JPH04167986A - Laser beam machining apparatus - Google Patents

Abstract

PURPOSE:To improve reliability of machining and the yield by measuring insulating resistant value in a sample, deciding machined quality at each scribed line, repeating the scribe-machining at the same position until this measured result satisfies the specification and raising laser beam power in the following machining by the prescribed quantity. CONSTITUTION:As a laser beam oscillator 1, Q switch YAG laser beam is used and the laser beam 11 is oscillated and this output is selected according to the sample 6. The laser beam electric source 2 supplies the necessary power and signal to the laser beam oscillator. Control signal to the laser beam oscillator is supplied from control system 10. A machining head deforms the laser beam to the desired form and the laser beam irradiates under condensing on the sample. Probes 8a, 8b are constituted with one set of two pieces and each interval of the probes is suitably set according to interval of the scribed line in the sample. Insulating resistant value in the sample is measured and the scribe machining is repeated or the laser beam power is raised by the prescribed quantity until the measured result satisfies the specification. By this method, the reliability is improved and the yield is improved.

Description

TECHNICAL FIELD The present invention relates to a laser processing apparatus, and more particularly to laser processing in which a thin film is scribed using a laser beam.

BACKGROUND OF THE INVENTION In recent years, devices for scribing thin film samples using laser light have been put into practical use.

For example, as shown in FIG. 5, a laser beam is applied to a sample 6 on which a conductive thin film (hereinafter referred to as thin film) 63 of tin oxide or indium oxide is deposited on the surface of a substrate 64 made of glass or metal. 11, and sample 6 or laser beam 1.
1 is scanned in a straight line to perform the scribing process.

In this case, patterns 6 on the left and right of the scribe line 61a
The final purpose is to electrically insulate 2a and 62b, and the insulation resistance must be greater than loOMl).

If the laser processing by the laser beam 11 is insufficient, the thin film 63 may be left in the middle of the scribe lines 61a to 61d.
If these remain, the insulation resistance of the patterns 62a to 62d deteriorates, resulting in scribing failure.

Here, as shown in FIG. 6, the laser processing device that performs the above laser processing includes a laser oscillator 1, a laser power source 2 that supplies power to the laser oscillator 1, and a laser beam that transmits the laser beam from the laser oscillator 1. an optical fiber 3 to be processed, a processing head 4 for condensing the laser beam, a stage 5 for scanning the processing head 4 in the X-axis direction and the Y-axis direction, and a stage 5 for placing the sample 6. It consists of a table 7 and a control system 10 that controls the laser power source 2 and the stage 5.

Usually, a Q-switched YAG laser is used as the laser oscillator 1, and the laser power and repetition frequency of this Q-switched YAG laser are determined by the material and film thickness of the sample 6, and the scanning speed.

For example, in the case of an ITO film of about 100 OA, the laser power is several W when the repetition frequency is 20 Kt+z and the scanning speed is 100 m/S.

As shown in FIG. 7(a), when the processing head 4 consists of a beam expander 41 and a condensing lens 42, the shape of the laser beam 11 on the surface of the sample 6 is circular.
The scribe pattern at this time has a circular arc or continuous shape, as shown in FIG. 8(a).

The scribe width g of the second scribe pattern is 1 laser beam
If the focal length of the condensing lens 42 is f, the diameter of the laser beam 11 incident on the condensing lens 42 is D, and the laser wavelength is λ, then N-4λf/(π
D).

Furthermore, as shown in FIG. 7(b), an imaging optical system may be used in the processing head 4.

That is, the aperture 43 is placed in front of the condenser lens 42.
/f-1/St +1. If the arrangement is such that the relational expression /S2 holds true, the image of the aperture 43 is 32 /S1
Since the image is reduced twice and formed on the sample 6, the aperture 4
By changing 3, there is an advantage that an arbitrary processed shape can be obtained.

When the aperture 43 is a rectangular opening, the scribe pattern has a rectangular or continuous shape as shown in FIG. 8(b), so there is an advantage that the erroneous part of the scribe pattern is on a straight line.

Here, the interval d between each laser spot is determined by the laser repetition frequency ν and the scanning speed ■, and c3−v/
There is a kind of relationship.

