JP2021133390A - Method for joining member to be joined, and joint body - Google Patents

Abstract

To provide a joining method by which joint processing can be quickly performed, and joining can be properly performed even if there is a gap between two members to be joined.SOLUTION: The method comprises: a process in which a first member to be joined and a second member to be joined are located to constitute an assembly; a process in which the assembly is irradiated with first and second lasers, the first laser forms a light absorptive region as a processing original point on a surface of the first member to be joined or the second member to be joined, and the second laser is radiated so as to include a position which becomes the processing original point, whereby a molten material is produced from the light absorptive region; and a process in which irradiation with the second laser is continued, a gas is generated in the molten material, and the first member to be joined and the second member to be joined are joined via the molten material by a pressure of the gas.SELECTED DRAWING: Figure 8

Description

The present invention relates to a method of joining members to be joined and a joined body.

Conventionally, a technique for joining two members to be joined using laser irradiation has been known.

For example, after installing a glass frit between two glass substrates to form an assembly, the two glass substrates are joined by irradiating the assembly with a laser to melt and solidify the glass frit. (For example, Patent Document 1).

Further, the transparent members can be joined to each other by irradiating the contact portion of the two transparent members with an ultrashort pulse laser to melt the irradiation region. Recently, as an application example of this, it has been proposed that different materials can be bonded to each other by using two ultrashort pulse lasers (for example, Patent Document 2).

Japanese Unexamined Patent Publication No. 2019-140128 Japanese Unexamined Patent Publication No. 2003-298620

NEW GLASS Vol. 27, No. 104, 2012, p49-52 NEW GLASS Vol. 27, No. 105, 2012, p15-19

Conventional techniques for joining two members to be joined by laser irradiation can be roughly divided into "adhesive-mediated method" and "direct joining method".

The "adhesive interposition method" is a method of interposing an "adhesive" that is melted by laser irradiation between the members to be joined. The "adhesive-mediated method" includes, for example, the method described in Patent Document 1 described above. On the other hand, the "direct joining method" is a method of directly joining two members to be joined without using an adhesive. The "direct joining method" includes, for example, the method described in Patent Document 2 described above.

Of these, the "adhesive-mediated method" has a problem in terms of bonding strength because it is easily affected by the difference in thermal expansion when the member to be bonded and the adhesive are made of different materials.

On the other hand, in the "direct joining method", since the joint portion does not contain different materials such as "adhesive", the influence of the decrease in strength due to the difference in thermal expansion is reduced. However, the "direct joining method" has a problem in terms of joining processing speed. That is, the ultrashort pulse laser used in this method is not suitable for supplying a large amount of thermal energy, and it is necessary to perform a huge number of pulse irradiations in order to form a large junction. ..

Further, in the "direct joining method", if there is a gap between the two members to be joined, it becomes difficult to perform proper joining. Therefore, it is necessary to control the gap with high accuracy, and a suitable joining device is required.

As described above, in the conventional bonding method using a laser, there is room for improvement in both the "adhesive-mediated method" and the "direct bonding method".

The present invention has been made in view of such a background. That is, in the present invention, the joining process can be performed relatively quickly without using an "adhesive", and even if there is some gap between the two members to be joined. , An object of the present invention is to provide a joining method capable of properly joining. Another object of the present invention is to provide a bonded body manufactured by such a bonding method.

In the present invention, it is a method of joining members to be joined.
(I) The first surface to be joined having the first surface and the second surface, and the second member to be joined having the third surface and the fourth surface are the second surface and the second surface. The process of arranging the surfaces of 3 so as to face each other to form an assembly, and
(II) A step of irradiating the assembly with a first laser and a second laser.
The irradiation of the second laser is
(A) Before irradiation with the first laser,
(B) It is started at the same time as the irradiation of the first laser, or (c) at any timing after the irradiation of the first laser.
The first laser is a short pulse laser, which is irradiated from the side of the first member to be joined to form a light absorbing region serving as a processing starting point on the second surface or the third surface. death,
The second laser is a continuous wave laser, and is irradiated so as to include a position serving as a processing starting point.
(III) In the step (II), a step of forming a melt from the light absorbing region and a step of forming a melt.
(IV) In the step of continuing the irradiation of the second laser, gas is generated inside the melt, and the pressure of the gas causes the melt to move to the second surface and / or the third. A process in which a joining region is formed between the first member to be joined and the second member to be joined.
The method is provided.

Further, in the present invention, the two members are joined to each other.
A first member having a first surface and
A second member having a second surface and
Between the first surface and the second surface, a joint arranged along the first surface and the second surface, and
With one or more cavities extending from the joint to the inside of the first member or the second member.
Have,
When viewed from a direction perpendicular to the first surface of the first member, the joint body is provided in which the projected area of the joint portion is larger than the total projected area of the cavity.

In the present invention, the joining process can be performed relatively quickly without using an "adhesive", and even if there is some gap between the two members to be joined, it is appropriate. It is possible to provide a joining method capable of performing joining. Further, in the present invention, it is possible to provide a bonded body manufactured by such a bonding method.

It is a figure which showed typically the flow of the joining method by one Embodiment of this invention. It is a figure which showed typically an example of the structure of the apparatus for carrying out the joining method by one Embodiment of this invention. It is sectional drawing which shows typically the assembly used in the joining method by one Embodiment of this invention. It is sectional drawing which shows typically one step in the joining method by one Embodiment of this invention. It is sectional drawing which shows typically one step in the joining method by one Embodiment of this invention. It is sectional drawing which shows typically one step in the joining method by one Embodiment of this invention. It is sectional drawing which shows typically one step in the joining method by one Embodiment of this invention. It is sectional drawing which shows typically one step in the joining method by one Embodiment of this invention. It is sectional drawing which shows typically one step in the joining method by one Embodiment of this invention. It is a figure which showed typically an example of the cross section of the joined body obtained by the joining method by one Embodiment of this invention. It is a schematic perspective view of the joint body by one Embodiment of this invention. It is a figure which showed typically the cross section along the line I-I in FIG. It is a schematic enlarged view of the cross section shown in FIG. It is a schematic perspective view of the joint according to another embodiment of the present invention. It is a figure which showed typically the cross section along the line II-II in FIG. It is a schematic perspective view of the joint according to still another embodiment of the present invention. It is a figure which showed typically the cross section along the line III-III in FIG.

