KR101453855B1 - Bonding method of multiple member using ultra short pulse laser - Google Patents

Abstract

Provided is a method for bonding multiple members having no adhesive or laser absorbing layer. The method for bonding the multiple members comprises the steps of providing the multiple members, which includes a plurality of members stacked on each other and having surfaces contacting each other, on a stage; oscillating an ultra short pulse laser beam from a laser beam source; dividing the laser beam into a plurality of beam components; forming a plurality of laser focuses by concentrating the beam components in line with each other in directions of thicknesses of the multiple members from peripheral portions of the interfacial surfaces of the multiple members; and forming a welding portion by a non-linear absorption phenomenon in the multiple members.

Description

TECHNICAL FIELD [0001] The present invention relates to a multi-member joining method using an ultra-short pulse laser,

The present invention relates to a method for joining multiple members, and more particularly, to a method for integrally joining multiple members by irradiating an ultrasound pulse laser to an interface between laminated members.

The multiple members include a plurality of mutually stacked members. The plurality of members may all be in the form of a substrate, or one of the plurality of members may take the form of a substrate and the other may take the form of a device. A method of melting the interface by irradiating a laser beam along the interface between the laminated members to integrally join the multiple members has been studied.

A conventional bonding apparatus using a laser is composed of a laser light source for emitting a laser beam, a transferring optical system for transmitting a laser beam, an objective lens for focusing the laser beam, and a precision stage for moving multiple substrates. However, since such a joining apparatus generates a laser beam with a single focus, it is difficult to accurately position the laser focus at the interface, and the length of the welded portion is small and the joint strength is low.

The present invention aims to provide a method of joining multiple members that can directly melt the interface of multiple members without an adhesive layer or a laser absorbing layer.

In addition, the present invention provides a multi-member member capable of increasing the bonding strength of multiple members by increasing the length of the welded portion, lowering the difficulty of forming the interface, and easily adjusting the number, spacing, To provide a bonding method.

A method of joining multiple members according to an embodiment of the present invention includes the steps of disposing multiple members on a stage including a plurality of members stacked one on top of the other so that their surfaces are in contact with each other; Separating the beam components into a plurality of beam components along a thickness direction of the plurality of members around the interface of the plurality of members to form a plurality of laser focuses; And forming a welded portion by nonlinear absorption phenomenon in the welded portion.

The plurality of members include a transparent member having no linear absorption in the wavelength band of the laser beam, and can be positioned close to the laser light source in the order of high transparency. The laser beam has a pulse duration of either picosecond or femtosecond and is a laser which causes a nonlinear absorption phenomenon of any one of multiphoton absorption, tunneling ionization, and avalanche absorption in multiple members. Strength can be provided.

A Fresnel zone element and a condenser may be positioned between the laser light source and the multiple members, and the Fresnel zone element may spatially separate a plurality of beam components.

The plurality of beam components may include a first beam component that is diffracted by the Fresnel zone element and a second beam component that is not diffracted, and the first beam component may comprise a component that is divergent and a component that is converged. The focal points of the plurality of first beam components may be vertically symmetrically positioned along the thickness direction of the multiple members with respect to the focus of the second beam component.

The energy intensity of each of the plurality of beam components can be controlled by adjusting the diffraction efficiency of the Fresnel zone element. The Fresnel zone element can move along the advancing direction of the laser beam to change a plurality of laser focus distances.

개로 분리시킬 수 있다. 프레넬 영역 소자는 레이저 빔의 진행 방향을 따라 복수개로 구비될 수 있고, 복수의 프레넬 영역 소자는 레이저 빔을

개(여기서 n은 프레넬 영역 소자의 개수)로 분리시킬 수 있다.The Fresnel zone element has a diffraction order (m) of 1 or 2, and the laser beam

Can be separated by a dog. A plurality of Fresnel zone elements may be provided along a traveling direction of the laser beam, and a plurality of Fresnel zone elements may be provided with a laser beam

(Where n is the number of Fresnel zone elements).

