JP3378243B1 - Laser processing method - Google Patents

Abstract

A laser processing method capable of shortening the processing time and improving the processing quality is provided. A processing object in which a plurality of unit regions are defined on a surface is prepared. The object to be processed is arranged so that one unit region is arranged within the scannable range of the pulse laser beam. By scanning the pulse laser beam, the pulse laser beam is incident on a plurality of processing points in the unit region arranged in the scannable range to form a hole.
The object to be processed is moved so that the unit region in which the hole is formed and the unit region adjacent to the unit region are arranged in the scannable range. By scanning the pulse laser beam, the pulse laser beam is incident on the processing points in the two unit regions arranged in the scannable range. In the unit area in which the hole is formed, the already formed hole becomes deep, and a new hole is formed in the unit area arranged in the scannable range for the first time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser processing method, and more particularly to a laser processing method for forming a plurality of holes in a processing object by combining scanning of a pulsed laser beam and movement of the processing object.

[0002]

2. Description of the Related Art Japanese Patent No. 3077539 discloses a laser processing method for forming a plurality of holes in an object to be processed. According to this method, the laser beam is scanned to perform processing within one rectangular flat area on the surface of the processing target. After that, the object to be processed is moved to perform processing in another rectangular plane area adjacent to the already processed rectangular plane area without overlapping with the already processed rectangular plane area. By repeating this, the entire surface of the object to be processed can be processed.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a laser processing method capable of shortening processing time and improving processing quality.

[0004]

According to one aspect of the present invention, (a) a step of preparing an object to be processed in which a plurality of unit regions arranged in at least one row are defined on the surface, (B) Arranging the object to be processed such that at least one unit region defined on the surface of the object is arranged within the scannable range of the pulsed laser beam scanned by the laser beam scanning means. Step (c) by scanning the pulse laser beam, the pulse laser beam is sequentially incident on a plurality of processing points in the unit area arranged in the scannable range in the step (b) to form a hole. And (d) a step of moving the object to be processed so that the unit area in which the holes are formed in step (c) and the unit area adjacent to the hole are arranged in a scannable range of the pulse laser beam. And (e) by scanning the pulse laser beam, the pulse laser beam is made incident on the processing points in at least two unit areas arranged in the scannable range in the step (b), and the step (b) has already been performed. In the unit area where the hole is formed in c), the hole that has already been formed is deepened, and in the unit area that is first arranged in the scannable range in step (d), a new hole is newly formed. A laser processing method is provided.

According to another aspect of the present invention, (f) the object to be processed is arranged such that a part of the surface is included in the scannable range of the pulsed laser beam scanned by the laser beam scanning means, and the scanning is performed. Forming a hole at the processing point by sequentially injecting a pulsed laser beam at the processing point within the possible range,
(G) A part of the area in which holes have already been formed remains in the scannable range, and a part of the surface of the object to be processed in which no holes have been formed is newly included in the scannable area. Moving the object to be processed so as to be arranged;
(H) By scanning the pulse laser beam, the pulse laser beam is made incident on a processing point on the surface of the object to be processed within the scannable range to deepen the hole located within the scannable range, and the step ( Laser processing including a step of forming a hole at a processing point in a region arranged in the scannable range for the first time in g), and a step of (i) repeatedly performing the steps (g) and (h). A method is provided.

By adopting the above method, the processing time can be shortened as compared with the conventional method.

[0007]

1 is a schematic view of a laser processing apparatus used in a laser processing method according to an embodiment of the present invention. The laser light source 1 emits a pulsed laser beam for processing. As the laser light source 1, for example, an Nd: YAG laser, an Nd: YLF laser, an Nd: YVO ₄ laser, a laser generating a harmonic wave of these, a carbon dioxide gas laser, or the like is used.