Hereinafter, an embodiment of the present invention will be described.

As described above, in the conventional "adhesive interposition method", when the member to be joined and the adhesive are made of different materials, the joint portion is easily affected by the difference in thermal expansion, which is a problem in terms of joint strength. There is. In addition, the "direct joining method" has problems in terms of joining processing speed and dimensional control of the gap between the two members to be joined.

The inventors of the present application have carried out diligent research and development in order to deal with such a problem. Then, the idea was obtained that a melt and a volatile gas are generated in the heated portion of the member to be joined by laser irradiation, and the melt is conveyed to the jointed portion by utilizing the pressure of the volatile gas.

If this can be realized, even in the "direct joining method", the joining portion can be formed over a wide range relatively easily. Further, in the method of transporting the melt by the pressure of the volatile gas, even if there is a relatively large gap between the two members to be joined, the melt can be interposed between the two members. Therefore, the joining process can be performed without paying much attention to the size of the gap.

However, in order to realize this new method, it is essential to ensure spatial selectivity and temporal continuity. That is, in order to realize a new method, it is necessary to combine a technique of selectively heating a desired position of a member to be joined and a technique of continuously heating the desired position.

The inventors of the present application have found that this problem can be solved by using two lasers.

That is, if a short pulse laser is used as the first laser, a light absorbing region can be formed only at a predetermined position, thereby solving the problem of spatial selectivity. Further, if a continuous wave laser is used as the second laser, it is possible to continue to supply the energy required for forming the volatile gas from the melt. Therefore, the problem of temporal continuity can be solved.

Based on the above studies, the inventors of the present application have completed the invention of the present application.

Therefore, in one embodiment of the present invention, it is a method of joining members to be joined.
(I) The first surface to be joined having the first surface and the second surface, and the second member to be joined having the third surface and the fourth surface are the second surface and the second surface. The process of arranging the surfaces of 3 so as to face each other to form an assembly, and
(II) A step of irradiating the assembly with a first laser and a second laser.
The irradiation of the second laser is
(A) Before irradiation with the first laser,
(B) It is started at the same time as the irradiation of the first laser, or (c) at any timing after the irradiation of the first laser.
The first laser is a short pulse laser, which is irradiated from the side of the first member to be joined to form a light absorbing region serving as a processing starting point on the second surface or the third surface. death,
The second laser is a continuous wave laser, and is irradiated so as to include a position serving as a processing starting point.
(III) In the step (II), a step of forming a melt from the light absorbing region and a step of forming a melt.
(IV) In the step of continuing the irradiation of the second laser, gas is generated inside the melt, and the pressure of the gas causes the melt to move to the second surface and / or the third. A process in which a joining region is formed between the first member to be joined and the second member to be joined.
The method is provided.

The joining method according to one embodiment of the present invention does not use dissimilar materials such as "adhesives". That is, in the manufactured joint body, the joint portion is composed of components derived from the member to be joined. Therefore, it is unlikely that the strength will be reduced due to the difference in thermal expansion between the member to be joined and the joint portion.

Further, in the joining method according to the embodiment of the present invention, a continuous wave laser is used as the second laser. Therefore, the members to be joined can be joined more quickly than the conventional "direct joining method".

Further, in the joining method according to the embodiment of the present invention, the melt is ejected to the outside by the pressure of the gas generated inside the melt. Since this "spout" has a corresponding volume, both members to be joined can be joined via the ejected material even if there is some gap between the two joining members. Therefore, in the joining method according to the embodiment of the present invention, both joining members can be properly joined even if there are some gaps between the members to be joined. Therefore, a device for controlling the gap between the members to be joined with high accuracy becomes unnecessary, and the joining process can be performed relatively easily.

(Joining method according to one embodiment of the present invention)
Hereinafter, a joining method according to an embodiment of the present invention will be described with reference to FIGS. 1 to 10.

FIG. 1 schematically shows a flow of a joining method according to an embodiment of the present invention.

As shown in FIG. 1, the joining method according to the embodiment of the present invention (hereinafter, referred to as "first method") is
The first surface to be joined having the first surface and the second surface and the second member to be joined having the third surface and the fourth surface are the second surface and the third surface. A step (step S110) of forming an assembly by arranging the two so as to face each other.
A step of irradiating the assembly with a first laser from the side of the first member to be joined, wherein the first laser is a short pulse laser and is the second surface or the third surface. In the step (step S120), in which a light absorbing region is formed,
A step of irradiating the light-absorbing region with a second laser, wherein the second laser is a continuous wave laser, and a melt is generated from the light-absorbing region (step S130). )When,
In the step of continuing the irradiation of the second laser, gas is generated inside the melt, and the pressure of the gas causes the melt to be generated on the second surface and / or the third surface. With the step (step S140), which spreads in the plane direction, thereby forming a bonding region between the first member to be joined and the second member to be joined after the irradiation of the second laser is completed. ,
A step of repeating steps S120 to S140 (step S150) at another position in the assembly.
Have.

However, the step S150 is a step performed when necessary, and is not an essential step in the first method.

FIG. 2 schematically shows an example of the configuration of an apparatus for carrying out the first method.

As shown in FIG. 2, the device 1 includes a first laser light source 10, a second laser light source 20, a dichroic mirror 30, a lens 40, and a base 50.

The first laser light source 10 can emit the first laser 12 toward the dichroic mirror 30.