The energy intensity of each of the plurality of first beam components may be equal to the energy intensity of the second beam component and the welds may be formed into a long oval shape along the thickness direction of the multiple members. The energy intensity of each of the plurality of first beam components may be lower than the energy intensity of the second beam component, and the welded portion may be formed in a convex oval shape in the middle portion. The energy intensity of each of the plurality of first beam components may be higher than the energy intensity of the second beam component and the welded portion may be formed into a dumbbell shape having both ends convex.

The stage can be composed of a three-dimensional precision stage capable of adjusting the height, and can move horizontally at predetermined time intervals.

By generating a plurality of laser focal points at the interface of the multiple members, the length of the welded portion can be increased more than that of the single beam focal point to increase the joint strength. And because the length of the weld is increased, it is possible to easily position the laser focus on the interface of multiple members, which can lower the difficulty of forming the interface.

In addition, since the beam intensities of the beam components can be set to be the same or extremely similar to each other according to the diffraction efficiency of the Fresnel zone element, the welding quality can be improved by forming a weld having a constant width at the interface of multiple members. The bonding method of this embodiment does not require an adhesive or a laser absorbing layer.

1 is a process flow diagram illustrating a method of joining multiple members in accordance with an embodiment of the present invention.
Fig. 2 is a configuration diagram of a laser machining apparatus for performing the joining of multiple members shown in Fig. 1. Fig.
3A is a schematic view showing a Fresnel region element having a diffraction order of 1 and a condenser.
3B is a schematic view showing a Fresnel region element having a diffraction order of 2 and a condenser.
FIGS. 4A and 4B are enlarged cross-sectional views illustrating the multiple members of the first step shown in FIG. 1. FIG.
5A is a schematic diagram showing an energy distribution of beam components and an energy absorption distribution of multiple members according to the first embodiment of the present invention.
FIG. 5B is a schematic view showing a welded portion of multiple members according to the energy absorption amount distribution of FIG. 5A. FIG.
FIG. 6 is an enlarged cross-sectional view showing the multiple members of the fourth step shown in FIG. 1;
FIG. 7A is a schematic diagram showing an energy distribution of beam components and an energy absorption distribution of multiple members according to a second embodiment of the present invention. FIG.
FIG. 7B is a schematic view showing a welded portion of multiple members according to the energy absorption amount distribution of FIG. 7A. FIG.
8A is a schematic view showing an energy distribution of beam components and an energy absorption amount distribution of multiple members according to a third embodiment of the present invention.
FIG. 8B is a schematic view showing a welded portion of multiple members according to the energy absorption amount distribution of FIG. 8A. FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art to which the present invention pertains. The present invention may be embodied in many different forms and is not limited to the embodiments described herein.

1 is a process flow diagram illustrating a method of joining multiple members in accordance with an embodiment of the present invention.

Referring to FIG. 1, the method of joining multiple members according to the present embodiment includes a first step (S10) of placing multiple members on a stage, a second step (S20) of oscillating an ultra-short pulse laser beam from a laser light source , A third step (S30) of separating the laser beam into a plurality of beam components, a fourth step of converging a plurality of beam components in a line along the thickness direction of the multiple members at the interface of the multiple members to form a plurality of laser focuses (S40), and a fifth step (S50) of forming a welded portion by nonlinear absorption phenomenon in the multiple members.

In the first step S10, the multiple members include a transparent member having no linear absorption in the wavelength range of the laser beam. In the third to fifth steps S30 to S50, a Fresnel zone element and a condenser are positioned between the laser light source and the multiple members. In the third step S30, the Fresnel zone element spatially separates a plurality of beam components, and in the fourth step S40, the concentrator focuses a plurality of beam components to form a plurality of laser focuses.

Fig. 2 is a configuration diagram of a laser machining apparatus for performing the joining of multiple members shown in Fig. 1. Fig.

2, the laser processing apparatus 100 may include a laser light source 10, a beam transmitting section 20, a Fresnel zone element 30, and a condenser 40. [ A dichroic mirror 51 may be provided between the Fresnel zone element 30 and the condenser 40.

In the second step S20, the laser light source 10 generates an ultrashort pulsed laser beam for splicing the multiple members 60 together. The laser beam may have a pulse duration of either picosecond or femtosecond.

