JP2003211276A - Method and device of laser beam machining - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of laser beam machining by which a resign part is machined by eliminating the thermal influence of the machining of a metallic layer and the machining time is shortened at the same time, thus both the quality and the time efficiency are improved. <P>SOLUTION: A laser beam on a first optical path is divided into a second and a third optical paths and the laser beam which advances on the second optical path is made incident on a first part to be machined at which a metallic film is tightly stuck on the surface of a resin member, and a hole is formed on the metallic film of the first part to be machined. The first part to be machined is moved to a position at which a laser beam which advances on the third optical path is made incident, and a second part to be machined at which the metallic film is tightly stuck on the surface of the resign member is arranged at a position at which the laser beam which advances on the second optical path is made incident. A hole is formed on the resin member by making the laser beam which advances on the third optical path incident on a region in which the resin member is exposed on the first part to be machined, and at the same time a hole is formed on the metallic film of the second part to be machined by making the laser beam which advances on the second optical path incident on the second part to be machined. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a processing method and a processing apparatus using a laser beam.

[0002]

2. Description of the Related Art A conventional method of processing a substrate having two metal layers (two-metal substrate) will be described with reference to FIGS. FIG. 5A is a cross-sectional view showing the outline of a two-metal substrate. For example, a resin layer 51 made of polyimide
A two-metal substrate having a copper layer 52 on its surface and an electrode layer 53 formed of copper inside is processed by an ultraviolet pulse laser beam 54.

As shown in FIG. 5B, an ultraviolet pulsed laser beam 54 is irradiated on the copper layer 52 to form a hole 52a exposing the resin layer 51.

As shown in FIG. 5C, following the perforation of the hole 52a, the pulse energy of the ultraviolet pulse laser beam 54 is reduced, and the hole 51 reaching the resin layer 51 to the electrode layer 53 is formed.
pierce a.

[0005]

However, according to the conventional methods, high quality processing is difficult.

Description will be made with reference to FIG. Copper layer 52
And the resin layer 51 are continuously processed, the heat transferred to the resin layer 51 during the processing of the copper layer 52 and the heat remaining in the copper layer 52 during the processing of the resin layer 51 affect the undercut 51b and the like. Defects are likely to occur. Therefore, the holes 52a 'are actually formed in the resin layer 51 like the holes 51a'.
The resin layer 51 immediately below the periphery of a is damaged, and the side surface becomes a hole having a bulge. Further, simply waiting for heat to be dissipated during processing of the copper layer 52 deteriorates the time efficiency of processing the substrate.

An object of the present invention is to process a resin part by eliminating the influence of heat when processing a metal layer, and to shorten the processing time, that is, to improve both quality and time efficiency. Is to provide.

[0008]

According to one aspect of the present invention, a laser beam that travels along a second laser optical path of the second and third laser optical paths branched from the first laser optical path is provided. First, the metal film adheres to the surface of the resin member
To form a hole in the metal film of the first processed part, and the first processed part is formed into the third processed part.
Of the laser beam traveling along the second laser optical path while moving to the position where the laser beam traveling along the laser optical path can enter, and the second processed portion in which the metal film is in close contact with the surface of the resin member. A step of arranging the beam at a position where the beam can enter, and a laser beam traveling along the third laser optical path is made incident on a region of the first processed portion where the resin member is exposed to form a hole in the resin member. At the same time forming
A step of causing a laser beam traveling along the second laser optical path to enter into the second processed portion to form a hole in the metal film of the second processed portion. Provided.

In the first processed portion, the metal film is processed by the laser beam traveling along the second laser optical path, and then the metal film is produced by the laser beam traveling along the third laser optical path. Heat is dissipated during metal film processing during the transfer period until the resin part is processed. Therefore, the laser processing method can provide high-quality processing. Further, since the holes are formed in the resin portion of the first processed portion and the holes are formed in the metal film of the second processed portion at the same time, the processing time can be shortened.

According to another aspect of the present invention, a laser light source for emitting a pulse laser beam, and the pulse laser beam emitted from the laser light source are used as a first pulse laser beam and a second pulse laser beam. An optical means capable of splitting and changing its power ratio, further comprising the first pulsed laser beam at a point in the first processing region,
System for making the pulsed laser beam of the laser beam incident on a point in the second processing region, first scanning means for scanning the first pulsed laser beam in the first processing region, and the second processing region. A laser processing apparatus having: a second scanning means for scanning the second pulsed laser beam; and a moving means for moving a processing object processed in the first processing area to the second processing area. Will be provided.

