JPH08318385A - Laser beam machine and its method for ceramic green sheet and the like - Google Patents

Abstract

PURPOSE: To form a through-hole or the like with a high positional accuracy on a machining material like a green sheet by detecting with a transmitting/ receiving means changes in the position of a floodlighting means due to heat at the time of laser machining, carrying out corrections of the position and then performing laser machining. CONSTITUTION: The position of a laser beam LL irradiation is detected by an optical sensor, and the light receiving signal is arithmetically processed by a means for calculating center of gravity, so that the precise centroidal position for the laser beam is calculated. Data for receiving position is recorded in a positional data recording RAMMD, also transmitted to a comparison/ correction commanding means and collated with the data in the positional data recording RAMMD. An AC servo motor 22 and a first and a second transporting unit 23, 24 in a means for driving a machining table are started by a correction commanding signal so as to control the position of the machining table 21. Lather beam machining is then implemented by the laser beam LL from an objective lens 3 in the output menas.

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 and a laser processing method for irradiating a ceramic green sheet or the like employed in a laminated electronic component with laser light to perform processing.

[0002]

2. Description of the Related Art Conventionally, as a laminated electronic component formed by laminating green sheets, for example, in a laminated inductor, a green sheet punched into a square shape of about 200 × 200 mm has a width of 200 mm. Row, vertical 1
After forming a unit pattern of parts by conductor printing in a grid of 00 lines, stacking this and cutting it out to one unit, one or more units per unit corresponding to the arrangement of this unit. It was the usual processing method to form the through hole.

For example, Japanese Patent Application Laid-Open No. Sho 61-61 discloses a method of using a laser beam to open the through hole.
No. 63405 (publicly known example) is disclosed.

That is, in the invention of this known example, a green sheet is placed on a table movable in two orthogonal directions,
This table is formed by irradiating a pulsed laser beam on the green sheet while moving this table in accordance with a required control method to form the through hole as described above. Even if a dimensional change occurs in the sheet due to material shrinkage, laser processing can be performed while correcting this.

[0005]

According to the above-mentioned known example, it is possible to effectively execute the laser processing by correcting the amount of change caused by the laser processing in the laser processing.

However, the following points are unsolved problems that cannot be achieved by the above-mentioned known inventions.

First, the first point is the adverse effect of heat generated during laser processing.

That is, in laser processing, light having high energy must be guided to a desired position by a mirror or the like, and the shape and area of the irradiation state must be controlled by a lens or a mask. Various related optical system parts absorb a part of the energy of the laser beam and become a heat source, and this heat deforms the optical system parts by thermal expansion, and is also transmitted to the optical system stand to deform it. As a result, the relational position between the optical axis of the laser beam and the processing table varies, and it is difficult to expect high-quality through-hole processing.

As the second point, the position of the center of gravity of the laser beam, that is, the portion having the largest energy amount in the irradiation region is divided into other regions having a relatively small energy amount, with high accuracy. There was concern about efficient laser processing, and it was pointed out that there should be improvements in processing accuracy and energy efficiency.

The present invention is intended to solve such a problem, and a first object of the present invention is to provide a laser generated due to heat generation when a laser processing is applied to a processed material such as a ceramic green sheet. It is an object of the present invention to provide a device capable of achieving precise through-hole processing by correcting the displacement between the optical axis and the processing table each time.

A second object of the present invention is to improve the accuracy of through hole processing by laser light by calculating the center of gravity of the laser light received by the laser light receiving means during the laser processing. To do.

A third object of the present invention is to provide a material such as a ceramic green sheet in which concave grooves or through holes can be freely formed during laser processing.

[0013]

The structure of the present invention for achieving the above object is as follows.

(1) A processing table on which a processing material to be processed by laser light is placed is movably arranged in two orthogonal directions on a plane intersecting the irradiation direction of laser light, and the laser light is received. A ceramic green sheet in which a light receiving means is connected to the processing table and the position of the laser light projecting means due to heat generated during laser processing is detected by the light receiving means and the position of the processing table can be corrected. Laser processing equipment.

(2) The light receiving means is provided with a light receiving element group provided with a plurality of light receiving elements, and the light receiving center of gravity position is calculated based on the data of the light receiving state of the laser light received by these light receiving elements. The above (1) provided with arithmetic processing means
Laser processing equipment such as the described ceramic green sheets.