Ultrathreshold pulsed lasers can easily cause nonlinear absorption phenomena in a transparent material due to the short pulse width and the high peak output obtained thereby. The energy absorbed by the material causes a change in physicochemical properties such as refractive index and density change in the absorptive region and this change is more pronounced in the vicinity of the condensed focus due to the nature of the nonlinear optical phenomena proportional to the laser intensity, .

Therefore, the ultrashort-pulse laser can easily join the multiple members 60 made of various materials such as a material having a high heat transfer coefficient or a material having a low light absorption rate in a single process, There is no occurrence of deterioration in physico-chemical transformation and bonding accuracy.

The beam transmission section 20 is located on the path of the laser beam emitted from the laser light source 10. The beam transmitting portion 20 may be composed of various optical devices, for example, a beam expander for increasing the width of the laser beam, an attenuator for adjusting the energy intensity of the laser beam expanded in the beam expander, and the like. In this case, the width and the energy intensity of the laser beam are controlled through the beam transmission unit 20.

The Fresnel zone element 30 is located on the path of the laser beam output from the beam transmission portion 20. [ The Fresnel zone element 30 is a type of multilevel phase relief diffractive optical element (MLPR DOE), which means a lens that adjusts the divergence or convergence of a beam by diffraction, and the theoretical diffraction efficiency eta is calculated by the following equation.

Here, N represents the number of multi-levels of the Fresnel zone element 30, and m represents the diffraction order. Assuming that the diffraction order (m) is 1, the diffraction efficiency? Is simplified as follows.

The diffraction efficiency η is 40.5% for a binary phase lens with N = 2 and the diffraction efficiency η is 81.1% for a quaternary phase lens with N = 4. For an 8-level lens with N = 8, the diffraction efficiency η is 95.0%, and for a 16-level lens with N = 16, the diffraction efficiency η is 98.7%.

Regardless of the number of multilevels, the diffraction efficiency of the Fresnel zone element 30 is less than 100%. Therefore, the laser beam incident on the Fresnel zone element 30 is incident on the first beam component diffracted by the Fresnel zone element 30 and the second beam component diffracted by the Fresnel zone element 30 without being affected by the Fresnel zone element 30, Beam component. In the third step S30, the Fresnel zone element 30 acts as a beam splitter which separates the laser beam into a plurality of laser beams according to diffraction.

In the fourth step S40, the condenser 40 receives a plurality of beam components separated from the Fresnel zone element 30 and focuses the provided plurality of beam components onto the interface of the multiple members 60. [ The condenser 40 may be constituted by a normal objective lens.

The dichroic mirror 51 is disposed between the Fresnel zone element 30 and the condenser 40 to change paths of a plurality of beam components. The dichroic mirror 51 can be coated with a material having a good reflection effect at this wavelength band so as to reflect most of the wavelength band of the laser beam. The dichroic mirror 51 is omitted when the Fresnel zone element 30 and the condenser 40 are positioned on a straight line.

Although FIG. 2 shows a transmissive Fresnel zone element 30 that transmits a laser beam, the Fresnel zone element 30 may be composed of a reflective Fresnel zone element. In this case, the dichroic mirror 51 shown in Fig. 2 is replaced with a reflective Fresnel area element. The reflective Fresnel zone device may be a liquid crystal on silicon (LCOS) device with a liquid crystal or a spatial light modulator of a digital micro-mirror device (DMD) type .

The stage 52 is positioned below the condenser 40 and the multiple members 60 are placed on the stage 52. The stage 52 may be constituted by a two-dimensional precision stage for moving the multiple members 60 in the horizontal direction (x-axis direction and y-axis direction) or a three-dimensional precision stage capable of height adjustment. 2, reference numeral 53 denotes a control unit for controlling the laser light source 10, the beam transmission unit 20, the stage 52, and the like.

In the third step S30, the Fresnel zone element 30 may have 1 or 2 diffraction order (m). The Fresnel zone element 30 with the diffraction order m of 1 separates the incident laser beam into three beam components and the Fresnel zone element 30 with the diffraction order m of 2 separates the incident laser beam Separate into five beam components.

