joint

Abstract

This invention provides a jointed body in which a strong bond is achieved at the joint where laser light is irradiated. [Solution] The bonded body comprises a first substrate and a second substrate to be bonded, and a first bonding material layer interposed between the opposing surfaces of the two substrates. The first bonding material layer has an opening at the bonding location of the two substrates, and the inside of the opening is filled with a material whose main component is the same as at least one of the main components of the first substrate and the second substrate. In addition, a region is formed inside or near the opening in which at least one of the same component as the main component of the first bonding material layer and a compound consisting of that component is dispersed.

Description

Technical Field

[0001] The present invention relates to a bonding technique using laser light.

Background Art

[0002] As one of the manufacturing techniques for semiconductor devices (such as MEMS), there is a technique for bonding two substrates (such as wafers) by utilizing the eutectic reaction of two types of metals. In this technique, a metal layer containing one of the two types of metals that cause the eutectic reaction as a main component and a metal layer containing the other metal as a main component are respectively formed on the bonding surfaces of the two substrates. Further, as a combination of the two types of metals that cause the eutectic reaction, for example, a combination of Al and Ge is used. Then, by causing the eutectic reaction at the contact portion of those metal layers, the two substrates are bonded.

[0003] Such a bonding technique is used, for example, for sealing sensors (such as gyro sensors, biosensors, etc.) and waveguides in a device. On the other hand, in order to cause the above-mentioned eutectic reaction, it is necessary to heat the contact portion of the two metal layers to the temperature at which the eutectic reaction occurs. Conventionally, in order to achieve this, while sandwiching the two substrates to bring the two metal layers into contact, the entire two substrates together with the sensor or the like to be sealed are heated (for example, see Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, with the conventional bonding technology described above, the sensor being sealed also gets heated, which posed a risk of heat damage to the sensor. Therefore, the sensors that could be sealed within the device were limited to those with high heat resistance. Furthermore, heating the bonding site (to the temperature at which the eutectic reaction occurs) required a long time, and after bonding, it was necessary to gradually relieve the thermal stress on the substrate (such as a wafer), requiring a long cooling time as well. This resulted in the problem of a long time required for each bonding process.

[0006] Another problem was that if the two metals mentioned above had different coefficients of thermal expansion, strain could occur at the joint between the two metal layers during heating and cooling. Therefore, in the conventional joining techniques described above, in order to suppress such strain, it was necessary to select two metals with similar coefficients of thermal expansion, which severely limited the freedom of selection.

[0007] Therefore, in recent years, a technique has been proposed to perform localized heating targeting the contact area of ​​two metal layers using laser light (see Patent Document 2). Specifically, two substrates are sandwiched between a quartz plate that is transparent to laser light and another component (such as a chuck), and in that state, laser light is irradiated onto the contact area of ​​the two metal layers through the quartz plate.

[0008] This laser-based bonding technology reduces thermal impact on the sensor because the contact area between the two metal layers is heated locally. As a result, it becomes possible to encapsulate sensors with low heat resistance within the device. Furthermore, because the bonding area between the two metal layers can be heated intensively with laser light, the temperature of the bonding area can be rapidly raised to the temperature at which a eutectic reaction occurs, thereby shortening the time required for the bonding process.

[0009] Furthermore, even if the two metals mentioned above have different coefficients of thermal expansion, and strain occurs during heating or cooling, this strain will only occur in the localized area irradiated by the laser light, resulting in a significantly smaller strain. Consequently, the impact of this strain on the joint between the two metal layers will be minimal. Therefore, when selecting the two metals, it becomes possible to choose those with different coefficients of thermal expansion, increasing the degree of selection flexibility.

[0010] On the other hand, in laser-based bonding technology, there was a problem in that simply irradiating the bonding site with laser light to create a eutectic reaction between two metals and then placing the resulting mixture between two substrates did not allow for a strong bond to be achieved at the bonding site.

[0011] Therefore, the objective of the present invention is to provide a joined body in which a strong bond is achieved at the joint where laser light is irradiated. [Means for solving the problem]

[0012] The bonded body according to the present invention has a novel structure that enables strong bonding at the bonding site irradiated with laser light, and has the following configuration (Aspect 1). The bonded body comprises a first substrate and a second substrate to be bonded, and a first bonding material layer interposed between the opposing surfaces of the two substrates. The first bonding material layer has an opening at the bonding site of the two substrates, and the inside of the opening is filled with a material whose main component is the same as at least one of the main components of the first substrate and the second substrate. In addition, a region is formed inside or near the opening in which at least one of the same component as the main component of the first bonding material layer and a compound consisting of that component is dispersed.

