Method for detecting whether grinding pad and grinding disc are attached or not

Abstract

The invention provides a method for detecting whether a grinding pad is attached to a grinding disc or not, and the method comprises the steps that a pressure sensing device is installed in the grinding disc for chemical mechanical grinding, and the pressure sensing device is connected with an alarm device of a grinding machine table and used for detecting whether the grinding pad is tightly attached to the grinding disc or not. The problem that whether the grinding pad and the grinding disc are tightly attached or not cannot be detected in the prior art is solved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing technology, and in particular to a method for detecting whether a grinding pad and a grinding disk are in contact with each other. Background Art

[0002] In the traditional Reflexion LK 300MM chemical mechanical polishing (CMP) machine, when the polishing pad of the polishing chamber is replaced during PM (Prevention Maintenance), it is necessary to tear off a small part of the polishing pad adhesive to align it with the polishing platen, and then press the polishing pad back and forth with a pressing tool while tearing off the adhesive to make the polishing pad and the polishing platen fully adhere together (such as Figure 1 However, if the liquid on the grinding disc is not wiped dry, or there are bubbles between the grinding pad and the grinding disc, or if the adhesive backing is forgotten to be removed when the grinding pad is replaced due to human negligence, the grinding pad will bubble or warp, and the alarm will not be triggered when the machine is restarted, causing the wafer to be broken when the machine is monitoring. Summary of the invention

[0003] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a method for detecting whether a polishing pad and a polishing disk are in close contact with each other, so as to solve the problem that the prior art cannot detect whether a polishing pad and a polishing disk are in close contact with each other.

[0004] To achieve the above-mentioned object and other related objects, the present invention provides a method for detecting whether a polishing pad and a polishing disc are in contact with each other, the method comprising:

[0005] A pressure sensing device is installed in the grinding disc for chemical mechanical grinding, and the pressure sensing device is connected to the alarm device of the grinding machine to detect whether the grinding pad and the grinding disc are tightly fitted.

[0006] Optionally, the pressure sensing device is resistant to acid and alkali corrosion and rust.

[0007] Optionally, the pressure sensing device is installed at the center of the grinding disc.

[0008] Optionally, the pressure sensing device has a pressure detecting portion, the top of which is flush with the surface of the grinding disc, and the surface is the surface that is in contact with the grinding pad.

[0009] Optionally, the pressure sensing device includes a capacitive pressure sensor.

[0010] Optionally, the method for judging whether the grinding pad and the grinding disc are in close contact includes:

[0011] The polishing pad is placed naturally on the polishing disc, and a natural pressure value is obtained by the pressure sensor;

[0012] The grinding pad is attached to the grinding disc, and the grinding disc is rotated;

[0013] Determine whether the pressure value obtained according to the pressure sensor is less than the natural pressure value and fluctuates between 0 and the natural pressure value. If the judgment result is yes, it means that they are not tightly fitted. If the pressure obtained according to the pressure sensor is a preset trigger value and remains unchanged, it means that the polishing pad and the polishing disc are tightly fitted.

[0014] Optionally, the preset value is 5N.

[0015] Optionally, the natural pressure value is 3N.

[0016] Optionally, if the polishing pad is not in close contact with the capacitive pressure sensor, the capacitive pressure sensor is not triggered and an alarm signal is output, and the machine PM will sound an alarm after the machine is restarted.

[0017] Optionally, applicable technology nodes include 55nm, 40nm, or less than or equal to 28nm.

[0018] As described above, the method for detecting whether the polishing pad and the polishing disc are in contact with each other of the present invention is to install a pressure sensor at the center of the polishing disc. When the polishing pad is in contact with the polishing disc, it contacts the pressure sensor and is triggered. The machine can be restored normally after PM to carry out subsequent operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Shown is a schematic diagram of a conventional polishing pad and a polishing disk.

[0020] Figure 2 Shown is a front view of a grinding disc provided with a pressure sensor according to the present invention.

[0021] Figure 3 A top view of a grinding disc provided with a pressure sensor according to the present invention is shown. DETAILED DESCRIPTION

[0022] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention 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 invention.

