CN106956216B - An online monitoring device for grinding and polishing processing status - Google Patents

Abstract

An on-line monitoring device for grinding and polishing processing status, which is characterized in that it includes a grinding and polishing disc (1) driven by a motor on a ring polishing machine and a retaining ring (4) driven by another motor to rotate, and the grinding and polishing disc (1) ) is installed with a polishing pad (3), a wafer carrier (2) is installed in the retaining ring (4), and the workpiece (5) is installed on the lower part of the wafer carrier (2) and driven by the retaining ring The light pad (3) is used for relative grinding and polishing, and the sensor (6) is installed on the wafer carrier (2). The sensor (6) is electrically connected to the signal conditioning circuit (7) fixedly installed on the platform (10). The signal conditioning circuit (7) is electrically connected to the data collector (8) fixedly installed on the platform (10), and the data collector (8) is connected to the computer through a conductive slip ring (9); the platform is installed on Keep the ring (4) on and rotate synchronously. The invention has low requirements on equipment, low cost and convenient operation.

Description

An online monitoring device for grinding and polishing processing status

technical field

The invention relates to the field of precision and ultra-precision machining, in particular to a finishing monitoring technology, in particular to an online monitoring device for grinding and polishing processing status based on sensor technology, high-speed data collection and processing.

Background technique

With the rapid development of optics, optoelectronics, integrated circuits and material technology, the requirements for surface quality of material processing are becoming higher and higher. In addition, some functional materials have broad application prospects and demands in optics, electronics, instrumentation, aerospace and other fields due to their unique properties. Most of the above materials use ultra-precision grinding and polishing as their processing methods, such as the commonly used chemical mechanical polishing (CMP). However, at present, many essential phenomena in grinding and polishing processing, such as the mechanism of material removal, the form of abrasive grain movement, and the influence of different process conditions, cannot be well explained, which makes it difficult to improve the surface quality of the wafer, and the production efficiency is low. It is not easy to realize problems such as automatic control. For example, when the workpiece has scratches and other defects during the polishing process and has not been removed, the polishing effect will not be achieved when the predetermined time for polishing is terminated. In addition, at present, the polishing efficiency and the quality of the workpiece after polishing need to be stopped and measured offline, which leads to waste of time and cost.

Chinese patent CN1726116A discloses a polishing state monitoring device, a polishing device and a method. The invention uses the light emitted by the light source to apply to the workpiece, and then uses a spectroscope to divide the reflected light reflected by the collected workpiece into light rays of respective wavelengths. The light receiving element will detect The light is converted into electrical information. By collecting the electrical information, the spectral data of the reflected light is obtained. Based on the obtained spectral data, the eigenvalues of the workpiece surface are calculated, and the polishing state is judged by the eigenvalues. Chinese patent CN102192928A discloses a device and method for monitoring the polishing state of a glass plate. The position measuring unit of the invention obtains the position of the glass plate using the polishing machine, and the current measuring unit obtains the current flowing into the polishing machine. By comparing the current values corresponding to different positions with the The reference value is compared to determine whether the polishing state is faulty.

All the above-mentioned on-line detection devices have the problems of complex structure, complex processing process, great influence from external interference, and low precision, which need to be solved.

Contents of the invention

The purpose of the present invention is to design a simple structure, easy to use, which can monitor the processing state of grinding and polishing online, quickly and accurately, in view of the existing on-line detection devices that have complex structures, are greatly affected by external interference, and have low precision. On-line monitoring device for grinding and polishing processing status.

The technical scheme adopted in the present invention is:

An on-line monitoring device for grinding and polishing processing status is characterized in that it includes a grinding and polishing disc 1 driven by a motor on a ring polishing machine and a retaining ring 4 driven by another motor to rotate, and a grinding and polishing disc is installed on the grinding and polishing disc 1. The wafer carrier 2 is installed in the pad 3 and the holding ring 4, and the workpiece 5 is installed on the lower part of the wafer carrier 2 and is ground and polished relative to the pad 3 under the drive of the holding ring. 2 is equipped with a sensor 6, the sensor 6 is electrically connected with the signal conditioning circuit 7 fixedly installed on the platform 10, the signal conditioning circuit 7 is electrically connected with the data collector 8 fixedly installed on the platform 10, and the data collector 8 is electrically connected through a conductive slide The ring 9 is connected with the computer; the platform is installed on the retaining ring 4 and rotates synchronously.

