JP2005262229A - Laser marking apparatus and method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser marking apparatus capable of marking a plurality of fine patterns with high accuracy over a wide range on a workpiece. <P>SOLUTION: In the laser marking apparatus 1, a laser beam L emitted from a laser generator 5 is reflected on the reflection mirrors 11 and 13 of a scanner 10 for fine patterns, then reflected on the reflection mirror 21 of a positioning scanner 20, and finally converged on the workpiece 50 through an fθ lens 30. In this instance, the reflection mirrors 11 and 13 of the scanner 10 for fine patterns are designed to be rotated around mutually independent rotary axes by galvano meters 12 and 14, the prescribed fine patterns are marked in arbitrary minute sections 50a on the workpiece 50. In addition, the reflection mirror 21 of the positioning scanner 20 is designed to be given two-dimensional rotary freedom by a gonio-stage 22. Thus, the region in which the fine patterns are marked is positioned in the arbitrary minute sections 50a on the workpiece 50 by the scanner 10 for fine patterns. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a laser marking apparatus that marks (engraves) an arbitrary pattern such as a character or a figure on a workpiece using laser light, and more particularly, a plurality of fine patterns over a wide range on the workpiece. The present invention relates to a laser marking apparatus and a laser marking method suitable for marking a pattern with high accuracy.

  Conventionally, as this type of laser marking device, a laser beam is scanned two-dimensionally by a pair of reflecting mirrors held by a pair of galvanometers for the X-axis and the Y-axis, thereby allowing any arbitrary on the workpiece A method of marking a pattern such as a character or a figure at a position is known (see Patent Document 1).

By the way, there are various uses for such a laser marking device. For example, when laser marking is performed on a semiconductor wafer in which a plurality of semiconductor chips are arranged in a grid pattern, a relatively large area is used. It is necessary to mark a fine pattern on each semiconductor chip located on a semiconductor wafer having
Japanese Patent No. 2700022

  However, in the above-described conventional laser marking apparatus, when the apparatus is designed on the assumption that marking is performed over a wide range on the workpiece, the full stroke of each galvanometer for scanning the laser beam is set on the workpiece. There is a problem in that it becomes necessary to assign the entire marking range, and the resolution at a minute angle necessary for marking a fine pattern is insufficient. On the other hand, if the device is designed on the premise of the resolution at the small angle required to mark a fine pattern, the full stroke of each galvanometer for scanning the laser beam can be applied to the entire marking range on the workpiece. It becomes impossible to assign, and it becomes difficult to perform marking over a wide range on the workpiece.

  The present invention has been made in consideration of such points, and provides a laser marking apparatus and a laser marking method capable of marking a plurality of fine patterns with high accuracy over a wide range on a workpiece. For the purpose.

  As a first solution, the present invention provides a laser marking apparatus for marking an arbitrary pattern such as a character or a figure on a workpiece using a laser beam, a laser oscillator for emitting a laser beam, and the laser oscillator Scanning the laser beam emitted from the laser oscillator and the laser beam emitted from the laser oscillator for marking a fine pattern within a narrow range on the workpiece by two-dimensionally scanning the laser beam emitted from the laser beam Thus, there is provided a laser marking apparatus comprising a positioning scanner for positioning a range where a fine pattern is marked by the fine pattern scanner at an arbitrary position on the workpiece.

  In the first solving means of the present invention, the fine pattern scanner includes at least a pair of reflecting mirrors that reflect laser light, and a rotation drive mechanism that rotates the reflecting mirrors around independent rotation axes. It is preferable to have.

  In the first solving means of the present invention, the positioning scanner includes a reflection mirror that reflects laser light, and a holding drive mechanism that holds the reflection mirror and provides the reflection mirror with a two-dimensional rotational degree of freedom It is preferable to have. The positioning scanner may include at least a pair of reflecting mirrors that reflect laser light, and a rotation drive mechanism that rotates the reflecting mirrors around independent rotation axes.

  Furthermore, in the first solving means of the present invention, it is preferable that the positioning scanner is disposed at a subsequent stage of the fine pattern scanner on the optical path of the laser light emitted from the laser oscillator.

  Furthermore, it is preferable that the first solving means of the present invention further includes a control device that integrally controls the fine pattern scanner and the positioning scanner.

  In the first solving means of the present invention, the workpiece is preferably a semiconductor wafer in which a plurality of semiconductor chips to be marked with a fine pattern are arranged in a grid pattern.

  As a second solution, the present invention provides a laser marking method for marking an arbitrary pattern such as a character or a figure on a workpiece using a laser beam. The laser beam emitted from a laser oscillator is used for a fine pattern. By scanning two-dimensionally with a scanner, a fine pattern is marked within a narrow range on the work piece, and the laser light emitted from the laser oscillator is scanned with a positioning scanner, thereby forming a fine pattern. A laser marking method is provided, in which a range where a mark is marked is positioned at an arbitrary position on the workpiece.

