JP2016165738A - Bonding method, bonding device and joined body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high bond strength even in bonding heterogeneous materials when bonding two members using ultrashort pulse lasers.SOLUTION: An abutment part 3 of two members 1 and 2 is irradiated with a first pulse laser 11, and a peripheral area 3a of a focal point 11a of the first pulse laser 11 is irradiated with a second pulse laser 13 of which the repeating frequency is different from that of the first pulse laser 11, in such a manner that irradiation periods are at least partially overlapped. In such a case, the repeating frequency of the first pulse laser 11 is set in such a manner that the amount of heating to the abutment part 3 per unit repeating time of a laser pulse becomes greater than a heat diffusion amount at the abutment part 3, and the repeating frequency of the second pulse laser 13 is set in such a manner that the amount of heating to the peripheral area 3a per unit repeating time becomes smaller than a heat diffusion amount in the peripheral area 3a.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a bonding method, a bonding apparatus, and a bonded body, and more particularly, to a bonding technique using an ultrashort pulse laser.

In recent years, research and development of bonding techniques using so-called ultrashort pulse lasers in the order of picoseconds (10 ^-12 seconds) or femtoseconds (10 ^-15 seconds) among pulsed lasers have been advanced.

  In this bonding technology, a transparent member is brought into contact with the ultrashort pulse laser, and the ultrashort pulse laser is irradiated so as to focus on the contact portion, and a multiphoton absorption phenomenon is applied to the irradiated region of the laser. Is caused to melt and bond the irradiated region (see, for example, Patent Document 1).

  In addition, as a method that can easily adjust the focal position of the laser at this time to the abutting portion of the two members to be joined, for example, Patent Document 2 discloses that the ultrashort pulse laser is incident on the member to be joined. When one of the members to be bonded is made of a transparent material, a filament region is formed in one member to be bonded by the self-focusing effect of the ultrashort pulse laser, and the filament region is divided into two members to be bonded. There has been proposed a joining method that is generated across the contact surface.

JP 2005-66629 A International Publication No. 2008/035770

  In this way, all conventional joining techniques using ultra-short pulse lasers are brought into contact by condensing and irradiating one ultra-short pulse laser toward or near the abutting part of two members to be joined. The part is heated and melted, and the irradiation time is very short. Therefore, the melt-solidified portion as the joint obtained by the above-described method is merely one that adheres to each other when each melted portion solidifies after each member related to the contact portion is once melted. This makes it difficult to obtain sufficient bonding strength.

  In addition, in the case of the above-described joining structure, since the joining strength is given only by the adhesion strength when each member related to the contact portion is once melted and then solidified, the same kind particularly in the case of joining different materials. If the adhesion strength is lower than when the materials are joined together, the joining strength may be further reduced.

  In view of the above circumstances, in the present specification, when joining two members using an ultrashort pulse laser, a technique to be solved by the present invention to obtain a high joint strength even when joining different materials. As an objective.

  The solution to the above problem is achieved by the joining method according to the present invention. That is, this joining method is a method in which two members are joined by irradiating a laser toward or near the contact part of two members and melting the contact part. First irradiation step of irradiating the pulse laser toward the contact portion, and second irradiation step of irradiating the second pulse laser having a different repetition frequency from the first pulse laser toward the peripheral region of the focal point of the first pulse laser The first irradiation step and the second irradiation step are performed so that at least a part of each irradiation period overlaps, and the amount of heating to the contact portion per unit repetition time of the laser pulse is applied. The repetition frequency of the first pulse laser is set so that it is larger than the thermal diffusion amount of the contact area, and the heating amount to the peripheral area per unit repetition time is larger than the thermal diffusion quantity of the peripheral area Small so characterized with a point of setting the repetition frequency of the second pulse laser.

  As described above, the present invention provides a new, unprecedented new technique by separately irradiating the first pulse laser for melting the member to be joined and the second pulse laser having a different repetition frequency from the first pulse laser. This is an attempt to form a joint of the form. As a result, the present inventors can control the temperature distribution of the melting region according to the irradiation modes of the first and second pulse lasers, and the predetermined melting in the irradiation region of the first pulse laser by controlling the temperature distribution. It has been found that a liquid flow can be generated. This is by setting the repetition frequency of the second pulse laser so that the heating amount per unit repetition time of the laser pulse for the peripheral region of the focal point of the first pulse laser is smaller than the thermal diffusion amount of the peripheral region, A rapid temperature rise occurs immediately after photoexcitation by the second pulse laser, and this temperature rise affects the temperature distribution around the irradiation region of the first pulse laser (the temperature gradient becomes gentler in the region where the influence is large). ).