3A is a schematic view showing a Fresnel region element having a diffraction order of 1 and a condenser.

Referring to FIG. 3A, the Fresnel zone element 30 has a plurality of concentric bands, and each band acts as a diffraction grating to cause diffraction of light. The laser beam LB incident on the Fresnel zone element 30 is divided into the first beam component LB1 diffracted through the Fresnel zone element 30 and the second beam component LB2 not diffracted.

At this time, the diffracted first beam component LB1 is composed of a component LB1-1 converged while passing through the Fresnel zone element 30 and a component LB1-2 emitted. In other words, the Fresnel region element 30 works simultaneously with the converging Fresnel region element having the diffraction order greater than zero and the diffusing Fresnel region element having the diffraction order less than zero. The converged component LB1-1 and the divergent component LB1-2 of the first beam component LB1 have the same energy intensity.

The energy ratio of the first beam component (LB1) and the second beam component (LB2) is determined according to the diffraction efficiency of the Fresnel zone element (30). Assuming that the diffraction efficiency of the Fresnel zone element 30 is 50%, the second beam component LB2 has an energy intensity of 50%, and the converged components LB1-1 and LB2 of the first beam component LB1 The divergent components (LB1-2) each have an energy intensity of 25%. The diffraction efficiency of the Fresnel zone element 30 can be appropriately selected in accordance with the energy intensities of the plurality of beam components required for bonding of the multiple members 60. [

The focal position of the second beam component LB2 not diffracted in Fig. The focal position A1 of the converged component LB1-1 of the first beam component LB1 is located closer to the condenser 40 than that of B and the focal position A2 of the divergent component LB1-2 is smaller than B Is located away from the concentrator 40. As described above, the Fresnel area element 30 having the diffraction order of 1 separates the incident laser beam LB into three components, and the three beam components LB1-1, LB1-2, and LB2 have different focal positions .

3B is a schematic view showing a Fresnel region element having a diffraction order of 2 and a condenser.

Referring to FIG. 3B, the Fresnel zone element 30 having the diffraction order of 2 has a structure in which the provided laser beam LB is divided into five beam components, that is, four diffracted first beam components LB1 and one diffracted Into a second beam component LB2. The four diffracted first beam components LB1 have two components LB1-1 and LB1-2 converging at different convergence angles and two components LB1-3 and LB1- 4). The four diffracted first beam components LB1-1, LB1-2, LB1-3, and LB1-4 have the same energy intensity.

And the focus position of the second beam component LB2 not diffracted in FIG. The focal positions of the two beam components LB1-1 and LB1-2 converged among the four first beam components LB1 are denoted by A1 and A2, respectively, and the two beam components LB1-3 and LB1 -4) were represented by A3 and A4, respectively. The five beam components LB2, LB1-1, LB1-2, LB1-3, LB1-4 separated by the Fresnel zone element 30 have different focal positions.

으로 표현될 수 있다. 이때 m은 회절 차수를 나타낸다.In the third step S30, the number of components of the laser beam separated by the Fresnel zone element 30 is

. ≪ / RTI > Where m represents diffraction order.

FIGS. 4A and 4B are enlarged cross-sectional views illustrating the multiple members of the first step shown in FIG. 1. FIG. FIG. 4A shows a case where the diffraction order of the Fresnel region element is 1, and FIG. 4B shows the case where the diffraction order of the Fresnel region element is 2. FIG.

Referring to Figs. 1 and 4A and 4B, the multiple members 60 include a plurality of mutually stacked members 61, 62. The plurality of members may all be in the form of a substrate, or one of the plurality of members may take the form of a substrate and the other may take the form of a device. 4A and 4B illustrate a case where the first member 61 and the second member 62 having a substrate shape are laminated to each other.

The plurality of members 61, 62 include at least one transparent member free of linear absorption in the wavelength band of the laser beam and can be arranged close to the concentrator 40 in order of higher transparency. The first member 61 and the second member 62 are both made of a transparent member or the second member 62 close to the condenser 40 is made of a transparent member and the first member 61 is opaque or translucent Member. The transparent member may be formed of glass or quartz or the like.