  According to the present invention, the marking range on the workpiece is divided into a plurality of minute sections, and fine pattern marking in each of these minute sections is performed by scanning the laser beam with a fine pattern scanner, The movement (positioning) between the minute sections is performed by scanning the laser beam with a positioning scanner. For this reason, two conflicting requirements of high resolution at a small angle and movement over a wide range can be realized by a two-stage scanner called a fine pattern scanner and a positioning scanner. Individual fine patterns can be marked with high accuracy.

BEST MODE FOR CARRYING OUT THE INVENTION

  Embodiments of the present invention will be described below with reference to the drawings.

  First, a laser marking device according to an embodiment of the present invention will be described with reference to FIG. In the present embodiment, as shown in FIG. 1, the marking range on the workpiece 50 is divided into a plurality of minute sections 50a, and the same minute pattern is formed in each of these minute sections 50a. A case where the mark is marked will be described as an example.

  As shown in FIG. 1, the laser marking apparatus 1 according to the present embodiment is for marking an arbitrary pattern such as characters and figures on a workpiece 50 using a laser beam L. Specifically, the laser marking device 1 includes a laser oscillator 5 that emits a laser beam L, a fine pattern scanner 10 that scans the laser beam L emitted from the laser oscillator 5, and a positioning scanner 20. The laser beam L scanned by the pattern scanner 10 and the positioning scanner 20 is condensed on the workpiece 50 through the fθ lens 30.

  Among these, the fine pattern scanner 10 marks the fine pattern in the minute section (narrow range) 50a on the workpiece 50 by two-dimensionally scanning the laser beam L emitted from the laser oscillator 5. To do. Specifically, the fine pattern scanner 10 includes at least a pair of reflection mirrors 11 and 13 that reflect the laser light L, and at least a pair of galvanometers 12 that rotate the reflection mirrors 11 and 13 about rotation axes that are independent from each other. , 14 and a galvanometer driver 15 connected to the galvanometers 12, 14. The galvanometers 12 and 14 and the galvanometer driver 15 constitute a rotation drive mechanism.

  The positioning scanner 20 scans the laser beam L emitted from the laser oscillator 5 in a two-dimensional manner so that a range in which a fine pattern is marked by the fine pattern scanner 10 is arbitrarily set on the workpiece 50. It positions to the position of. Specifically, the positioning scanner 20 includes a reflection mirror 21 that reflects the laser light L, a goniometer stage 22 that holds the reflection mirror 21 and gives the reflection mirror 21 a two-dimensional degree of freedom of rotation, and a goniometer. And a stage controller 23 connected to the stage 22. The gonio stage 22 and the stage controller 23 constitute a holding drive mechanism. Here, since the scanning range of the laser light L by the positioning scanner 20 is wider than the scanning range of the laser light L by the fine pattern scanner 10, the positioning scanner 20 uses the light of the laser light L emitted from the laser oscillator 5. It is preferable that it is arranged at the rear stage of the fine pattern scanner 10 on the road.

  In the above description, the fine pattern scanner 10 (galvanometer driver 15) and the positioning scanner 20 (stage controller 23) are connected to the control device 40, and the arrangement and marking of the minute sections 50a on the workpiece 50 are performed. The fine pattern scanner 10 and the positioning scanner 20 can be integratedly controlled in accordance with the pattern (characters, figures, etc.) to be recorded. At this time, as a mode of marking on the workpiece 50, in addition to a mode in which the same pattern is drawn in each micro section 50a, a mode in which different patterns are drawn in each micro section 50a, or a plurality of micro sections It is possible to adopt a mode in which one meaningful pattern is drawn across the plurality of minute sections. In these embodiments, the pattern itself drawn on each minute section 50a is not necessarily a meaningful pattern.

  Next, the operation of the present embodiment having such a configuration will be described.

  In the laser marking device 1 shown in FIG. 1, the laser light L emitted from the laser oscillator 5 is reflected by the reflection mirrors 11 and 13 of the fine pattern scanner 10 and then reflected by the reflection mirror 21 of the positioning scanner 20. Finally, the light is condensed on the workpiece 50 through the fθ lens 30.

  At this time, the reflection mirrors 11 and 13 of the fine pattern scanner 10 are rotated about independent rotation axes by the galvanometers 12 and 14 under the control of the galvanometer driver 15. By controlling the angles of the mirrors 11 and 13, a predetermined fine pattern is marked in an arbitrary minute section 50 a on the workpiece 50.

  Further, the reflection mirror 21 of the positioning scanner 20 is given a two-dimensional degree of freedom of rotation by the gonio stage 22 under the control of the stage controller 23, and the angle of the reflection mirror 21 is controlled. As a result, a range where a fine pattern is marked by the fine pattern scanner 10 is positioned at an arbitrary minute section 50 a on the workpiece 50.

  In the above, the galvanometer driver 15 and the stage controller 23 are integrally controlled by the control device 40, and the galvanometers 12 and 14 change the angle of the reflection mirror 21 while the goniostage 22 sequentially changes the angle of the reflection mirrors 11 and 13. By marking the fine pattern by changing the angle, the same fine pattern is sequentially marked in the plurality of minute sections 50 a on the workpiece 50.

