KR100870710B1 - Method of monitoring malfunction of galvano scanner - Google Patents

Abstract

A scanner malfunction sensing method is provided to sense whether a scanner is out of order during laser marking, increase the accuracy of the marking, and stop unnecessary marking on a substrate by the scanner which is out of order, thereby increase work efficiency. A laser enable signal in which a laser enable section for emitting a laser beam(10) is included is generated. In order to move scanners(71,72) to a target location, target location data is inputted to the scanner. Actual location data measuring the current location of the scanner moved by the target location data is acquired. A location error value which is the difference between actual position data and target location data in the laser enable section is calculated. When the location error value is greater than the critical value which is the reference for determining whether the scanner malfunctions, the malfunction of the scanner is processed.

Description

Detection of scanner malfunction {Method of monitoring malfunction of galvano scanner}

1 shows a schematic configuration of a typical laser marking system.

2 shows an example of a conventional data flow in the laser marking system of FIG.

3 is a diagram illustrating an example of a process of marking using draw data and jump data;

4 is a diagram illustrating a data flow for implementing a scanner malfunction detection method according to an embodiment of the present invention using the laser marking system of FIG. 1.

5 is a diagram illustrating a position error value masked by a laser enable signal.

<Description of the symbols for the main parts of the drawings>

10 laser oscillator 20 laser controller

30: control unit 40: computer

50: D / A converter 61, 62: scanner driver

71, 72: Scanner 100: Laser Marking System

The present invention relates to a method for detecting a scanner malfunction. Specifically, a laser is calculated by calculating an error between position data input to the scanner and position data measured after the actual scanner is moved while laser marking a character or a figure using the scanner. The present invention relates to a scanner malfunction detection method capable of determining whether marking is normal.

The laser marking system refers to a system for marking desired characters, figures, etc. on a substrate such as a semiconductor package or a lower surface of a wafer using a laser beam.

1 is a view showing a schematic configuration of a general laser marking system, Figure 2 is a view showing an example of a conventional data flow in the laser marking system of Figure 1, Figure 3 is a marking using the draw data and jump data It is a figure which shows an example of a process.

1 to 3, the laser marking system 100 measures the intensity and frequency of the laser oscillator 10 from which the laser beam 1 is emitted, and the laser beam 1 emitted from the laser oscillator 10. A scanner for marking letters or figures while the laser controller 20 for adjustment and the mirrors 73 and 75 are moved by a predetermined angle to irradiate the incident laser beam 1 to a desired position on the substrate 2. 71 and 72 are provided. The mirrors 73 and 75 are respectively mounted to the motors 74 and 76 so as to be able to rotate about the axes of the motors 74 and 76 called galvanometers. In addition, a computer 40 for controlling the entire laser marking system 100 is provided, and the control unit 30 for controlling the scanners 71, 72 and the laser controller 20 inside the computer 40. Is installed.

Data for controlling the scanners 71 and 72 is output from the control unit 30 and input to the scanners 71 and 72 through the D / A converter 50 and the scanner drivers 61 and 62. do. For example, digital scanner data corresponding to any one of values in the range of 0 to 65535 is output from the control unit 30. The digital scanner data is converted into analog scanner data corresponding to any one of voltage values in the range of -3V to + 3V by the D / A converter 50 and transmitted to the scanner drivers 61 and 62. . In order to irradiate a laser beam to a desired position on the substrate 2, the incident angle and the reflection angle between the laser beam 1 and the mirrors 73 and 75 are adjusted by moving the mirrors 73 and 75 to a desired position. Determine the irradiation position of the laser beam. As such, data for moving the scanners 71 and 72 to the target position is called target position data, and the target position data is input from the scanner driver 61 and 62 to the scanner 71 and 72 side. .

Meanwhile, FIG. 3 illustrates a process of marking a "TV" character using the laser marking system 100. The target position data includes draw data, which is data for moving the scanners 71 and 72 while the laser beam 1 is emitted, and moves the scanners 71 and 72 while the laser beam is not emitted. Jump data, which is data to be included. As shown in FIG. 3, the scanner 71 and 72 are moved by mixing the draw data and the jump data over the P1 to P8 points, thereby enabling marking using a laser.