[0013] The bonded body according to Embodiment 1 described above may have the following configuration (Embodiment 2). This bonded body further comprises a second bonding material layer having a main component different from that of the first bonding material layer, and the second bonding material layer has an intervening portion interposed between the first bonding material layer and the second substrate, and an intrusion portion that enters into the first substrate through the opening from that portion. Furthermore, the material filling the inside of the opening is spread throughout the entire region between the intrusion portion of the second bonding material layer and the second substrate, and in the intrusion portion, the same component as the main component of the first bonding material layer is dispersed at a high concentration at the interface with that region and at the interface with the first substrate on the opposite side of that region. As an example, the main component of both the first substrate and the second substrate is Si, the main component of the first bonding material layer is Ti, and the main component of the second bonding material layer is Au (Embodiment 3).

[0014] In the joint according to the above embodiment 2 or 3, the same component as the main component of the first joining material layer may also be dispersed within the intrusion portion (embodiment 4).

[0015] In a joint according to any of the above embodiments 2 to 4, a first mass formed from a compound containing the same two components as the main component of the first jointing material layer and the main component of the second substrate, and a second mass formed from a compound containing the same two components as the main component of the second jointing material layer and the main component of the second substrate, may be scattered between the above region and the second substrate (Embodiment 5).

[0016] The bond according to any of the above embodiments 2 to 5 may further include a barrier layer formed on the opposing surface of the second substrate (embodiment 6). Here, this barrier layer is a layer mainly containing a compound having the same components as the main components of the second substrate.

[0017] The bonded body according to Embodiment 1 described above may have the following configuration (Embodiment 7). In this bonded body, a plurality of granular lumps, each composed of the same main component as the first bonding material layer, are scattered along a virtual surface that curves convexly toward the first substrate side, with the edge of the opening as its peripheral edge. In addition, an oxide composed of the same main component as the first bonding material layer is dispersed in the region from the virtual surface to the inside of the opening. As an example, the main component of the first substrate is SiO2, the main component of the second substrate is Si, and the main component of the first bonding material layer is Ti (Embodiment 8).

[0018] In the bonded body according to the above embodiment 8, an electrically conductive portion containing TiSi may be formed on the peripheral edge of the opening in the first bonding material layer (embodiment 9).

[0019] The bond according to any of the above embodiments 7 to 9 may further include a barrier layer formed on the opposing surface of the second substrate (embodiment 10). Here, this barrier layer is a layer mainly composed of a compound having the same components as the main components of the second substrate.

[0020] The bonded body according to Embodiment 1 described above may have the following configuration (Embodiment 11). In this bonded body, in the region inside the opening on the opposing surface of the second substrate, there are scattered lumps of compound containing the same two components as the main component of the first bonding material layer and the main component of the second substrate, which are formed in a droplet-like manner from that region into the second substrate. For example, the main component of the first substrate is glass, the main component of the second substrate is Si, and the main component of the first bonding material layer is Ti (Embodiment 12).

[0021] In the bond according to the above embodiment 11 or 12, an oxide layer containing an oxide as the main component, which has the same components as the minor components of the first substrate, may be formed in the region on the inner side of the opening on the opposing surface of the second substrate (embodiment 13). [Effects of the Invention]

[0022] According to the present invention, it is possible to provide a joined body in which a strong bond is achieved at the joint where laser light is irradiated.

Brief Description of the Drawings

[0023] [Figure 1] It is a conceptual diagram illustrating a bonding device used for forming a bonded body according to the present invention. [Figure 2] It is a conceptual diagram illustrating a first base material and a second base material that are bonding targets in the first embodiment. [Figure 3] It is a cross-sectional view schematically showing the state of a bonding portion of the bonded body obtained in the first embodiment. [Figure 4] It is a cross-sectional view schematically showing the state of a bonding portion of a first modification example of the bonded body obtained in the first embodiment. [Figure 5] It is a cross-sectional view schematically showing the state of a bonding portion of a second modification example of the bonded body obtained in the first embodiment. [Figure 6] It is a cross-sectional view schematically showing the state of a bonding portion of a third modification example of the bonded body obtained in the first embodiment. [Figure 7] It is a conceptual diagram illustrating a first base material and a second base material that are bonding targets in the second embodiment. [Figure 8] It is a cross-sectional view schematically showing the state of a bonding portion of the bonded body obtained in the second embodiment. [Figure 9] It is a cross-sectional view schematically showing the state of a bonding portion of a modification example of the bonded body obtained in the second embodiment. [Figure 10] It is a conceptual diagram illustrating a first base material and a second base material that are bonding targets in the third embodiment. [Figure 11] It is a cross-sectional view schematically showing the state of a bonding portion of the bonded body obtained in the third embodiment. [Figure 12] It is a cross-sectional view schematically showing another example of the state of a bonding portion obtained in the third embodiment.