The first laser 12 is a short pulse laser. The pulse width of the first laser 12 is, for example, 50 nanoseconds (nsec) or less. The pulse width of the first laser 12 is preferably 1 nsec or less, more preferably 20 picoseconds (psec) or less.

The wavelength of the first laser 12 may be, for example, 1064 nm, 1030 nm, 780 nm, 532 nm, 515 nm, 390 nm, 355 nm, 343 nm, 266 nm, or 257 nm.

The pulse energy of the first laser 12 is not particularly limited. The pulse energy of the first laser 12 is, for example, 1 μJ / shot or more, preferably 10 μJ / shot or more, and more preferably 100 μJ / shot or more.

The second laser light source 20 can emit the second laser 22 toward the dichroic mirror 30.

The second laser 22 is a continuous wave laser. The wavelength of the second laser 22 is, for example, in the range of 400 nm to 2000 nm. The continuous wave laser referred to here refers to a laser in which the power density is maintained at a certain level or higher without interruption during the irradiation time. That is, if the irradiation time of the continuous wave laser is, for example, 50 μsec, the power density of the continuous wave laser is maintained above a certain level for a period of 50 μsec. Further, in the continuous wave laser, if the irradiation time is, for example, 100 seconds, the power density of the continuous wave laser is maintained above a certain level for a period of 100 seconds.

The power density of the second laser 22 is, for example, in the range of ^{1 MW / cm 2 to} 100 GW / cm ^2.

The dichroic mirror 30 has a function of transmitting through the first laser 12 and reflecting the second laser 22. As the dichroic mirror 30, in addition to the above example, an article having a function of reflecting the first laser 12 and transmitting the second laser 22 may be used. In this case, the first laser and the second laser 22 may be used. The laser arrangement is swapped.

In addition to the dichroic mirror, the first laser 12 and the second laser 22 may be merged by other means such as a polarizing beam splitter.

The base 50 has a function of holding an assembly 60 having a member to be joined.

Hereinafter, each step of the first method will be described with reference to the apparatus 1 shown in FIG.

(Step S110)
First, an assembly 60 including a first joined body and a second joined body is prepared.

The form of the first bonded body and the second bonded body is not particularly limited. Here, as an example, it is assumed that both the first bonded body and the second bonded body have the form of a substrate. Therefore, the first bonded body and the second bonded body are referred to as a first substrate and a second substrate, respectively.

FIG. 3 schematically shows a cross section of the assembly 60.

As shown in FIG. 3, the assembly 60 has a first substrate 110 and a second substrate 120.

The first substrate 110 has a first surface 112 and a second surface 114 facing each other. Further, the second substrate 120 has a third surface 122 and a fourth surface 124 facing each other. The first substrate 110 and the second substrate 120 are arranged so that the second surface 114 and the third surface 122 face each other.

In the example shown in FIG. 3, there is a gap 130 between the first substrate 110 and the second substrate 120. However, the gap 130 does not have to be substantially present. For example, the dimension of the gap 130 (distance between the first substrate 110 and the second substrate 120) may be, for example, in the range of 0 to 20 μm.

As will be described later, the first laser 12 is incident from the side of the first substrate 110 in the assembly 60. Therefore, the first substrate 110 is made of a material that is transparent to the wavelength of the first laser 12.

Further, when the second laser 22 is incident from the side of the first substrate 110, the first substrate 110 is made of a material that is transparent to the wavelength of the second laser 22.

The first substrate 110 may be made of, for example, glass, sapphire, silicon, or the like.

On the other hand, the second substrate 120 does not have material restrictions like the first substrate 110. The second substrate 120 may be made of a material that is opaque to the first laser 12 and the second laser 22. The second substrate 120 may be made of, for example, glass, sapphire, resin, semiconductor, ceramics, or the like.

However, as will be described later, when the first laser 12 and the second laser 22 are focused on the third surface 122 of the second substrate 120 or the inside of the second substrate 120, the second substrate 120 Is composed of a material that is transparent to the wavelengths of the first laser 12 and the second laser 22. Further, when the second laser 22 is incident from the side of the second substrate 120, the second substrate 120 is made of a material transparent to the wavelength of the second laser 22. The transparent wavelength referred to here means a wavelength at which the absorption coefficient α of the object to be processed is 100 / cm or less.

In this case, the second substrate 120 may be made of, for example, glass, sapphire, silicon, or the like.

In particular, the second substrate 120 may be made of the same material as the first substrate 110.

The assembly 60 is placed on the table 50.

(Step S120)
Next, the first laser 12 is irradiated from the side of the first substrate 110 of the assembly 60. As described above, the first laser 12 is a short pulse laser.

The first laser 12 is irradiated so that a light absorbing region is formed on at least one of the second surface 114 of the first substrate 110 or the third surface 122 of the second substrate 120. .. As long as this is realized, the focal position of the first laser 12 is not particularly limited.

For example, the first laser 12 is a cross-sectional view of the assembly 60.
(1) On the second surface 114 of the first substrate 110,
(2) A depth position on the inner side of the first substrate 110 with respect to the surface of the second surface 114 of the first substrate 110, particularly in the range of 1 μm to 10 μm from the second surface 114.
(3) Any height position in the gap 130,
(4) On the third surface 122 of the second substrate 120, or (5) on the inner side of the second substrate 120 than the surface of the third surface 122 of the second substrate 120, particularly the third surface 122. Depth position in the range of 1 μm to 30 μm,
It may be irradiated so as to be focused by such as.

In the following description, as an example, assuming the case of the above (1), that is, the case where the first laser 12 is focused on the second surface 114 of the first substrate 110, the first The method will be described. However, it is clear that the following description is also referred to in the cases (2) to (5) described above.

When the first laser 12 is focused on the second surface 114 of the first substrate 110, the spot diameter on the second surface 114 of the first laser 12 is, for example, 0.5 μm to 50 μm. The range.

