CN111546228A - Grinding pad temperature control method and device and grinding equipment - Google Patents

Abstract

The invention provides a method, a device and a grinding device for controlling the temperature of a grinding pad, wherein the surface temperature of the grinding pad is set as an initial grinding temperature before a sample is ground, the surface temperature of the grinding pad is monitored in the process of grinding the sample, then the surface temperature of the grinding pad is adjusted to the initial grinding temperature when the temperature change value of the surface of the grinding pad exceeds a preset threshold value, so that the surface temperature of the grinding pad is set as the optimal temperature for grinding the sample before the sample is ground, the speed of grinding the sample is favorably and accurately controlled, the surface temperature of the grinding pad is detected in real time in the process of grinding the sample, when the surface temperature change value of the grinding pad exceeds the preset threshold value, the surface temperature of the grinding pad is enabled to reach the optimal temperature for grinding the sample through a grinding control sheet, the surface temperature of the grinding pad is accurately controlled, and the stability of chemical mechanical grinding is favorably improved, the grinding efficiency is improved.

Description

A kind of grinding pad temperature control method, device and grinding equipment

technical field

The present invention relates to the technical field of semiconductors, and in particular, to a method, device and polishing equipment for controlling the temperature of a polishing pad.

Background technique

Chemical Mechanical Planarization (CMP) is a process for planarizing the surface of a wafer during semiconductor manufacturing. In the chemical mechanical polishing process, the temperature of the polishing pad has a great influence on the polishing rate, but the existing chemical mechanical polishing process cannot effectively adjust the surface temperature of the polishing pad, thereby affecting the polishing effect.

SUMMARY OF THE INVENTION

In view of this, the purpose of the present invention is to provide a polishing pad temperature control method, device and polishing equipment, which can effectively control the surface temperature of the polishing pad and improve the polishing effect.

For achieving the above object, the present invention has the following technical solutions:

A method for controlling the temperature of a polishing pad, comprising:

Set the surface temperature of the polishing pad to the initial grinding temperature before grinding the sample;

monitoring the surface temperature of the polishing pad during the grinding of the sample;

When the change value of the surface temperature of the polishing pad exceeds a preset threshold, the surface temperature of the polishing pad is adjusted to the initial polishing temperature.

Optionally, the adjusting the surface temperature of the polishing pad to the initial grinding temperature includes:

The surface temperature of the polishing pad is monitored by grinding the control sheet and during the process of grinding the control sheet, until the surface temperature of the polishing pad reaches the initial grinding temperature.

Optionally, the method for setting the temperature of the polishing pad surface to the initial grinding temperature before grinding the sample includes:

The control sheet was ground prior to grinding the samples so that the surface temperature of the grinding pad reached the initial grinding temperature.

Also includes:

A bearing area is provided, and the bearing area is used to carry the control sheet for grinding the control sheet.

Optionally, also include:

Milling of the samples was performed at the initial milling temperature.

A polishing pad temperature control device, comprising:

A temperature setting unit for setting the surface temperature of the polishing pad as the initial grinding temperature before grinding the sample;

A temperature monitoring unit for monitoring the surface temperature of the polishing pad during the process of grinding the sample;

The temperature adjustment unit is configured to adjust the surface temperature of the polishing pad to the initial polishing temperature when the change value of the surface temperature of the polishing pad exceeds a preset threshold.

Optionally, the temperature adjustment unit is specifically configured to grind the control sheet and monitor the surface temperature of the polishing pad during the process of grinding the control sheet until the surface temperature of the polishing pad reaches the initial grinding temperature.

Optionally, the temperature setting unit is specifically configured to grind the control sheet before grinding the sample until the surface temperature of the grinding pad reaches the initial grinding temperature.

Optionally, also include:

The first unit, the first unit is used for setting a bearing area, and the bearing area is used for bearing the control sheet for grinding the control sheet.

A grinding equipment, comprising: a grinding platform, a grinding pad and a grinding head, the grinding pad is arranged on the grinding platform, the grinding head is arranged on the grinding pad, and further comprises: the grinding head described in any one of the above Pad temperature control device.