Modes for Carrying Out the Invention

[0024] [1] Bonding Device Figure 1 is a conceptual diagram illustrating a joining apparatus used to form a joined body according to the present invention. In the example shown in Figure 1, the joining apparatus is a device that joins two substrates to be joined (a first substrate 101 and a second substrate 102) using laser light, and comprises a chamber mechanism 1, a pressurizing mechanism 2, a laser light source 3, and a control unit 4. The configuration of each part will be described in detail below.

[0025] <Chamber mechanism 1> The chamber mechanism 1 includes a first chamber component 11, a second chamber component 12, a drive unit 13, and an exhaust unit 14.

[0026] The first chamber component 11 and the second chamber component 12 constitute a sealed space (hereinafter referred to as "chamber 10") for performing the joining process, and are configured to selectively form and open the chamber 10 by relatively moving closer together or further apart in the vertical direction. More specifically, they are as follows.

[0027] The first chamber component 11 consists of a first cylindrical portion 111 and a stage 112 supported without gaps inside the first cylindrical portion 111. The first cylindrical portion 111 is positioned so that its central axis is aligned with the vertical direction, and the stage 112 is horizontally supported by the first cylindrical portion 111. Here, the stage 112 is a stage that is transparent to laser light and is made of, for example, quartz. Two substrates (first substrate 101 and second substrate 102) are placed on the stage 112 with the second substrate 102 stacked on top of the first substrate 101.

[0028] The second chamber component 12 consists of a second cylindrical portion 121 positioned above the first cylindrical portion 111 and coaxially with the first cylindrical portion 111, and a top plate 122 that closes the opening at the upper end of the second cylindrical portion 121. The upper end of the first cylindrical portion 111 and the lower end of the second cylindrical portion 121 are in contact without any gaps, thereby forming a chamber 10 between the stage 112 and the top plate 122.

[0029] The drive unit 13 is the part that moves at least one of the first chamber component 11 and the second chamber component 12 in the vertical direction, thereby bringing them relatively closer together and further apart.

[0030] The exhaust section 14 is the part that reduces the internal pressure of the chamber 10 until the chamber 10 (specifically, the space between the diaphragm 21 and the stage 112, which will be described later) becomes a vacuum. A pressure adjustment device such as a vacuum pump is used in the exhaust section 14. The chamber mechanism 1 may further include a gas supply section that supplies a processing gas (such as Ar gas) into the chamber 10.

[0031] <Pressurization mechanism 2> The pressurizing mechanism 2 is a mechanism that applies pressure to the two base materials (first base material 101 and second base material 102) from the side opposite to the stage 112. In this embodiment, the pressurizing mechanism 2 consists of a diaphragm 21 and a drive unit 22 that operates the diaphragm 21, and applies pressure to the back surface 102b of the second base material 102, which is located on the side opposite to the stage 112 of the two base materials. More specifically, it is as follows.

[0032] The diaphragm 21 is supported without gaps inside the second cylindrical portion 121 so that it can contact the back surface 102b of the second base material 102 when the chamber 10 is formed.

[0033] The drive unit 22 operates the diaphragm 21 by transmitting pressure to the diaphragm 21 using the transmission medium 23. More specifically, the transmission medium 23 is filled between the diaphragm 21 and the top plate 122 within the second chamber component 12, and the drive unit 22 operates the diaphragm 21 via the transmission medium 23 by changing the pressure applied to the transmission medium 23. Here, the transmission medium 23 may be a liquid or a gas.

[0034] <Laser light source 3> The laser light source 3 is the part that emits laser light and is positioned below the stage 112, which is transparent to laser light. The laser light source 3 also irradiates the stage 112 with laser light towards the joint between the two substrates (first substrate 101 and second substrate 102) on the stage 112.

[0035] <Control Unit 4> The control unit 4 consists of processing units such as a CPU and an MPU, and controls various operating parts of the bonding device (chamber mechanism 1, pressurization mechanism 2, laser light source 3, etc.). Specifically, it is as follows:

[0036] During the joining process, the control unit 4 forms the chamber 10 by bringing the first chamber component 11 and the second chamber component 12 close together and joining them while the two substrates (first substrate 101 and second substrate 102) are placed on the stage 112. The control unit 4 then controls the exhaust unit 14 to reduce the internal pressure of the chamber 10 (specifically, the space between the diaphragm 21 and the stage 112 within the chamber 10) until a vacuum is achieved. The control unit 4 also supplies a processing gas (such as Ar gas) into the chamber 10 as needed.

[0037] Subsequently, the control unit 4 controls the pressurizing mechanism 2, thereby applying pressure to the back surface 102b of the second substrate 102 with the diaphragm 21.