FIG. 4 schematically shows a state in which the first laser 12 is focused on the second surface 114 of the first substrate 110. In FIG. 4, the broken line R1 represents the central axis of the first laser 12.

By irradiating the assembly 60 with the first laser 12, a light absorbing region 160 is formed on the second surface 114 of the first substrate 110.

The first laser 12 is preferably irradiated with one shot.

(Step S130)
Next, the light absorbing region 160 generated in step S120 is irradiated with the second laser 22.

Irradiation of the second laser 22 is started while the light absorbing region 160 is present, that is, while the corresponding positions of the second surface 114 and / or the third surface 122 are hot.

FIG. 5 schematically shows a state in which the light absorbing region 160 on the second surface 114 of the first substrate 110 is irradiated with the second laser 22. In FIG. 5, the broken line R2 represents the central axis of the second laser 22.

As mentioned above, the second laser 22 is a continuous wave laser.

It is preferable that the second laser 22 irradiates the second surface 114 of the first substrate 110 so as to form a spot larger than that of the first laser 12. For example, the spot of the second laser 22 on the second surface 114 may have dimensions in the range of 1 μm to 100 μm.

When the light-absorbing region 160 is heated by the irradiation of the second laser 22, a melt is generated around the light-absorbing region 160, and a melted portion is formed here.

FIG. 6 schematically shows a state in which a molten portion 164 containing the melt 162 is formed in and in the vicinity of the light absorbing region 160.

As shown in FIG. 6, the first melt 162 usually occurs in the light absorbing region 160 and above it (inside the first substrate 110 near the second surface 114). This is because the temperature at these positions tends to rise most during the irradiation of the second laser 22.

(Step S140)
Further, when the irradiation of the second laser 22 is continued, the melting portion 164 further expands. Further, a part of the melt 162 is volatilized inside the melting portion 164, and gas starts to be generated.

The generated gas is discharged from the inside of the melting portion 164 toward the gap 130 between the first substrate 110 and the second substrate 120.

With the release of this gas, the melt 162 is also ejected outward from the second surface 114 of the first substrate 110. As a result, the melt 162 is diffused over the gap 130. Hereinafter, the released melt is particularly referred to as "release melt 166".

Note that if there is substantially no gap 130 between the first substrate 110 and the second substrate 120, the released melt 166 is diffused over the interface between the second surface 114 and the third surface 122. NS.

FIG. 7 schematically shows a state in which the released melt 166 spreads along the plane direction of the second surface 114 of the first substrate 110 and the third surface 122 of the second substrate 120. In FIG. 7, the broken line R2 represents the central axis of the second laser 22.

As shown in FIG. 7, the ejection of the gas creates a cavity 168 inside the melting portion 164.

Further, when the irradiation of the second laser 22 is continued, the molten portion 164 is further expanded. Along with this, the amount of gas released also increases. Therefore, the spread of the released melt 166 is further promoted. In addition, the cavity 168 included in the melting portion 164 also increases.

FIG. 8 schematically shows a state in which the released melt 166 spreads over a wide range over the surface directions of the second surface 114 of the first substrate 110 and the third surface 122 of the second substrate 120. .. In FIG. 8, the broken line R2 represents the central axis of the second laser 22.

As shown in FIG. 8, the molten portion 164 expands in a balloon shape by continuing the irradiation of the second laser 22.

After that, when the irradiation of the second laser 22 is stopped, the heat source for gas generation disappears, so that the gas release is completed, and the release of the melt 162 is also stopped accordingly. Further, the released melt 166 solidifies, and at this time, the first substrate 110 and the second substrate 120 are joined.

FIG. 9 schematically shows a cross section of the assembly 60 after the step S140.

After the irradiation of the second laser 22 is completed, the emitted melt 166 changes to the junction region 170. Therefore, the first substrate 110 and the second substrate 120 are bonded through the bonding region 170.

The melting portion 164 changes to a melting mark 172.

In the first method, the cavity 168 remains as it is even after the step S140. Therefore, a melt mark 172 having a cavity 168 is formed on the upper part of the joint region 170.

As described above, in the first method, a bonded body having a characteristic bonded morphology is formed.

(Step S150)
Further, if necessary, steps S120 to S140 may be repeated at different positions in the assembly 60.

For example, at another position on the second surface 114 of the first substrate 110, the first laser 12 is irradiated so that a light absorbing region 160 is created. After that, the second laser 22 is irradiated to form the junction region 170.

By repeating this, the first substrate 110 and the second substrate 120 are bonded through the plurality of bonding regions 170.

FIG. 10 schematically shows an example of a cross section of the joined body obtained by the first method.

As shown in FIG. 10, in this example, the bonded body 200 has melting marks 172 at six positions on the second surface 114 of the first substrate 110. Therefore, it can be seen that during the production of the bonded body 200, the above-mentioned steps S120 to S140 are repeated at at least 6 different positions.

Each melting mark 172 has a cavity 168.

In the joint body 200, the joint regions corresponding to the melting marks 172 are connected to each other, and as a result, one large joint portion 278 is formed. Therefore, each junction region is unknown.

Here, in the present application, the "joint portion" means a set of one or more joint regions included in the joint body. Further, the "joint region" represents a region formed by solidification of the released melt 166 emitted from one light-absorbing region 160, as described above.

For example, when the joint body contains one joint region, the joint portion represents the one joint region. Further, for example, when the joint body has a plurality of joint regions, all the joint regions are collectively referred to as a joint portion. Further, for example, as in the example shown in FIG. 10, when a plurality of joint regions (each positions cannot be visually recognized from the figure) are combined to form a single large region, the single region is formed. Is referred to as the joint 278.

In FIG. 9, the top view, the melting mark 172 (and the cavity 168) exists at the center of the joint region 170. In other words, the junction region 170 extends circularly around the melt marks 172 (and cavities 168). However, this is only an example, and the relative positional relationship between the melting mark 172 (and the cavity 168) and the bonding region 170 is not particularly limited. That is, the melting mark 172 (and the cavity 168) is not always at the center of the joining region 170.

