TWI566870B - Laser processing method and laser processing object - Google Patents

Description

Laser processing method and laser processing object

The present invention relates to a processing method and a processed article, and more particularly to a laser processing method and a laser processed article.

In many advanced material processing processes and precision machining processes, traditional processing techniques are no longer sufficient, and laser processing technology is required to meet the needs of the process. Traditional continuous wave laser processing technology mainly uses thermal effects to process target workpieces (such as substrates), such as cutting, drilling or surface modification. 1 is a schematic view of a conventional laser cutting, in which the upper and lower halves of FIG. 1 are shown before and after cutting of the substrate, respectively. Referring to FIG. 1, in the prior art, the laser light B is incident on the substrate SUB from one side of the substrate SUB, and is concentrated at the focus X, wherein the focus portion X and the area A1 thereon are removed by the high temperature of the laser light B. The area A2 below the focus X is broken by the thermal stress generated by the thermal effect. Therefore, the substrate SUB can be cut into two halves by translating the laser light B along a predetermined path R.

For an isotropic substrate, the thermal stress causes a thermal stress to break around the heat source (such as the focus X), resulting in a thermal stress. The surface SA is prone to burrs. In order to improve the flatness of the processed surface of the substrate SUB (for example, including the fracture surface SA and the laser light removal surface SC), it is generally necessary to remove the burrs of the fracture surface SA by a subsequent process, however, this will increase the process steps and time. On the other hand, thermal stress is extremely susceptible to environmental temperature. When the ambient temperature is not properly controlled, the substrate SUB is easily thermally uneven, so that the fracture surface SA deviates from the originally set fracture surface SB, and the precision of the processing is lowered. Further, in the case where the laser light B is incident on the substrate SUB on one side, the depth of focus of the laser light B in the substrate SUB is required to be sufficient to ensure that the substrate SUB can be broken. However, since the laser light B converges in the substrate SUB, a taper is generated in the longitudinal direction of the substrate SUB, which is disadvantageous for the micromachining process of the fine elements. Therefore, how to improve the precision, speed and component quality of laser processing is one of the problems that researchers are trying to solve.

The present invention provides a laser processing method that can improve the precision and speed of laser processing.

The invention further provides a laser processed article having good component quality.

A laser processing method of the present invention includes the steps of: providing a substrate, wherein the substrate has a first surface and a second surface opposite to the first surface; the first surface is illuminated by the first laser light, and the second laser light is irradiated The two sides, wherein the direction of transmission of the first laser light and the second laser light is opposite in the normal direction of the substrate.

In an embodiment of the invention, the first laser light and the second laser light are derived from a laser light source or are respectively derived from a plurality of laser light sources.

In an embodiment of the invention, the first laser light and the second laser light are continuous waves, respectively.

In an embodiment of the invention, the first laser light and the second laser light are respectively pulsed and dimmed, and the time difference between the first laser light and the second laser light reaching the substrate is not zero.

In an embodiment of the invention, the first laser light and the second laser light are respectively pulsed and dimmed, and the time difference between the first laser light and the second laser light reaching the substrate is zero.

In an embodiment of the invention, the first laser light illuminates the first surface along the first direction, wherein the angle between the first direction and the first surface and the second surface is between 0 degrees and 180 degrees, respectively.

In an embodiment of the invention, the angle between the first direction and the first surface and the second surface is 90 degrees.

In an embodiment of the invention, the first laser light is focused on the first surface or the substrate, and the second laser light is focused on the second surface or the substrate.

In an embodiment of the invention, the first laser light is focused above the first surface, and the second laser light is focused below the second surface.

In an embodiment of the invention, the first laser light illuminates the first surface in the first direction, and the distance between the first laser light and the second laser light in the second direction perpendicular to the first direction is less than or equal to The thickness of the substrate.

In an embodiment of the invention, the distance between the first laser light and the second laser light in the second direction is equal to zero.

In an embodiment of the invention, the first laser light illuminates the first surface in the first direction, and the distance between the first laser light and the second laser light in the second direction perpendicular to the first direction is greater than the substrate thickness.