The laser processing apparatus moves the processing object processed in the first processing area by moving means and further processes it in the second processing area. By dividing the machining into two stages and providing a time interval there, it is possible to eliminate the thermal influence of the machining target on the machining in the first machining region. Therefore, it becomes possible to realize high-quality processing. Further, since the processing in the first processing area and the processing in the second processing area can be performed at the same time, the processing time can be shortened as compared with the case where different types of processing are performed in one processing area. To be done.

[0012]

1 is a schematic view of a laser processing apparatus according to an embodiment of the present invention. A pulse laser beam is emitted from the laser oscillator 10. The laser oscillator 10 is, for example, an Nd: YAG laser. The pulsed laser beam is incident on the mask 11, passes through a through hole provided in the mask 11, and passes through an EOM (electric optical modulator) 1
Incident on 2. The polarizing plate 13 divides into two pulsed laser beams having different energies, that is, a reflected pulsed laser beam and a transmitted pulsed laser beam. The reflected pulsed laser beam is reflected by the galvano scanner 15, and the transmitted pulsed laser beam is reflected by the reflection mirror 14 to the galvano scanner 17.

The EOM 12 is composed of a Pockels element using, for example, LiTaO ₃ or LiNbO ₃ . The Pockels element changes the polarization direction of light passing through it according to an applied electric field. The polarizing plate 13 changes the ratio of the intensity of the reflected light and the transmitted light in the polarizing plate 13 according to the polarization direction of the incident light. Therefore, it is possible to adjust the ratio of the intensities of the pulse laser beam incident on the galvano scanner 15 and the pulse laser beam incident on the galvano scanner 17 by the EOM 12 and the polarizing plate 13.

The galvano scanner 15 and the galvano scanner 17 are constituted by including a pair of swingable reflecting mirrors, and scan the pulsed laser beam in a two-dimensional direction. The pulsed laser beam scanned by the galvano scanner 15 passes through the fθ lens 16 and TAB (tape automated bonding).
It is incident on the tape 20 for processing and is processed. Galvano scanner 1
The pulsed laser beam scanned at 7 passes through the fθ lens 18 and enters the TAB tape 20 for processing. The processing areas of the galvano scanners 15 and 17 have a length in the length direction of the TAB tape 20 (direction of arrow 30) and a width in the width direction (direction crossing the direction of arrow 30 on the TAB tape 20). Hold. fθ lens 16 and fθ
The lens 18 has a through hole of the mask 11 and a tape 20 for TAB
Image on the surface of. The roll mechanism 19 moves the TAB tape 20 in the direction of arrow 30.

As shown in FIG. 2, an object to be processed, here,
A unit processing area X is formed in the length direction of the TAB tape 20.
(1), X (2), ... X (i), X (i + 1),
.. are arranged in this order, and adjacent unit processing areas
X (i) and X (i + 1) are in contact with each other. Unit addition
The work area is the TAB tape 20 by the roll mechanism 19.
Galvano scanner 15 or 17 without moving
On the TAB tape 20 that can be processed only by scanning with
Refers to a cohesive area. Each unit processing area has n
Processed parts are distributed. That is, within the unit processing area X (i)
Is a processed part a_i1, A _i2,, a_inIs located
It The pulsed laser beam is scanned by a galvano scanner.
Unit processing that entered the processing area of the galvano scanner
It is incident on n processed parts arranged in the region. Na
Even if the number n of processed parts differs depending on the unit processing area,
Good.

FIG. 3A shows the processing of the galvano scanner 15.
The unit machining area X (1) enters the area and the galvano scan
Processed by the pulsed laser beam scanned by
Part a ₁₁~ A_1nShows the state of being subjected to the first stage processing.
When this first stage processing is completed, the TAB tape 20
Is sent in the direction of arrow 30 by the roll mechanism 19 and
The unit processing area X (2) is provided in the processing area of the scanner unit 15.
enter in.

FIG. 3B shows the processing of the galvano scanner 15.
The unit machining area X (2) enters the area and the galvano scan
Processed by the pulsed laser beam scanned by
Part a _{twenty one}~ A_2nShows the state of being subjected to the first stage processing.
When this first stage processing is completed, the TAB tape 20
Is sent in the direction of arrow 30 by the roll mechanism 19 and
In the processing area of the scanner unit 15, the unit processing area X (3) is
enter in. The same applies hereinafter.