Rather, it has been confirmed by the inventors that the junction region 170 is often distributed unevenly with respect to the melting marks 172 (and the cavity 168) in the top view.

By the way, the junction region 170 shown in FIG. 9 is derived from the released melt 166 in FIG. Also, the released melt 166 is a part of the melt 162 that originally existed in the cavity 168. Therefore, ideally, the volume of the junction region 170 (referred to as Vp1) is close to the volume of the cavity 168 (referred to as Vq1). As a result, the volume (referred to as Vp) of the joint portion 278 (see FIG. 10), which is an aggregate of the joint regions 170, is ideally substantially equal to the total volume (referred to as Vq) of the cavity 168.

However, a part of the melt 162 volatilizes as a gas, or the density changes in the process of melt resolidification. Therefore, in practice, the volume Vp of the joint 278 may be in the range of 15% to 250% of the total volume Vq of the cavity 168. In particular, the volume Vp of the junction can be in the range of 30% to 120% of the total volume Vq of the cavity 168.

The joining method according to the embodiment of the present invention has been described above by taking the first method as an example. However, the above description is merely an example of the joining method according to the embodiment of the present invention. That is, the joining method according to the embodiment of the present invention is not limited to the first method, and various modifications can be made.

For example, in the first method, the second laser 22 is irradiated from the same side as the first laser 12, that is, from the side of the first substrate 110.

However, instead of this, the second laser 22 may be irradiated from the side opposite to the first laser 12, that is, the side of the second substrate 120. In this case, as the second substrate 120, a material transparent to the wavelength of the second laser 22 is used.

Alternatively, the second laser 22 may be irradiated from both the side of the first substrate 110 and the side of the second substrate 120. In this case, the temperature of the light-absorbing region 160 is raised more quickly, and the joining process can be performed more quickly.

Further, in the first method, the second laser 22 starts irradiation after the irradiation of the first laser 12 is started.

However, the irradiation of the second laser 22 is
(A) Before irradiation with the first laser 12,
It may be started at any timing (b) at the same time as the irradiation of the first laser 12 or (c) after the irradiation of the first laser 12.

That is, in one embodiment of the present invention, as long as the melt portion 164 is generated starting from the light absorbing region 160 and the melt 162 is ejected from the melt portion 164 toward the outside, the first laser 12 and The second laser 22 may start irradiating each other at any time.

In addition, various changes are possible.

(Joint body according to one embodiment of the present invention)
Next, a bonded body according to an embodiment of the present invention will be described with reference to FIGS. 11 to 13.

FIG. 11 shows a schematic perspective view of a joined body according to an embodiment of the present invention. Further, FIG. 12 schematically shows a cross section along the line I-I in FIG. Further, FIG. 13 shows an enlarged view of a part of the cross section shown in FIG.

As shown in FIGS. 11 and 12, the joint body (hereinafter, referred to as “first joint body”) 500 according to the embodiment of the present invention includes the first member 510 and the second member 520, both of which. It has a joint 578 arranged between the two.

In the examples shown in FIGS. 11 and 12, the first joint body 500 has a gap 530 between the first member 510 and the second member 520. However, this gap 530 does not have to be substantially present. That is, the first member 510 and the second member 520 may be in contact with each other.

The first member 510 has a first surface 512 and a second surface 514 facing each other. The second member 520 has a third surface 522 and a fourth surface 524 facing each other.

The joint portion 578 includes a plurality of spot-shaped joint regions 570. For example, in the example shown in FIG. 11, the joint portion 578 is composed of a total of 25 spot-shaped joint regions 570 arranged in 5 rows and 5 columns in a top view.

It should be noted that the aspect of the joint region 570 shown in FIG. 11 is merely an example, and the number and arrangement forms of the joint regions 570 are not particularly limited.

FIG. 13 shows a schematic enlarged view of a cross section of one joint region 570.

As shown in FIG. 13, the joint region 570 extends over the gap 530 between the first member 510 and the second member 520. Hereinafter, the direction in which the joint region 570 extends between the first member 510 and the second member 520 is also referred to as an "in-plane" direction.

In the upper part of the joint region 570, there is a melting mark 572 extending from the second surface 514 of the first member 510 to the inside of the first member 510.

The “melting mark 572” means a portion formed by quenching the molten portion generated by laser irradiation, as described above. A cavity 568 is formed inside the melting mark 572. Therefore, the melting marks 572 can be easily identified.

As is clear from FIG. 13, when viewed from the direction perpendicular to the in-plane direction, the projected area of the joint region 570 (referred to as Sp1) is wider than the projected area of the cavity 568 (referred to as Sq1).

As a result, in the first joint body 500, the projected area (referred to as Sp) of the joint portion 578 represented by the total projected area of each joint region 570 when viewed from the direction perpendicular to the in-plane direction. , It is wider than the total projected area of the cavity 568 (referred to as Sq).

For example, the ratio Sp / Sq may be 2 or more. The ratio Sp / Sq is preferably 4 or more and 11 or less.

The first bonded body 500 having such characteristics does not contain a dissimilar material such as an adhesive in each joint region 570. Therefore, the first joint body 500 has a good joint strength because a difference in thermal expansion is unlikely to occur between the first member 510 or the second member 520 and the joint region 570.

Such a first bonded body 500 may be manufactured, for example, by the above-mentioned first method.

Hereinafter, each portion of the first bonded body 500 will be described in more detail.

(First member 510)
The material and shape of the first member 510 are not particularly limited.

The first member 510 may be made of, for example, glass, sapphire, or silicon.

Further, the first member 510 may have, for example, a substrate-like, sheet-like, or block-like form as shown in FIG.

When the first member 510 is a substrate, the thickness of the first member 510 is not particularly limited. The thickness of the first member 510 may be, for example, in the range of 20 μm to 10000 μm.