In a method for controlling the temperature of a polishing pad provided by the embodiment of the present invention, the surface temperature of the polishing pad is set to the initial polishing temperature before grinding the sample, the temperature of the surface of the polishing pad is monitored during the process of grinding the sample, and then the temperature of the surface of the polishing pad is monitored When the change value exceeds the preset threshold, adjust the temperature of the surface of the polishing pad to the initial grinding temperature. In this way, the surface temperature of the polishing pad is set to the optimum temperature for the sample to be ground before grinding the sample, which is beneficial to accurately control the rate of grinding the sample. Then, in the process of grinding the sample, the temperature of the surface of the polishing pad is detected in real time. When the surface temperature change value of the polishing pad exceeds the preset threshold, the surface temperature of the polishing pad reaches the optimal temperature of the polishing sample through the grinding control sheet, and the precise control The surface temperature of the polishing pad is beneficial to improve the stability of chemical mechanical polishing and improve the efficiency of polishing.

Description of drawings

In order to illustrate the embodiments of the present invention or the technical solutions in the prior art more clearly, 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 invention, for those of ordinary skill in the art, other drawings can also be obtained according to these drawings without creative effort.

1 shows a schematic flow chart of a method for controlling the temperature of a polishing pad according to an embodiment of the present invention;

FIG. 2 shows a schematic top view of the structure of a grinding apparatus according to an embodiment of the present invention.

Detailed ways

In order to make the above objects, features and advantages of the present invention more clearly understood, the specific embodiments of the present invention 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 invention, but the present invention 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 invention. Similar promotion, therefore, the present invention is not limited by the specific embodiments disclosed below.

As described in the background art, in the chemical mechanical polishing process, the temperature of the polishing pad has a great influence on the polishing rate (RR). The existing chemical mechanical polishing machine is adjusted by the optical feedback temperature sensor and the circulating water temperature. The system controls the temperature of the polishing pad. The optical feedback sensor installed on the polishing head monitors the surface temperature of the polishing pad. When the surface temperature of the polishing pad is lower than the temperature required for grinding the sample, the circulating water temperature adjustment system in the polishing platform is responsible for Heating increases the surface temperature of the polishing pad, but the circulating water temperature adjustment system has a long path for heating the polishing pad. The circulating water needs to pass through the polishing platform to the bottom of the polishing pad. During the transmission process, the heat of the circulating water is continuously dissipated and reaches the bottom of the polishing pad. The temperature at this time is lower than the initial temperature of the circulating water. In addition, because the material of the polishing pad is polyurethane, which is a poor conductor of heat, the effect on the upper surface of the polishing pad is small or slow when the bottom of the polishing pad is heated, so that the polishing pad is heated. The surface temperature of the pad is much lower than the initial temperature of the circulating water, which cannot effectively adjust the surface temperature of the polishing pad to the optimum temperature for grinding the sample, resulting in unstable grinding rate, thus affecting the grinding effect of the sample.

To this end, the present application proposes a method for controlling the temperature of a polishing pad. Before grinding the sample, the surface temperature of the polishing pad is set to the initial grinding temperature, and the temperature of the surface of the polishing pad is monitored during the process of grinding the sample, and then the temperature of the surface of the polishing pad is monitored When the change value exceeds the preset threshold, adjust the temperature of the surface of the polishing pad to the initial grinding temperature. In this way, the surface temperature of the polishing pad is set to the optimum temperature for the sample to be ground before grinding the sample, which is beneficial to accurately control the rate of grinding the sample. Then, in the process of grinding the sample, the temperature of the surface of the polishing pad is detected in real time. When the surface temperature change value of the polishing pad exceeds the preset threshold, the surface temperature of the polishing pad reaches the optimal temperature of the polishing sample through the grinding control sheet, and the precise control The surface temperature of the polishing pad is beneficial to improve the stability of chemical mechanical polishing and improve the efficiency of polishing.

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

Referring to FIG. 1 , in step S01 , the surface temperature of the polishing pad is set as the initial polishing temperature before polishing the sample.

In the examples of the present application, the initial grinding temperature is the optimum temperature when grinding the sample, that is, when the surface temperature of the polishing pad reaches the initial grinding temperature, the effect of grinding the sample is the best. In this embodiment, the parameter of the initial grinding temperature, that is, the optimum temperature when grinding the sample, can be added to the Process Release Standard (PRS) of the Chemical Mechanical Polish (CMP) process, replacing the existing each The Dow Chemical Mechanical Polishing process grinds a fixed number of control slices before grinding the sample, allowing precise control of the grinding rate.

