JPH08309575A - Laser beam machine - Google Patents

Abstract

PURPOSE: To provide a laser beam machine capable of accurately detecting the light quantity not emitted on an object to be machined in the case where the shutter is closed during laser irradiation. CONSTITUTION: An optical reflector means 126 for reflecting machining laser beams 104a at the time of stoppage of a shutter mechanism 122 is provided in that shutter mechanism 120, 122 which is arranged in the optical path of the machining laser beams 104a generated from a laser light source 102 and which is freely closed or opened. As a result, a reflected light beam 104c reflected by the optical reflector means 126 is received by a light quantity detector 112, causing the shutter mechanism 120 to be closed, and thereby enabling the accurate detection of the light quantity not emitted on an object 206 to be machined.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser processing apparatus.

[0002]

2. Description of the Related Art In a semiconductor manufacturing process, a spare cell (redundancy circuit) is previously provided in a circuit, and when a defect is found in a part of cells as a result of circuit inspection by a probe device or the like, By performing a so-called redundancy process for replacing a defective cell with a spare cell, the generation of defective chips is relieved and the yield is improved. Such redundancy processing irradiates a special circuit (fuse circuit) formed in a chip with a high-energy laser spot light to cut it by a so-called laser processing device, or a laser spot light is applied to a high resistance wiring layer. This is done by irradiating to reduce the resistance.

By the way, such a laser processing apparatus scans and condenses a processing laser generating section for generating a processing laser beam and a laser beam emitted from the processing laser generating section and mounts it on a stage. It is mainly composed of a laser processing part for irradiating the work piece. The processing laser generation unit is integrally housed in the housing, and supplies laser light to the laser processing unit as necessary. A shutter mechanism that can be opened and closed is provided at the laser emission port of the housing. This shutter mechanism is driven to open and close in response to a signal from the controller, and is automatically closed if any abnormality occurs in the device even during laser irradiation, shutting off laser light irradiation. Is configured to.

In order to detect the open / closed state of the shutter, in the conventional laser processing apparatus, an open / closed state detector is attached to the shutter to detect the open / closed state of the shutter. The open / closed state detector detects the open / closed state of the shutter by including, for example, a fin attached to the shutter and a detector that optically detects the operation of the fin.

[0005]

In the conventional apparatus as described above, in order to detect the closing of the shutter during laser irradiation, a mechanism for constantly monitoring the open / closed state detector provided in the shutter must be provided. There was a problem that it could not be done. Further, since the detector only detects the open / closed state of the shutter, there is a problem in that it is impossible to detect the amount of light that has not been irradiated to the workpiece because the shutter is closed during irradiation.

The present invention has been made in view of the problems of the conventional laser processing apparatus as described above. Even if the shutter open / close state detector and a mechanism for constantly monitoring the same are not provided, laser irradiation is performed. An object of the present invention is to obtain a laser processing apparatus capable of detecting that a shutter is closed therein, and being able to determine the amount of light that has not been irradiated to the workpiece by closing the shutter.

[0007]

In order to solve the above problems, the present invention provides a laser light source (1) which emits a processing laser beam.
02) and its processing laser light to form spot light and irradiate it onto the workpiece (206).
4), and a shutter mechanism (120, 1 which is openable / closable) arranged in the optical path of the processing laser beam.
22) and a light reflecting means (126) for reflecting the processing laser light when the shutter mechanism (120, 122) is closed.
And a light quantity detector (112) for receiving the processing laser light reflected by the light reflecting means (126).

Further, according to the present invention, when the shutter mechanism (120, 122) is closed and the processing is restarted, the shutter mechanism (120, 122) is responsive to the light amount detected by the light amount detector (112). The output amount of the processing laser light after the laser beam is released again is determined.

[0009]

In the above structure, when the shutter mechanism (120, 122) is closed during laser irradiation, the processing laser light is reflected by the light reflecting means (126),
Since the light amount detector (112) is irradiated, simply by monitoring the output of the light amount detector (112), without using a shutter open / close state detector or the like which is necessary for a conventional laser processing apparatus, The shutter mechanism (12
0, 122) can be detected to be closed.

Further, since the light quantity of the processing laser light which has not been irradiated to the work piece due to the closing of the shutter mechanism (120, 122) can be obtained by the light quantity detector (112), the residual quantity remains when the processing is restarted. It is possible to irradiate the object to be processed (206) with the laser light for processing of the amount of light necessary for the above processing without excess or deficiency.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a laser processing apparatus according to the present invention will be described in detail below with reference to the accompanying drawings. 1 is a block diagram showing a schematic structure of a laser processing apparatus according to the present invention, and FIG. 2 is a shutter mechanism 1.
It is a block diagram which expands and shows 20.