In a conventional laser marking system, the target position data is scanned without checking whether the scanner mirror is properly moved by the target position data transmitted from the scanner driver to the scanner side, that is, whether the laser beam is correctly irradiated to a desired position on the substrate. Was sent unilaterally from the scanner side. In the conventional data flow system, since the marking by the laser beam is not performed when the scanner is moved by the jump data, the measured position data measuring the position after the target position data and the scanner mirror are actually moved. Even if the error is large, it does not matter much. However, when the scanner is moved by the draw data, the marking by the laser beam is performed. Therefore, when the error between the target position data and the measured position data becomes large, it means that the accurate marking is not performed at the desired position. This deterioration problem occurs.

As described above, in the conventional laser marking system, since there is no feedback process for checking whether the scanner is moved to the correct position according to the movement command, even if an error occurs in the laser marking due to a malfunction of the scanner during the actual marking process, There was a problem that there was no way to prevent.

The present invention has been made to solve the above-mentioned problem, and in real time by calculating the error between the target position to move the scanner and the actual position after the scanner while the laser beam is irradiated on the substrate during the marking process In order to detect a malfunction of a scanner, an object of the present invention is to provide a scanner malfunction detection method that can improve the accuracy of laser marking and prevent a decrease in production efficiency due to abnormal marking.

In order to achieve the above object, the scanner malfunction detection method of the present invention is a method used to mark a desired character or figure by using a scanner for irradiating a laser beam to a desired position on a substrate, so that the laser beam is emitted. Generating a laser enable signal including a laser enable period; Inputting target position data into the scanner to move the scanner to a target position; Acquiring measured position data of measuring a current position of the scanner moved by the target position data; Calculating a position error value that is a difference value between the target position data and the measured position data within the laser enable period; And treating the scanner as a malfunction of the scanner when the position error value is larger than a threshold that is a reference for determining whether the scanner malfunctions.

In the scanner malfunction detection method according to the present invention, preferably, the calculating step includes: calculating a position error value that is a difference between the target position data and the measured position data within and outside the laser enable period; And masking the position error value by using the laser enable signal to leave the position error value corresponding to the target position data input within the laser enable period.

In the scanner malfunction detection method according to the present invention, preferably, the target position data is input within the laser enable period while moving the scanner from an initial position at which the marking starts to an end position at which the marking ends. And draw data to be moved, and jump data input outside the laser enable period by moving the scanner from an end position at which the previous marking ends to an initial position at which the next marking starts, wherein the laser enable The position error value corresponding to the target position data input within the section is a difference value between the draw data and the measured position data.

In the scanner malfunction detection method according to the present invention, preferably, a difference value between the draw data and the measured position data is smaller than a difference value between the jump data and the measured position data.

Hereinafter, a preferred embodiment of a scanner malfunction detection method according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 4 is a diagram illustrating a data flow for implementing a scanner malfunction detection method according to an embodiment of the present invention using the laser marking system of FIG. 1. FIG. 5 is a diagram illustrating a position error value masked by a laser enable signal. It is a figure which shows.

As shown in FIG. 1, the laser marking system 100 to which the scanner malfunction detection method of the present invention is applied includes a laser oscillator 10 from which the laser beam 1 is emitted, and a laser emitted from the laser oscillator 10. The laser controller 20 for adjusting the intensity and frequency of the beam 1 and the mirror 73 and 75 are moved by a predetermined angle to irradiate the incident laser beam 1 to a desired position on the substrate 2. It is provided with a scanner (71, 72) for marking a character or figure. The mirrors 73 and 75 are mounted to the motors 74 and 76, respectively, called galvanometers, and are rotatable based on the axes of the motors 74 and 76.

In addition, a computer 40 for controlling the entire laser marking system 100 is provided, and the control unit 30 for controlling the scanners 71, 72 and the laser controller 20 is provided inside the computer 40. It is installed. Referring to FIG. 4, a signal for controlling a laser and a signal for controlling a scanner are output from the control unit 30.

The signal for controlling the laser includes a laser enable signal and a laser modulation signal.