(3) A laser processing method for a ceramic green sheet or the like, which comprises the following steps. A processing material to be processed by laser light is placed on a processing table that is movable in two orthogonal directions on a surface intersecting the irradiation direction of the laser light. The processing table is moved, and the light receiving means provided in series on the processing table is aligned with the laser beam. The light receiving means is irradiated with laser light to detect and record initial light receiving position data. Laser processing is performed by irradiating a required portion of the processed material with laser light. The processing table is moved to align the light receiving means with the laser light. The light receiving means is irradiated with the laser beam, and the subsequent light receiving position data is detected and recorded. Comparing the light receiving position data of the initial and subsequent,
The difference amount is detected. The processing table position is corrected so that the difference amount disappears. Do the above.

(4) The laser processing method for a ceramic green sheet or the like according to the above (3), which is configured by adding the following steps (1) to (3). 〓 Laser light is received by multiple photo detectors. = The position of the center of gravity of the laser light is calculated from the data received by the light receiving elements.

(5) In the laser processing method, the laser processing method for a ceramic green sheet or the like according to (3) or (4), wherein the processing by laser light is formed in a concave groove or a through hole.

[0019]

[Operation] The operation of the present invention described above is as follows.

That is, a processing material to be processed by laser light is placed on a processing table which is movable in two orthogonal directions on a plane intersecting with the irradiation direction of the laser light, the processing table is moved, and the processing table is moved. Align the light receiving means connected to the laser light, irradiate the laser light to the light receiving means to detect the initial light receiving position data, and calculate the light receiving center of gravity based on the difference in the laser energy irradiation amount from this light receiving data. Record the position data, irradiate laser light to the required part of the processed material to perform laser processing, then move the processing table, align the light receiving means with the laser light, and irradiate the laser light to the light receiving means. The second light receiving position table is detected and recorded, the first and second light receiving position data are compared, the difference amount is detected, and the processing table position is corrected so that the difference amount disappears. And it is intended to perform the following laser processing.

[0021]

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

(1) Structure As shown in FIGS. 1 and 2, the laser processing apparatus LD includes a laser processing function unit LD ₁ and a table position control function unit LD _2.
Since each of the functional units is configured as follows, each functional unit will be described below.

The laser processing function unit LD _{1 In} the optical system stand 2 which is continuously provided on the support post 1 in a cantilever manner, the optical system unit 4 for shaping the laser light to the laser light source 5 of the output means Nb is arranged. A movable table 11 is movably arranged on a fixed table 10 connected to the support posts 1, and a processing table capable of carrying a processing material WP such as a ceramic green sheet on the movable table 11. 21
Is arranged so as to be movable relative to the movable table 11, and the processed material WP is located below the objective lens light source 3.

That is, the fixed base 10 and the movable base 11 are
First and second feeding units 23 and 24 such as a ball screw feeder linked to an AC servomotor 22 of the processing table driving means Na are incorporated, and the first feeding unit 23 fixes the fixing base 10 to each other. The movable table 11 is configured to be movable in the (X)-(X ') direction on the above, and similarly, the processing table 21 is moved to the (Y)-(Y) on the movable table 11 by the second feeding unit 24. It is configured such that it can be moved in the ') direction, and the processing material WP is moved so that the desired laser processing area is exposed to the laser light LL from the objective lens 3 of the light projecting means Ma. is there.

Table position control function unit LD _{2 The} control function unit LD ₂ is a means for projecting light M as shown in FIG.
A light receiving element 25 as a light receiving means Mb for receiving the laser beam LL from the objective lens 3 as a is arranged at one side of the processing table 21.
Regarding No. 5, in this embodiment, an optical sensor having several hundreds of thousands of pixels having a positional resolution of several μm, which is used by being built in a CCD camera, is adopted, and the pixel is illuminated. The position of the laser light LL is configured so as to be grasped as a large number of received light signals, and the received light signals are arithmetically processed by the centroid calculating means Mc according to a procedure described later to calculate a precise centroid position of the laser light. The center of gravity position data is stored in the position data recording RAM.
In addition to being recorded in Md, it is also communicated to the collation / correction command means Me, collated with the data in the position data recording RAM Md, and processed table driving means N by the correction command signal.
The AC servomotor 22 in a and the first and second feeding units 23 and 24 are started to control the position of the processing table 21, and laser processing is performed by the laser light LL from the objective lens 3 in the output means Nb. It is configured so that it can be implemented.

(2) Operation Next, the ceramic green sheet GS as the processed material WP
3 to FIG. 5 regarding the laser processing for performing perforation processing on the
It will be described with reference to the control explanatory diagram, the center-of-gravity position detection explanatory diagram, the flowchart, and the like shown in FIG.