  The present invention has been made on the basis of the above findings, and according to the present invention, the flow of the melt is promoted in the melted region generated around the region irradiated with the first pulse laser. Therefore, by forming a molten region across the abutting part, the melt of one member adjacent to the other and the melt of the other member are mixed and solidified, so that a different structure from that before melting is applied. Generated across the tangent. Accordingly, it is possible to form a joint structure that is much stronger than the conventional joining method across both members, and it is possible to significantly improve the joining strength.

  Moreover, the joining method according to the present invention may irradiate the second pulse laser toward a plurality of points in the peripheral region.

  In view of the point of the present invention in the temperature control of the melting region, it is preferable to irradiate a suitable number of second pulse lasers in the peripheral region of the focal point of the first pulse laser that becomes the starting point of the melting region. According to this irradiation mode, the temperature distribution can be controlled more precisely. Therefore, an appropriate temperature distribution according to the material of the members to be joined is given to the melting region to form a strong melt-solidified part. Is possible.

  Further, the bonding method according to the present invention may set the focal point of the second pulse laser to a position offset in the irradiation direction with respect to the focal position of the first pulse laser.

  In this way, by setting the focal point of the second pulse laser to a position offset in the irradiation direction with respect to the focal position of the first pulse laser, it is possible to induce the flow of the melt to the offset side. Become. As a result, the movement of the predetermined element to the offset side becomes active, and it becomes possible to form a structure in which the predetermined element is dense on the offset side. Therefore, when the contribution of the dense elements to the strength of the melt-solidified portion is high, it is possible to further improve the strength of the melt-solidified portion. Alternatively, by setting the offset direction and the amount of the second pulse laser so as to form a dense structure of the element on the side of the member having a relatively small element contributing to the strength, Strength can be improved.

  In this case, the joining method according to the present invention may be such that the offset amounts of the plurality of focal positions of the second pulse laser are different between the focal points adjacent to each other when viewed from the irradiation direction.

  As described above, the three-dimensional distribution of the predetermined element in the melting region greatly depends on the focal number of the second pulse laser and its position. From this, when irradiating a plurality of second pulse lasers, by changing the offset amount of the focal position of each second pulse laser between the focal points adjacent to each other when viewed from the irradiation direction, It is possible to increase the degree of freedom in forming a three-dimensional distribution of a predetermined element. Therefore, for example, when the degree of contribution of the above-mentioned predetermined element to the strength of the melt-solidified portion is high, it is a kind of anchor effect in the melt-solidified portion by forming a shape in which the dense structure of this element has irregularities in the irradiation direction Thus, it is possible to further improve the bonding strength.

  Moreover, the joining method according to the present invention may fix both the focal positions in the irradiation period of the first pulse laser and the second pulse laser.

  As described above, since the bonding method according to the present invention can induce a predetermined flow of the melt by controlling the temperature distribution in the melting region, from the viewpoint of easily and accurately controlling the temperature distribution. In the irradiation period of the first and second pulse lasers, it is preferable that the respective focal positions are fixed.

  In the bonding method according to the present invention, both the irradiation periods of the first pulse laser and the second pulse laser may be 1.0 seconds or more.

  In this way, by ensuring an irradiation period of a predetermined time or more, the contact portion of the member to be joined is sufficiently melted by the first pulse laser, and the temperature distribution of the melted region is mutually interfered with the second pulse laser. The desired melt flow can be generated by appropriately controlling the effect. Therefore, a melt-solidified part having a desired structure can be formed, and it is possible to reliably improve the bonding strength.

  The bonding method according to the present invention may use a femtosecond laser for both the first pulse laser and the second pulse laser.

  In the case of a pulse laser having a pulse width of femtosecond order, the energy can be concentrated only in the condensing region. Therefore, for example, when a member made of a transparent material is bonded to a pulse laser such as glass. Only the contact portion or the vicinity thereof can be melted. In addition, within the practical output range, the second pulse laser does not melt the peripheral region of the focus of the first pulse laser and can affect the temperature distribution of the melting region generated by the first pulse laser. A femtosecond laser is suitable for the following heating.

  The present invention can also be provided as a joined body formed by joining two members by the joining method according to the above description.

  In this case, it is preferable that at least one member located on the incident side of both the pulse lasers among the two members to be joined is a plate glass. The two members according to the present invention may be made of different materials.