FIG. 3C shows the processing of the galvano scanner 15.
The unit machining area X (i) enters the area and the galvano scan
Processed by the pulsed laser beam scanned by
Part a _i1~ A_inShows the state of being subjected to the first stage processing.
At the same time, the processing area of the galvano scanner 17 has a unit
Processing area X (1) enters and runs with galvano scanner 17.
By the pulsed laser beam to be inspected, the processed part a₁₁~ A
_1nIs subjected to the second stage processing. Unit processing area X
When both (i) and X (1) are finished, for TAB
The tape 20 is sent in the direction of arrow 30 by the roll mechanism 19.
Be done.

In FIG. 3D, following the machining shown in FIG. 3C, the unit machining area X (i + 1) enters the machining area of the galvano scanner 15 and, at the same time, enters the machining area of the galvano scanner 17. The state where the unit processing area X (2) has entered is shown. The first part of processing is carried out by the pulse laser beam scanned by the galvano scanner 15 on the parts a _{i + 1,1} to a _{i + 1, n} . At the same time, the processed parts a _{21 to} a
_2n is processed by the pulse laser beam scanned by the galvano scanner 17.

With reference to FIGS. 4A and 4B, description will be continued on the laser processing method according to the embodiment. The object to be processed is the TAB tape 20, and the copper layer 41 and the copper layer 42 are formed on both surfaces of the base film 40 made of a resin such as polyimide.
Are glued together. The thickness of the base film 40 is, for example, 25 to 50 μm, and the thickness of the copper layer 41 and the copper layer 42 is, for example, 9 to 18 μm.

In FIG. 4A, the pulse laser beam 43 scanned by the galvano scanner 15 shown in FIG.
This _shows a state in which a hole 41 a penetrating the copper layer 41 is formed by making the copper layer 41 of the processed portion a _1i on the B tape 20 incident. This is the first stage processing described above. The formation of the holes 41a requires, for example, a pulsed laser beam that gives a pulse energy density of about 20 J / cm ^{2 to} the surface of the copper layer. The roll mechanism 19 has already punched the hole 41a,
The processed portion a _1i on the TAB tape 20 where the base film 40 is exposed at the bottom of the la 1a is _attached to the galvano scanner 17
To the processing area. During that time, the heat at the time of processing the hole 41a is dissipated, and the vicinity of the hole 41a is cooled.

In FIG. 4B, the pulse laser beam 44 scanned by the galvano scanner 17 shown in FIG. 3 is made incident on the base film 40 of the processed portion a _1i , and a hole 40a penetrating the base film 40 is formed. It shows how it is formed. This is the above-described second stage processing. The formation of the holes 40a requires, for example, a pulse laser beam which gives the base film 40 a pulse energy density of about ² J / cm ² .

By thus providing a time interval between the processing of the copper layer 41 and the processing of the base film 40,
Good quality processing can be realized. Further, when the base film 40 of the processed portion a _1i is processed by the galvano scanner 17, the copper layer 4 of the processed portion a _ij is processed in the processing area of the galvano scanner 15.
That No. 1 has been processed was described above with reference to FIG. Therefore, the processing time can be shortened.

In order to improve the time efficiency of processing, EO
It is preferable to appropriately distribute the power of the pulsed laser beam by the M12 and the polarizing plate 13. 70% or more of the power is distributed to the processing of the copper layer 41. As one of the optimum examples, an Nd: YAG laser is used for the laser oscillator 10, the wavelength of the pulsed laser beam is 355 nm (third harmonic), the pulse width is 50 nsec, the pulse frequency is 10 kHz, and the output is 1.
Consider the case of 0W. If a hole with a hole diameter of 50 μm is drilled, the power is divided into 90% for processing the copper layer 41 and 10% for processing the base film 40, resulting in a thickness of 12 μm.
The copper layer 41 of m and the base film 40 of 25 μm in thickness can be penetrated through the holes by irradiation of 15 shots. At this time, the pulse energy density of the pulse laser beam incident on the copper layer 41 is about 20 J / cm ² , and the pulse energy density of the pulse laser beam incident on the base film 40 is about ² J / cm ² . In this optimal example,
In the processing area of the galvano mirror 17 shown in FIG. 3C, the base film 40 of the processed portion a _1i is processed, and at the same time, in the processed area of the galvano mirror 15, the copper layer 41 of the processed portion a _ii is processed. Will be.

In the actual processing, fine adjustment is performed around the division ratio calculated in advance.

The wavelength of the pulse laser beam used is preferably 600 nm or less. If the wavelength exceeds 600 nm, the absorption rate for the copper foil will be 10% or less,
This is because it becomes difficult to process the copper layer.

Here, an example of a mask imaging optical system for forming an image of the through hole of the mask 11 on the surface of the TAB tape 20 is described. This is a TAB using a focusing lens.
Even if it is a condensing optical system that can focus the pulse laser beam on the tape for use 20, the situation is exactly the same.