In FIGS. 4A and 4B, multiple members composed of the first member 61 and the second member 62 are shown, but the number of the members stacked may be three or more. Even in this case, the plurality of members are arranged close to the condenser 40 in the order of high transparency.

The first member 61 and the second member 62 are stacked on each other so that their surfaces are in contact with each other. That is, no adhesive layer exists between the first member 61 and the second member 62, and there is no laser absorbing layer that helps laser absorption.

In the fourth step S40, the condenser 40 focuses a plurality of beam components separated from the Fresnel zone element 30 around the interface of the multiple members 60 to form a plurality of laser foci. A plurality of laser focuses are aligned in a line along the thickness direction of the multiple members 60 because the diffracted first beam components and the second beam component that is not diffracted are different in focal position.

In Fig. 4A, A1 and A2 represent the focal positions of the two first beam components diffracted by the Fresnel zone element 30, and B represent the focal positions of the second diffracted beam component. In Fig. 4B, A1, A2, A3 and A4 denote the focal positions of the four first beam components diffracted by the Fresnel zone elements 30 and B denote the focal positions of the second diffracted beam component.

Wherein the multi-member (60) comprises a transparent member free of linear absorption in the wavelength range of the laser beam and wherein the laser beam is multiphoton absorption in the multiple member (60), tunneling ionization, lt; RTI ID = 0.0 > avalanche < / RTI > absorption. Therefore, in the fifth step S50, the periphery of the interface of the multiple members 60 is melted to form a welded portion, and the joining of the first member 61 and the second member 62 is performed.

Since the laser focus of the first beam component is vertically symmetrical with respect to the laser focus of the second beam component, the laser focus of the second beam component is positioned as close as possible to the interface of the multiple member 60, Can be concentrated on the interface of the multiple members (60). For this, the height of the multiple members 60 can be precisely adjusted by applying a three-dimensional precision stage to the stage 52 supporting the multiple members 60.

In the fourth step S40, the plurality of beam components may have the same or extremely similar energy intensity. For example, assuming that a Fresnel zone element 30 with a diffraction order of 1 has a diffraction efficiency of 66.6%, the three beam components can have extremely similar energy intensities. Assuming that the Fresnel zone element 30 with a diffraction order of 2 has a diffraction efficiency of 80%, the five beam components can have the same energy intensity.

FIG. 5A is a schematic view showing an energy distribution of beam components and an energy absorption amount distribution of multiple members according to the first embodiment of the present invention, and FIG. 5B is a schematic view showing a welded portion of multiple members according to the energy absorption amount distribution of FIG. 5A.

Referring to FIGS. 5A and 5B, when the plurality of beam components have the same or extremely similar energy intensity, the energy absorption amount distribution of the multiple members 60 forms a long oval shape along the thickness direction of the multiple members 60. FIG. Since the energy absorption amount distribution coincides with the degree of melting of the multiple members 60, the welded portion 65 formed inside the multiple members 60 is formed in a shape almost identical to the energy absorption amount distribution.

The stage 52 supporting the multiple members 60 in the fourth step S40 and the fifth step S50 may be automatically moved by a predetermined distance along the horizontal direction at predetermined time intervals. Therefore, a plurality of welds 65 can be automatically formed along the interface of the multiple members 60. [

As described above, in this embodiment, by generating a plurality of laser foci around the interface of the multiple members 60, it is possible to increase the bonding strength by increasing the length of the welded portion 65 as compared with the case of the single beam focus. Further, since the length of the welded portion 65 is increased, the laser focus can be easily positioned at the interface of the multiple members 60, so that difficulty in forming an interface can be reduced.

In addition, since the energy intensities of the beam components can be set to be the same or extremely similar to each other according to the diffraction efficiency of the Fresnel zone element 30, the welding part 65 having a constant width at the interface of the multiple members 60 is formed, . Such a joining method does not require an adhesive or a laser absorbing layer since the interface of the multiple members 60 is directly melted with a laser.

Referring to FIG. 2, the Fresnel zone element 30 can move back and forth along the traveling direction of the laser beam. For this purpose, the Fresnel zone element 30 may be provided with a uniaxial stage 31. Thereby changing the focal position of the first beam component by varying the distance between the Fresnel zone element 30 and the concentrator 40 to control the divergence and convergence of the diffracted first beam component.