  Moreover, the solution of the above-mentioned problem is achieved by the joining device according to the present invention. That is, this joining apparatus is an apparatus for joining two members by irradiating a laser toward or near the contact part of two members and melting the contact part. A first light source for irradiating a laser, a second light source for irradiating a second pulse laser having a different repetition frequency from the first pulse laser, and first and second pulses emitted from the first and second light sources. An optical system for condensing the laser in two members, and a spatial light phase modulator disposed on the path of the optical system and performing phase modulation of the second pulse laser, the optical system and the spatial light phase The modulator is configured to irradiate the first pulse laser toward the contact portion and to irradiate the second pulse laser toward the peripheral region of the focal point of the first pulse laser. Double pulse laser Irradiation is performed so that at least a part of each irradiation period overlaps, and the amount of heating to the contact portion per unit repetition time of the laser pulse is larger than the amount of thermal diffusion of the contact portion. The repetition frequency of the one-pulse laser is set, and the repetition frequency of the second pulse laser is set so that the amount of heating to the surrounding area per unit repetition time is smaller than the amount of thermal diffusion in the surrounding area. Also good.

  As described above, according to the bonding apparatus according to the present invention, the irradiation region of the first pulse laser is centered by the mutual interference effect between the first pulse laser and the second pulse laser, as in the bonding method according to the present invention. As a result, a predetermined temperature distribution is given to the melted region generated as described above, and the flow of the melt in the region is promoted. Therefore, by forming a molten region across the abutting part, the melt of one member adjacent to the other and the melt of the other member are mixed and solidified, so that a different structure from that before melting is applied. Generated across the tangent. Accordingly, it is possible to form a joint structure that is much stronger than the conventional joining method across both members, and it is possible to significantly improve the joining strength.

  Moreover, the solution of the above problem is achieved by the joined body according to the present invention. That is, this bonded body is a bonded body in which a melted and solidified part is formed at a contact part of two members made of different materials and at least one member is made of glass. In the region on one member side of the melt-solidified portion, the ratio of the predetermined element constituting the other member is increased compared to the ratio of the predetermined element contained in one member, and melting The region on the other member side of the solidified portion is characterized by the fact that the ratio of the predetermined element constituting one member is increased compared to the ratio of the predetermined element contained in the other member.

  When joining two members made of glass with at least one member, there are many restrictions on the joining method in the past, and only joining using an ultrashort pulse laser can be applied. It is. However, in that case, the melting and solidification that can occur by condensing on the contact portion occurs in a very short time as described above, and thus it is difficult to change the structure (element distribution) before and after melting. . On the other hand, in the joined body according to the present invention, in the region on one member side of the melt-solidified portion formed across the two members, the ratio of the predetermined element constituting the other member is one member. In the region on the other member side of the melt-solidified portion, the ratio of the predetermined element constituting one member is the ratio of the predetermined element included in the other member. Increased compared to. In this way, by moving the elements in the melt-solidified portion, the structure as the melt-solidified portion can be made uniform. Therefore, it is possible to strengthen the melt-solidified portion and improve the bonding strength.

  As described above, according to the present invention, when two members are bonded using an ultrashort pulse laser, it is possible to obtain high bonding strength even when bonding different materials.

It is a figure for demonstrating the whole structure of the joining apparatus which concerns on 1st embodiment of this invention. It is a principal part perspective view for demonstrating the joining method which concerns on 1st embodiment of this invention. It is the principal part top view which looked at the to-be-joined member shown in FIG. 2 from the irradiation direction of each pulse laser. It is the principal part side view which looked at the to-be-joined member shown in FIG. 2 from the direction orthogonal to the irradiation direction of each pulse laser. It is a principal part side view for demonstrating the state of the fusion | melting area | region at the time of irradiating each pulse laser in the aspect shown in FIG. FIG. 3A is a plan view and FIG. 3B is a side sectional view showing a three-dimensional distribution of a predetermined element in a melt-solidified portion of a joined body obtained when each pulse laser is irradiated in the mode shown in FIG. 2. It is a principal part side view for demonstrating the joining method which concerns on 2nd embodiment of this invention. It is a principal part side view for demonstrating the state of the fusion | melting area | region at the time of irradiating each pulse laser in the aspect shown in FIG. It is a sectional side view which shows the three-dimensional distribution of the predetermined element in the melt solidification part of the joining body obtained when each pulse laser is irradiated in the aspect shown in FIG. It is a principal part perspective view for demonstrating the joining method which concerns on 3rd embodiment of this invention. FIG. 11 is a side sectional view of a joined body obtained when each pulse laser is irradiated in the mode shown in FIG. 10 as viewed from the direction of arrow A, and a side sectional view showing a three-dimensional distribution of a predetermined element in a melt-solidified portion. is there. FIG. 11 is a side cross-sectional view of a joined body obtained when each pulse laser is irradiated in the mode shown in FIG. 10 as viewed from the direction of arrow B, showing a three-dimensional distribution of a predetermined element in a melt-solidified portion. is there.

  Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 shows an overall configuration of a bonding apparatus 10 according to an embodiment of the present invention. The bonding apparatus 10 includes a first laser oscillator 12 as a first light source capable of oscillating a first pulse laser 11 and a second laser oscillator as a second light source capable of irradiating a second pulse laser 13. 14 and an optical system 15 for condensing and entering the first and second pulse lasers 11 and 13 oscillated from the first and second laser oscillators 12 and 14 into two members 1 and 2 to be described later. And a spatial light phase modulator 16 disposed on the path of the optical system 15 and performing phase modulation of the second pulse laser 13, and a table 17 on which the two members 1 and 2 are mounted. .

  Here, the two members 1 and 2 to be joined may be made of any material, but at least one member 1 on the side on which the pulse lasers 11 and 13 are incident is made of, for example, glass. A material made of a material transparent to the pulse lasers 11 and 13 is preferable.

  In addition, as will be described later, these two members to be joined 1 and 2 mean that there is no gap between them (in a state where the gap is small enough not to cause trouble in laser joining according to the present invention). .) It is good to contact. For example, when the two members to be bonded 1 and 2 are both made of glass, the two members to be bonded 1 and 2 are brought into direct contact (so-called optical contact) without interposing an adhesive or the like. You may make it aim at fixation.

  At this time, the surface 1a (the lower surface in FIG. 1) of one of the members 1 facing each other and the surface 2a of the other member 2 to be bonded (upper surface in FIG. 1). The roughness Ra is set to 2.0 nm or less. By setting the surface roughness Ra of each of the surfaces 1a and 2a within the above-described range, the two members 1 and 2 can be brought into contact with each other without being displaced. Of course, from the viewpoint of improving adhesion, the thickness is preferably 1.0 nm or less, and more preferably 0.2 nm or less.

  Of course, the abutting means is not limited to the above-described configuration. For example, although not shown in the drawing, the holding member that holds the two members 1 and 2 and the two members 1 and 2 are connected. You may make it form the contact part 3 between the two to-be-joined members 1 and 2 by providing the pressing member etc. which press toward the table 17. FIG. Alternatively, the above exemplary means may be combined.

  Hereinafter, the detail of each component of the joining apparatus 10 is demonstrated.

  The optical system 15 includes a plurality of mirrors 18 and a lens 19. In the present embodiment, as shown in FIG. 1, the optical system 15 includes a beam splitter 20 that combines the first pulse laser 11 and the second pulse laser 13 oscillated from different directions, and each mirror 18. And an objective lens 21 for condensing the two pulse lasers 11 and 13 transmitted through the lens 19 into the two members 1 and 2.

  The spatial light phase modulator 16 is configured to be able to modulate the spatial phase distribution of the second pulse laser 13 out of the incident first pulse laser 11 and second pulse laser 13. Specifically, the second pulse laser 13 is branched by a phase hologram prepared in advance, and together with the first pulse laser 11, a predetermined phase (three-dimensional position) in the two members 1 and 2 to be joined. It can be irradiated. In the present embodiment, as shown in FIG. 2, the second pulse laser 13 is branched into four, and each second pulse laser 13 is irradiated so as to irradiate the peripheral region 3 a of the focal point 11 a of the first pulse laser 11. The three-dimensional position of the focal point 13a is set. When viewed from the irradiation direction of the pulse lasers 11 and 13 (in the depth direction of the joined members 1 and 2 having a plate shape in FIG. 1), the focal point of the first pulse laser 11 is shown in FIG. The positions of the focal points 13a of the four second pulse lasers 13 are set so as to be rotationally symmetric with respect to 11a. Further, when viewed from the direction orthogonal to the irradiation direction of each of the pulse lasers 11 and 13 (the left-right direction in FIG. 1), as shown in FIG. 4, the focal point 11a of the first pulse laser 11 has two joints. The focal point 13a of each second pulse laser 13 is set on the contact portion 3 between the members 1 and 2 and the irradiation direction of the focal point 11a of the first pulse laser 11, that is, the joined members 1 and 2. Is set at a position offset by a predetermined amount d on the upper side in the depth direction (on the side of one member 1 to be joined).