In this embodiment, the initial grinding temperature of each chemical mechanical polishing process may be different or the same. For example, when Shallow Trench Isolation (STI) chemical mechanical polishing is required, the initial polishing temperature is T ₁ , and when oxide chemical mechanical polishing is performed, the initial polishing temperature is T ₂ , _T1 and _T2 may be the same or different. Before each chemical mechanical polishing process is carried out, the surface temperature of the polishing pad is set to the initial grinding temperature when the sample is ground in the process, that is, the optimal temperature. The subsequent grinding of the sample at this initial grinding temperature is conducive to accurate and precise grinding. Control the rate at which the sample is ground.

In this embodiment, the method for setting the temperature of the surface of the polishing pad to the initial grinding temperature before grinding the sample may include: grinding the control sheet before grinding the sample, so that the surface temperature of the polishing pad reaches the initial grinding temperature.

Specifically, the surface temperature of the polishing pad can be increased by controlling the number of grinding control sheets, and the surface temperature of the polishing pad can be detected before grinding the sample, denoted as T ₃ , and the initial grinding temperature required when the sample is obtained is obtained, Denoted as T ₄ , to obtain the difference between the initial polishing temperature required for polishing the sample and the surface temperature of the polishing pad before polishing the sample, denoted as T ₄ -T ₃ . Then, the specific value of the surface temperature of the polishing pad can be improved by grinding a control piece, denoted as a, according to the difference T ₄ -T ₃ between the initial grinding temperature when grinding the sample and the surface temperature of the grinding pad before grinding the sample, and grinding a piece The control sheet can increase the surface temperature a of the polishing pad to obtain the number of control sheets (T ₄ -T ₃ )/a required to reach the initial grinding temperature during grinding.

For example, grinding a control sheet can increase the surface temperature of the polishing pad by 0.5 °C, the surface temperature of the polishing pad before grinding the sample is 38 °C, and the initial grinding temperature required for grinding the sample is 40 °C, then the initial grinding of the sample is achieved. The temperature is the optimum temperature, and the number of grinding control sheets is 4. It should be noted that the control films in this embodiment are the same control films, thereby improving the stability of chemical mechanical polishing and reducing the probability of various problems caused by different grinding rates.

In this embodiment, the surface temperature of the polishing pad can also be monitored in real time during the process of grinding the control sheet, and when the surface temperature of the polishing pad reaches the initial grinding temperature of the grinding sample, the grinding control sheet is stopped. In the process of grinding the control piece, the grinding of the next control piece can be performed after one piece of control piece is consumed, or the next control piece can be ground after partially consumed. The control films in this embodiment may be the same control films, or may be different control films. In a specific embodiment, the control sheet can be a defective product of some samples, or can be some other substitutes with lower quality than the samples, thereby reducing the manufacturing cost.

In this embodiment, a wafer box can also be set up, and the bearing region is used to carry the control sheet, so that the control sheet can be provided in time during the grinding process, so as to prevent the situation from being idle during the grinding process, and improve the efficiency of the grinding process. Grinding efficiency. The bearing area can be close to the polishing pad to facilitate the polishing of the control sheet. In a specific embodiment, the size of the bearing area can be set according to the required number of control sheets.

In step S02, the surface temperature of the polishing pad is monitored during the process of grinding the sample.

In the chemical mechanical polishing process, the wafer is placed on the polishing head, the polishing surface of the wafer is facing the polishing pad, and pressure is applied to the wafer through the polishing head. At the same time, a polishing liquid is supplied between the wafer and the polishing pad. The relative motion between the wafers and the chemical reaction with the polishing liquid realize the planarization of the wafer surface. In the process of continuously supplying the polishing liquid, the surface temperature of the polishing pad may drop. When the surface temperature of the polishing pad is lower than the initial polishing temperature, the polishing effect will be affected, and the performance of the product will be affected.