A laser processed article of the present invention is formed by laser cutting to form a laser cut surface. The laser cutting surface comprises a strip-shaped first laser action area, a strip-shaped second laser action area and a strip-shaped non-laser action area, wherein the first laser action area and the second laser action area are respectively located The opposite sides of the non-laser action zone. When the beam is transmitted to the first laser action zone or the second laser action zone, it is diffusely reflected and is specularly reflected when the beam is transmitted to the non-laser zone.

In an embodiment of the invention, the material of the laser processed material is an inorganic non-metal material.

In an embodiment of the invention, the material of the laser processed object is a transparent material, and the light transmittance of the non-laser action region is higher than that of the first laser action region and the second laser action region. Transmittance.

In an embodiment of the invention, the material of the laser processed article is a non-transparent material.

In an embodiment of the invention, the laser cutting surface is a flat surface, a curved surface or a multi-fold surface.

Based on the above, the above-described embodiment of the present invention uses dual laser light to process the opposite sides of the substrate to improve the precision and speed during laser processing, and to provide the laser processed article with good component quality.

In order to make the above features and advantages of the present invention more apparent, the following is a special The embodiments are described in detail below in conjunction with the drawings.

10‧‧‧Laser processing

A1, A2‧‧‧ area

B, BB‧‧ ‧ laser light

B1‧‧‧first laser light

B2‧‧‧second laser light

BB1‧‧‧ reflection pattern

BB2‧‧‧ point noise

D1‧‧‧ first direction

D2‧‧‧ second direction

DD‧‧‧ distance

H‧‧‧thickness

O1, O2, O3‧‧‧ aperture

R, R’‧‧‧Preset route

R1‧‧‧first laser action zone

R2‧‧‧second laser action zone

R3‧‧‧ non-laser zone

RR‧‧‧ Path

S‧‧‧ laser cutting surface

S1‧‧‧ first side

S2‧‧‧ second side

SA, SB‧‧‧ fracture surface

SC‧‧‧Laser light removal surface

SUB‧‧‧ substrate

T, T1, T2‧‧‧ Depth of focus

W1, W2‧‧‧ width

X, X1, X2‧‧‧ focus

Θ1, θ2‧‧‧ angle

Figure 1 is a schematic illustration of a conventional laser cutting.

2 is a schematic diagram of a laser processing method in accordance with a first embodiment of the present invention.

3 is a schematic view of laser light reflected by the laser processed material of FIG. 2.

4 is a cross-sectional view showing a laser processing method in accordance with a second embodiment of the present invention.

Figure 5 is a cross-sectional view showing a laser processing method in accordance with a third embodiment of the present invention.

Figure 6 is a cross-sectional view showing a laser processing method in accordance with a fourth embodiment of the present invention.

Figure 7A is a cross-sectional view showing a laser processing method in accordance with a fifth embodiment of the present invention.

7B is a schematic cross-sectional view of a laser processing method of the prior art.

2 is a schematic view of a laser processing method according to a first embodiment of the present invention, wherein the upper and lower halves of FIG. 2 are respectively shown before and after substrate processing. Referring to FIG. 2, the laser processing method is, for example, a laser cutting method, and the laser processing method Includes the following steps. First, a target workpiece such as a substrate SUB is provided. The substrate SUB can be any substrate that is intended to be laser processed (eg, cut, drilled, or surface modified, etc.). For example, the material of the substrate SUB may be an inorganic non-metal material, such as a semiconductor substrate, glass, ceramics, etc., but not limited thereto. The substrate SUB has a first surface S1 and a second surface S2, wherein the first surface S1 is opposite to the second surface S2 and is, for example, parallel to each other, but is not limited thereto.

Next, the first surface S1 is irradiated with the first laser light B1, and the second surface S2 is irradiated with the second laser light B2, wherein the first laser light B1 and the second laser light B2 are transmitted in opposite directions. For convenience of drawing, FIG. 2 indicates the first laser light B1 and the second laser light B2 by arrows.