The sensor 6 is used to monitor the physical quantity during the grinding and polishing process and convert it into an electrical signal; it is composed of one or more of an acoustic emission sensor, a load sensor, a temperature sensor and an acceleration sensor.

The signal conditioning circuit performs necessary amplification, filtering, attenuation, excitation, multiplexing, etc. on the signal collected by the sensor.

The data collector collects the conditioned electrical signal, converts the analog signal into a digital signal, and preprocesses the data.

The computer monitors the grinding and polishing process and predicts the result by using a signal processing method according to the collected signals.

The sensor is fixed on the wafer carrier by a sensor fixture.

The rotating inner ring of the conductive slip ring 9 is fixed on the central axis of the platform 10 and connected with the data collector 8; the stationary outer ring is connected with the computer.

The beneficial effects of the present invention are:

The invention monitors the grinding and polishing state online through various sensors, and can measure various physical quantities such as acoustic emission, force, and vibration and display them in real time. Therefore, the operator can take appropriate operations according to the measured grinding and polishing state, so as to improve the processing efficiency and quality.

The present invention collects multiple physical quantities at the same time and considers them comprehensively, can obtain more comprehensive processing state information, and is beneficial to realize the control of the grinding and polishing process.

In addition, the on-line monitoring device proposed by the present invention is adapted to the traditional ring throwing machine, which has low requirements on equipment, low cost and convenient operation.

Description of drawings

Fig. 1 is a functional block diagram of the grinding and polishing on-line monitoring device of the present invention.

Fig. 2 is a structural diagram of the grinding and polishing on-line monitoring device of the present invention.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings and embodiments.

as shown in picture 2.

An on-line monitoring device for grinding and polishing processing status, which includes a grinding and polishing disc 1, a wafer carrier 2, a retaining ring 4, a sensor 6, a signal conditioning circuit 7, a data collector 8 and a computer, and the grinding and polishing disc 1 is composed of a motor Driven, the retaining ring 4 is driven by another motor to rotate, and the grinding and polishing pad 3 is installed on the grinding and polishing disc 1, and the wafer carrier 2 is installed in the retaining ring 4, and the workpiece 5 is installed on the bottom of the wafer carrier 2 and Driven by the retaining ring, it is ground and polished relative to the light pad 3. A sensor 6 is installed on the wafer carrier 2. The sensor 6 is electrically connected to the signal conditioning circuit 7 fixedly installed on the platform 10. The signal conditioning circuit 7 is electrically connected to the data collector 8 fixedly installed on the platform 10, and the data collector 8 is connected to the computer through a conductive slip ring 9; the platform is installed on the retaining ring 4 and rotates synchronously. The sensor 6 is used to monitor the physical quantity in the grinding and polishing process and convert it into an electrical signal; it is composed of one or more of an acoustic emission sensor, a load sensor, a temperature sensor and an acceleration sensor. The signal conditioning circuit performs necessary amplification, filtering, attenuation, excitation, multiplexing, etc. on the signal collected by the sensor. The data collector collects the conditioned electrical signal, converts the analog signal into a digital signal, and preprocesses the data. The computer monitors the grinding and polishing process and predicts the result by using a signal processing method according to the collected signals. The sensor is fixed on the wafer carrier by a sensor fixture. The rotating inner ring of the conductive slip ring 9 is fixed on the central axis of the platform 10 and connected with the data collector 8; the stationary outer ring is connected with the computer.

Example 1:

For example, during the grinding and polishing process, the acoustic emission sensor installed on the wafer carrier collects the acoustic emission signal generated by the abrasive particles and the workpiece, and the weak current signal obtained by the sensor is amplified and filtered through the signal conditioning circuit, and the data is collected. The device collects the processed analog voltage signal with a sampling rate of 2M and a resolution of 16 bits, and converts it into a digital signal and transmits it to the computer for display and storage. By analyzing the signal on the computer side, such as performing wavelet transformation on the signal, when the signal characteristics corresponding to the scratch defect of the workpiece appear, the operator can perform appropriate operations on the grinding and polishing process to improve the processing status of the grinding and polishing; The mathematical relationship between the intensity of the emission signal and the removal rate of grinding and polishing materials, through the calculation of the intensity of the acoustic emission signal during the processing, the material removal rate of grinding and polishing is estimated.