The laser beam emitted from the laser light source 1 enters the mask 2. The laser beam that has passed through the through-hole provided in the mask 2 enters the folding mirror 3. The laser beam reflected by the folding mirror 3 enters the galvano scanner 4. The galvano scanner 4
It is configured to include a pair of swingable reflecting mirrors, and scans a laser beam in a two-dimensional direction. The laser beam scanned by the galvano scanner 4 is focused by the fθ lens 5 and is incident on the processing object 8 held on the XY stage 6. The fθ lens 5 forms an image of the through hole of the mask 2 on the surface of the processing object 8. The XY stage 6 can move the processing object 8 in a two-dimensional direction parallel to the surface thereof.

The workpiece 8 is, for example, a printed wiring board,
Examples include tape for automatic tape bonding (TAB) and ceramic green sheets.

A laser processing method according to an embodiment of the present invention will be described with reference to FIG. 2 (A) to (D)
Shows a plan view of the processing object 8. A plurality of unit regions 10 arranged in a grid pattern are defined on the surface of the processing object 8. Inside each of the unit areas 10, a plurality of processing points where holes are to be formed are defined. For example, unit area 1
0s are arranged in 4 rows and 8 columns, and the lengths of the unit areas 10 in the vertical direction and the horizontal direction are 50 mm and 25 mm, respectively.
Is. By the two unit areas 10 adjacent in the row direction,
A square having a side length of 50 mm is formed.

By operating the galvano scanner 4 shown in FIG. 1, the laser beam can be made incident on an arbitrary point within the scannable range 20. Scannable range 20
The planar shape of is a square having a side length of 50 mm, for example.

As shown in FIG. 2A, the processing object 8 is moved so that the unit area 10 (1) to be processed first is arranged within the scannable range 20. FIG. 2A shows a case where the unit area 10 (1) to be processed first is located at the lower left corner of the processing object 8. Unit area 10
The unit area 10 (2) to the right of (1) is the scannable range 2
It is placed outside 0.

The galvano scanner 4 shown in FIG. 1 is operated to scan the pulse laser beam, and the unit area 10 (1)
A pulse laser beam is made to enter each processing point one by one, and a hole is formed at each processing point.

As shown in FIG. 2B, the object 8 to be processed is moved so that the unit area 10 (1) and the unit area 10 (2) on the right side thereof are arranged within the scannable range 20. The galvano scanner 4 is operated to scan the pulse laser beam, and the pulse laser beam is made to enter the processing points in the unit region 10 (1) and the unit region 10 (2) one by one. In the unit area 10 (1), the hole already formed becomes deeper. A new hole is formed in the unit area 10 (2). This means that a total of two shots of the pulse laser beam are incident on each processing point in the unit area 10 (1). In this embodiment, a hole having a required depth is formed by using a two-shot pulse laser beam.

As shown in FIG. 2C, the unit area 10
(2) and the processing object 8 is moved so that the unit area 10 (3) on the right side thereof is arranged within the scannable range 20.
The pulsed laser beam is made incident on the processing points in the unit areas 10 (2) and 10 (3) arranged in the scannable range 20.

As shown in FIG. 2D, the unit area 10
The object 8 is moved so that (3) and the unit area 10 (4) on the right side thereof are arranged within the scannable range 20.
The pulsed laser beam is made incident on the processing points in the unit areas 10 (3) and 10 (4) arranged in the scannable range 20. When the processing of the unit area 10 at the lower right corner shown in FIG. 2D is completed, the processing target 8 is moved in the vertical direction, and the processing of the unit area 10 in the second row from the bottom is performed.

By repeating the movement of the processing object 8 and the scanning of the pulsed laser beam, it is possible to process all the unit regions 10 on the surface of the processing object 8.

Next, the processing time of the laser processing method according to the above embodiment will be described. It is assumed that 25 × 50 processing points are defined in the unit region 10 at a pitch of 1 mm.
The time required for the galvano scanner 4 to scan the laser beam by 1 mm is 0.7 ms.

The scanning time required for making the pulsed laser beam incident on all the processing points in one unit area 10 is 0.7 ms × 25 × 50 = 875 ms. The time required to scan all the processing points in the eight unit areas 10 in the bottom row is 875 ms × 2 × 8 = 14 s.
In the case of the embodiment, since the unit areas 10 are arranged in four rows, the scanning time required to process all the unit areas 10 is 14 s × 4 = 56 s.