[0023] See also Figures 1 to 3It should be noted that the illustrations provided in this embodiment are only schematic illustrations of the basic concept of the present invention. Although the illustrations only show components related to the present invention and are not drawn according to the number, shape and size of components in actual implementation, the form, quantity and proportion of each component in actual implementation may be changed arbitrarily, and the component layout may also be more complicated.

[0024] This embodiment provides a method for detecting whether a polishing pad and a polishing disc are in contact with each other, the method comprising:

[0025] A pressure sensing device is installed in the grinding disc for chemical mechanical grinding, and the pressure sensing device is connected to the alarm device of the grinding machine to detect whether the grinding pad and the grinding disc are tightly fitted.

[0026] In this embodiment, if the liquid on the grinding disk is not wiped off, or there are bubbles between the grinding pad and the grinding disk, or if human factors cause carelessness and forgetting to tear off the adhesive on the back of the grinding pad, the grinding pad does not contact the pressure sensing device, and the pressure sensing device is not triggered, the machine PM will alarm after the machine is restored, thereby greatly avoiding wafer fragments when the machine is used as a monitor, reducing fragments and machine downtime, and helping to reduce costs and alleviate the burden on operators.

[0027] Specifically, the pressure sensing device is resistant to acid and alkali corrosion and rust.

[0028] Specifically, the pressure sensing device is installed at the center of the grinding disc.

[0029] Specifically, the pressure sensing device has a pressure detecting portion, the top of which is flush with the surface of the grinding disc, and the surface is the surface that is in contact with the grinding pad.

[0030] Specifically, the pressure sensing device includes a capacitive pressure sensor.

[0031] Specifically, the method for judging whether the polishing pad and the polishing disk are in close contact includes: placing the polishing pad naturally on the polishing disk and obtaining a natural pressure value through the pressure sensor; attaching the polishing pad to the polishing disk and rotating the polishing disk; judging whether the pressure value obtained by the pressure sensor is less than the natural pressure value and fluctuates between 0 and the natural pressure value. If the judgment result is yes, it indicates that they are not in close contact. If the pressure obtained by the pressure sensor is a preset trigger value and remains unchanged, it indicates that the polishing pad and the polishing disk are in close contact.

[0032] More specifically, the trigger value is 5N.

[0033] More specifically, the natural pressure value is 3N.

[0034] Specifically, if the polishing pad is not in close contact with the capacitive pressure sensor, the capacitive pressure sensor is not triggered and outputs an alarm signal, and the machine PM will sound an alarm after the machine is restored.

[0035] In this embodiment, the alarm signal may be a high level signal or a low level signal, and may be set according to needs.

[0036] In this embodiment, the capacitive pressure sensor is composed of two conductors and an insulating medium. The grinding pad itself has a certain weight. When the grinding pad is tightly fitted with the grinding platen, the weight (pressure) of the grinding pad itself acts between the two conductors of the capacitor, and the distance between the two conductors will change, thereby causing a change in the capacitance value. When the grinding pad contacts the capacitive pressure sensor and applies pressure to it, the capacitor structure inside the sensor will change, resulting in a change in the capacitance value. This change can be converted by the transducer inside the capacitive pressure sensor into an electrical signal for detecting the presence of an object.

[0037] The specific use process of the capacitive pressure sensor includes a zero calibration step, a pressurization step and a detection step.

[0038] In the zero calibration process, before the polishing pad and the polishing platen are attached, that is, before the capacitive pressure sensor is triggered, the machine itself will automatically perform zero point detection to ensure that the output of the sensor is zero or close to zero before the polishing pad and the polishing platen are tightly attached, that is, when no pressure is applied. If the zero point output of the sensor exceeds the standard, it means that the zero point deviation of the sensor is out of range and calibration is required.