Example 2:

For example, in the process of chemical mechanical polishing, the load sensor installed on the wafer carrier collects the resistance in the horizontal direction between the workpiece and the polishing pad, and the electrical signal collected by the sensor is amplified and filtered through the signal conditioning circuit. The 16-bit resolution of the data collector collects the processed analog voltage signal, converts it into a digital signal and transmits it to the computer to realize the display and storage functions. By analyzing the signal on the computer side, such as using the friction resistance in the horizontal direction of the workpiece and the pressure in the vertical direction, the friction coefficient between the workpiece and the polishing pad can be calculated, and the polishing liquid can be obtained by comparing the friction coefficients obtained by different calculations. To determine the type of softened layer qualitatively produced by the chemical action of the polishing fluid workpiece; to establish the mathematical relationship between the friction resistance and the removal rate of the grinding and polishing material, and to estimate the grinding and polishing material through the calculation of the friction resistance in the process removal rate.

Example 3:

For example, during the grinding and polishing process, the acceleration sensor installed on the wafer carrier collects the vibration signal of the wafer carrier and the workpiece, and the signal conditioning circuit performs necessary amplification and filtering on the electrical signal collected by the sensor. The data collector The processed analog voltage signal is collected with 16-bit resolution, converted into digital signal and transmitted to the computer to realize display and storage functions. By analyzing the signal on the computer side, such as vibration signal strength analysis, a relationship model between vibration signal strength and surface roughness is established, and the surface roughness of the processed workpiece is estimated by calculating the vibration signal strength.

The working principle of the present invention is:

As shown in Figure 1.

1. When grinding and polishing, the grinding and polishing pad on the ring polishing machine is driven by the motor, and another motor drives the workpiece under the wafer carrier through the retaining ring to generate relative rotation, thereby realizing the grinding and polishing of the workpiece .

2. The sensor collects the physical quantity in the grinding and polishing process and converts it into an electrical signal. The electrical signal is amplified and filtered by the signal conditioning circuit, and then sent to the data collector. The data collector converts the analog voltage signal into a digital signal and passes it through. Send it to the computer, and realize the display, storage and processing of the signal through the computer. The collected signals can be processed and analyzed on the computer side to obtain the processing status of grinding and polishing, so that appropriate operations can be taken.

The preferred embodiment of the present invention has been illustrated, and various changes or modifications may be made by those skilled in the art without departing from the scope of the present invention.

The parts not involved in the present invention are the same as the prior art or can be realized by adopting the prior art.

Claims (4)

1. An on-line monitoring device for grinding and polishing processing status, which is characterized in that it includes a grinding and polishing disc (1) driven by a motor on the ring polishing machine and a retaining ring (4) driven by another motor to rotate. A polishing pad (3) is installed on (1), a wafer carrier (2) is installed in the retaining ring (4), and the workpiece (5) is installed on the lower part of the wafer carrier (2) and driven by the retaining ring The grinding and polishing process is performed opposite to the grinding and polishing pad (3), and the sensor (6) is installed on the wafer carrier (2), and the sensor (6) and the signal conditioning circuit (7) fixedly installed on the platform (10) ), the signal conditioning circuit (7) is electrically connected to the data collector (8) fixedly installed on the platform (10), and the data collector (8) is connected to the computer through a conductive slip ring (9); the platform Installed on the holding ring (4) and rotate synchronously; the sensor (6) is used to monitor the physical quantity in the grinding and polishing process and convert it into an electrical signal; one of the acoustic emission sensor, load sensor, temperature sensor and acceleration sensor The sensor is fixed on the wafer carrier by the sensor fixture; the rotating inner ring of the conductive slip ring (9) is fixed on the central axis of the platform (10), and the data collector ( 8) Connected to each other; the stationary outer ring is connected to the computer; the grinding and polishing state is monitored online through a variety of sensors, and the physical quantities of acoustic emission, force, and vibration are measured and displayed in real time, so that the operator can take appropriate actions according to the measured grinding and polishing state. operation, improve processing efficiency and quality. 2. The on-line monitoring device for grinding and polishing processing status according to claim 1, characterized in that said signal conditioning circuit performs necessary amplification, filtering, attenuation, excitation, multiplexing, etc. on the signal collected by the sensor. 3. The on-line monitoring device for grinding and polishing processing status according to claim 1, characterized in that said data collector collects conditioned electrical signals, converts analog signals into digital signals, and preprocesses the data. 4. The on-line monitoring device for grinding and polishing processing status according to claim 1, characterized in that said computer uses a signal processing method to monitor the process of grinding and polishing and predict the results according to the collected signals.