The laser enable signal is a signal for controlling whether the laser beam 1 is emitted or not. In the laser enable period, the laser beam 1 is emitted from the laser oscillator 10 and the laser beam 1 is outside the laser enable period. ) Is stopped.

The laser modulation signal is a signal for modulating the frequency of the pulsed laser beam. The laser modulation signal is combined with the laser enable signal and applied to the laser controller 20 and the laser oscillator 10 to have a predetermined frequency. Is output.

The signal for controlling the scanners 71 and 72 includes a signal for controlling the angles of the mirrors 73 and 75 to irradiate the laser beam 1 to a desired position on the substrate 2.

The signals for controlling the angles of the mirrors 73 and 75 are output from the control unit 30 as digital data (digital scanner data), and are converted into analog data through the D / A converter 50. (Analog scanner data). The analog scanner data is input to the scanners 71 and 72 through the scanner drivers 61 and 62, whereby the position control of the scanners 71 and 72 is possible.

Data for deflecting the mirrors 73 and 75 at a desired angle, that is, data for moving the scanners 71 and 72 to a target position is called target position data. The target position data includes draw data and jump data.

The draw data is for moving the scanners 71 and 72 from an initial position at which the marking starts to an end position at which the marking ends, and is synchronized with the laser enable section. Is entered. The jump data is for moving the scanners 71 and 72 from an end position where the previous marking ends to an initial position where the next marking starts, and is input outside the laser enable section. That is, the draw data is data for moving the scanners 71 and 72 to a desired position while the laser beam is emitted and the laser marking is performed, and the jump data is simply to prepare for the next marking while the laser beam is not emitted. The data moves the scanners 71 and 72 to the initial point of marking.

When the movement of the scanners 71 and 72 is completed by the target position data, the current position value of the scanner is measured, and the measured position data is measured by measuring the actual position of the scanners 71 and 72 which have been moved. It is called. The scanner drivers 61 and 62 detect the positions of the current mirrors 73 and 75 when the scanners 71 and 72 are moved by the target position data. Thus, the scanner drivers 61 and 62 detect the positions of the current mirrors 73 and 75. The data detected and measured by the data is the actual position data.

In the scanner drivers 61 and 62, the difference between the target position data and the measured position data is calculated. This difference is referred to as a position error value. Since the position error value is a measure reflecting the difference between the target position to which the laser beam is to be irradiated and the actual laser beam irradiation position, the position error value is a criterion for determining whether the laser marking quality is good.

Hereinafter, a method of detecting a scanner malfunction according to the present embodiment in marking desired characters or figures using the laser marking system 100 configured as described above will be described with reference to FIGS. 1, 4, and 5. Shall be.

The target position data is input to the scanners 71 and 72 to move the mirrors 73 and 75 to the target positions. In addition, a laser enable signal is also generated to perform laser marking while the scanners 71 and 72 are moved. Since the draw data section and the laser enable section are synchronized, the marking by the actual laser beam is performed only while the scanners 71 and 72 are moved by the draw data.

When the mirrors 73 and 75 are moved to a predetermined position by the draw data and the jump data, the measured position data is obtained by measuring the position where the mirrors 73 and 75 are actually moved.

Inside the circuit of the scanner drivers 61 and 62, a position error value which is a difference between the target position data transmitted to the scanner 71 and 72 side and the measured position data obtained as described above is calculated. Since the actual laser marking is performed by the draw data and only a simple movement is performed by the jump data, it is common to make the marking speed by the draw data slower than the movement speed by the jump data for precise laser marking. Therefore, when looking at the position error value calculated as described above, the difference between the draw data and the measured position data is smaller than the difference between the jump data and the measured position data.

Thereafter, the position error value is masked using the laser enable signal. In general, masking means that when the first signal includes useful data and ineffective data, the first signal is combined with the first signal by combining a second signal different from the first signal, thereby leaving useful data from the first signal. Ineffective data is the process of elimination. Since the actual laser beam is emitted and the marking is a section in which draw data is input, the position error value corresponding to the jump data becomes ineffective regardless of the numerical value. Therefore, the position error value corresponding to the jump data generated outside the laser enable period through the masking process is removed, and only the position error value corresponding to the draw data generated within the laser enable period is left.