[0038] Here, the diaphragm 21 can flexibly change shape according to the shape of the back surface 102b of the second substrate 102 when pressure is applied to the back surface 102b of the second substrate 102. Therefore, it can adhere closely to the back surface 102b of the second substrate 102 and apply uniform pressure, which can deform (including elastic deformation) the second substrate 102. In addition, the diaphragm 21 can continue to apply uniform pressure to the back surface 102b by following the shape change of the back surface 102b of the second substrate 102 that accompanies the deformation of the second substrate 102. Consequently, by applying uniform pressure to the back surface 102b of the second substrate 102 with the diaphragm 21, even with relatively small pressure, it is possible to deform the second substrate 102 so that the bonding material layer (such as the first bonding material layer 201 described later) is sandwiched between the two substrates (first substrate 101 and second substrate 102) without any gaps, and maintain that state. Furthermore, by reducing the pressure required for joining, the required strength of the stage 112 (the strength to withstand the pressure during joining) also decreases accordingly, and as a result, it becomes possible to make the thickness of the stage 112 relatively small.

[0039] After the pressurization mechanism 2 applies pressure to the back surface 102b of the second substrate 102, the control unit 4 maintains this state and controls the laser light source 3 to irradiate the joint between the two substrates (the first substrate 101 and the second substrate 102) (specifically, the portion of the joining material layer corresponding to the joint) with laser light via the stage 112.

[0040] Furthermore, in the bonding apparatus described above, the diaphragm 21 may have a suction surface that adsorbs the back surface 102b of the second substrate 102 (i.e., it may have a function of chucking the first substrate 101). The bonding apparatus may also further include an alignment mechanism for adjusting the positional relationship between the first substrate 101 placed on the stage 112 and the second substrate 102 held (adsorbed) by the diaphragm 21. For example, the alignment mechanism can adjust the positional relationship between the first substrate 101 placed on the stage 112 and the second substrate 102 held (adsorbed) by the diaphragm 21 by adjusting the position of at least one of the first chamber component 11 and the second chamber component 12 in the horizontal plane.

[0041] In the bonding apparatus described above, the pressurizing mechanism 2 is not limited to one composed of a diaphragm 21, but may be appropriately changed to another mechanism capable of applying pressure to the back surface 102b of the second substrate 102 (including direct pressure with the transmission medium 23). Furthermore, the positional relationship between the stage 112 and the pressurizing mechanism 2 (diaphragm 21) may be appropriately changed to an inverted positional relationship, and the positions of other parts (such as the laser light source 3) may also be appropriately changed accordingly.

[0042] In the bonding apparatus described above, when the first substrate 101 is placed on the stage 112, the back surface 101b of the first substrate 101 comes into surface contact with the mounting surface of the stage 112 (the surface on which the first substrate 101 is placed). If the first substrate 101 is mainly composed of a material with a different refractive index from the material constituting the stage 112 (for example, if the stage 112 is a quartz plate and the first substrate 101 is a Si wafer), laser light is more likely to be reflected at the interface between the stage 112 and the first substrate 101. Therefore, in order to prevent such reflection of laser light, an anti-reflective film may be formed on the mounting surface of the stage 112.

[0043] Similarly, on the back surface of the stage 112 (the surface opposite to the mounting surface, which is in contact with the air outside the chamber 10), the laser light is reflected due to the difference in refractive index between the stage 112 and the air. Therefore, to prevent such reflection of the laser light, an anti-reflective coating may be formed on the back surface of the stage 112.

[0044] [2] Items to be joined and joining methods [2-1] First Embodiment [2-1-1] Items to be joined Figure 2 is a conceptual diagram showing an example of a first substrate 101 and a second substrate 102 to be joined in the first embodiment. As shown in this figure, in this embodiment, a first joining material layer 201 is formed on the opposing surface 101a on the first substrate 101 side of the opposing surfaces 101a and 102a (surfaces to be joined) of these two substrates, and a second joining material layer 202 is further formed on the first joining material layer 201.

[0045] Here, the main component of the first bonding material layer 201 is a material that can efficiently absorb laser light and convert it into heat. The main component of the second bonding material layer 202 is a material different from the main component of the first bonding material layer 201, and is a material that undergoes some kind of change (shape change, dispersion of the main component (including diffusion and precipitation), etc.) due to the heat generated by the irradiation of the first bonding material layer 201 with laser light, thereby increasing the bonding strength at the bonding site. Details of this change will be described later. Furthermore, the main component of the second bonding material layer 202 is a material with a lower melting point than the main component of the first bonding material layer 201.

[0046] For example, the main component of both the first substrate 101 and the second substrate 102 is Si, the main component of the first bonding material layer 201 is Ti, and the main component of the second bonding material layer 202 is Au. However, the main components of the first substrate 101 and the second substrate 102 may be other than Si, or their main components may be different from each other. Furthermore, instead of Ti, a material such as Cr can be used for the main component of the first bonding material layer 201. Additionally, instead of Au, Cu or Al can be used for the main component of the second bonding material layer 202.

[0047] In this embodiment, the first bonding material layer 201 is formed by sputtering. On the other hand, the second bonding material layer 202 may be formed by sputtering or by other methods such as vapor deposition.