Even when the object to be processed is not the TAB tape 20 but the substrate mounted on the XY stage, the quality and time-efficient processing can be similarly performed by lengthening the stroke of the stage.

Furthermore, it is conceivable to use a beam splitter as an optical means for dividing the pulse laser beam emitted from the pulse oscillator 10.

Although the embodiments of the present invention have been illustrated above, it will be apparent to those skilled in the art that various modifications, improvements, combinations and the like can be made.

[0031]

As described above, according to the present invention,
The resin portion can be processed by eliminating the influence of heat accumulated during processing of the metal layer, and the processing time can be shortened.
As a result, both quality and time efficiency can be improved in the processing of the processing object in which the metal layer is in close contact with the resin member.

[Brief description of drawings]

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

FIG. 2 is a diagram formally showing a unit processing area and a processed portion of a TAB tape.

3A to 3D are views for explaining a laser processing method according to an embodiment of the present invention.

4A and 4B are cross-sectional views of a TAB tape for explaining a laser processing method according to an embodiment of the present invention.

5A to 5D are sectional views of a 2-metal substrate for explaining a conventional method for processing a 2-metal substrate.

[Explanation of symbols]

X (i) Unit processing area a _ij Work piece 10 Laser oscillator 11 Mask 12 EOM 13 Polarizing plate 14 Reflecting mirror 15 Galvano scanner 16 fθ lens 17 Galvano scanner 18 fθ lens 19 Roll mechanism 20 TAB tape 30 Arrow 40 Base film 40a Hole 41, 42 Copper layer 41a Hole 43, 44 Pulse laser beam 51 Resin layer 51a, 51a 'Hole 51b Undercut 52 Copper layer 52a Hole 53 Electrode layer 54 Ultraviolet pulse laser beam

Claims (9)

[Claims] 1. A laser beam propagating along a second laser light path of a second and a third laser light path branched from a first laser light path, in which a metal film adheres to a surface of a resin member. A step of forming a hole in the metal film of the first processed portion by making it incident on the first processed portion; and a laser beam that advances the first processed portion along the third laser optical path. And a second processed portion in which the metal film is in close contact with the surface of the resin member is arranged at a position where a laser beam advancing along the second laser optical path can be incident. A laser beam that travels along the third laser optical path is incident on a region of the first processed portion where the resin member is exposed to form a hole in the resin member, and at the same time, the second processed portion is formed. Part along the second laser optical path By the incidence of the laser beam, the laser processing method and a step of forming a hole in the metal film of the processed portion of the second. 2. The difference between the time for forming a hole that penetrates the metal film of the first processed portion and the time for forming a hole that penetrates the resin portion of the first processed portion. But the second
When the power of the laser beam traveling through the laser optical path and the power of the laser beam traveling through the third laser optical path are the same, the time for which the hole that penetrates the metal film is formed and the hole that penetrates the resin portion is formed. The laser processing method according to claim 1, further comprising a step of branching the laser beam traveling along the first laser optical path into laser beams traveling along the second and third laser optical paths so as to be shorter than a difference with time. 3. The laser processing method according to claim 1, wherein the first processed portion and the second processed portion are different portions of one tape-shaped processing target object. 4. The hole formed in the metal film of the first and second processed portions is a hole penetrating the metal film, and a laser beam traveling along the third laser optical path is formed in the hole. 4. The laser processing method according to claim 1, wherein the resin member is exposed on the bottom surface. 5. The laser processing method according to claim 1, wherein 70% or more of the power of the laser beam traveling along the first laser optical path is incident on the second laser optical path. 6. The laser processing method according to claim 1, wherein the wavelength of the laser beam is 600 nm or less. 7. A laser light source for emitting a pulsed laser beam, and optical means for dividing the pulsed laser beam emitted from the laser light source into a first pulsed laser beam and a second pulsed laser beam, and An optical system for making the first pulsed laser beam incident on a point in the first processing region and the second pulsed laser beam incident on a point in the second processing region; and the first processing region in the first processing region. Scanning means for scanning the pulse laser beam of No. 1, second scanning means for scanning the second pulse laser beam in the second processing area, and a processing target processed in the first processing area. Things,
A laser processing apparatus comprising: a moving unit that moves the second processing region. 8. The laser processing apparatus according to claim 7, wherein the optical unit is capable of changing the power ratio between the first pulse laser beam and the second pulse laser beam. 9. The laser processing apparatus according to claim 7, wherein the laser light source emits a laser beam having a wavelength of 600 nm or less.