[0039] In the pressurization link, when the grinding pad fits tightly with the grinding platen, the capacitive pressure sensor is triggered, and the grinding pad applies a certain pressure to the capacitive sensor. In the capacitive pressure sensor, the grinding pad pressure acts on the movable plate, causing the plate to displace. This displacement causes the distance between the plates to change, which in turn affects the capacitance value. If the grinding pad fits tightly with the grinding platen, when the pressure increases, the distance between the plates decreases, and the capacitance value increases; conversely, if the grinding pad does not fit tightly with the grinding pad, when the pressure decreases, the distance between the plates increases, and the capacitance value decreases, the internal transducer converts these capacitance values ​​into electrical signals, and amplifies them through the circuit and connects them to the machine alarm device.

[0040] In the detection stage, according to the weight of the polishing pad itself, the trigger value for judging whether the polishing pad and the grinding disc are tightly fitted is set to 5V (or 5N). If the voltage value detected is 5V (or 5N) when the grinding disc is rotating, it means that the polishing pad and the grinding disc are tightly fitted. If the voltage value detected is between 0V-2.9V (or 0N~2.9N), it means that the polishing pad and the grinding disc are not tightly fitted, thus triggering the machine alarm.

[0041] Specifically, applicable technology nodes include 55nm, 40nm, or less than or equal to 28nm.

[0042] In summary, the method for detecting whether the polishing pad and the polishing disc are in contact with each other in the present invention is to install a pressure sensor at the center of the polishing disc. When the polishing pad is attached to the polishing disc, it contacts the pressure sensor and is triggered. The machine can be restored normally after PM to perform subsequent operations. Therefore, the present invention effectively overcomes various shortcomings in the prior art and has a high industrial utilization value.

[0043] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A method for detecting whether a polishing pad and a polishing disc are in contact with each other, characterized in that: The method comprises: A pressure sensing device is installed in the grinding disc for chemical mechanical grinding, and the pressure sensing device is connected to the alarm device of the grinding machine to detect whether the grinding pad and the grinding disc are tightly fitted.

2. The method for detecting whether a polishing pad and a polishing disc are in contact with each other according to claim 1, characterized in that: The pressure sensing device is resistant to acid and alkali corrosion and rust.

3. The method for detecting whether a polishing pad and a polishing disc are in contact with each other according to claim 1, characterized in that: The pressure sensing device is installed at the center of the grinding disc.

4. The method for detecting whether a polishing pad and a polishing disc are in contact with each other according to claim 1, wherein: The pressure sensing device has a pressure detecting portion, the top of which is flush with the surface of the grinding disc, and the surface is the surface that is in contact with the grinding pad.

5. The method for detecting whether a polishing pad and a polishing disc are in contact with each other according to any one of claims 1 to 4, characterized in that: The pressure sensing device includes a capacitive pressure sensor.

6. The method for detecting whether a polishing pad and a polishing disc are in contact with each other according to claim 5, characterized in that: The method for judging whether the grinding pad and the grinding disc are closely fitted comprises: The polishing pad is placed naturally on the polishing disc, and a natural pressure value is obtained by the pressure sensor; The grinding pad is attached to the grinding disc, and the grinding disc is rotated; Determine whether the pressure value obtained according to the pressure sensor is less than the natural pressure value and fluctuates between 0 and the natural pressure value. If the judgment result is yes, it means that they are not tightly fitted. If the pressure obtained according to the pressure sensor is a preset trigger value and remains unchanged, it means that the polishing pad and the polishing disc are tightly fitted.

7. The method for detecting whether a polishing pad and a polishing disc are in contact with each other according to claim 6, characterized in that: The trigger value is 5N.

8. The method for detecting whether a polishing pad and a polishing disc are in contact with each other according to claim 6, wherein: The natural pressure value is 3N.

9. The method for detecting whether a polishing pad and a polishing disc are in contact with each other according to claim 6, wherein: If the polishing pad is not in close contact with the capacitive pressure sensor, the capacitive pressure sensor will not be triggered and will output an alarm signal, and the machine PM will sound an alarm after the machine is restored.

10. The method for detecting whether a polishing pad and a polishing disc are in contact with each other according to claim 1, characterized in that: Applicable technology nodes include 55nm, 40nm or less than or equal to 28nm.

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