As shown in FIG. 1, a laser processing apparatus according to the present invention includes a processing laser generator 100 for generating a processing laser beam 104a and a processing laser generator 100.
A laser processing section 200 that scans and collects the processing laser beam 104a emitted from the laser beam and irradiates the workpiece 206 placed on the stage 208 with the laser processing section 200, and the processing laser generating section 100 and the laser processing section 200. The control unit 300 mainly controls the operation of the above.

The processing laser generator 100 includes a processing laser light source 102, a beam expander 106 for expanding a laser beam 104 emitted from the laser light source 102 into a larger parallel beam, and an expanded laser beam 104. A beam splitter 108 for separating the processing laser beam 104a and the monitoring laser beam 104b is provided. Further, the processing laser generation unit 100 uses the laser light 10 for monitoring separated by the beam splitter 108.
4b and semi-transmissive mirror 110, and semi-transmissive mirror 1
The laser beam 104b for monitoring reflected by the laser beam 10b (and the mirror 126 of the shutter mechanism 120 as described later).
Light amount detector 1 for receiving the reflected light 104c) reflected by
It has twelve. Further, the processing laser generator 100
Is a mirror 114 for reflecting the processing laser beam 104a separated by the beam splitter 108, and the laser processing unit 2
A shutter mechanism 120 capable of blocking the processing laser beam 104a emitted to the laser beam 00 is provided. And
The above-mentioned members forming the processing laser generation unit 100 are integrally housed in the housing 130.

The shutter mechanism 120 will be described with reference to FIG. As shown, the shutter mechanism 120
Is installed in the vicinity of the opening 132 of the housing 130, and a shutter 122 that opens and closes the opening 132,
A shutter drive device 124 that drives the shutter 122
It has. Further, a mirror 126 is attached to the housing side of the shutter 122. As shown by the solid line in FIG. 2, when the shutter 122 is closed, the processing laser beam 104a is reflected and the semi-transmissive mirror 110 is turned on. It is possible to send to the light amount detector 112 via the light source. Note that the dotted line in the figure indicates the optical path through which the processing laser beam 104a is emitted to the laser processing section 200 when the shutter 122 is opened.

Returning to FIG. 1 again, the laser processing unit 200 of the laser processing apparatus will be described. Laser processing unit 200
Includes a laser scanning system 202, a condensing optical system 204 that condenses a processing laser, and a stage 208 on which a workpiece 206 such as a wafer is placed. Stage 208
Is driven by a drive mechanism (not shown) in the X direction, Y direction, Z direction,
It can be driven in the θ direction, and the main controller 302
It is possible to optimally position the processing position of the processed portion 206 (that is, the irradiation position of the processing laser light) based on the wafer error map stored in advance.

The control section 300 is mainly composed of a main controller 302 and an interface means 304 composed of a CRT and a keyboard. The main controller 302 is
The shutter drive information and the light amount information are received from the shutter drive mechanism 120 and the light amount detector 112, and an optimum control command corresponding to the information is output to the laser light source 102, the shutter drive mechanism 120, the laser scanning system 202, the stage 208, and the like. By doing so, the laser processing apparatus can be optimally controlled. Further, the main controller 302 outputs the processing state of the laser processing apparatus to the CRT of the interface means 304, and the operator issues a necessary command to the interface means 30.
4 can be input to the main controller 302 from the keyboard.

Next, the operation of the laser processing apparatus according to the present invention will be described by taking as an example the case where the redundancy processing is performed on the wafer by the laser processing apparatus.
In order to better understand the effect of the device of the present invention, in the middle of the redundancy process, for example, a fail-safe mechanism works to close the shutter 122, which shuts off the emission of the processing laser 104a and confirms the safety. After
Laser processing shall be restarted again.

First, the stage 208 is driven to align the workpiece 206 at a predetermined processing position based on an error map for the workpiece 206 stored in the main controller 302 in advance. Then, a command is sent to the shutter mechanism 120 to open the shutter 122 and oscillate the laser light source 102. The laser beam 104 emitted from the laser light source 102 is expanded into a larger parallel beam through the beam expander 106, and is transmitted through the beam splitter 108 to be separated into a processing laser beam 104a and a monitoring laser beam 104b.

The monitor laser beam 104b is reflected from the beam splitter 108 by the semi-transmissive mirror 110 and received by the light amount detector 112. The light amount detector 112 appropriately outputs the detected value to the main controller 302. The main controller 302 determines the stage 208 of the laser processing unit 200 based on the detected value.
It is possible to obtain the light amount of the processing laser light 104a with which the workpiece 206 placed on the workpiece is irradiated.

On the other hand, the processing laser beam 104a is reflected by the mirror 114 from the beam splitter 108 and reaches the shutter mechanism 120. Since the shutter 122 of the shutter mechanism 120 is opened during laser processing, the processing laser beam 104 a is applied to the opening 132 of the housing 130.
And is emitted to the laser processing unit 200. In the laser processing unit 200, the processing laser beam 104a is scanned by the laser scanning system 202 so as to accurately irradiate the processing position of the workpiece 206, and then focused by the focusing system 204 into spot light. By irradiating the processing position of the processing unit 206, predetermined laser processing (for example, cutting of a fuse circuit) is performed.