  The first pulse laser 11 and the second pulse laser 13 are both focused and irradiated into the two members 1 and 2, but their repetition frequencies are set to different sizes. Here, for the first pulse laser 11, the amount of heating to the contact portion 3 per unit repetition time of the laser pulse is larger than the thermal diffusion amount of the contact portion 3 per unit repetition time. The repetition frequency is set. For the second pulse laser 13, the amount of heating to the peripheral region 3 a per unit repetition time of the laser pulse is smaller than the thermal diffusion amount of the peripheral region 3 a of the focal point 11 a of the first pulse laser 11. The repetition frequency is set.

  For example, when the two members 1 and 2 are both made of silicate glass, the threshold value of the repetition frequency is set to 50 kHz. That is, the repetition frequency of the first pulse laser 11 is set to a range exceeding 50 kHz (for example, 50 kHz or more and 1000 kHz or less). The repetition frequency of the second pulse laser 13 is set to at least less than 50 kHz (for example, 0.001 kHz or more and 10 kHz or less). Of course, it is desirable that this threshold value be appropriately changed depending on the material (particularly the thermal diffusivity) of the members 1 and 2 to be joined, the outputs of the pulse lasers 11 and 13, and the like.

  Further, as other irradiation conditions, for example, when the two members 1 and 2 are both made of silicate glass, the wavelength of the first pulse laser 11 is set to 400 nm or more and 2000 nm or less, and the pulse width is It is set to 10 fs (femtosecond) or more and 10000 fs or less, and the output is set to 0.01 μJ or more and 10 μJ or less. The wavelength of the second pulse laser 13 is set to 400 nm or more and 2000 nm or less, the pulse width is set to 10 fs or more and 10000 fs or less, and the output is set to 0.01 μJ or more and 10 μJ or less. In addition, the irradiation period of the first pulse laser 11 and the irradiation period of the second pulse laser 13 overlap in the entire period in this embodiment, and the length thereof is set to, for example, not less than 0.1 seconds and not more than 10 seconds. The During this time, the table 17 is fixed, and the positions of the focal points 11a and 13a of the first and second pulse lasers 11 and 13 are not changed during the irradiation period.

  Hereinafter, an example of a bonding method using the bonding apparatus 10 having the above-described configuration will be described mainly based on FIGS. 5 and 6.

  First, as described above, the first pulse laser 11 and the second pulse laser 13 in which the irradiation conditions such as the repetition frequency are appropriately set are oscillated from the respective laser oscillators 12 and 14. Then, after oscillating both pulse lasers 11 and 13 by a beam splitter 20, the spatial light phase modulator 16 modulates the phase distribution of the second pulse laser 13 and passes it through the objective lens 21. Thereby, the first pulse laser 11 is irradiated toward the contact portion 3 and a plurality of second pulse lasers 13 are irradiated toward the peripheral region 3a of the focal point 11a of the first pulse laser 11 (FIG. 2 to FIG. 2). 4).

  At this time, in the irradiation region 11b of the first pulse laser 11, heating and melting occur due to the multiphoton absorption phenomenon. Therefore, by continuing the irradiation of the first pulse laser 11, the melting region 4 is enlarged around the irradiation region 11b (FIG. 5). Further, since the repetition frequency of the first pulse laser 11 is set in a range that exceeds the threshold of the repetition frequency at which heat can be stored as described above, the amount of heating per unit repetition time in the contact portion 3 is the amount of thermal diffusion. It will be in a state that always exceeds. Therefore, the temperature gradient in the irradiation region 11b and the vicinity thereof becomes relatively gentle.

  On the other hand, in the irradiation region 13b of the second pulse laser 13, heating occurs as in the irradiation region 11b of the first pulse laser 11, but the repetition frequency is set to be less than the threshold value of the repetition frequency at which heat can be stored. Therefore, the thermal diffusion amount per unit repetition time in the peripheral region 3a exceeds the heating amount. Therefore, although a steep temperature gradient occurs in the irradiation region 13b, heating and melting do not occur.