[0048] [2-1-2] Joining method Next, a bonding method for joining two substrates (a first substrate 101 and a second substrate 102; see Figure 2) using laser light will be described. In the bonding method of this embodiment, the lamination process and the bonding process are performed using the bonding apparatus described above. These processes will be described in detail below. Note that the bonding method of this embodiment may include a forming process for forming the first bonding material layer 201 and the second bonding material layer 202 described above.

[0049] In the lamination process, first, the first substrate 101 is placed on the stage 112 with the first bonding material layer 201 and the second bonding material layer 202 facing upwards (see Figure 2). Next, the second substrate 102 is placed on top of the first substrate 101 such that the first bonding material layer 201 and the second bonding material layer 202 are sandwiched between the first substrate 101 and the second substrate 102.

[0050] In the bonding process, laser light is irradiated onto the bonding area of ​​the two substrates (first substrate 101 and second substrate 102) via the stage 112 (see Figure 1). Specifically, laser light is irradiated onto the portion of the first bonding material layer 201 corresponding to the bonding area via the stage 112. This heats the first bonding material layer 201 at the laser irradiation area, bonding the two substrates together.

[0051] Specifically, the control unit 4 of the bonding device forms a chamber 10 by bringing the first chamber component 11 and the second chamber component 12 close together and joining them while the two substrates (first substrate 101 and second substrate 102) are placed on the stage 112. The control unit 4 then controls the exhaust unit 14 to reduce the internal pressure of the chamber 10 until a vacuum is created inside the chamber 10. Subsequently, the control unit 4 applies pressure to the back surface 102b of the second substrate 102 with the diaphragm 21 by controlling the pressurizing mechanism 2. Then, while maintaining the applied pressure, the control unit 4 controls the laser light source 3 to irradiate the bonding area of ​​the two substrates with laser light via the stage 112.

[0052] With this joining method, the first joining material layer 201 can efficiently absorb laser light at the joining point, and as a result, the heat generated at that point efficiently causes changes in the second joining material layer 202, thereby increasing the joining strength at the joining point.

[0053] [2-1-3]Zygote Figure 3 is a schematic cross-sectional view showing the state of the joint in a joint obtained by the above joining method. As shown in this figure, irradiation with laser light causes the first joining material layer 201 to change into one having an opening 201X at the joining location (the laser light irradiation location). The inside of the opening 201X is then filled with a material whose main component is the same as the main component of the first substrate 101 (Si, for example). Specifically, the inside of the opening 201X is filled with the first substrate 101 that has melted and re-solidified due to the heat. As a result, the first substrate 101 and the second substrate 102 are joined together through the opening 201X.

[0054] Furthermore, the second bonding material layer 202 changes to have an intervening portion 202P that is interposed between the first bonding material layer 201 and the second base material 102, and an intrusion portion 202Q that enters into the first base material 101 through the opening 201X without any breaks (when viewed in cross-section, there are no breaks; in other words, when viewed in plan, there are no holes or cracks). As an example, the intrusion portion 202Q changes to a triangular shape as shown in Figure 3. This change increases the bonding strength at the joint.

[0055] Furthermore, the entire region R1 between the intrusion portion 202Q of the second bonding material layer 202 and the second substrate 102 becomes a state where the material filling the inside of the opening 201X (for example, a material mainly composed of Si) expands. In addition, the intrusion portion 202Q becomes a state in which the same component as the main component of the first bonding material layer 201 (for example, Ti) is dispersed at a high concentration (including diffusion and precipitation) at the interface S1 with region R1 and the interface S2 with the first substrate 101 on the opposite side of region R1. At this time, the intrusion portion 202Q may also have the same component as interface S1 or S2 dispersed inside it. These states further increase the bonding strength at the bonding site.

[0056] [2-1-4] Variation <First variation> Figure 4 is a schematic cross-sectional view showing the state of the joint area for a first modified example of the joint obtained in the first embodiment. As shown in this figure, the joint may be in a state where the first lump 301 and the second lump 302 are scattered between region R1 and the second substrate 102. Here, the first lump 301 is formed from a compound (for example, TiSi) containing the same two components as the main component of the first joining material layer 201 (for example, Ti) and the main component of the second substrate 102 (for example, Si). The second lump 302 is formed from a compound (for example, AuSi) containing the same two components as the main component of the second joining material layer 202 (for example, Au) and the main component of the second substrate 102 (for example, Si).

[0057] <Second variation> Figure 5 is a schematic cross-sectional view showing the state of the joint in a second modified example of the joint obtained in the first embodiment. As shown in this figure, the intrusion portion 202Q may not only appear as a continuous layer when viewed in cross-section (in other words, as a state where there are no holes or cracks when viewed from above), but may also appear as a state where it is divided in the middle when viewed in cross-section (in other words, as a state where holes or cracks occur when viewed from above).