(Second member 520)
The material and shape of the second member 520 are not particularly limited.

The second member 520 may be made of, for example, glass, sapphire, resin, semiconductor, or ceramics.

Further, the second member 520 may have, for example, a substrate-like, sheet-like, or block-like form as shown in FIG.

When the second member 520 is a substrate, the thickness of the second member 520 is not particularly limited. The thickness of the second member 520 may be in the range of, for example, 20 μm to 10000 μm.

The second member 520 may be made of the same material as the first member 510.

(Joining area 570)
The joining region 570 contains components derived from the first member 510.

The cavity 568 has, for example, a maximum dimension of a cross section along the in-plane direction in the range of 1 μm to 100 μm.

When viewed from a direction perpendicular to the in-plane direction, the positional relationship between the joint region 570 and the cavity 568 is not particularly limited as long as the cavity 568 is included in the joint region 570.

For example, the cavity 568 may be located at the center of the junction region 570 when viewed from a direction perpendicular to the in-plane direction. However, in many cases, the cavity 568 is located off-center of the junction region 570.

When both the first member 510 and the second member 520 are made of glass, the joint region 570 may have a virtual temperature higher than the virtual temperature of the first member 510 and the second member 520. ..

Here, the "virtual temperature" is one of the index values indicating the chemical structure of glass. Simply put, even if the glass has the same composition, it exhibits different physical properties due to the difference in cooling behavior, and the virtual temperature changes. Therefore, by evaluating the virtual temperature of the glass, it is possible to grasp the difference in the cooling history.

When the first bonded body 500 is manufactured by the first method, the bonded region 570 is exposed to a quenching environment different from other places. Therefore, the junction region 570 indicates a "virtual temperature" that is higher than the virtual temperature of the first member 510 and the second member 520.

The virtual temperature can be evaluated by spectroscopic evaluation such as Raman spectroscopy or infrared spectroscopy. The virtual temperature is described in detail in Non-Patent Documents 1 and 2.

In the first joint body 500, the difference ΔTk between the virtual temperature of the joint region 570 and the virtual temperature of the first member 510 or the second member 520 is, for example, in the range of 10 ° C to 200 ° C.

(Gap 530)
The distance between the second surface 514 of the first member 510 and the third surface 522 of the second member 520, that is, the dimension of the gap 530 is not particularly limited. The gap 530 is, for example, in the range of 0 to 20 μm, and may be in the range of 10 μm to 20 μm.

In the "direct joining method" described in Patent Document 2 as described above, if there is a gap between the first member 510 and the second member 520, it is difficult to join them.

On the other hand, in the first bonded body 500, for example, by using the above-mentioned first method, a bonded body having a gap 530 of 20 μm can also be manufactured.

(Joint according to another embodiment of the present invention)
Next, a bonded body according to another embodiment of the present invention will be described with reference to FIGS. 14 and 15.

FIG. 14 shows a schematic perspective view of a joined body according to another embodiment of the present invention. Further, FIG. 15 schematically shows a cross section along the line II-II in FIG.

As shown in FIGS. 14 and 15, the joint body (hereinafter referred to as “second joint body”) 600 according to another embodiment of the present invention includes the first member 610, the second member 620, and the second member 620. It has a joint 678 arranged between the two.

The first member 610 has a first surface 612 and a second surface 614 facing each other. The second member 620 has a third surface 622 and a fourth surface 624 facing each other.

In the example shown in FIGS. 14 and 15, the second joint body 600 has a gap 630 between the first member 610 and the second member 620. However, this gap 630 does not have to be substantially present.

Regarding the features of the first member 610, the second member 620, and the gap 630, the description regarding the first member 510, the second member 520, and the gap 530 in the first joint body 500 described above can be referred to. Therefore, it will not be described further here.

The joint portion 678 is arranged in a frame shape between the first member 610 and the second member 620. As a result, a closed space 680 is formed between the first member 610 and the second member 620.

The joint 678 contains a component derived from the first member 610.

Although not explicitly shown in FIG. 15, the joint 678 has a plurality of melt marks. The melting marks may have, for example, an arrangement as shown in FIG. 10 described above. Specifically, the melting marks may be arranged in a frame shape along the in-plane direction of the second surface 614 of the first member 610. Further, in this case, the melting marks may be arranged periodically or randomly.

Regarding the melting marks, the description in the first bonded body 500 described above can be referred to. Therefore, it will not be described further here.

Here, in the second joint body 600, when viewed from a direction perpendicular to the in-plane direction, the projected area Sp of the joint portion 678 is based on the total projected area Sq of the cavity (not shown in FIG. 15). It also has the characteristic of being wide.

For example, the ratio Sp / Sq may be 2 or more and 4 or more and 11 or less when viewed from a direction perpendicular to the in-plane direction.

Further, the second joint body 600 is characterized in that the volume Vp of the joint portion 678 is in the range of 15% to 250% of the total volume Vq of the cavity, for example, in the range of 30% to 120%. Therefore, the volume Vp of the joint portion 678 can be adjusted by setting the total volume Vq of the cavity to a desired value.

The second joint body 600 having such characteristics does not contain a dissimilar material such as an adhesive in the joint portion 678. Therefore, the second joint body 600 has a good joint strength because a difference in thermal expansion is unlikely to occur between the first member 610 or the second member 620 and the joint portion 678.

Such a second bonded body 600 may be manufactured, for example, by the above-mentioned first method.

(Joint according to still another embodiment of the present invention)
Next, a bonded body according to still another embodiment of the present invention will be described with reference to FIGS. 16 and 17.

FIG. 16 shows a schematic perspective view of a joined body according to still another embodiment of the present invention. Further, FIG. 17 schematically shows a cross section along the line III-III in FIG.

As shown in FIGS. 16 and 17, the joint body (hereinafter referred to as “third joint body”) 700 according to still another embodiment of the present invention includes the first member 710 and the second member 720. , With a joint 778 located between the two.