As shown in FIG. 5, a position error value generated within a laser enable period is compared with a threshold that serves as a reference for determining whether the scanners 71 and 72 malfunction. In this case, the threshold is preset in the circuit of the scanner driver 61 (62), and if the position error value is smaller than the threshold value, it means that the scanner operates normally within the allowable error range, If the position error value is greater than the threshold, the scanner is said to be malfunctioning.

The comparison result of the position error value and the threshold value is transmitted from the scanner driver 61, 62 to the computer 40 side using an RS-232 communication cable.

In the scanner malfunction detection method according to the present embodiment as described above, data for moving the scanner to a target position and a position where the actual scanner is moved while marking a character or a figure while irradiating a laser beam onto a substrate is performed. By comparing the measured data, it is possible to know whether the scanner malfunctions or performs abnormal marking. Therefore, if an error occurs in the position accuracy during laser marking, the error can be detected in real time. Since the marking operation can be stopped, the production efficiency can be improved.

Meanwhile, as mentioned above, since the moving speed of the scanners 71 and 72 due to the draw data is slow, the position error value corresponding to the draw data is smaller than the position error value corresponding to the jump data. At this time, if the threshold value is set high based on the position error value corresponding to the jump data, the position error value corresponding to the draw data becomes difficult to pass the threshold value set as described above. Therefore, it is not possible to check whether the scanners 71 and 72 malfunction in the marking process at all, and the marking operation is continuously performed while the precision of the marking is ignored. However, if the threshold value is set too low based on the position error value corresponding to the draw data, the scanner always detects a malfunction because the position error value corresponding to the jump data having no value exceeds the threshold value set at the low level. .

Therefore, the scanner malfunction detection method according to the present embodiment sets a threshold value for determining whether the scanner malfunctions using only position error values generated within the laser enable period, that is, corresponding to the draw data in which the actual marking is performed. As a result, it is possible to accurately detect whether the scanner actually malfunctions during the marking process.

Although the preferred embodiments and modifications have been described above, the scanner malfunction detection method according to the present invention is not limited to the above-described examples, and the modifications or combinations of the examples are within the scope not departing from the technical spirit of the present invention. Various types of scanner malfunction detection methods may be embodied in the following.

The scanner malfunction detection method of the present invention can detect the malfunction of the scanner in real time during the laser marking, improve the accuracy of the marking, and stop the unnecessary marking of the substrate using the malfunctioning scanner to improve the overall production efficiency. There is an effect that can be improved.

In addition, the scanner malfunction detection method according to the present embodiment, since the threshold value for determining whether the scanner malfunctions by setting only the position error value generated within the section where the actual laser marking is made, occurs in the marking process The effect is to accurately detect the actual error.

Claims (4)

A scanner malfunction detection method used to mark a desired character or figure using a scanner for irradiating a laser beam to a desired position on a substrate, Generating a laser enable signal including a laser enable period for causing the laser beam to be emitted; Inputting target position data into the scanner to move the scanner to a target position; Acquiring measured position data of measuring a current position of the scanner moved by the target position data; Calculating a position error value that is a difference value between the target position data and the measured position data within the laser enable period; And And treating the scanner as a malfunction of the scanner when the position error value is larger than a threshold which is a reference for determining whether the scanner is malfunctioning. The calculating step, Calculating a position error value which is a difference between the target position data and the measured position data within and outside the laser enable period; And masking the position error value by using the laser enable signal, leaving the position error value corresponding to the target position data input within the laser enable period. How to detect malfunctions. delete The method of claim 1, The target position data is, The scanner is moved from an initial position at which the marking starts to an end position at which the marking ends, and draw data input within the laser enable section and the next marking starts from an end position at which the previous marking ends. A jump data input outside the laser enable period and moving the scanner to an initial position; And a position error value corresponding to the target position data input within the laser enable period is a difference value between the draw data and the measured position data. The method of claim 3, And a difference value between the draw data and the measured position data is smaller than a difference value between the jump data and the measured position data.

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