[0058] <Third variation> Figure 6 is a schematic cross-sectional view showing the state of the joint in a third modified example of the joint obtained in the first embodiment. As shown in this figure, a barrier layer 203 may be formed on the opposing surface 102a on the second substrate 102 side, the barrier layer 203 containing a compound mainly composed of the same components as the main components of the second substrate 102. Here, the compound that is the main component of this barrier layer 203 is an oxide or a nitride. This barrier layer 203 may be formed by chemically treating the surface of the second substrate 102 (the surface that becomes the opposing surface 102a) (such as oxidation or nitriding), or by growing it on the surface of the second substrate 102 using methods such as vapor deposition or sputtering.

[0059] This suppresses heat diffusion toward the second substrate 102, and as a result, a portion of the second bonding material layer 202 (the portion that becomes the penetration portion 202Q) becomes more easily deformed toward the first substrate 101 through the opening 201X.

[0060] [2-2] Second Embodiment [2-2-1] Target to be joined Figure 7 is a conceptual diagram showing an example of the first substrate 101 and the second substrate 102 to be joined in the second embodiment. As shown in this figure, in this embodiment, the first joining material layer 201 is formed on the opposing surface 101a on the first substrate 101 side of the opposing surfaces 101a and 102a (surfaces to be joined) of these two substrates.

[0061] Here, the main component of the first bonding material layer 201 is a material that can efficiently absorb laser light and convert it into heat.

[0062] For example, the main component of the first substrate 101 is SiO2 (such as synthetic quartz), the main component of the second substrate 102 is Si, and the main component of the first bonding material layer 201 is Ti. However, the main component of the first substrate 101 may be something other than SiO2. Similarly, the main component of the second substrate 102 may be something other than Si. Furthermore, instead of Ti, a material such as Cr can be used as the main component of the first bonding material layer 201.

[0063] In this embodiment as well, the first bonding material layer 201 is formed by sputtering, similar to the first embodiment.

[0064] [2-2-2] Joining method Next, a bonding method for joining two substrates (a first substrate 101 and a second substrate 102; see Figure 7) using laser light will be described. In this bonding method as well, the lamination process and the bonding process are performed using the bonding apparatus described above. These processes will be described in detail below. Note that this bonding method as well as this embodiment may include a forming process for forming the first bonding material layer 201 described above.

[0065] In the lamination process, first, the first substrate 101 is placed on the stage 112 with the first bonding material layer 201 facing upwards (see Figure 7). Next, the second substrate 102 is placed on top of the first substrate 101 so that the first bonding material layer 201 is sandwiched between the first substrate 101 and the second substrate 102.

[0066] In the bonding process, laser light is irradiated onto the bonding area of ​​the two substrates (first substrate 101 and second substrate 102) via the stage 112 (see Figure 1). Specifically, laser light is irradiated onto the portion of the first bonding material layer 201 corresponding to the bonding area via the stage 112. This heats the first bonding material layer 201 at the laser irradiation area, bonding the two substrates together.

[0067] With this joining method, the first joining material layer 201 can efficiently absorb laser light at the joining point, and as a result, the joining strength at the joining point can be increased.

[0068] [2-2-3]Zygote Figure 8 is a schematic cross-sectional view showing the state of the joint area of ​​a joint obtained by the above joining method. As shown in this figure, irradiation with laser light causes the first joining material layer 201 to change into one having an opening 201X at the joining area (the area irradiated with laser light). The inside of the opening 201X is then filled with a material whose main component is the same as the main component of the first substrate 101 (SiO2, for example). Specifically, the inside of the opening 201X is filled with the first substrate 101 that has melted and re-solidified due to heat. As a result, the first substrate 101 and the second substrate 102 are joined together through the opening 201X.

[0069] Furthermore, the joined body consists of multiple lumps 303, each composed of a compound (specifically TiSi or TiO) with the same components as the main component of the first joining material layer 201 (for example, Ti), which are scattered along a virtual surface 30X that curves convexly toward the first substrate 101 and has the edge of the opening 201X as its periphery. For example, the lumps 303 are formed by the granular precipitation of the above compound. Moreover, the region R2 from the virtual surface 30X to the inside of the opening 201X is in a dispersed state (including diffusion and precipitation) of an oxide (for example, TiO) with the same components as the main component of the first joining material layer 201. These conditions enhance the bonding strength at the joint.

[0070] As a specific example, if the main component of the first substrate 101 is SiO2 (such as synthetic quartz), the main component of the second substrate 102 is Si, and the main component of the first bonding material layer 201 is Ti, then in the bonded body, an electrically conductive portion (including layered portions) containing TiSi may be formed around the periphery of the opening 201X in the first bonding material layer 201. Therefore, by utilizing the formation of such an electrically conductive portion, it becomes possible to electrically connect the wiring provided on the first substrate 101 side with the wiring provided on the second substrate 102 side.

