred embodiments of the present application. Although the present application has been disclosed above with preferred embodiments, it is not intended to limit the present application. Any person skilled in the art, without departing from the scope of the technical solution of the present application, can use the methods and technical contents disclosed above to make many possible changes and modifications to the technical solution of the present application, or be modified into equivalents of equivalent changes. Example. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present application without departing from the content of the technical solutions of the present application still fall within the protection scope of the technical solutions of the present application.

Claims (10)

1. a grinding method, is characterized in that, comprises: providing a control sheet having a surface to be ground; The surface to be polished is modified by a polishing pad; a strong alkaline polishing liquid is arranged between the polishing pad and the surface to be polished. 2. The method according to claim 1, wherein the grinding liquid comprises at least one of the following substances: potassium hydroxide, calcium hydroxide, sodium hydroxide, barium hydroxide, and cesium hydroxide. 3. The method according to claim 1, wherein a surfactant is provided between the polishing pad and the surface to be polished. 4. The method of claim 1, wherein the polishing pad is not activated. 5 . The method according to claim 1 , wherein the hardness of the surface of the polishing pad is in the range of 53° to 63°; in the process of using the polishing pad to modify the surface to be polished, the The rotation speed is less than or equal to 30 rpm; the pressure applied on the control sheet is less than or equal to 1 psi, and the modification time range is 180-300 sec. 6 . The method according to claim 1 , wherein in the process of using a polishing pad to modify the surface to be polished, a finishing operation on the surface of the polishing pad with a finisher is not performed. 7 . 7. The method according to any one of claims 1-6, wherein before the surface to be polished is modified with a polishing pad, the method further comprises: Coarse grinding and fine grinding are performed on the surface to be ground by chemical mechanical grinding. 8. The method according to claim 7, characterized in that, before the chemical mechanical grinding method is used to perform rough grinding and fine grinding on the surface to be ground, the method further comprises: The film layer on the surface to be ground is peeled off. 9. The method according to any one of claims 1-6, wherein after the surface to be polished is modified with a polishing pad, the method further comprises: The control sheet is subjected to acid solution soaking treatment. 10. The method according to claim 9, characterized in that, after the control sheet is subjected to acid solution soaking treatment, the method further comprises: Detecting the surface to be ground of the control sheet to obtain a detection result; When the detection result is failed, returning to the step of modifying the surface to be polished with a polishing pad.

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