In the process of grinding the sample, the surface temperature of the polishing pad can be monitored in real time, so as to effectively monitor the surface temperature of the polishing pad and avoid the large change of the surface temperature of the polishing pad affecting the polishing effect. During the grinding process, the surface temperature of the polishing pad can also be detected at periodic intervals, and a shorter time interval can be selected to avoid failure to detect the surface temperature change of the polishing pad in time during the grinding process.

In step S03, when the change value of the surface temperature of the polishing pad exceeds a preset threshold, the surface temperature of the polishing pad is adjusted to the initial polishing temperature.

In the examples of the present application, the surface temperature change value of the polishing pad is the difference between the initial polishing temperature of the polishing pad surface set and the surface temperature of the polishing pad monitored during the polishing process. The initial polishing temperature of the surface of the polishing pad is denoted as T ₄ , and the surface temperature of the polishing pad monitored during polishing is denoted as T ₃ . The preset threshold is the maximum value of the surface temperature change of the polishing pad that can be tolerated. When the surface temperature change value of the polishing pad T ₄ -T ₃ exceeds the preset threshold value, it means that the surface temperature of the polishing pad has changed greatly at this time. The surface temperature of the changed polishing pad is lower, which affects the polishing effect of the sample. In order to improve the polishing effect, it is necessary to increase the surface temperature of the polishing pad to the initial polishing temperature in time. When the surface temperature change value T ₄ -T ₃ of the polishing pad is lower than the preset threshold, it means that the surface temperature change of the polishing pad is small at this time, and the variation range is within the allowable range, and the polishing process can be continued without any other operation. In this embodiment, the preset threshold can be determined according to the actual situation in each process. For example, in a process that does not require high grinding technology, a larger threshold can be selected, and in a process that requires high grinding technology , you can choose a smaller threshold.

In this embodiment, the surface temperature of the polishing pad can reach the optimum temperature of the grinding sample by grinding the control sheet. Specifically, the surface temperature of the polishing pad can be monitored in real time during the process of grinding the control sheet. The initial grinding temperature of the grinding sample is the optimum temperature to stop grinding the control sheet, thereby improving the stability of the chemical mechanical grinding process, improving the grinding effect, and reducing the probability of regrinding the sample. In this embodiment, in the process of grinding the control film, the grinding of the next control film may be performed after one control film is consumed, or the next control film may be ground after a portion of the control film is consumed. The films can be the same control film or different control films.

The above describes the polishing pad temperature control method in the embodiment of the present application in detail. In addition, the present application also provides a polishing pad temperature control device, including:

A temperature setting unit for setting the surface temperature of the polishing pad as the initial grinding temperature before grinding the sample;

The temperature monitoring unit is used to monitor the surface temperature of the polishing pad during the grinding process;

The temperature adjustment unit is configured to adjust the surface temperature of the polishing pad to the initial polishing temperature when the surface temperature change value of the polishing pad exceeds a preset threshold.

Optionally, the temperature adjustment unit is specifically configured to monitor the surface temperature of the polishing pad by grinding the control sheet and monitor the surface temperature of the polishing pad until the surface temperature of the polishing pad reaches the initial grinding temperature.

In this embodiment, during the grinding process, the temperature monitoring unit can monitor the surface temperature of the grinding pad in real time. When the temperature change value of the grinding pad exceeds the preset threshold, the temperature adjustment unit can control the sheet by grinding and control the sheet during the grinding process. During the process, the surface temperature of the grinding pad is monitored in real time, and when the surface temperature of the grinding pad reaches the initial grinding temperature, the grinding control sheet is stopped, thereby improving the grinding efficiency and effect.

Optionally, the temperature setting unit is specifically configured to grind the control sheet before grinding the sample until the surface temperature of the grinding pad reaches the initial grinding temperature.

In this embodiment, before grinding the sample, the temperature control unit can make the surface temperature of the polishing pad reach the initial grinding temperature by grinding the control sheet. During the process of grinding the control sheet, the surface temperature of the polishing pad can be monitored in real time. When the temperature reaches the initial grinding temperature, stop grinding the control tablet. The initial grinding temperature can also be achieved by first determining the number of flakes required to reach the initial grinding temperature, and then grinding the same number of flakes.

Optionally, also include:

A first unit, the first unit is used for setting a bearing area, and the bearing area is used for bearing the control sheet so as to grind the control sheet.