In detail, the first laser light B1 illuminates the first surface S1 along the first direction D1. The first direction D1 is a direction in which the first surface S1 points to the second surface S2, and the first direction D1 is, for example, perpendicular to the first surface S1, that is, the angle θ1 between the first direction D1 and the first surface S1 is equal to 90 degrees. But not limited to this. On the other hand, since the first surface S1 of the embodiment is parallel to the second surface S2, the angle between the first direction D1 and the second surface S2, that is, the angle between the opposite direction of the first direction D1 and the second surface S2 Θ2 is also equal to 90 degrees, but it is not limited to this. In another embodiment, when the first face S1 and the second face S2 are not parallel to each other, the angle θ2 is, for example, between 0 degrees and 180 degrees, and is not equal to 90 degrees.

The first laser light B1 and the second laser light B2 may be continuous waves, respectively, but are not limited thereto. In another embodiment, the first laser light B1 and the second laser light B2 may be pulsed dimming, respectively, and the first laser light B1 and the second laser light B2 are The time difference of the substrate SUB may be 0 or not 0. In addition, the first laser light B1 and the second laser light B2 may be derived from a laser light source and split into the first laser light B1 and the second laser light B2 transmitted in the opposite direction, for example, by erecting the optical path. Alternatively, the first laser light B1 and the second laser light B2 may be derived from two laser light sources, respectively. Of course, at least one of the first laser light B1 and the second laser light B2 may be derived from two or more laser light sources, and may be combined by a light combining element before being irradiated to the substrate SUB.

As shown in the upper half of FIG. 2, the first laser light B1 and the second laser light B2 of the present embodiment are aligned, for example, in the first direction D1. In other words, the offset amount of the first laser light B1 and the second laser light B2 in the second direction D2 perpendicular to the first direction D1 is zero. Alternatively, it may be considered that the line connecting the focus X1 of the first laser light B1 and the focus X2 of the second laser light B2 is parallel to the first direction D1.

In this embodiment, the first laser light B1 and the second laser light B2 are respectively focused on the substrate SUB, wherein the focus portion X1 is located between the first surface S1 and the focus portion X2, and the focus portion X2 is located at the second surface S2 and Focus is between X1. The method of focusing is, for example, a setting through a focusing mirror, wherein a focal length of the focusing mirror for concentrating the first laser light B1 and a focusing mirror for concentrating the second laser light B2 can be independently set. It should be noted that the present invention does not need to limit the depths of focus T1, T2 of the first laser light B1 and the second laser light B2 (ie, the distance between the focus portion X1 and the first surface S1 and the distance between the focus portion X2 and the second surface S2). ). The first laser light B1 can also be focused on the first surface S1 and the second laser light B2 can be focused on the substrate SUB according to different laser power levels, different laser light sources or different design requirements. Or, the first The two laser light B2 can be focused on the second surface S2, and the first laser light B1 is focused on the substrate SUB. Still alternatively, the first laser light B1 is focused on the first surface S1, and the second laser light B2 is focused on the second surface S2. That is, the depths of focus T1, T2 of the first laser light B1 and the second laser light B2 may be zero. Furthermore, the first laser light B1 can also be focused above the first surface S1, and the second laser light B2 can be focused below the second surface S2. That is to say, the focus X1 and the focus X2 are located outside the substrate SUB.

By causing the first laser light B1 and the second laser light B2 to be incident on the substrate SUB from opposite sides of the substrate SUB, respectively, the substrate SUB can be guided to be broken along the line connecting the two focal points X1 and X2. Therefore, the present embodiment can preferably control the direction in which the substrate SUB is broken and reduce the generation of the burrs, and the subsequent process of removing the burrs can be omitted, and the speed of the laser processing process can be improved. Further, since the present embodiment breaks the substrate SUB by the guidance of the stress between the two peeling points (referring to the focus X1 and the focus X2), the influence of the ambient temperature on the processing precision can be reduced. Furthermore, the double-sided light incident of the present embodiment can achieve the effect of cutting the substrate SUB at a smaller depth of focus T1, T2 compared to the one-side light incident of the prior art, thereby contributing to the reduction of the aforementioned taper. The impact of precision machining.