Here, the operation when the shutter 122 is closed by the operation of a safety mechanism (not shown) during laser processing will be described. In the conventional laser processing apparatus, in order to detect that the shutter is closed during laser irradiation, it is necessary to provide an open / closed state detector on the shutter and constantly monitor the output thereof. Further, it was not possible to detect the light amount of the processing laser light that was not applied to the workpiece due to the shutter being closed during the irradiation.

In this respect, in the laser processing apparatus according to the present invention, when the shutter 122 is closed, the processing laser beam 10 is used.
Reference numeral 4a denotes a mirror 126 provided inside the shutter 122.
Is reflected by. Therefore, the processing laser beam 104a
Does not go out to the outside of the housing 130, and its reflected light 104c passes through the semi-transmissive mirror 110 and is received by the light amount detector 112. As described above, the detection value of the light amount detector 112 is output to the main controller 302 at any time, and the main controller 302 changes the detection value to change the shutter 1
It is possible to detect that 22 is closed.

As described above, according to the present invention, even if a shutter open / closed state detector is provided and its output is not monitored, the shutter 122 can be easily changed from the output of the light amount detector 112.
You can know that he was closed. Further, since the change of the light quantity can be directly detected by the light quantity detector 112, the work piece 2 is
It is possible to easily and accurately obtain the light amount of the processing laser light 104a that is not irradiated on the light beam 06. As described above, according to the present invention, it is possible to easily and accurately obtain the light amount of the processing laser beam 104a which is insufficient due to the interrupted processing, and therefore the laser processing is restarted after the safety of the laser processing apparatus is confirmed. Sometimes, the laser beam for processing 10
The workpiece 206 can be accurately irradiated with 4a.
Therefore, even if the laser processing is interrupted, the processing can be completed without making the workpiece being processed defective, and the yield can be improved. Note that these processing states are the CRT of the interface 304.
Is output appropriately, so that the operator can directly control the laser processing apparatus if necessary.

The preferred embodiment of the laser processing apparatus according to the present invention has been described above with reference to the drawings.
The present invention is not limited to such examples, and those skilled in the art can make various modifications and changes within the scope of the technical idea described in the claims.
Needless to say, these are also included in the technical scope of the present invention.

For example, in the above embodiment, the mirror 1
Although the reflected light 104c reflected by 26 is received by the same detector as the light amount detector 112 for receiving the monitor laser light 108, the light amount detector for the monitor laser light and the reflected light 104c are received. It is also possible to separately form the light amount detector of. In the above embodiment,
Taking a laser processing device for redundancy processing as an example,
Although the present invention has been described, it is needless to say that the present invention is not limited to such an embodiment and can be applied to all kinds of laser processing apparatuses in which an openable / closable shutter mechanism is arranged in the optical path of the processing laser light. .

[0026]

As described above, according to the present invention, the fact that the shutter (122) arranged in the optical path of the processing laser beam is closed during laser irradiation can be easily and easily detected by the light amount detector (112). Since it can be accurately detected, the light amount of the processing laser light that has not been emitted to the workpiece (206) due to the closing of the shutter (122) can be accurately obtained. Therefore, after the processing is restarted, the shortage of laser light can be radiated to the work piece (206) without excess or deficiency, so that even when the processing is interrupted, the work piece (206) being processed is defective. It is possible to end the processing without doing so, and it is possible to improve the yield.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a schematic configuration of a laser processing apparatus according to the present invention.

FIG. 2 is an explanatory view showing an enlarged shutter mechanism portion applied to the laser processing apparatus shown in FIG.

[Explanation of symbols]

 100 Processing Laser Generation Unit 102 Laser Light Source 104 Laser Beam 104a Processing Laser Light 104b Monitoring Laser Light 104c Reflected Light 112 Light Quantity Detector 120 Shutter Mechanism 122 Shutter 124 Shutter Drive Device 126 Mirror 200 Laser Processing Unit 300 Control Unit 302 Main Control vessel

Claims (2)

[Claims] 1. A laser light source that emits a processing laser beam,
In a laser processing apparatus having a condensing optical system for condensing the processing laser light to form a spot light and irradiating it onto a workpiece, an openable and closable optical fiber arranged in the optical path of the processing laser light. A shutter mechanism, a light reflecting means for reflecting the processing laser light when the shutter mechanism is closed, and a light quantity detector for receiving the processing laser light reflected by the light reflecting means. Laser processing equipment. 2. The output amount of the processing laser light after the shutter mechanism is reopened is determined according to the light amount detected by the light amount detector.
The laser processing apparatus described in.