CN109946305A - A non-contact detection mechanism for blade wear for wafer cutting - Google Patents

Abstract

The invention relates to a non-contact detection mechanism for blade wear for wafer cutting, wherein a pulse generating circuit is used to send out a pulse signal to control a blade mounted on a Z axis to move to a worktable; the laser sensor is used to detect the blade Whether the height measurement position is reached; the signal conversion circuit converts the received current signal into a high-level signal when the laser sensor detects that the blade has reached the height measurement position and transmits it to the motion controller. After the high-level signal, the Z-axis driver is controlled to return the blade on the Z-axis. The pulse receiving circuit is used to receive the number of pulses sent by the pulse generating circuit in the whole process; the height measuring circuit is set according to the number of pulses obtained. The pulse equivalent calculates the wear of the blade. The invention has the characteristics of high precision, good stability and high safety.

Description

A non-contact detection mechanism for blade wear for wafer cutting

technical field

The invention relates to the technical field of wafer cutting, in particular to a non-contact detection mechanism for blade wear used for wafer cutting.

Background technique

Wafer cutting equipment is an important equipment in the semiconductor processing industry. It is mainly used for the processing of brittle and hard materials such as silicon integrated circuits and wafers. The processing method is contact removal material processing.

During processing, the system controls the Z-axis to drive the blade down to scribe the wafer. During the processing, the tool is constantly worn, and after each processing is completed, the Z-axis will return to a fixed position. If the wear amount of the tool is not measured, the corresponding cutting depth will gradually become shallower, resulting in the wafer not being cut through. Therefore, it is necessary to know the wear status of the tool, so that the system can control the tool to drop to an appropriate position for compensation, so as to ensure a constant depth of penetration of the wafer; therefore, it is necessary to perform a corresponding detection operation of the blade wear amount.

The traditional blade wear detection adopts the contact height measurement method, which uses a certain voltage between the blade and the worktable, accesses the A/D conversion and R/V conversion circuits, and finally judges the difference between the blade and the blade by calculating the resistance through the voltage change. Whether the worktable is in contact, and then calculate the wear amount of the tool through the calculation formula. On the one hand, because the resistance values of different types of blades from different manufacturers are often quite different, the span from tens of ohms to hundreds of thousands of ohms is very large, and it is difficult to achieve when switching between large resistance and small resistance blades. High-precision height measurement can still be achieved; on the other hand, the air spindle generates an induced electromotive force on the metal shell of the spindle, and the air spindle is easily affected by the surrounding environment such as water and air, resulting in the voltage between the two when the blade and the table are not in contact. There will be a certain value change, which will affect the measurement accuracy. Alternatively, a loop is formed when the blade is in contact with the worktable, and the current signal is converted into a falling edge or a rising edge signal through the conversion circuit, and the system captures this pulse signal to determine whether the blade is in contact with the worktable, and then wear the blade through the pulse position. amount is calculated. No matter what the method is, the principle is contact height measurement. Disadvantages of this method: (1) The blade and the worktable are damaged to a certain extent at the contact point of height measurement; (2) If the system does not respond in time or the signal fails after contact, the blade fails to lift in time, which will cause the blade to cut into the work. The machine is seriously damaged, causing a safety accident.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a blade wear non-contact detection mechanism for wafer cutting, which has the characteristics of high precision, good stability and high safety.

The technical solution adopted by the present invention to solve the technical problem is to provide a non-contact detection mechanism for blade wear for wafer cutting, which includes a pulse generating circuit, a pulse receiving circuit, an altimetry circuit, a laser sensor, a signal conversion circuit, A motion controller and a Z-axis driver, the pulse generating circuit is used to send out a pulse signal to control the blade mounted on the Z-axis to move to the worktable; the laser sensor is used to detect whether the blade reaches the height measuring position; the signal conversion When the laser sensor detects that the blade has reached the height measuring position, the circuit converts the received current signal into a high-level signal and transmits it to the motion controller. After receiving the high-level signal, the motion controller controls the Z-axis driver to make The blade on the Z axis is returned, and the pulse receiving circuit is used to receive the number of pulses sent by the pulse generating circuit in the whole process; the height measuring circuit calculates the wear amount of the blade according to the obtained number of pulses combined with the set pulse equivalent.

The height measuring circuit calculates the wear amount of the blade by ΔR=R-(Z-n×PE), where R represents the original radius of the blade, Z represents the vertical distance between the center of the blade circle and the laser sensor in the Z-axis direction at the initial position, and n represents the height measurement The total number of pulses in the process, PE represents the set pulse equivalent.

The worktable is composed of two layers of materials, namely a ceramic layer and a metal layer, wherein the metal layer is grounded.

The laser sensor includes a laser emitting device and a laser receiving device, and the laser emitting device and the laser receiving device are arranged opposite to each other, and both are located between the blade and the worktable.

The pulse generating circuit, the pulse receiving circuit and the height measuring circuit are integrated on a circuit board.

beneficial effect

Compared with the prior art, the present invention has the following advantages and positive effects due to the adoption of the above-mentioned technical solution: the present invention detects whether the blade is in place through a laser sensor, and calculates the wear amount of the blade by the number of pulses in the height measurement process, The test results have the characteristics of high precision, good stability and high safety, and can adapt to the height measurement of different types of blades from different manufacturers.

Description of drawings

Fig. 1 is a schematic diagram of the present invention;

Fig. 2 is the circuit diagram of the laser sensor receiving device in the present invention;

Fig. 3 is a schematic diagram of the blade wear detection of the present invention.