[0071] [2-2-4] Variation Figure 9 is a schematic cross-sectional view showing the state of the joint in a modified example of the joint obtained in the second embodiment. As shown in this figure, a barrier layer 204 may be formed on the opposing surface 102a on the second substrate 102 side, the barrier layer 204 containing a compound mainly composed of the same components as the main components of the second substrate 102. Here, the compound that is the main component of this barrier layer 204 is an oxide or a nitride. This barrier layer 204 may be formed by chemically treating the surface of the second substrate 102 (the surface that becomes the opposing surface 102a) (such as oxidation or nitriding), or by growing it on the surface of the second substrate 102 using methods such as vapor deposition or sputtering.

[0072] This suppresses heat diffusion toward the second substrate 102, and as a result, the lump 303 is more likely to form on the first substrate 101 side relative to the opening 201X.

[0073] Furthermore, in this modified example, the main components of the first substrate 101 and the second substrate 102 may be selected such that the main component (compound) of the barrier layer 204 and the main component of the first substrate 101 are of the same type. With such selection, when laser light is irradiated, an opening 201X is formed in the portion of the first bonding material layer 201 corresponding to the bonding location. At the same time, the first substrate 101 and the barrier layer 204, which have the same main components, melt and mix together due to the heat, and as a result, the inside of the opening 201X is filled with the re-solidified material. Therefore, the first substrate 101 and the second substrate 102 are firmly bonded together through the opening 201X.

[0074] [2-3] Third Embodiment [2-3-1] Target to be joined Figure 10 is a conceptual diagram showing an example of the first substrate 101 and the second substrate 102 to be joined in the third embodiment. As shown in this figure, in this embodiment, the first joining material layer 201 is formed only on the opposing surface 101a on the side of the first substrate 101, out of the opposing surfaces 101a and 102a (surfaces to be joined) of these two substrates.

[0075] Here, the main component of the first bonding material layer 201 is a material that can efficiently absorb laser light and convert it into heat.

[0076] For example, the main component of the first substrate 101 is glass, the main component of the second substrate 102 is Si, and the main component of the first bonding material layer 201 is Ti. However, the main component of the first substrate 101 may be something other than glass. Similarly, the main component of the second substrate 102 may be something other than Si. Furthermore, instead of Ti, a material such as Cr can be used as the main component of the first bonding material layer 201.

[0077] In this embodiment as well, the first bonding material layer 201 is formed by sputtering, similar to the first embodiment.

[0078] [2-3-2] Joining method Next, a bonding method for joining two substrates (a first substrate 101 and a second substrate 102; see Figure 10) using laser light will be described. In this bonding method as well, the lamination process and the bonding process are performed using the bonding apparatus described above. These processes will be described in detail below. Note that this bonding method as well as this embodiment may include a forming process for forming the first bonding material layer 201 described above.

[0079] In the lamination process, first, the first substrate 101 is placed on the stage 112 with the first bonding material layer 201 facing upwards (see Figure 10). Next, the second substrate 102 is placed on top of the first substrate 101 so that the first bonding material layer 201 is sandwiched between the first substrate 101 and the second substrate 102.

[0080] In the bonding process, laser light is irradiated onto the bonding area of ​​the two substrates (first substrate 101 and second substrate 102) via the stage 112 (see Figure 1). Specifically, laser light is irradiated onto the portion of the first bonding material layer 201 corresponding to the bonding area via the stage 112. This heats the first bonding material layer 201 at the laser irradiation area, bonding the two substrates together.

[0081] With this joining method, the first joining material layer 201 can efficiently absorb laser light at the joining point, and as a result, the joining strength at the joining point can be increased.

[0082] [2-3-3]Zygote Figure 11 is a schematic cross-sectional view showing the state of the joint area of ​​a joint obtained by the above joining method. As shown in this figure, irradiation with laser light causes the first joining material layer 201 to change into one having an opening 201X at the joining area (the area irradiated with laser light). The inside of the opening 201X is then filled with a material whose main component is the same as the main component of the first substrate 101 (for example, glass). Specifically, the inside of the opening 201X is filled with the first substrate 101 that has melted and re-solidified due to the heat. As a result, the first substrate 101 and the second substrate 102 are joined together through the opening 201X.

[0083] Furthermore, in the joint, in the region 102r inside the opening 201X of the opposing surface 102a on the second substrate 102 side, there are scattered lumps 304 in which a compound (for example, TiSi) containing the same two components as the main component of the first joining material layer 201 (for example, Ti) and the main component of the second substrate 102 (for example, Si) is formed in a droplet-like manner from the region 102r into the second substrate 102. For example, the lumps 304 are formed by the droplet deposition of the above compound. This state increases the bonding strength at the joint.