When the scanning of the pulsed laser beam is completed, X
The workpiece 8 is horizontally moved by 25 mm on the Y stage 6. This moving time is 0.2 s. Further, the time required to move the processing object 8 by 50 mm in the vertical direction is 0.4 s. When processing the eight unit areas 10 arranged in one row, the processing target 8 moves eight times. In the case of the embodiment, since the unit areas 10 are arranged in four rows, the moving time of the XY stage 6 required to process all the unit areas 10 is 0.2 s × 8 × 4 + 0.4 s ×
3 = 7.6s.

The pulse width of the pulse laser beam is 0.05
ms, the time required for the pulse laser beam to be incident on all processing points is 0.05 ms × 25 × 50 × 32 × 2 =
It is 4s. Here, 32 on the left side is the number of unit regions 10, and 2 on the left side is the number of shots incident on one processing point. When the above scanning time, moving time of the XY stage 6, and incident time of the pulsed laser beam are summed up,
It will be 67.6s.

The unit area 10 shown in FIG.
When performing the processing of (1), as shown in FIG.
The unit areas 10 (1) and 10 (2) are the scannable range 20.
It may be placed inside. In this state, the unit area 10 (1)
It is also possible to process only. In this case, the unit area 10 (1) is processed as shown in FIG. 2 (E), and then the unit areas 10 (1) and 10 (1) shown in FIG. 2 (B) are processed.
It is not necessary to move the processing object 8 before processing (2). Therefore, the moving time of the XY stage 6 is further shortened.

Similarly, when processing the unit area at the right end of FIG. 2 (E), it is not necessary to move the processing object 8. Therefore, when processing the unit area 10 of one row, the number of movements of the XY stage 6 can be omitted twice.

Next, for comparison, a description will be given of the time when the processing is performed by the conventional method of moving the XY stage 6 so that the scannable ranges 20 do not overlap on the surface of the processing object 8. In this method, two unit areas 10 adjacent to each other in the row direction shown in FIG. 2A are processed by one scanning. The scanning time by the galvano scanner 4 is 0.7 ms × 50 × 50 × 16 = 28 s. Here, 16 on the left side is the total number of sets when two unit areas are considered as one set.

The pulse frequency of the pulsed laser beam is set to 1 k
Hz (cycle 1 ms) and pulse width 0.05 ms. The time required to make two shots incident on one processing point is 1 ms + 0.05 ms = 1.05 ms.

The total time for which the pulsed laser beam is incident on the processing point is 1.05 ms × 50 × 50 × 16 = 42.
s.

When the time required to move the object to be processed 50 mm is 0.4 s, the total moving time of the object 8 is 0.4 s × 15 = 6 s. When the above scanning time, moving time of the XY stage 6 and the incident time of the pulsed laser beam are summed up, the processing time becomes 76 s.

As can be seen from this comparison result, by adopting the processing method according to the above-mentioned embodiment, the processing time can be shortened as compared with the conventional processing method. Further, in the conventional method, two shots are incident on one processing point at intervals of 1 ms. For this reason, the influence of heat due to the incidence of the first shot affects the processing of the second shot, and the processing quality deteriorates. On the other hand, in the case of the above embodiment,
When one shot is incident on one processing point, the second shot is incident after the scanning time of the pulse laser beam and the operation time of the XY stage 6 have elapsed. Therefore, during the processing of the second shot, it is less likely to be affected by heat due to the incidence of the first shot. Thereby, the processing quality can be improved.

In the above embodiment, the case where two holes of the pulse laser beam are incident on one processing point to form a hole has been described. Therefore, the scannable range 20 shown in FIGS. 2A to 2D moves on the surface of the processing object 8 while overlapping the half area thereof. When the pulsed laser beam of n shots is incident on one processing point, the scannable range 20 moves on the surface of the processing object 8 while overlapping the area having the area of (n-1) / n. The object 8 to be processed may be moved in this manner.