For example, when the repetition frequency is 20 Kllz and the scanning speed is -100 mm/s, d-'B+m is obtained.

Therefore, when the spot diameter is about 20I1m, each laser pulse is 3. The processed shape overlaps by about /4.

The control system 10 controls the laser power, repetition frequency, and stage 5 described above.

In the conventional method of processing the W film 63 using the laser beam 11, as long as the laser oscillator, pressure head 4, stage 5, etc. remain in the same state as at the time of initial adjustment, the quality of the laser processing can be improved. That is, the insulation resistance of the patterns 62a to 62d is maintained.

However, it is normal for the laser oscillator 1, the processing nozzle 4, and especially the laser beam oscillator 1 to deteriorate over time, and as this deterioration occurs, the laser power decreases, so the scribe width g and scribe line 61, a~ The depth of 61d is insufficient, and the insulation resistance of the patterns 62a to 62d becomes lower than the desired value.

Normally, the insulation resistance of the patterns 62a to 62d is measured using a separate measuring device after the entire sample 6 has been scribed.

If a defective product occurs in the sample 6, it is necessary to re-scribe the defective part under the same conditions or increase the laser power a little, and then re-inspect it, which makes the work extremely complicated.

In addition, when scribing again, it is difficult to scribe on the same line as the previous time unless the XY stage is very precise, and in normal cases, the scribing position will be shifted and the scribing width g will be There is a risk that the pattern width and scribe width may become wider and the specification values for pattern width and scribe width may not be satisfied.

Therefore, there is a problem in that the processing quality is not guaranteed until it is inspected with a different measuring device, and even if the scribing process is redone, it does not necessarily go well.

Purpose of the Invention The present invention has been made to eliminate the problems of the conventional methods as described above, and provides a laser that can improve the reliability of scribing processing and improve the yield of scribed samples. The purpose is to provide processing equipment.

Composition of the Invention A laser processing apparatus according to the present invention is a laser processing apparatus that performs scribing processing on a thin film on a sample using a laser beam, and insulating the thin film divided by the scribing processing in synchronization with the scribing processing. A measuring means for measuring the resistance, and when the measurement result of the measuring means is less than a predetermined value set in advance, control is performed to perform scribing processing on the same processing location, and the laser power of the laser beam used for the next scribing processing is controlled to a predetermined value. The present invention is characterized in that it is provided with a control means for controlling to increase the amount by a fixed amount.

Example Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention.

In the figure, a laser processing apparatus according to an embodiment of the present invention includes a laser oscillator 1, a laser power supply 2 that supplies power to the laser oscillator 1, an optical fiber 3 that transmits laser light from the laser oscillator 1, and a laser A heating device 4 for condensing light, a stage 5 for scanning the processing head 4 in the X-axis direction and the Y-axis direction, a stage 7 on which the sample 6 is placed, and a sample 6, a resistance measuring device 9, and a control system 10 controlling the laser power source 2 and stage 5 according to the measurement results of the resistance measuring device 9.

A Q-switched YAG laser is used as the laser oscillator 1, which generates a laser beam 1 with a wavelength of 106 μm.

Further, the laser oscillator 1 has a laser output horn of several W to several ±W class, and the laser output is selected according to the sample 6.

Furthermore, the Q-switch frequency of the laser oscillator 1 is determined according to the laser power of the laser beam 11 and the scanning speed of the stage 5.

On the other hand, depending on the sample 6, a second harmonic generation element and a laser oscillator with a wavelength of 053 μm may be used, and other solid lasers or gas lasers may be used.

A laser power source 2 supplies the laser oscillator 1 with necessary power and signals. Note that control signals to the laser oscillator 1 such as laser power, repetition frequency, and start and stop of oscillation are supplied from a control system 10.

The optical fiber 3 is used to guide the laser beam 11 emitted from the laser oscillator 1 to the processing head 4. This optical fiber 3 is used because the processing head 4 is moved and scanned by the stage 5.

Therefore, when the sample 6 is moved and scanned without moving the processing head 4 for scanning, an ordinary mirror optical system may be used without using the optical fiber 3.