The first member 710 has a first surface 712 and a second surface 714 facing each other. The second member 720 has a third surface 722 and a fourth surface 724 facing each other.

In the example shown in FIGS. 16 and 17, the third joint body 700 has a gap 730 between the first member 710 and the second member 720. However, this gap 730 does not have to be substantially present.

Regarding the features of the first member 710, the second member 720, and the gap 730, the description regarding the first member 510, the second member 520, and the gap 530 in the first joint body 500 described above can be referred to. Therefore, it will not be described further here.

In the second joint body 600, the joint portion 778 is arranged as a "layer" having a surface area of a certain value or more between the first member 610 and the second member 620. The surface area is, for example, 100 cm ² or more.

The joint 778 contains a component derived from the first member 610.

Although not explicitly shown in FIG. 17, the joint 778 has a plurality of melt marks. The melting mark may have, for example, a two-dimensional arrangement as shown in FIG. 10 described above.

Regarding the melting marks, the description in the first bonded body 500 described above can be referred to. Therefore, it will not be described further here.

Here, in the third joint body 700, when viewed from a direction perpendicular to the in-plane direction, the projected area Sp of the joint portion 778 is based on the total projected area Sq of the cavity (not shown in FIG. 17). It also has the characteristic of being wide.

For example, the ratio Sp / Sq is 2 or more when viewed from a direction perpendicular to the in-plane direction. The ratio Sp / Sq is preferably 4 or more and 11 or less.

Further, the third joint body 700 is characterized in that the volume Vp of the joint portion 778 is in the range of 15% to 250% of the total volume Vq of the cavity, for example, in the range of 30% to 120%. Therefore, the volume Vp of the joint portion 778 can be adjusted by setting the total volume Vq of the cavity to a desired value.

In the third joint body 700 having such characteristics, the joint portion 778 does not contain a dissimilar material such as an adhesive. Therefore, the third joint body 700 has a good joint strength because a difference in thermal expansion is unlikely to occur between the first member 710 or the second member 720 and the joint portion 778.

Such a third bonded body 700 may be manufactured, for example, by the above-mentioned first method.

The joined body according to the embodiment of the present invention has been described above by taking the first joined body 500 to the third joined body 700 as an example. However, it is clear that the bonded body according to the embodiment of the present invention is not limited to the above configuration.

For example, in the first joint 500, the melt marks 572 and cavities 568 in each joint region 570 extend to the side of the first member 510. However, apart from this, the melt marks 572 and the cavity 568 may extend to the side of the second member 520. In this case, the joint portion 578 is composed of a component derived from the second member 520.

The same can be said for the second joint body 600 and the third joint body 700.

Further, in the joined body according to the embodiment of the present invention, the form of the joined portion is not particularly limited. For example, the joint may include a combination of a spot-shaped joint region 570 such as the first joint 500 and a frame-shaped joint 678 such as the second joint 600. Alternatively, the joint may include a combination of a spot-like joint region 570 such as the first joint 500 and a planar joint 778 such as the third joint 700.

In addition, various changes are possible.

Next, examples of the present invention will be described. In the following description, Examples 1 to 17 are examples, and Examples 21 to 25 are comparative examples.

(Example 1)
A first glass substrate having first and second surfaces and a second glass substrate having third and fourth surfaces were prepared. Non-alkali glass having a thickness of 100 μm was used for both glass substrates.

The first and second glass substrates were arranged so that the second surface and the third surface faced each other to form an assembly. A gap of 12 μm was provided between the two glass substrates.

Next, the first laser and the second laser were irradiated from the side of the first glass substrate toward the same position of the assembly.

The first laser was an ultrashort pulse laser having a wavelength of 780 nm. The pulse width was 228 femtoseconds (fsec) and the pulse energy was 200 μJ / shot.

The first laser irradiates perpendicularly to the first surface of the first glass substrate. Further, the first laser was irradiated so as to be focused on the third surface of the lower second glass plate. The spot diameter on the third surface was 1.18 μm.

The number of irradiations of the first laser is one.

The second laser was a continuous wave laser having a wavelength of 1070 nm. The average power of the second laser is 40W. The second laser irradiates perpendicularly to the first surface of the first glass substrate. Further, the second laser was irradiated so as to be focused on the third surface of the second glass substrate. The spot diameter on the third surface was 1.62 μm. The power density on the third surface was 1940.6 MW / cm ² .

The irradiation time of the second laser is 40 microseconds (μsec).

The first laser and the second laser were irradiated at the same time.

After the laser irradiation, a bonding region was formed at the focal position and the upper part in the vicinity thereof, through which the first glass substrate and the second glass substrate were bonded.

(Examples 2 to 17)
Two glass substrates were joined by the same method as in Example 1.

However, in Examples 2 to 17, the irradiation conditions of the first laser and / or the second laser were changed from those of Example 1.

In both Examples 2 to 17, a bonding region was formed in the upper part of the focal position and its vicinity after the laser irradiation, and the first glass substrate and the second glass substrate were bonded through the bonding region.

(Examples 21 to 25)
Two glass substrates were joined by the same method as in Example 1.

However, in Examples 21 to 25, the focal positions of the first laser and the second laser were changed from those in Example 1.

In Examples 21 to 25, the first glass substrate and the second glass substrate could not be joined in any case.

Table 1 below summarizes the conditions of the first laser used in each example. Table 2 summarizes the conditions of the second laser used in each example.

なお、表１において、「焦点位置」の欄の−（マイナス）は、第１および第２のレーザの焦点が第２のガラス基板の第３の表面よりも外側であること、すなわち第１および第２のレーザが、間隙または第１のガラス基板に焦点化されていることを表す。

In Table 1,-(minus) in the "focal position" column means that the focal points of the first and second lasers are outside the third surface of the second glass substrate, that is, the first and second lasers. Indicates that the second laser is focused on the gap or the first glass substrate.