FIG. 6 is an enlarged cross-sectional view showing the multiple members of the fourth step shown in FIG. 1;

Referring to FIG. 6, the focal positions A1 and A2 of the two first beam components are changed in accordance with the change of the position of the Fresnel zone element 30. That is, the focal positions A1 and A2 of the two first beam components are changed on the basis of the focal position B of the second diffracted beam component, The focus distance can be varied.

In FIG. 6, the case where the distance between a plurality of laser focal points is larger than that in the case of FIG. 4A is shown as an example. As the laser focus distance increases, the welded portion 65 formed at the interface of the multiple members 60 also has an enlarged length. Conversely, a plurality of laser focuses can be continuously formed by reducing the distance between a plurality of laser focuses.

On the other hand, in the fourth step S40, the first beam component may have a different energy intensity from the second beam component. In this case, the shape of the welded portion 65 can be changed by changing the energy absorption amount distribution of the multiple member 60.

FIG. 7A is a schematic view showing an energy distribution of beam components and an energy absorption amount distribution of multiple members according to a second embodiment of the present invention, and FIG. 7B is a schematic view showing a welded portion of multiple members according to the energy absorption amount distribution of FIG. 7A.

7A and 7B, the energy intensity of the second beam component that is not diffracted is higher than the energy intensity of the diffracted first beam component. For this, the Fresnel zone element 30 having a diffraction order of 1 has a diffraction efficiency lower than 66.67%. As the diffraction efficiency is lowered, the difference between the energy intensity of the first beam component and the energy intensity of the second beam component can be increased .

The Fresnel zone element 30 having a diffraction order of 2 has a diffraction efficiency lower than 80%. As the diffraction efficiency is lowered, the difference between the energy intensity of the first beam component and the energy intensity of the second beam component can be increased. 7A and 7B, the case where the diffraction order of the Fresnel zone element 30 is 1 is shown as an example.

In this case, the energy absorption amount distribution of the multi-piece member 60 has an elliptical shape with a convex central portion, and the welding portion 65 formed in the multiple members has a convex elliptical shape in the middle portion. When the special layer such as the reinforcing layer is placed on the surface where the first member 61 and the second member 62 are in contact, the melting point and the softening point of the special layer are different from the melting point and the softening point of the other part. If more energy is required to melt the special layer, the special portion can be easily melted by forming the welded portion 65 having the convex portion at the center portion.

FIG. 8A is a schematic view showing an energy distribution of beam components and an energy absorption amount distribution of multiple members according to a third embodiment of the present invention, and FIG. 8B is a schematic view showing a welded portion of multiple members according to the energy absorption amount distribution of FIG. 8A.

8A and 8B, the energy intensity of the diffracted first beam component is higher than the energy intensity of the second diffracted beam component. For this, the Fresnel zone element 30 having a diffraction order of 1 has a diffraction efficiency higher than 66.67%, and the difference between the energy intensity of the first beam component and the energy intensity of the second beam component can be increased as the diffraction efficiency is increased .

The Fresnel zone element 30 having a diffraction order of 2 has a diffraction efficiency higher than 80%. As the diffraction efficiency increases, the difference between the energy intensity of the first beam component and the energy intensity of the second beam component can be increased. 8A and 8B, the case where the diffraction order of the Fresnel zone element 30 is 1 is shown as an example.

In this case, the energy absorption amount distribution of the multiple members 60 is a dumbbell shape having convex ends at both ends, and the welding portion 65 formed in the multiple members 60 also has a convex dumbbell shape at both ends. When the special layer such as the reinforcing layer is placed on the surface where the first member 61 and the second member 62 are in contact, the melting point and the softening point of the special layer are different from the melting point and the softening point of the other part. When less energy is required for melting the special layer, the energy intensity applied to the special layer can be reduced by forming the convex welded portion 65 at both ends.