A processing head 4 receives a laser beam 1 incident from an optical fiber 3.
1 into a desired shape and then focuses the laser beam 11 onto the sample 6. As in the past, it consists of a beam expander, a focusing lens, and in some cases an aperture. .

The stage 7 is for placing and fixing the sample 6, and is usually adapted to be applied to samples 6 of various shapes.

The probes 8a, 8b are composed of a set of two, and the interval between the probes 8a, 8b can be set as appropriate depending on the interval between the scribe lines of the sample 6.

The resistance measuring device 9 is for measuring the resistance value M1 between the two probes 8a and 8b, and has a function of converting the measurement result into an electrical signal and outputting it to the control system 10. Note that the electric signal may be either an analog voltage or an A/D (analog/digital) converted digital signal.

The control system 10 reads the electrical signal from the resistance M1 regulator 9 at any time, and the electrical signal from the resistance measuring instrument 9 is set to a desired value (usually 100
(approximately MΩ) or higher.

FIG. 2 is a perspective view of the stage 7 shown in FIG. 1. In the figure, a sample 6 placed on a stage 7 is scribed with a laser beam 11, and a scribe line 61 a - 61 is formed.
d and patterns 62a to 62d are formed.

The probes 8a and 8b are driven by a drive mechanism 1 fixed to the stage 7.
2, the specimen 6 is moved while maintaining a set interval corresponding to the interval between the scribe lines 6]a to 61d.

This drive mechanism 12 moves the probes 8a and 8b arbitrarily according to commands from the control system 1o, and when measuring resistance, the probes 8a and 8b are moved according to commands from the control system 1o.
8b in contact with the surface of the sample 6, and when moving the probe 8b.
a, 8b away from the surface of the sample 6.
, 8b also perform up-down operations.

FIG. 3 is a flowchart showing the operation of one embodiment of the present invention. The operation of one embodiment of the present invention will be explained using these FIGS. 1 to 3.

First, move the processing head 4 and probes 8a, 8b to the first scribing position (step 21 in FIG. 3),
The probes 8a and 8b are brought into contact with the surface of the sample 6.

At the same time that the laser beam 11 is emitted from the laser oscillator 1, the processing head 4 is moved and scanned by the stage 5 to perform scribing processing (step 22 in FIG. 3).

When the movement of the machining head 4 by the stage 5 is completed, the laser oscillation of the laser oscillator 1 is stopped, and the insulation resistance between the patterns 62a to 62d formed by the strip machining is measured by the resistance measuring device 9 (step in FIG. 3). 2
3).

The control system 10 determines whether the insulation resistance between the patterns 62a to 62d exceeds a desired value based on the electrical signal from the resistance measuring device 9 (step 24 in FIG. 3).

When the control system 10 determines that the insulation resistance between the patterns 62a to 62d is greater than or equal to the desired value, it determines whether the scribing process or reprocessing is to be performed (step 25 in FIG. 3).
If it is determined that the scribing process is not reworking, the process moves to the next 1+1th scribing process (step 26 in FIG. 3).

When the control system 10 determines that there is no insulation between the patterns 62a to 62d, it starts the first scribing operation 7L again.
is executed, and it is determined based on the electric signal from the resistance measuring device 9 whether the insulation resistance between the patterns 62a to 626 is equal to or greater than the desired value (step 2 in FIG. 3).
2-24).

At this time, the control system 10 determines that the insulation resistance between the patterns 62a to 62d is equal to or higher than a desired value, and
If it is determined that the scribe process or reprocessing is required (step 24.25 in Figure 3), the laser power is set to a predetermined value (for example, when moving to the next 1+1 scribe process (step 27 in Figure 3) (about 10-6) t; Raise (step 28 in Figure 3).

Thereafter, the above-described operation is repeated to perform scribing on the sample 6.

However, if the insulation resistance between the patterns 62a to 62d does not exceed the desired value even after scribing to the same location a preset number of times, an abnormality will be detected and the device operation will be stopped and the device should be inspected and Readjust.

Note that the rate of increase in laser power during reprocessing and the limit value for the number of repetitions may be set to optimal values by conducting experiments in advance depending on the sample 6.