From the numerical values of the "focus position" in Table 1, in Examples 21 to 22, the focus of the first laser was too far from the second surface of the first glass substrate, so that the light absorbing region was formed on the second surface. It is expected that it was not possible to form. As a result, it is considered that even if the irradiation position was heated by the second laser, the melt could not be ejected from the molten portion toward the outside of the first glass substrate, and the joint portion was not formed.

Further, in Examples 23 to 25, the focus of the first laser was too far from the third surface of the second glass substrate, so that the light absorbing region could not be formed on the third surface. It is expected to be. As a result, it is considered that even if the irradiation position was heated by the second laser, the melt could not be ejected from the molten portion toward the outside of the second glass substrate, and the joint portion was not formed.

(evaluation)
In the joints obtained in Examples 1 to 17, the projected area Sp of the joint portion (joint region), the total projected area Sq of the cavity, and the ratio Sp / Sq were evaluated. In addition, the volume Vp of the joint portion (joint region), the total volume Vq of the cavity, and the ratio Vp / Vq were evaluated.

The results are shown in Table 3 below.

1 Equipment 10 First laser light source 12 First laser 20 Second laser light source 22 Second laser 30 Dichroic mirror 40 Lens 50 units 60 Assembly 110 First substrate 112 First surface 114 Second surface 120 2nd substrate 122 3rd surface 124 4th surface 130 Gap 160 Light absorbing area 162 Melt 164 Melting part 166 Emitting melt 168 Cavity 170 Joining area 172 Melting mark 200 Joining body 278 Joining part 500 First Joint 510 First member 512 First surface 514 Second surface 520 Second member 522 Third surface 524 Fourth surface 530 Gap 568 Cavity 570 Joint area 57 2 Melt mark 578 Joint 600 Second joint Body 610 First member 612 First surface 614 Second surface 620 Second member 622 Third surface 624 Fourth surface 630 Gap 678 Joint part 680 Sealed space 700 Third joint 710 First member 712 First surface 714 Second surface 720 Second member 722 Third surface 724 Fourth surface 730 Gap 778 Joint

Claims (22)

It is a method of joining members to be joined.
(I) The first surface to be joined having the first surface and the second surface, and the second member to be joined having the third surface and the fourth surface are the second surface and the second surface. The process of arranging the surfaces of 3 so as to face each other to form an assembly, and
(II) A step of irradiating the assembly with a first laser and a second laser.
The irradiation of the second laser is
(A) Before irradiation with the first laser,
(B) It is started at the same time as the irradiation of the first laser, or (c) at any timing after the irradiation of the first laser.
The first laser is a short pulse laser, which is irradiated from the side of the first member to be joined to form a light absorbing region serving as a processing starting point on the second surface or the third surface. death,
The second laser is a continuous wave laser, and is irradiated so as to include a position serving as a processing starting point.
(III) In the step (II), a step of forming a melt from the light absorbing region and a step of forming a melt.
(IV) In the step of continuing the irradiation of the second laser, gas is generated inside the melt, and the pressure of the gas causes the melt to move to the second surface and / or the third. A process in which a joining region is formed between the first member to be joined and the second member to be joined.
The method. The method of claim 1, wherein the first laser has a wavelength that is transparent to the first member to be joined. The method of claim 1 or 2, wherein the second laser has a wavelength that is transparent to the first or second member to be joined. The method according to any one of claims 1 to 3, wherein the first member to be joined is made of glass, sapphire, or silicon. The method according to any one of claims 1 to 4, wherein the second member to be joined is made of glass, sapphire, resin, semiconductor, or ceramics. The method according to any one of claims 1 to 5, wherein the second member to be joined is made of the same material as the first member to be joined. The method according to any one of claims 1 to 6, wherein in the step (II), the second laser is irradiated from the side of the first member to be joined. The method according to any one of claims 1 to 6, wherein in the step (II), the second laser is irradiated from the side of the second member to be joined. In the step (I), the first member to be joined and the second member to be joined are arranged with each other so as to form a gap of 0 to 20 μm between the first member to be joined and the second member to be joined. The method according to any one of 8. In step (II), the first laser is focused on the second surface, the third surface, or the gap between the second surface and the third surface. The method according to any one of claims 1 to 9, wherein the method is irradiated to. The method according to claim 10, wherein in the step (II), the second laser is irradiated so as to be focused at the focal position of the first laser. In addition, at another position in the assembly
(V) The method according to any one of claims 1 to 11, further comprising a step of repeating the steps (II) to (IV). It is a zygote in which two members are joined to each other.
A first member having a first surface and
A second member having a second surface and
Between the first surface and the second surface, a joint arranged along the first surface and the second surface, and
With one or more cavities extending from the joint to the inside of the first member or the second member.
Have,
A joint body in which the projected area of the joint portion is wider than the total projected area of the cavity when viewed from a direction perpendicular to the first surface of the first member. The bonded body according to claim 13, wherein the distance between the first surface and the second surface is in the range of 0 to 20 μm. 13. The joined body described. The joint body according to any one of claims 13 to 15, wherein the joint portion is arranged as a plurality of spot regions between the first member and the second member. The bonded body according to any one of claims 13 to 16, wherein the first member is made of glass, sapphire, or silicon. The bonded body according to any one of claims 13 to 17, wherein the second member is made of glass, sapphire, resin, semiconductor, or ceramics. The bonded body according to any one of claims 13 to 18, wherein the first member is made of the same material as the second member. The first member and the second member are glass substrates.
The joined body according to any one of claims 13 to 19, wherein the virtual temperature of the joint portion is higher than the virtual temperature of the first member and the second member. The joint according to any one of claims 13 to 20, wherein the projected area of the joint is at least twice as large as the total projected area of the cavity. The joint according to any one of claims 13 to 21, wherein the volume of the joint is in the range of 15% to 250% of the total volume of the cavity.

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