  Therefore, as shown in the figure, by setting the focal points 11a and 13a (irradiation regions 11b and 13b) at positions where the temperature gradients formed by the irradiation of the pulse lasers 11 and 13 interfere with each other, the temperature gradient is predetermined. A three-dimensional distribution is shown, and a predetermined flow of the melt in the melting region 4 is induced according to the distribution. In the present embodiment, since the focal point 13a of the second pulse laser 13 is set at a position offset by a predetermined amount d in the irradiation direction with respect to the focal point 11a of the first pulse laser 11, for example, irradiation with the first pulse laser 11 is performed. Between the region 11b and the irradiation region 13b of the second pulse laser 13, a flow F1 is generated from the center in the depth direction of the melting region 4 toward the upper end. When such a flow F1 occurs, a melting portion 4a having a relatively large amount of a predetermined element in the melting region 4, for example, Si, which is a main component of glass, is present on the upper end side in the depth direction of the melting region 4. Arise. Accordingly, a flow F2 from the upper end side in the depth direction of the melting region 4 toward the center side is generated outside the irradiation region 13b of the second pulse laser 13 (on the side opposite to the focal point 11a). Si contained in the melt in the flow F2 is relatively small. As described above, the flows F1 and F2 including the movement of the specific element are circulated in the melting region 4, and as a result, a region where the predetermined element is dense and a region where the predetermined element is sparse are gradually formed.

  FIGS. 6A and 6B are (a) a plan view and a (b) side sectional view of a principal part of a joined body 5 obtained by performing the above-described joining method. That is, in this embodiment, as shown in FIG. 6B, the melt-solidified portion 6 has a substantially egg shape, and the focal point 13 a of the second pulse laser 13 with respect to the focal point 11 a of the first pulse laser 11. The offset side has a relatively large diameter. Further, the large diameter side (one bonded member 1 side) of the melt-solidified portion 6 is affected by the irradiation mode (position and number of focal points 13a) of the second pulse laser 13, as shown in FIG. 6 (a). In this case, the shape is close to a rectangle.

  6 (a) and 6 (b) show the relative content ratios of predetermined elements (here, Si) in the melt-solidified portion 6 in different colors. As shown in FIG. 6B, regions 6a where Si is relatively dense are formed in layers. In this embodiment, the Si dense region 6a is formed on the side of one member 1 to be joined, that is, on the side where the focal point 13a of the second pulse laser 13 is offset from the focal point 11a of the first pulse laser 11. . On the other hand, a region 6b where Si is relatively sparse is formed on the side opposite to the Si dense region 6a, that is, on the other member 2 side.

  As described above, according to the bonding method and the bonding apparatus 10 according to the present invention, the first pulse laser 11 and the second pulse laser 13 are caused to be centered on the irradiation region 11b of the first pulse laser 11 due to the mutual interference effect. A predetermined temperature distribution is provided in the melting region 4 and the flow of the melt in the melting region 4 is promoted. Therefore, by forming the melted region 4 across the contact portion 3, the melted liquid of one of the joined members 1 adjacent to each other and the melted liquid of the other joined member 2 are mixed and solidified, A melt-solidified portion 6 as a structure different from that before melting is generated across the contact portion 3. Therefore, it is possible to form a significantly stronger bonded structure across both the members 1 and 2 compared to the conventional bonding method, and it is possible to significantly improve the bonding strength.

  In the present embodiment, the second pulse laser 13 is irradiated toward a plurality of points in the peripheral region 3a of the focal point 11a of the first pulse laser 11, and the focal point 13a of the second pulse laser 13 is irradiated to the first pulse. The position was offset in the depth direction with respect to the position of the focal point 11a of the laser 11.

  Thus, if a plurality of focal points 13a of the second pulse laser 13 are provided around the focal point 11a of the first pulse laser 11, a precise temperature gradient can be applied to the melting region 4 accordingly. It is possible to form a strong melt-solidified portion 6 by applying an appropriate temperature distribution according to the material of the members 1 and 2 to be joined to the melt region 4. Further, by setting the focal point 13a of the second pulse laser 13 to an offset position with respect to the focal point 11a of the first pulse laser 11 as described above, the flow of the melt can be induced to the offset side. It becomes. As a result, the movement of the predetermined element (for example, Si) to the offset side becomes active, and it becomes possible to form the structure 6a in which the predetermined element is dense on the offset side. Therefore, when the contribution degree with respect to the intensity | strength of the melt solidification part 6 of the element which becomes dense like Si is high, it becomes possible to aim at the further strength improvement of the melt solidification part 6. FIG. Of course, the intermediate region 6c straddling the contact portion 3 is a newly formed structure by melting the portions to be bonded 4 of each of the members 1 and 2 to be joined and mixing with each other. Even if the region having a high contribution to the strength, such as the region 6a, is not formed in a portion straddling the contact portion 3, the strength of the molten and solidified portion 6 as a whole can be sufficiently ensured.

  The first embodiment of the present invention has been described above, but the bonding method, the bonding apparatus, and the bonded body can naturally take any form within the scope of the present invention.