Preliminary Operation Ceramic powder is mixed and dispersed with a binder containing polyvinyl butyral as a main component and an organic solvent to prepare a ceramic slurry, which is formed into a green sheet having a thickness of 50 μm by a doctor blade method. Then, the green sheet GS which is not processed is formed by press punching into a size of 200 × 200 mm. The next green sheet GS is placed on the processing table 21 and fixed.

Next, a drive command is given to the AC servomotor 22 in the processing table driving means Na to move the processing table 21, and the laser light LL from the objective lens 3 is irradiated to the origin position of the light receiving element 25 of the light receiving means Mb. The position of the processing table 21 is adjusted as described above.

That is, as shown in FIG. 3, as a result of the above adjustment processing, the laser beam LL is the origin S ₀ (0, 0, 0, ₀ of the light receiving element 25.
The position data is calculated by the center-of-gravity calculation means Mc.

Now, for example, the above-mentioned laser beam LL is shown in FIG.
If a region divided by a plurality of pixels (F to I) and (R to F) shown in (1) is irradiated, in this case, the irradiation center position is a section (G, D) indicated by grid-like hatching, Sections (F, Lo-He), (F, Lo-He), (G, Lo-
C), (G, ho-he) (H, ro-he), (I, ro-he)
Will be arranged (area indicated by hatching in FIG. 4).

In this way, the center of gravity position of the laser light LL is calculated from the width of the total energy receiving area of each of the light receiving elements 25 thus detected and received, and the shape and the position on the coordinates. In the model of FIG. 4, if the section (G, D) is calculated as the barycentric position as a result of the calculation process, the irradiation barycentric position of the laser beam LL at this time is the center position (section). (G, D)), this position is the origin S ₀ (0, 0) in FIG.
Then, the position data is stored in the position recording RAM 27, and the laser beam processing device stands by for laser processing (see FIG. 5, SP1).

In this case, since the laser beam LL emitted from the objective lens 3 is merely used for detecting the position of the laser beam LL, if the energy amount of the laser beam LL is adjusted to be reduced, the laser beam LL is emitted. This is sufficient, and on the contrary, it is preferable for preventing heat generation or damage of the light receiving element 25.

Laser Machining Operation Next, the green sheet GS is subjected to laser machining. In this case, the origin S ₀ (0, 0,
0) After the position is detected, the AC servomotor 22 is operated by a preset procedure by a numerical control means (not shown) or the like to start the first and second feeding units 23 and 24 to move the movable table 11 and The processing table 21 is moved to a desired position in the direction of the arrow (X)-(X ') or (Y)-(Y'), and the laser light LL is emitted from the objective lens 3 onto the green sheet GS. , Through holes with a diameter of about 100 μm are formed in a grid-like array such as 100 rows in length.

In this case, the laser light L from the objective lens 3
It is needless to say that the energy irradiation amount of L is made stronger than the energy value at the time of the above-mentioned position matching so that the laser light LL has a sufficient amount for perforating the green sheet GS (see SP2). Next, after the perforation processing of the first green sheet GS is completed, this is replaced with an unprocessed green sheet GS, and the second green sheet GS is placed on the processing table 21.

Next, an origin check (SP3) operation is performed. In this case, the AC servomotor 22 is activated again to move the processing table 21 so that the light receiving element 25 faces below the objective lens 3. As in the origin check operation, the energy value of the laser light LL is weakened and the light is received by the light receiving element 25. At this time, the center-of-gravity position data calculated by the center-of-gravity calculating means Mc for the laser light LL is stored in the position data recording RAM Ma. The center of gravity is at the origin S
_{If the} coincidence with ₀ (0, 0) is detected, then the laser processing of (SP2) may be continued.

However, when thermal expansion is induced in the optical system pedestal 2 in which the optical system unit 4 and the laser light source 5 are incorporated due to the temperature rise caused by the laser processing, the position of the objective lens 3 is the origin S ₀ ( It is detected that the position is displaced from the (0, 0) position (SP4). The actual position of the objective lens 3 is, for example, the measured position S ₁ shown in FIG.
If it is (a, b), the measured position S ₁ data is recorded in the position data recording RAM Ma, while the origin S ₀ data read from the position data recording RAM Ma and the measured position S ₁ data are recorded. Are compared by the collation / correction command means Me, and the light-receiving element 25 and the machining table 21 are moved by the amount of deviation (direction of arrow W in FIG. 3). In this case, the command of the collation / correction command means Me is driven by the machining table. The means Na is notified, the first or second feeding unit 23 or 24 is started, the movable table 11 or the processing table 21 is moved, and the laser beam LL is the origin S _0.
Match (0,0).