It is worth mentioning that when the first laser light B1 and the second laser light B2 are respectively pulsed and dimmed, the time difference between the first laser light B1 and the second laser light B2 reaching the substrate SUB is modulated, and the substrate SUB arrives late. The laser light can guide the initial stress generated by the laser light reaching the substrate SUB first, and induce the substrate SUB to break along the line connecting the two focal points X1, X2. Moreover, the laser light generates a shock wave in the substrate SUB, and the shock wave caused by the two laser lights is constructively involved/ Or when the two lasers generate constructive interference, the ability of the laser to break the substrate SUB can be further improved.

The substrate SUB can be cut into two halves by shifting the first laser light B1 and the second laser light B2 along the preset path R. Referring to the lower half of Fig. 2, the laser workpieces 10 formed by the above laser cutting have a laser cutting plane S, respectively. The laser cutting plane S includes a strip-shaped first laser action area R1, a strip-shaped second laser action area R2, and a strip-shaped non-laser action area R3, wherein the first laser action area R1 and the second mine The radiation action regions R2 are respectively located on opposite sides of the non-laser action region R3. The first laser action region R1 is a region where the corresponding substrate SUB is removed by the first laser light B1, and the second laser action region R2 is a region where the corresponding substrate SUB is removed by the second laser light B2, non-laser The action region R3 is a region where the substrate SUB is broken due to stress.

The types of the first laser action zone R1, the second laser action zone R2, and the non-laser zone R3 are related to the laser power, the depth of focus T1, T2. Further, the width W1 of the first laser action region R1 is positively correlated with the power of the first laser light B1, the depth of focus T1 of the first laser light B1, and the depth of focus (or numerical aperture) of the focusing mirror used. The depth of focus refers to the length of the focus of the laser light in the direction of the optical axis. When the numerical aperture is larger, the depth of focus is shallower, and the range of action of the laser light in the optical axis direction becomes shorter. Similarly, the width W2 of the second laser action region R2 is positively correlated with the power of the second laser light B2, the depth of focus T2 of the second laser light B2, and the depth of focus (or numerical aperture) of the focusing mirror used. In this embodiment, the width W1 of the first laser action region R1 is approximated to the depth of focus T1 of the first laser light B1, and the second laser action region The width W2 of R2 is approximated to the depth of focus T2 of the second laser light B2.

In addition, the first laser action region R1 and the second laser action region R2 of the present embodiment do not fall in the same plane as the non-laser action region R3. Further, the laser cutting surface S of the embodiment is a multi-fold surface, wherein the surface of the laser processing object 10 corresponding to the non-laser action region R3 is substantially connected and pre-wired by the focus portion X1 and the focus portion X2. A plane formed by the route R is provided, and the surface of the laser processed object 10 corresponding to the first laser action zone R1 and the second laser action zone R2 is a slope formed by a change in the range of the laser action with respect to the direction of propagation of the laser.

Since the first laser action region R1 and the second laser action region R2 are formed by laser peeling, and the non-laser action region R3 is formed by stress fracture, the optical characteristics of the first laser action region R1 are similar to each other. The optical characteristics of the second laser action region R2 are expressed, and the optical characteristics of the first laser action region R1 and the second laser action region R2 are different from those of the non-laser region R3.

3 is a schematic view of laser light reflected by the laser processed material of FIG. 2. Referring to FIG. 3, when the elongated laser light BB obliquely incident on the laser cutting surface S is covered by an irradiation range S, the laser light BB is specularly reflected when it is transmitted to the non-laser action region R3. A reflection pattern BB1 similar to the pattern of the elongated laser light BB is formed in the reflection area RA of the light beam. On the other hand, when the laser light BB is transmitted to the first laser action area R1 or the second laser action area R2, it is diffusely reflected, and a plurality of point noises BB2 are formed on both sides of the reflection pattern BB1. In other words, the surface of the laser cutting surface S corresponding to the first laser action area R1 and the second laser action area R2 is a diffuse reflection surface, and the laser cut surface S corresponds to the non-laser action area R3. The surface is specular reflection.

The material of the laser workpiece 10 may be a transparent material or a non-transparent material. When the material of the laser processed material 10 is a transparent material (such as glass), the light transmittance of the non-laser action region R3 is higher than the light transmittance of the first laser action region R1 and the second laser action region R2. . Further, when the material of the laser processed object 10 is a transparent material, the light transmittance of the surface of the laser processed object 10 corresponding to the non-laser action region R3 is substantially the same as that of the original material of the laser processed object 10. The transmittance, and the surface of the laser workpiece 10 corresponding to the first laser action area R1 and the second laser action area R2 presents a matte surface that is difficult for the human eye to see through.