  FIGS. 7 to 9 show an example (second embodiment of the present invention) in which the position of the focal point 13a of the second pulse laser 13 is different from that of the first embodiment. That is, in this embodiment, as shown in FIG. 7, the focal points 13 a of the plurality of second pulse lasers 13 irradiated to the peripheral region 3 a of the focal point 11 a of the first pulse laser 11 are the focal points 11 a of the first pulse laser 11. Is set at a position offset by a predetermined amount d on the lower side in the depth direction of the members 1 and 2 (the other member 2 side). Since other irradiation conditions and configurations are the same as those of the first embodiment, description thereof is omitted.

  When the position of the focal point 13a of the second pulse laser 13 is set as described above, the following phenomenon occurs in the melting and solidification process. That is, in the present embodiment, the focal point 13a of the second pulse laser 13 is set at a position offset by a predetermined amount d below the focal point 11a of the first pulse laser 11 in the depth direction. As shown in FIG. 3, between the irradiation region 11b of the first pulse laser 11 and the irradiation region 13b of the second pulse laser 13, a flow F3 from the center side in the depth direction of the melting region 4 toward the lower end side is generated. By generating such a flow F3, a melted portion 4a having a relatively large amount of a predetermined element (for example, Si) in the melted region 4 is generated on the lower end side in the depth direction of the melted region 4. Accordingly, a flow F4 from the lower end in the depth direction of the melting region 4 toward the center is generated outside the irradiation region 13b of the second pulse laser 13 (on the side opposite to the focal point 11a). Si contained in the melt in the flow F2 is relatively small. As described above, the flows F1 and F2 including the movement of the specific element are cyclically generated in the melting region 4, and as a result, the region where the predetermined element is dense is located on the lower side in the depth direction of the melting region 4. A sparse region is gradually formed on the upper side in the depth direction of the melting region 4.

  Accordingly, the melt-solidified portion 6 of the joined body 5 obtained by carrying out the joining method described above has the same overall shape as that of the first embodiment as shown in FIG. 9, but the direction is reversed. That is, the large-diameter side region of the melt-solidified portion 6 is on the side of one member 1 to be joined in the first embodiment (FIG. 6B), whereas in the present embodiment, the other to-be-joined portion is present. The side of the member 2 has a relatively large diameter. Further, when the relative content ratio of the predetermined element (here, Si) in the melt-solidified portion 6 is viewed, the region 6a where Si is relatively dense is the second region with respect to the focal point 11a of the first pulse laser 11. It is formed on the side where the focal point 13a of the two-pulse laser 13 is offset, that is, on the other member 2 side in this embodiment.

  In this way, by changing the offset direction of the focal point 13a of the second pulse laser 13, the formation position of the region 6a where the predetermined element is relatively dense also changes. , 2 and the like, by adjusting the offset direction and the offset amount d, it is possible to form the melt-solidified portion 6 having an appropriate structure according to the combination of the members 1 and 2 to be bonded, and the combination is limited. It becomes possible to give sufficient joining strength to joined object 5 without receiving.

  10-12 is a figure for demonstrating the joining method and joined body which concern on 3rd embodiment of this invention, Comprising: The position of the focus 13a of the 2nd pulse laser 13 is set to 1st embodiment and 2nd embodiment. It is different from any of the forms. That is, in the present embodiment, as shown in FIG. 10, the depth direction positions of the focal points 13 a of the plurality (four) of the second pulse lasers 13 irradiated to the peripheral region 3 a of the focal point 11 a of the first pulse laser 11 are determined. They are different from each other.

  When the position of the focal point 13a of the second pulse laser 13 is set in this way, the temperature distribution given to the melting region 4 is different from that of the first and second embodiments. This also changes the flow phenomenon. As a result, for example, as shown in FIG. 11, when the bonded body 5 is viewed from a predetermined direction (the direction of arrow A in FIG. 10), the Si dense tissue 6 a causes the focal point 13 a of the second pulse laser 13 to be the first. On the side offset to the upper side in the depth direction with respect to the focal point 11a of the pulse laser 11 (right side in FIG. 11), it is formed on the upper end side in the depth direction of the melted and solidified portion 6 as in the first embodiment. On the other hand, on the side (left side in FIG. 11) where the focal point 13a of the second pulse laser 13 is set at the same level position in the depth direction as the focal point 11a of the first pulse laser 11, the case of the first embodiment. It can also be seen that it is located on the lower side in the depth direction. This form was similarly seen at the positions of other focal points 13a adjacent on the left and right (FIG. 12).