In this embodiment, the first unit is used to set a bearing area, the bearing area carries the control sheet required to increase the temperature of the polishing pad, and the control sheet can be provided in time during the process of grinding the control sheet, which is convenient for the grinding process and improves the grinding efficiency. efficiency. In a specific embodiment, the first unit may be close to the polishing pad, thereby facilitating the polishing of the control sheet.

In addition, the embodiment of the present application also provides a polishing apparatus, as shown in FIG. 2 , including: a polishing platform, a polishing pad 100 and a polishing head 200 , the polishing pad 100 is arranged on the polishing platform, and the polishing head 200 is arranged on the polishing pad 100 above, further comprising: the above-mentioned polishing pad temperature control device.

In the embodiment of the present application, the grinding platform is a component used to carry the pressure exerted by the grinding head 200, which may also be called a pressure plate. The grinding platform is provided with a grinding pad 100, and the grinding pad 100 is used for grinding samples. Between the pads 100 is the sample to be ground, such as a wafer.

Each embodiment in this specification is described in a progressive manner, and the same and similar parts between the various embodiments may be referred to each other, and each embodiment focuses on the differences from other embodiments. Especially, for the apparatus embodiment and the grinding apparatus embodiment, since they are basically similar to the method embodiment, the description is relatively simple, and the relevant part can be referred to the partial description of the method embodiment.

The above descriptions are only preferred embodiments of the present invention. Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art, without departing from the scope of the technical solution of the present invention, can make many possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above, or modify them 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 invention without departing from the content of the technical solutions of the present invention still fall within the protection scope of the technical solutions of the present invention.

Claims (10)

1. a grinding pad temperature control method, is characterized in that, comprises: Set the surface temperature of the polishing pad to the initial grinding temperature before grinding the sample; monitoring the surface temperature of the polishing pad during the grinding of the sample; When the change value of the surface temperature of the polishing pad exceeds a preset threshold, the surface temperature of the polishing pad is adjusted to the initial polishing temperature. 2. The method according to claim 1, wherein the adjusting the surface temperature of the polishing pad to the initial polishing temperature comprises: The surface temperature of the polishing pad is monitored by grinding the control sheet and during the process of grinding the control sheet, until the surface temperature of the polishing pad reaches the initial grinding temperature. 3. The method according to claim 1, wherein the method for setting the temperature of the polishing pad surface to the initial grinding temperature before grinding the sample comprises: The control sheet was ground prior to grinding the samples so that the surface temperature of the grinding pad reached the initial grinding temperature. 4. The method according to claim 2 or 3, characterized in that, further comprising: A bearing area is provided, and the bearing area is used to carry the control sheet so as to grind the control sheet. 5. The method according to any one of claims 1-3, characterized in that, further comprising: Milling of the samples was performed at the initial milling temperature. 6. A polishing pad temperature control device, characterized in that, comprising: A temperature setting unit for setting the surface temperature of the polishing pad as the initial grinding temperature before grinding the sample; A temperature monitoring unit for monitoring the surface temperature of the polishing pad during the process of grinding the sample; The temperature adjustment unit is configured to adjust the surface temperature of the polishing pad to the initial polishing temperature when the change value of the surface temperature of the polishing pad exceeds a preset threshold. 7. The device according to claim 6, wherein the temperature adjustment unit is specifically used to monitor the surface temperature of the grinding pad by grinding the control sheet and in the process of grinding the control sheet, until the surface temperature of the grinding pad The initial grinding temperature is reached. 8 . The device according to claim 7 , wherein the temperature setting unit is specifically configured to grind the control sheet before grinding the sample until the surface temperature of the grinding pad reaches the initial grinding temperature. 9 . 9. The device according to claim 7 or 8, characterized in that, further comprising: A first unit, the first unit is used for setting a bearing area, and the bearing area is used for bearing the control sheet so as to grind the control sheet. 10. A grinding equipment, comprising: a grinding platform, a grinding pad and a grinding head, the grinding pad is arranged on the grinding platform, and the grinding head is arranged on the grinding pad, it is characterized in that, also comprises: The polishing pad temperature control device according to any one of claims 6-9.

Images