4 is a cross-sectional view showing a laser processing method in accordance with a second embodiment of the present invention. Referring to FIG. 4, the laser processing method of the present embodiment is substantially the same as the laser processing method of FIG. The main difference is that the first laser light B1 of the present embodiment is focused on the first surface S1, and the second laser light B2 is focused on the substrate SUB. In other words, the focus X1 is located on the first side S1, and the focus X2 is located between the first side S1 and the second side S2. Further, the first laser light B1 and the second laser light B2 of the present embodiment are not aligned in the first direction D1. In other words, the offset amount (distance DD) of the first laser light B1 and the second laser light B2 in the second direction D2 is not zero. However, in order to achieve the purpose of causing the substrate SUB to break along the line connecting the two focal points X1, X2, the distance DD is preferably less than or equal to the thickness H of the substrate SUB. However, under different system erections (for example, changing the laser source or changing the laser power, etc.), the distance DD is greater than the thickness H of the substrate SUB, and the aforementioned induced fracture effect may also be achieved. As shown in the lower half of FIG. 4, the substrate SUB of the present embodiment is broken, for example, along the path RR, and the laser cutting surface S is, for example, a curved surface. It is worth mentioning that the conventional technology does not control the direction of the fracture surface by a single laser incident on one side of the substrate. However, in this embodiment, the depth of focus or the modulation of the first laser light B1 and the second laser light B2 are modulated. The variable distance DD can change the curved shape and the degree of bending of the laser cutting surface S. In another embodiment, the laser cutting surface S may also be a multi-folded surface composed of a plurality of planes.

Figure 5 is a cross-sectional view showing a laser processing method in accordance with a third embodiment of the present invention. Referring to FIG. 5, the laser processing method of the present embodiment is substantially the same as the laser processing method of FIG. The main difference is that the first laser light B1 and the second laser light B2 of the embodiment are respectively concentrated on the first surface S1 and the second surface S2. Since the substrate SUB is broken along the line connecting the two focal points X1, X2 (such as the path RR), the laser cutting surface S is a plane parallel to the first direction D1.

In addition, the transmission direction of the first laser light B1 (ie, the first direction D1) of the present embodiment is not perpendicular to the first surface S1, and the transmission direction of the second laser light B2 (ie, the opposite direction of the first direction D1) is not vertical. On the second side S2. In other words, the angles θ1 and θ2 between the first direction D1 and the first surface S1 and the second surface S2 are not equal to 90 degrees. Further, the substrate SUB of the present embodiment is inclined, for example, with respect to the first direction D1. Since the first surface S1 is parallel to the second surface S2, the angle θ1 and the included angle θ2 complement each other, that is, the sum of the angle θ1 and the angle θ2 is 180 degrees, but the present invention is not limited thereto. For example, in another embodiment, the first surface S1 may not be parallel to the second surface S2, and the included angles θ1, θ2 are between 0 degrees and 180 degrees, respectively.

The above laser processing is exemplified by laser cutting, but the present invention is not limited thereto. Figure 6 is a cross section of a laser processing method in accordance with a fourth embodiment of the present invention schematic diagram. Referring to FIG. 6, the first laser light B1 and the second laser light B2 are respectively concentrated on the first surface S1 and the second surface S2 of the substrate SUB, and are collectively translated along the preset path R to surface-modify the substrate SUB. . Compared with the prior art, surface modification is performed on a single side of the substrate with a single laser light, and this embodiment can at least improve the speed at the time of laser processing.

Figure 7A is a cross-sectional view showing a laser processing method in accordance with a fifth embodiment of the present invention. 7B is a schematic cross-sectional view of a laser processing method of the prior art. Referring to FIG. 7A, the first laser light B1 and the second laser light B2 are respectively concentrated on the first surface S1 and the second surface S2 of the substrate SUB, respectively, and are respectively moved along the preset paths R, R' for drilling.