[0084] Furthermore, in this bonded structure, an oxide layer 305 containing an oxide as the main component, which has the same components as the minor components of the first substrate 101, may be formed in the region 102r inside the opening 201X of the opposing surface 102a on the second substrate 102 side (see Figure 12). Specifically, if the main component of the first substrate 101 is glass and the glass contains Al, Ca, etc. as minor components, then an Al2O3 layer or a CaO layer may be formed as the oxide layer 305.

[0085] The above-described embodiments and modifications should be considered in all respects as illustrative and not restrictive. The scope of the present invention is indicated by the claims, rather than by the above-described embodiments and modifications. Furthermore, the scope of the present invention is intended to include all modifications within the meaning and scope equivalent to the claims. [Explanation of Symbols]

[0086] 1. Chamber mechanism 2. Pressurization mechanism 3. Laser light source 4. Control Unit 10 Chambers 11. First Chamber Component 12 Second Chamber Component 13 Drive unit 14 Exhaust section 21 Diaphragm 22 Drive unit 23. Transmedia 30X Noodles R1 and R2 domains S1 and S2 interfaces 101 First substrate 102 Second substrate 101a, 102a Opposite planes Back of 101b and 102b 102r domain 111 1st Ring Department 112 ステージ 121 2nd Ring Section 122 ceiling 201 First bonding material layer 201X Opening 202 Second bonding material layer 202P Intermediate Part 202Q Intrusion Part 203, 204 バリアFloor 301 First block 302 Second block 303, 304 blocky materials 305 acid layer

Claims

1. The first substrate and the second substrate to be joined, A first bonding material layer interposed between the opposing surfaces of the first and second substrates and having an opening at the joint of the substrates, Equipped with, The inside of the opening is filled with a material whose main component is the same as at least one of the main components of the first substrate and the second substrate. A bonded body in which a region is formed inside or near the opening in which at least one of the same component as the main component of the first bonding material layer and a compound consisting of that component is dispersed.

2. The invention further comprises a second bonding material layer, the second bonding material layer having a different main component from the first bonding material layer, The second bonding material layer has an intervening portion that is interposed between the first bonding material layer and the second substrate, and an intrusion portion that enters into the first substrate through the opening from that portion. The material filling the inside of the opening extends throughout the entire region between the intrusion portion and the second substrate, The bonded body according to claim 1, wherein the same component as the main component of the first bonding material layer is dispersed at a high concentration at the interface with the region and at the interface with the first substrate on the opposite side of that region in the aforementioned penetration portion.

3. The main component of the first substrate and the main component of the second substrate are both Si. The main component of the first bonding material layer is Ti, The bonded body according to claim 2, wherein the main component of the second bonding material layer is Au.

4. The bonded body according to claim 2 or 3, wherein the same components as the main component of the first bonding material layer are also dispersed within the penetration portion.

5. The bonded body according to claim 2 or 3, wherein a first mass formed from a compound containing the same two components as the main component of the first bonding material layer and the main component of the second substrate, and a second mass formed from a compound containing the same two components as the main component of the second bonding material layer and the main component of the second substrate, are scattered between the region and the second substrate.

6. The joint according to claim 2 or 3, further comprising a barrier layer having as its main component a compound having the same main component as the main component of the second substrate, the barrier layer being formed on the opposing surface of the second substrate.

7. Multiple granular objects, each composed of the same main component as the first bonding material layer, are scattered along a virtual surface that curves convexly toward the first substrate side, with the edge of the opening as its peripheral edge. The bonded body according to claim 1, wherein an oxide having the same components as the main component of the first bonding material layer is dispersed in the region from the virtual surface to the inside of the opening.

8. The main component of the first substrate is SiO ２ And, The main component of the second substrate is Si, The bonded body according to claim 7, wherein the main component of the first bonding material layer is Ti.

9. The bonded body according to claim 8, wherein an electrically conductive portion containing TiSi is formed on the peripheral edge of the opening in the first bonding material layer.

10. The joint according to any one of claims 7 to 9, further comprising a barrier layer having as its main component a compound having the same main component as the main component of the second substrate, the barrier layer being formed on the opposing surface of the second substrate.

11. The bonded body according to claim 1, wherein, in the region inside the opening of the opposing surface on the second substrate side, a plurality of lumps are scattered, each containing two components identical to the main component of the first bonding material layer and the main component of the second substrate, and formed in a drop-like manner from that region into the second substrate.

12. The main component of the first substrate is glass. The main component of the second substrate is Si, The bonded body according to claim 11, wherein the main component of the first bonding material layer is Ti.

13. The bonded body according to claim 11 or 12, wherein an oxide layer containing an oxide having the same components as the secondary components of the first substrate as its main component is formed in the region inside the opening of the opposing surface on the second substrate side.

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