This embodiment is characterized by controlling the laser power or by changing the command value sent from the control system 10 to the laser power supply 2 itself. For example, in the case of a YAG laser, the input terminal setting to the excitation lamp is All you have to do is change the value.

As mentioned above, the processing quality can be checked for each scribe line 61a to 61b by measuring the insulation resistance value of the sample 6 using the probes 8a, 8b and the resistance measuring device 9 at the same time as the scribing process is performed on the sample 6 using the processing head 4. Pass/fail judgment can be made.

In addition, even if the processing quality is rejected, it can be rescued by re-scribing the sample 6 using the processing nozzle 4, which improves the reliability of the equipment and the yield of the sample 6. be able to.

FIG. 4 is a block diagram showing another embodiment of the present invention. In the figure, in another embodiment of the present invention, an attenuator 13 is installed in the processing head 4, and the laser power of the laser beam 11 from the processing head 4 to the sample 6 is adjusted by this attenuator 13. The structure is similar to that of the first embodiment, and the same parts are given the same reference numerals. Further, the operations of these same parts are also similar to those in the embodiment of the present invention.

If the control system 10 determines that the insulation resistance between the patterns 62a to 62d is equal to or higher than the desired value, and determines that the scribing process is re-processing, the control system 10 leaves the command value to the laser power source 2 as is, and continues to operate the laser. Power supply 2 to laser oscillator 1
By controlling the attenuator 13, the laser power of the laser beam 11 from the processing plate 4 to the sample 6 is increased by a predetermined value while input power to the sample 6 is kept at a constant optimum value.

As a result, fluctuations in laser power are reduced, laser processing can be performed in a very stable state, and processing quality and reliability can be further improved.

In this way, in synchronization with the scribing process on the sample 6 by the processing head 4, the insulation resistance value of the sample 6 is measured by the probes 8a, 8b and the resistance II regulator 9, and the processing quality is evaluated for each of the slide lines 61a to 61d. The reliability of the scribing process is improved by repeatedly scribing the same processed area until the measurement result satisfies the standard, and by increasing the laser power of the laser beam 11 used for the next scribing process by a predetermined amount. It is possible to improve the yield of the scribed sample 6.

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, the insulation resistance value of the sample is measured in synchronization with the scribing process for the thin film on the sample, and the process quality is determined for each slide line, and the measurement results or standards are determined. The reliability of scribing can be improved by repeating the scribing process on the same processing location until the scribing process is satisfied, and by increasing the laser power of the laser beam used for the next scribing process by a predetermined amount. This has the effect of improving the yield of sample.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing one embodiment of the present invention, and FIG.
FIG. 3 is a flowchart showing the operation of one embodiment of the present invention, FIG. 4 is a configuration diagram showing another embodiment of the present invention, and FIG. 5 is a perspective view of the mounting table shown in FIG. A diagram showing scribing processing, Fig. 6 is a configuration diagram showing a conventional example, Fig. 7 (a) is a diagram showing a processing optical system of a conventional example, and Fig. 7 (b) is an image formed on a processing optical system of a conventional example. FIG. 8(11) is a diagram showing the scribing shape using the optical system in FIG. 7(a), and FIG. 8(b) is the same as in FIG. 7(b).
) is a diagram showing the scribed shape by the processing optical system. Explanation of symbols of main parts 1...-Laser oscillator 2...Laser power supply 6...Sample 7...Mountain stage 8a, 8b...Probe 9/Resistance measuring device 10 Control System] 1 Laser beam 12 Drive mechanism 13 Attenuators 61a to 61d ・Scribe lines 62a to 62d
Pattern ■ Applicant NEC Corporation Agent Patent Attorney Excerpt It Ill Letter Figure 1 Figure 2 Figure 4 Zb 71 (a) 8 (Q) Figure (b) Figure (b)

Claims (1)

[Claims] (1) A laser processing device that performs a scribing process on a thin film on a sample using a laser beam, and a measuring means that measures the insulation resistance of the thin film divided by the scribing process in synchronization with the scribing process; When the measurement result of the measuring means is less than or equal to a predetermined value, the control means controls to perform a scribing process on the same processing location, and also controls to increase the laser power of the laser beam used for the next scribing process by a predetermined amount. A laser processing device characterized by being provided with.