Referring to FIG. 7A and FIG. 7B, the single laser light B is drilled on one side of the substrate SUB, and the depths of focus T1 and T2 of the first laser light B1 and the second laser light B2 of the present embodiment are compared with those of the prior art. It may be smaller than the depth of focus T of the laser light B. Therefore, compared with the prior art, the embodiment can relatively slow down the taper phenomenon, so that the apertures O1 and O2 formed by the laser drilling of the embodiment are smaller than the aperture O3 formed by the laser drilling of the prior art. . In addition, the present embodiment can have a relatively symmetrical perforated structure and can shorten the time required for drilling, as compared with the prior art.

In summary, the above embodiments of the present invention use dual laser light to process the opposite sides of the substrate to improve the precision and speed of the laser processing, and to make the processed laser processed object have good components. quality.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the invention, and any one of ordinary skill in the art without departing from the invention. In the spirit and scope, the scope of protection of the present invention is subject to the definition of the appended patent application.

10‧‧‧Laser processing

B1‧‧‧first laser light

B2‧‧‧second laser light

D1‧‧‧ first direction

D2‧‧‧ second direction

R‧‧‧Preset route

R1‧‧‧first laser action zone

R2‧‧‧second laser action zone

R3‧‧‧ non-laser zone

S‧‧‧ laser cutting surface

S1‧‧‧ first side

S2‧‧‧ second side

SUB‧‧‧ substrate

T1, T2‧‧‧ Depth of focus

W1, W2‧‧‧ width

X1, X2‧‧‧ Focus

Θ1, θ2‧‧‧ angle

Claims (16)

A laser processing method includes: providing a substrate having a first surface and a second surface opposite to the second surface; and illuminating the first surface with a first laser light, and Illuminating the second surface with a second laser light, wherein a direction of transmission of the first laser light and the second laser light is opposite in a normal direction of the substrate, wherein the first laser light is along a first direction Illuminating the first surface, the distance between the first laser light and the second laser light in a second direction perpendicular to the first direction is greater than zero. The laser processing method of claim 1, wherein the first laser light and the second laser light are derived from a laser light source or are respectively derived from a plurality of laser light sources. The laser processing method of claim 1, wherein the first laser light and the second laser light are continuous waves, respectively. The laser processing method of claim 1, wherein the first laser light and the second laser light are respectively pulsed and dimmed, and the time difference between the first laser light and the second laser light reaching the substrate Not 0. The laser processing method of claim 1, wherein the first laser light and the second laser light are respectively pulsed and dimmed, and the time difference between the first laser light and the second laser light reaching the substrate Is 0. The laser processing method of claim 1, wherein an angle between the first direction and the first surface and the second surface is between 0 and 180 degrees, respectively. The laser processing method of claim 6, wherein an angle between the first direction and the first surface and the second surface is 90 degrees. The laser processing method of claim 1, wherein the first laser light is focused on the first surface or the substrate, and the second laser light is focused on the second surface or the substrate. The laser processing method of claim 1, wherein the first laser light is focused above the first surface, and the second laser light is focused below the second surface. The laser processing method of claim 1, wherein the distance between the first laser light and the second laser light in the second direction is less than or equal to the thickness of the substrate. The laser processing method of claim 1, wherein the distance between the first laser light and the second laser light in the second direction is greater than the thickness of the substrate. A laser processed object is formed by laser cutting to form a laser cutting surface, the laser cutting surface comprising a strip of first laser action area, a strip of second laser action area, and a strip of non-laser An action area, wherein the first laser action area and the second laser action area are respectively located on opposite sides of the non-laser action area, when a light beam is transmitted to the first laser action area or the second laser action The zone is diffusely reflected and is specularly reflected when the beam is transmitted to the non-laser zone. The laser processed article of claim 12, wherein the material of the laser processed material is an inorganic non-metallic material. The laser processed article of claim 12, wherein the material of the laser processed material is a transparent material, and the light transmittance of the non-laser action region is higher than the first laser action region and the second Light penetration rate of the laser action area. The laser processed article of claim 12, wherein the material of the laser processed article is a non-transparent material. The laser processed article of claim 12, wherein the laser cutting surface is a plane, a curved surface or a multi-fold surface.