Detailed ways

The present invention will be further described below in conjunction with specific embodiments. It should be understood that these examples are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

Embodiments of the present invention relate to a non-contact detection mechanism for blade wear used in wafer cutting, as shown in FIG. 1 , including a pulse generating circuit 3 , a pulse receiving circuit 4 , an altimetry circuit 5 , a laser sensor 6 , and a signal conversion circuit. Circuit 7, motion controller 8 and Z-axis driver 9, the pulse generating circuit 3 is used to send out a pulse signal to control the blade 1 installed on the Z-axis to move to the table 2; the laser sensor 6 is used to detect the blade 1 Whether the height measurement position is reached; the signal conversion circuit 7 converts the received current signal into a high-level signal when the laser sensor 6 detects that the blade reaches the height measurement position and transmits it to the motion controller 8. The motion controller 8. After receiving the high-level signal, control the Z-axis driver 9 to return the blade on the Z-axis, and the pulse receiving circuit 4 is used to receive the number of pulses sent by the pulse generating circuit 3 in the whole process; the height measuring circuit 5 Calculate the wear amount of the blade according to the obtained pulse number combined with the set pulse equivalent.

Wherein, the blade 1 is installed on the Z axis, and is controlled by the Z axis to move up and down; the worktable 2 is composed of two layers of materials, which are divided into a metal layer and a ceramic layer, and the metal layer is grounded. The pulse generating circuit 3 includes the following contents: transistors, resistors, potentiometers, capacitors, and the like.

As shown in Figure 2, the output of the laser sensor receiving device is an analog current output signal. When the laser is received, the signal pin generates a high-level signal, and when no laser is received, the signal pin generates a low-level signal. The signal conversion circuit 6 is integrated in the 4N25 optocoupler to convert the analog current signal into the switch output signal. When the current signal is received, it becomes a high-level signal, that is, 1, and it is a low-level signal when no current signal is received. flat, which is 0.

As shown in FIG. 3 , the working principle of this embodiment is: during system design, the vertical distance between the laser sensor and the workbench in the Z direction is calibrated. After the control system issues the altimetry command, firstly start the air spindle to drive the blade to rotate at the altimetry speed, and then start the pulse generator circuit 3 to send out pulses to control the Z axis to descend to the position close to the laser sensor 6 at a fast speed, and then slowly When the blade 2 reaches the height measuring position, it blocks the laser emitted by the laser sensor transmitter, and the laser sensor receiver cannot receive the laser signal, and the output current The analog signal is converted from high level to low level, and the signal conversion circuit 6 converts the received current signal into a high level signal. The system receives the high level signal and considers that the height measurement has been completed, and issues a command to immediately raise the Z axis back to its original position. , the air spindle stops. The altimetry circuit will count the number of pulses sent out by the system in the whole process, and then combine the set pulse equivalent and the distance calibration value between the laser sensor and the working disk in the Z-axis direction to calculate the wear amount of the blade, so as to complete the altimetry operation. The specific calculation formula is: ΔR=R-(Z-n×PE), where R represents the original radius of the blade, Z represents the vertical distance between the center of the blade and the laser sensor in the Z-axis direction at the initial position, and n represents the total height during the height measurement process. The number of pulses, PE represents the set pulse equivalent.

It is not difficult to find that the invention detects whether the blade is in place through the laser sensor, and calculates the wear amount of the blade by the number of pulses in the process of height measurement, so that the detection result has the characteristics of high precision, good stability and high safety, and can adapt to different Height measurement of different types of blades from manufacturers.

Claims (5)

1. a blade wear non-contact detection mechanism for wafer cutting, comprising a pulse generating circuit, a pulse receiving circuit, an altimeter circuit, a laser sensor, a signal conversion circuit, a motion controller and a Z-axis driver, it is characterized in that, The pulse generating circuit is used to send out a pulse signal to control the blade mounted on the Z-axis to move to the worktable; the laser sensor is used to detect whether the blade has reached the height measuring position; the signal conversion circuit is used to detect whether the blade has reached the laser sensor. When measuring the height position, the received current signal is converted into a high-level signal and transmitted to the motion controller, and the motion controller controls the Z-axis driver to return the blade on the Z-axis after receiving the high-level signal. The pulse receiving circuit is used for receiving the pulse quantity sent by the pulse generating circuit in the whole process; the height measuring circuit calculates the wear amount of the blade according to the obtained pulse quantity combined with the set pulse equivalent. 2 . The non-contact detection mechanism of blade wear for wafer cutting according to claim 1 , wherein the height measuring circuit calculates the amount of blade wear by ΔR=R-(Z-n×PE), wherein R Represents the original radius of the blade, Z represents the vertical distance between the center of the blade and the laser sensor in the Z-axis direction at the initial position, n represents the total number of pulses in the height measurement process, and PE represents the set pulse equivalent. 3 . The non-contact detection mechanism for blade wear for wafer cutting according to claim 1 , wherein the worktable is composed of two layers of materials, which are a ceramic layer and a metal layer, wherein the metal layer is grounded. 4 . 4. The non-contact detection mechanism for blade wear for wafer cutting according to claim 1, wherein the laser sensor comprises a laser emitting device and a laser receiving device, and the laser emitting device and the laser receiving device are opposite to each other. set, and both are located between the blade and the table. 5 . The non-contact detection mechanism for blade wear for wafer cutting according to claim 1 , wherein the pulse generating circuit, the pulse receiving circuit and the height measuring circuit are integrated on a circuit board. 6 .