  As described above, according to the bonding method and the bonded body 5 according to the present embodiment, the structure (Si dense region 6a) in which the predetermined element in the melt-solidified portion 6 is densely distributed more complicatedly in three dimensions. Is possible. Therefore, it is possible to give a kind of anchor effect to the melted and solidified portion 6 correspondingly, and it is possible to further improve the bonding strength.

  In the above description, the irradiation conditions (output, pulse width, irradiation time, etc.) of the pulse lasers 11 and 13 are set constant during the irradiation period. is there. In short, regardless of whether it is constant during the irradiation period, depending on the material of the members 1 and 2 to be joined, the required joining strength, the joining area (size and shape of the melt-solidified portion 6), etc. Therefore, it is important to adjust the irradiation conditions as appropriate.

1, 2 to-be-joined member 3 contact part 3a peripheral region 4 fusion region 5 joined body 6 fusion solidification part 6a Si dense region 6b Si sparse region 6c intermediate region 10 joining device 11 first pulse laser 11a focus 11b irradiation region 12 Laser oscillator 13 Second pulse laser 13a Focus 13b Irradiation area 14 Second laser oscillator 15 Optical system 16 Spatial light phase modulator 17 Table 20 Beam splitter 21 Objective lens

Claims (12)

In a method of joining the two members by irradiating a laser toward the contact portion of the two members or the vicinity thereof and melting the contact portion,
The laser irradiation includes a first irradiation step of irradiating the first pulse laser toward the contact portion, and a second pulse laser having a repetition frequency different from that of the first pulse laser. A second irradiation step for irradiating the surrounding area,
The first irradiation step and the second irradiation step are performed such that at least a part of each irradiation period overlaps,
The repetition frequency of the first pulse laser is set so that the amount of heating to the contact portion per unit repetition time of the laser pulse is larger than the amount of thermal diffusion of the contact portion, and the unit repetition time per unit repetition time A joining method, wherein a repetition frequency of the second pulse laser is set so that a heating amount to the peripheral region is smaller than a thermal diffusion amount of the peripheral region.   The bonding method according to claim 1, wherein the second pulse laser is irradiated toward a plurality of points in the peripheral region.   The bonding method according to claim 1, wherein the focal point of the second pulse laser is set at a position offset in the irradiation direction with respect to the focal position of the first pulse laser.   The bonding method according to claim 3, wherein the offset amounts of the plurality of focal positions of the second pulse laser are made different between the focal points adjacent to each other when viewed from the irradiation direction.   The joining method according to any one of claims 1 to 4, wherein a focal position in an irradiation period of the first pulse laser and the second pulse laser is fixed together.   The joining method according to any one of claims 1 to 5, wherein both the irradiation periods of the first pulse laser and the second pulse laser are 1.0 seconds or more.   The joining method according to claim 1, wherein a femtosecond laser is used for both the first pulse laser and the second pulse laser.   A joined body formed by joining the two members by the method according to claim 1.   The joined body according to claim 8, wherein at least one of the two members is a plate glass.   The joined body according to claim 8 or 9, wherein the two members are made of different materials. An apparatus for joining the two members by irradiating a laser toward the contact portion of the two members or the vicinity thereof and melting the contact portion,
A first light source for irradiating a first pulse laser;
A second light source for irradiating a second pulse laser having a different repetition frequency from the first pulse laser;
An optical system for condensing the first and second pulse lasers irradiated from the first and second light sources in the two members;
A spatial light phase modulator disposed on the path of the optical system and performing phase modulation of the second pulse laser;
The optical system and the spatial light phase modulator can irradiate the first pulse laser toward the contact portion and irradiate the second pulse laser toward a peripheral region of the focal point of the first pulse laser. Composed of
The irradiation of the first pulse laser and the irradiation of the second pulse laser are performed so that at least a part of each irradiation period overlaps,
The repetition frequency of the first pulse laser is set so that the amount of heating to the contact portion per unit repetition time of the laser pulse is larger than the amount of thermal diffusion of the contact portion, and the unit repetition time per unit repetition time The joining apparatus according to claim 1, wherein a repetition frequency of the second pulse laser is set so that a heating amount to the peripheral region is smaller than a thermal diffusion amount of the peripheral region. In a joined body in which a melt-solidified part is formed at the contact part of two members made of different materials and at least one member made of glass,
The melt-solidified part is formed across the two members,
In the region on the one member side of the melt-solidified portion, a ratio of the predetermined element constituting the other member is increased as compared with a ratio of the predetermined element included in the one member, and the melting In the region on the other member side of the solidified portion, a ratio of the predetermined element constituting the one member is increased as compared with a ratio of the predetermined element included in the other member. Joined body.

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