With reference to FIG. 3, description will be made on a processing method for forming a hole by making a three-shot pulse laser beam incident on one processing point. In this case, the scannable range 20 is large enough to include the three unit areas 10.

As shown in FIG. 3A, the workpiece 8 is moved so that the unit area 10 (1) at the lower left corner is located within the scannable range 20. At this time, the unit area 10
The unit area 10 (2) to the right of (1) is the scannable range 2
Not located within 0. In this state, the unit area 10
The processing in (1) is performed.

As shown in FIG. 3B, the unit area 10
The workpiece 8 is moved so that (1) and 10 (2) are arranged within the scannable range 20. At this time, the unit area 10 (3) on the right of the unit area 10 (2) is not arranged in the scannable range 20. In this state, processing within the unit areas 10 (1) and 10 (2) is performed.

As shown in FIG. 3C, the unit area 10
The object 8 is moved so that (1) to 10 (3) are arranged within the scannable range 20. In this state, processing within the unit areas 10 (1) to 10 (3) is performed.

As shown in FIG. 3D, the unit area 10
(1) is out of the scannable range 20 and the unit area 10
The processing object 8 is moved so that (4) is newly arranged in the scannable range 20. Unit area 1 in this state
Processing within 0 (2) to 10 (4) is performed. In this way, the movement of the processing object 8 may be controlled so that the scannable range 20 moves on the surface of the processing object 8 while overlapping the area having the area of 2/3 thereof.

The unit area 10 shown in FIG.
When processing only the inside of (1), as shown in FIG. 3 (E), the unit regions 10 (1) to 10 (3) can be scanned within the scannable range 2
It may be arranged within 0. Further, when processing the inside of the unit regions 10 (1) and 10 (2) shown in FIG. 3 (B), the unit regions 10 (1) to 10 (3) are processed as shown in FIG. 3 (F).
May be arranged within the scannable range 20. In the state of FIG. 3 (E) and FIG. 3 (F), processing is performed only in the unit area 10 (1) and by processing in the unit areas 10 (1) and 10 (2), respectively. The number of movements of 8 can be omitted twice. If the same processing method is applied to the right end of the processing object 8, the unit area 10 for one line is
When machining, the number of movements of the workpiece 8 can be omitted by four times.

The scannable range 20 is (n-1) / n
When the processing object 8 is moved so as to move on the surface of the processing object 8 while overlapping the area of the area of FIG.
If the moving method similar to (E) and FIG. 3 (F) is adopted,
When processing the unit area 10 for one line, the number of movements is set to (n
-1) × 2 times can be omitted. Further, the stroke of the XY stage 6 in the row direction can be shortened.
As a result, it is possible to save space in the laser processing apparatus.

In the above embodiment, the unit areas 10 are arranged in a grid pattern (matrix shape), but the above embodiment is also applied to the case where the unit areas are arranged in a line on the surface of the workpiece. be able to.

More generally, all the processing points on the object to be processed can be processed by carrying out the following steps.

First, the object to be processed is arranged so that a part of the surface is included in the scannable range 20 of the pulsed laser beam scanned by the laser beam scanning means (galvano scanner). A pulse laser beam is sequentially incident on the processing points within the scannable range 20 to form holes at the processing points. A part of the area where the hole has already been formed remains in the scannable range 20,
The object to be processed is moved so that a part of the surface of the object to be processed, in which a hole is not yet formed, is newly arranged in the scannable range 20.

By scanning the pulsed laser beam, the pulsed laser beam is made incident on the processing point on the surface of the object to be processed within the scannable range 20. The hole located in the scannable range 20 becomes deeper, and a hole is newly formed at the processing point in the area arranged in the scannable range 20 for the first time.

By repeating the scanning of the pulsed laser beam and the movement of the object to be processed, holes can be formed at all processing points.

The present invention has been described above with reference to the embodiments.
The present invention is not limited to these. For example, it will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.

[0043]

As described above, according to the present invention,
The time for forming a plurality of holes in the object to be processed can be shortened by combining the scanning with the pulsed laser beam and the movement of the object to be processed.