개로 분리시키므로, 복수의 프레넬 영역 소자를 구비하는 경우

개의 초점 분할이 가능하다. 여기서, n은 프레넬 영역 소자(30)의 개수를 나타낸다.Although a case of using one Fresnel zone element 30 has been described above, a plurality of Fresnel zone elements 30 may be provided along the traveling direction of the laser beam. A laser beam is irradiated onto each of the Fresnel zone elements 30

Therefore, when a plurality of Fresnel zone elements are provided

It is possible to divide the focus of two. Here, n represents the number of Fresnel zone elements 30.

When two Fresnel zone elements having a diffraction order of 1 are used, the laser beam can be split into nine in the third step S30. If two Fresnel zone elements having a diffraction order of 2 are used, the laser beam can be split into 25 laser beams in a third step S30.

As described above, in the joining method of the present embodiment, the number of beam components separated in the third step S30 can be determined by adjusting the diffraction order and the number of the Fresnel zone elements 30, The distance between the plurality of laser focal points can be adjusted. In addition, the shape of the welded portion 65 can be variously changed by varying the energy absorption amount distribution of the multiple members 60 in accordance with the diffraction efficiency of the Fresnel zone element 30.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, Of course.

100: laser processing apparatus 10: laser light source
20: beam transmission part 30: Fresnel area element
40: Concentrator 60: Multiple members
65:

Claims (14)

Disposing a plurality of members including a plurality of mutually stacked members on the stage such that the surfaces are in contact with each other;
Oscillating an ultra-short pulse laser beam from a laser light source;
Separating the laser beam into a plurality of beam components;
Focusing the plurality of beam components in a line along the thickness direction of the multiple members around the interface of the multiple members to form a plurality of laser focuses; And
Forming a welded portion by nonlinear absorption phenomenon in the multiple members
And a plurality of members. The method according to claim 1,
Wherein the plurality of members includes a transparent member having no linear absorption in a wavelength band of the laser beam and is arranged close to the laser light source in order of high transparency. 3. The method of claim 2,
Wherein the laser beam has a pulse duration of either picosecond or femtosecond and is capable of generating either a nonlinear absorption phenomenon of multiphoton absorption, tunneling ionization, and avalanche absorption in the multi- To provide a resulting laser intensity. 4. The method according to any one of claims 1 to 3,
A fresnel zone element and a condenser are positioned between the laser light source and the multiple members,
Wherein the Fresnel zone element spatially separates the plurality of beam components. 5. The method of claim 4,
The plurality of beam components comprising a first beam component diffracted by the Fresnel zone element and a second beam component not diffracted,
Wherein the first beam component comprises a component to be diverged and a component to be converged. 6. The method of claim 5,
Wherein a focus of the plurality of first beam components is positioned vertically symmetrically with respect to a focus of the second beam component along a thickness direction of the multiple members. 6. The method of claim 5,
Wherein the energy intensity of each of the plurality of beam components is controlled by adjusting a diffraction efficiency of the Fresnel zone element. 5. The method of claim 4,
And the Fresnel zone element moves along the traveling direction of the laser beam to change the distance between the plurality of laser foci. 5. The method of claim 4,
The Fresnel zone element has a diffraction order (m) of 1 or 2, and the laser beam

A method of joining multiple members separated by openings. 10. The method of claim 9,
Wherein the plurality of Fresnel zone elements are provided along a traveling direction of the laser beam,
Wherein the plurality of Fresnel zone elements

(Where n is the number of Fresnel zone elements). 8. The method of claim 7,
Wherein the energy intensity of each of the plurality of first beam components is equal to the energy intensity of the second beam component,
Wherein the welding portion is formed in a long oval shape along the thickness direction of the multiple members. 8. The method of claim 7,
Wherein the energy intensity of each of the plurality of first beam components is lower than the energy intensity of the second beam component,
Wherein the welding portion is formed in a convex oval shape in the middle portion. 8. The method of claim 7,
Wherein the energy intensity of each of the plurality of first beam components is higher than the energy intensity of the second beam component,
Wherein the welding portion is formed in a dumbbell shape having convex portions at both ends. 5. The method of claim 4,
Wherein the stage is composed of a three-dimensional precision stage whose height is adjustable, and moves horizontally at predetermined time intervals.

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