  As described above, according to the present embodiment, the marking range on the workpiece 50 is divided into the plurality of minute sections 50a, and the fine pattern marking in each of the minute sections 50a is performed by the fine pattern scanner 10. While the scanning is performed by the laser light L, the movement (positioning) between the minute sections 50 a is performed by the scanning of the laser light L by the positioning scanner 20. For this reason, two conflicting demands of high resolution at a small angle and movement over a wide range can be realized by a two-stage scanner, that is, a fine pattern scanner 10 and a positioning scanner 20. A plurality of fine patterns can be marked with high accuracy over a range. Thereby, for example, the same fine pattern is marked on each semiconductor chip on a semiconductor wafer (a semiconductor wafer before dicing (several tens of centimeters)) in which a plurality of semiconductor chips are arranged in a grid pattern. It can be suitably used for such applications.

  In the above-described embodiment, the case where the gonio stage 22 gives the reflection mirror 21 two-dimensional rotational freedom in the positioning scanner 20 has been described as an example. When the upper minute sections 50a are arranged one-dimensionally, the degree of freedom of rotation given to the reflection mirror 21 by the gonio stage 22 may be one-dimensional.

  In the above-described embodiment, the positioning scanner 20 includes the reflecting mirror 21 and the gonio stage 22 that gives the reflecting mirror 21 a two-dimensional degree of freedom of rotation. Any drive mechanism can be used as long as it can provide a desired degree of freedom of rotation in two dimensions. Further, in this case, similarly to the fine pattern scanner 10, a scanner having a pair of reflecting mirrors and a pair of galvanometers for rotating them may be used. Specifically, as in the laser marking device 1 ′ shown in FIG. 2, as the positioning scanner 20 ′, at least a pair of reflecting mirrors 25 and 27 that reflect the laser beam L and the reflecting mirrors 25 and 27 are independent of each other. It is preferable to use one having at least a pair of galvanometers 26 and 28 that rotate around the rotation axis. Note that a galvanometer driver 29 connected to the control device 40 is connected to the galvanometers 26 and 28, and the galvanometer driver 29 and the galvanometer driver 29 constitute a rotational drive mechanism for the pair of reflecting mirrors 25 and 27. Has been. Here, the galvanometer has a problem that it is difficult to move a large-diameter reflecting mirror with a small rotational torque at a high speed, but the size of the fine pattern, the required accuracy, and the required marking range. Depending on the required processing speed or the like, it is possible to employ a positioning scanner 20 ′ as shown in FIG. 2 instead of the positioning scanner 20 as shown in FIG.

The figure which shows the whole structure of the laser marking apparatus which concerns on one embodiment of this invention. The figure which shows the whole structure of the laser marking apparatus which concerns on other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,1 'Laser marking apparatus 5 Laser oscillator 10 Fine pattern scanner 11, 13 Reflection mirror 12, 14 Galvanometer 15 Galvanometer driver 20, 20' Positioning scanner 21 Reflection mirror 22 Goniometer 23 Stage controller 25, 27 Reflection mirror 26, 28 Galvanometer 29 Galvanometer Driver 30 fθ Lens 40 Control Device 50 Workpiece 50a Minute Section L Laser Light

Claims (8)

In a laser marking device that marks an arbitrary pattern such as letters and figures on a workpiece using laser light,
A laser oscillator that emits laser light;
A fine pattern scanner for marking a fine pattern within a narrow range on the workpiece by two-dimensionally scanning the laser beam emitted from the laser oscillator;
A positioning scanner for positioning a range where a fine pattern is marked by the fine pattern scanner at an arbitrary position on the workpiece by scanning the laser beam emitted from the laser oscillator; A laser marking device characterized by the above.   2. The fine pattern scanner includes at least a pair of reflection mirrors that reflect laser light, and a rotation drive mechanism that rotates the reflection mirrors about rotation axes that are independent from each other. The laser marking apparatus as described.   The positioning scanner includes a reflection mirror that reflects laser light, and a holding drive mechanism that holds the reflection mirror and gives the reflection mirror a two-dimensional degree of freedom of rotation. Or the laser marking apparatus of 2.   3. The positioning scanner includes at least a pair of reflecting mirrors that reflect laser light, and a rotation drive mechanism that rotates the reflecting mirrors around independent rotation axes. The laser marking device described in 1.   5. The positioning scanner according to claim 1, wherein the positioning scanner is arranged at a subsequent stage of the fine pattern scanner on an optical path of a laser beam emitted from the laser oscillator. 6. Laser marking device.   6. The laser marking device according to claim 1, further comprising a control device that integrally controls the fine pattern scanner and the positioning scanner.   7. The workpiece is a semiconductor wafer in which a plurality of semiconductor chips to be marked with a fine pattern are arranged in a grid pattern. Laser marking device. In the laser marking method of marking arbitrary patterns such as letters and figures on the workpiece using laser light,
By scanning the laser beam emitted from the laser oscillator two-dimensionally with a fine pattern scanner, a fine pattern is marked within a narrow area on the workpiece, and the laser beam emitted from the laser oscillator is A laser marking method, wherein a range where a fine pattern is marked is positioned at an arbitrary position on the workpiece by scanning with a positioning scanner.

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