As a result, a new origin position of the objective lens 3 by the optical system mount 2 which is deformed by heat is set, so that the processing table 21 is finally determined on the basis of the current laser light LL position. The new coordinate system has been shifted, and the positional relationship between the green sheet GS and the laser beam LL on the processing table 21 is maintained at a highly accurate processing position in which an error is corrected (SP5). reference).

Therefore, if the laser processing is carried out in this state, a precise through hole having no positional deviation can be formed.

In the same manner as described above, the origin check is performed every time the laser machining process is completed, the moving coordinate system of the machining table 21 is corrected, and the laser machining is repeated to form a green sheet having through holes. A conductor pattern is printed on the GS by screen printing, and the conductor pattern is laminated and pressed at 400 ° C./m ² at 90 ° C., cut to fit individual component units, and then cut in the atmosphere for 9 minutes.
It is fired at 00 ° C. to form a laminated electronic component.

[0040]

The remarkable effects achieved by the present invention described above are as follows.

Since the laser processing is performed after performing the position correction so as to match the change in the position of the laser light, through holes and the like can be formed in the processed material such as the green sheet with high positional accuracy. In this case, the conformity with the printing process of the conductor pattern or the like is enhanced, and the one having high reliability of conduction through the through hole can be obtained.

Since the laser processing is carried out by calculating the center of gravity of the laser light, it is possible to form a through hole or the like with extremely high precision.

Since the recessed groove and the through hole can be processed by the laser beam, the laser processing can be continuously achieved, and the working efficiency is greatly improved.

[Brief description of drawings]

FIG. 1 is a perspective view of a laser processing apparatus showing an embodiment of the present invention.

FIG. 2 is a functional block diagram of FIG.

FIG. 3 is a control explanatory view of the processing table of FIG.

4A and 4B are explanatory diagrams for detecting the position of the center of gravity of the laser light in FIG.

5 is a flowchart of FIG.

[Explanation of symbols]

LD laser processing device LD ₁ laser processing function unit LD ₂ table position control function unit Ma light projecting means Mb light receiving means Mc center of gravity calculating means Md position data recording RAM Me collating / correcting command means Na table driving means Nb output means 1 support post 2 Optical system stand 3 Objective lens 4 Optical system unit 5 Laser light source 10 Fixed stand 11 Movable stand 21 Machining table 22 AC servo motor 23 First feeding unit 24 Second feeding unit 25 Light receiving element LL Laser light WP (GS) Processed material (green sheet)

Claims (5)

[Claims] 1. A processing table on which a processing material to be processed by laser light is placed is movably arranged in two orthogonal directions on a surface intersecting the irradiation direction of laser light, and a light receiving device for receiving the laser light is received. Means for connecting the processing table to the processing table, and detecting the change of the position of the laser beam projecting means due to heat generation during laser processing by the light receiving means, and correcting the position of the processing table. Laser processing equipment. 2. The light receiving means is provided with a light receiving element group having a plurality of light receiving elements provided side by side, and a calculation for calculating a light receiving center of gravity position based on data of a light receiving state of laser light received by these light receiving elements. The laser processing apparatus for a ceramic green sheet according to claim 1, further comprising a processing means. 3. A laser processing method for a ceramic green sheet or the like, which comprises the following steps. A processing material to be processed by laser light is placed on a processing table that is movable in two orthogonal directions on a surface intersecting the irradiation direction of the laser light. The processing table is moved to align the light receiving means provided on the processing table with the laser light. The light receiving means is irradiated with laser light to detect and record initial light receiving position data. Laser processing is performed by irradiating a required portion of the processed material with laser light. The processing table is moved to align the light receiving means with the laser light. The light receiving means is irradiated with the laser beam, and the subsequent light receiving position data is detected and recorded. Comparing the light receiving position data of the initial and subsequent,
The difference amount is detected. The processing table position is corrected so that the difference amount disappears. Do the above. 4. A laser processing method for a ceramic green sheet or the like according to claim 3, which is configured by adding the following steps 〓 to 〓. 〓 Laser light is received by multiple photo detectors. = The position of the center of gravity of the laser light is calculated from the data received by the light receiving elements. 5. The laser processing method for a ceramic green sheet or the like according to claim 3, wherein in the laser processing method, processing by laser light is formed in a concave groove, a through hole or the like.