[Brief description of drawings]

FIG. 1 is a schematic view of a laser processing apparatus used in an embodiment of the present invention.

FIG. 2 is a plan view of an object to be processed for explaining the laser processing method according to the embodiment of the present invention.

FIG. 3 is a plan view of an object to be processed for explaining a laser processing method according to another embodiment of the present invention.

[Explanation of symbols]

1 laser light source 2 mask 3 folding mirror 4 galvano scanner 5 fθ lens 6 XY stage 8 Object to be processed 10 unit area 20 scannable range

Front page continuation (58) Fields surveyed (Int.Cl. ⁷ , DB name) B23K 26/00-26/38 H05K 3/00

Claims (3)

(57) [Claims] 1. A step of: (a) preparing an object to be processed in which a plurality of unit areas arranged in at least one row are defined on the surface; and (b) a pulse scanned by a laser beam scanning means. Arranging the object to be processed so that at least one unit area defined on the surface of the object is arranged within a scannable range of the laser beam; and (c) scanning the pulsed laser beam. Accordingly, in the step (b), a pulse laser beam is sequentially incident on a plurality of processing points in the unit region arranged in the scannable range to form holes, and (d) the step (c) ), Moving the object to be processed so that the unit region in which the hole is formed and the unit region adjacent thereto are arranged in the scannable range of the pulse laser beam, and (e) scanning the pulse laser beam By so doing, the pulse laser beam is made incident on the processing points in at least two unit areas arranged in the scannable range in the step (b), and the unit in which the hole has already been formed in the step (c). In the area, deepen the holes already formed,
A laser processing method, further comprising the step of newly forming a hole in the unit area arranged in the scannable range for the first time in the step (d). 2. (f) The object to be processed is arranged so that a part of the surface is included in the scannable range of the pulsed laser beam scanned by the laser beam scanning means, and at the processing point within the scannable range. Forming a hole at the processing point by sequentially injecting a pulsed laser beam, and (g) a part of the area where the hole is already formed remains in the scannable range, and A step of moving the object to be processed so that a part of the area where the hole is not yet formed is newly arranged within the scannable range; and (h) the scannable by scanning with a pulse laser beam. A pulse laser beam is made incident on a processing point on the surface of the object to be processed within the range to deepen the hole located in the scannable range, and within the area initially arranged in the scannable range in the step (g). Forming holes at the processing points That process and the laser machining method and a step of repeatedly executing (i) a wherein step (g) and step (h). 3. A step (j) of preparing an object to be processed in which a plurality of unit regions arranged in at least one row are defined on the surface, and (k) a pulse scanned by a laser beam scanning means. Arranging the object to be processed so that a unit area located at one of the first ends and (N-1) unit areas continuous with the unit area are arranged within a scannable range of the laser beam; l) By scanning with a pulsed laser beam, pulses are sequentially applied to a plurality of processing points in the unit area located at the first end among the unit areas arranged in the scannable range in the step (k). Forming a hole by injecting a laser beam; and (m) scanning the pulsed laser beam to make the first unit of the N unit regions arranged in the scannable range in the step (k). Ream located on the end side of The procedure of sequentially injecting the pulsed laser beam to a plurality of processing points in M consecutive unit areas is changed from M = 2 to M = N until M = 2.
Is performed by incrementing by one, and (M
-1) Deepening already formed holes in one unit area, and forming a new hole in one unit area continuous to the unit area; (n) Arranging within the scannable range One unit area on the first end side out of the unit areas that are arranged is out of the scannable range, and one unit area on the opposite side to the first end of the unit areas arranged in the scannable range. A step of moving the processing object such that one unit area adjacent to the unit area is newly arranged in the scannable range; and (o) scanning the pulse laser beam to perform the step (n). ), A pulsed laser beam is made incident on the processing points in the N unit areas arranged in the scannable range, and in the unit areas where holes are already formed, holes already formed are Deepen the above In step (n), a new hole is formed in the unit area arranged within the scannable range for the first time, and (p) step (n) and step (o) are alternately repeated. A laser processing method having: