Method of joining

Abstract

In the first joining method, the second joining object is overlapped with the first joining object in an atmosphere lower than a prescribed gas pressure, and then, while the atmosphere is maintained, a fixing portion that fixes the second joining object to the first joining object is formed in a ring shape along the outer periphery of the first joining object, whereby the ring shape is sealed. In the second joining method, the second joining object is overlapped with the first joining object having a plurality of device regions in an atmosphere lower than a prescribed gas pressure, and then, while the atmosphere is maintained, a fixing portion that fixes the second joining object to the first joining object is formed in a manner so as to become a ring shape that surrounds the plurality of device regions, whereby the ring shape is sealed.

Description

Technical Field

[0001] This invention relates to laser-based bonding techniques. Background Technology

[0002] In devices such as MEMS (Micro Electro Mechanical Systems), components such as sensors (accelerometers, gyroscopes, etc.), micromechanical devices (actuators, etc.), and electronic circuits are sometimes sealed within cavities (for example, see Patent Document 1). In the manufacturing process of such devices, two mating objects (a mating object having a recess that forms a cavity, and a mating object that closes the recess) are used. After the aforementioned component is placed within the recess, these two mating objects are joined together, thereby sealing the aforementioned component within the cavity while simultaneously forming it.

[0003] On the other hand, depending on the type of component sealed within the cavity, maintaining an appropriate internal pressure within the cavity becomes important to improve the component's performance. As an example, when the component is an accelerometer, the internal pressure of the cavity is preferably a moderately low value so that air resistance can be used to attenuate the accelerometer. As another example, when the component is a gyroscope sensor, the internal pressure of the cavity is preferably as low as possible (in other words, the vacuum level should be as high as possible).

[0004] Previously, the following method was used to make the internal pressure of the cavity reach the target internal pressure (an appropriate value corresponding to the component):

[0005] (1) First, align (align) the two joining objects in terms of their positional relationship and then make the two joining objects coincide;

[0006] (2) Next, a temporary engagement is performed to maintain the adjusted positional relationship;

[0007] (3) After that, the two objects to be joined are placed in the chamber and the internal pressure of the chamber is reduced to the same level as the internal pressure of the target cavity.

[0008] (4) Then, the main engagement for sealing the cavity is performed in the cavity.

[0009] Existing technical documents

[0010] Patent documents

[0011] Patent Document 1: Japanese Patent Application Publication No. 2013-251743 Summary of the Invention

[0012] The technical problem that the invention aims to solve

[0013] In the aforementioned existing method, the differential pressure generated by reducing the internal pressure of the cavity is used to allow the air inside the cavity to flow out through the gap (the part other than the temporarily joined part) formed between the joint surfaces when the two joint objects are overlapped, thereby reducing the internal pressure of the cavity to the target internal pressure.

[0014] The inventors have discovered that existing methods struggle to reduce the internal pressure of a cavity to the target pressure, or even if possible, it takes an extremely long time. The inventors believe this is because, after aligning two mating objects, even with a pressure differential, the flow resistance at the gap between the mating surfaces increases, making it difficult for air to flow out through the gap.

[0015] Therefore, the object of the present invention is to efficiently reduce the internal pressure of the cavity to a target internal pressure in a joining method that joins two joining objects to form a cavity.

[0016] Technical solutions for solving technical problems

[0017] The first joining method of the present invention includes a lamination step and a fixing portion forming step (Scheme 1). In the lamination step, a second joining object is overlapped with a first joining object in an atmosphere lower than a predetermined pressure. After the lamination step, in the fixing portion forming step, while maintaining the above atmosphere, a fixing portion is formed in a ring shape along the outer periphery of the first joining object to fix the second joining object to the first joining object, thereby sealing the inner ring.

[0018] The second bonding method of the present invention includes a lamination step and a fixing portion forming step (Scheme 2). In the lamination step, a second bonding object is overlapped with a first bonding object having multiple device regions in an atmosphere below a specified pressure. After the lamination step, in the fixing portion forming step, while maintaining the above atmosphere, a fixing portion is formed in such a ring-like manner that the second bonding object is fixed to the first bonding object, thereby sealing the annulus.

[0019] In the bonding method of Scheme 2 above, recesses that form cavities can be formed in each device region of the first bonding object. In the lamination step, as the atmosphere, an atmosphere that reduces the gas pressure to the same value or a value close to the target internal pressure value of the cavity (the target internal pressure in the sealed cavity) can be used (Scheme 3).

[0020] According to any of the above-described schemes 1 to 3, in the lamination step, by using a simple method such as overlapping the two joining objects in an atmosphere lower than the specified pressure, the pressure inside the cavity before sealing can be made the same as the pressure of the atmosphere at that time. Moreover, by simply adjusting the pressure of the atmosphere during the lamination step to approximately the same as the target internal pressure value of the sealed cavity, the pressure inside the cavity before sealing can be reduced to the same level as the target internal pressure value. Then, in the subsequent fixing part formation step, by forming the fixing part into a ring shape while maintaining the above-described atmosphere and sealing the inside of the ring, even when the joining objects are exposed to an atmosphere of the specified pressure (atmospheric pressure, etc.) or a higher pressure atmosphere, the pressure inside the ring can be maintained at the target internal pressure value.

[0021] The third joining method of the present invention includes a displacement step, a stacking step, and a fixing portion forming step (Scheme 4). In the displacement step, after making the chamber in which the first joining object and the second joining object are disposed a vacuum, a predetermined gas is injected, thereby displacing the chamber into an atmosphere filled with the predetermined gas. In the stacking step, the first joining object is overlapped with the second joining object in an atmosphere filled with the predetermined gas. After the stacking step, in the fixing portion forming step, while maintaining the above atmosphere, a fixing portion is formed in a ring shape along the outer periphery of the first joining object to fix the second joining object to the first joining object, thereby sealing the inner ring.

[0022] The fourth bonding method of the present invention includes a displacement step, a stacking step, and a fixing portion forming step (Solution 5). In the displacement step, after a vacuum is created in a chamber containing a first bonding object and a second bonding object having multiple device regions, a predetermined gas is injected, thereby displacing the chamber into an atmosphere filled with the predetermined gas. In the stacking step, the first bonding object is overlapped with the second bonding object in an atmosphere filled with the predetermined gas. After the stacking step, in the fixing portion forming step, while maintaining the aforementioned atmosphere, a fixing portion is formed in a ring-like manner to fix the second bonding object to the first bonding object, thereby sealing the annulus.

[0023] According to scheme 4 or 5 above, by creating a vacuum in the chamber during the replacement step and then injecting a specified gas, the chamber can be easily replaced with an atmosphere primarily composed of the specified gas. Then, in the lamination step, by using a simple method such as overlapping the two mating objects in an atmosphere filled with the specified gas, the cavity before sealing can be filled with gas in the same way as the current atmosphere. Furthermore, by appropriately selecting the type of gas filling the chamber, the cavity before sealing can be filled with the desired gas. Then, in the subsequent fixing part formation step, by forming the fixing part in a ring shape while maintaining the aforementioned atmosphere and sealing the ring, the ring can be maintained in a state filled with the desired gas even when the mating objects are exposed to air.

[0024] In any of the bonding methods of Schemes 2, 3 and 5 above, the second bonding object may have a device region corresponding to the device region of the first bonding object. In the stacking step, at least one of the first bonding object and the second bonding object may be aligned so that the corresponding device regions are aligned with each other. After the alignment is performed, the second bonding object is overlapped with the first bonding object (Scheme 6).

[0025] According to the above scheme 6, when wiring, electrodes, etc. are formed in the corresponding two device areas, their positional relationship can be adjusted so that they can be correctly electrically connected when joined.

[0026] The bonding method of any one of the above-described schemes 1 to 6 may include the following manner (Scheme 7). The bonding method may further include a metal layer forming step, which, as a step performed before the lamination step, forms a metal layer on at least one of the bonding surfaces of the first bonding object and the second bonding object. Furthermore, in the fixing part forming step, an annular fixing part can be formed by locally irradiating the metal layer located between the first bonding object and the second bonding object with a laser, thereby locally heating the irradiated area of ​​the laser.

[0027] According to the above-described scheme 7, at the laser irradiation site (the site where the fixed joint is to be formed), the metal layer can be melted together with the first and second bonding objects, or the metal, which is the main component of the metal layer, can diffuse into the first and second bonding objects. As a result, at each interface between the first and second bonding objects and the metal layer, compounds (metal silicides, etc.) or alloys (metal-Si alloys, etc.) of the main components of the first and second bonding objects and the metal are formed. In other words, a fixed joint that firmly bonds the first and second bonding objects can be formed. Moreover, by forming such a fixed joint into a ring shape under an atmosphere below a specified pressure, the area within the ring can be reliably sealed while remaining under a pressure below the specified pressure.

[0028] The fifth joining method of the present invention includes a temporary joining step and a main joining step (Scheme 8). In the temporary joining step, the first joining object and the second joining object are temporarily joined using the joining method of any one of Schemes 1 to 7 described above. After the temporary joining step, in the main joining step, the first joining object and the second joining object are further fixed in a region inside the annular fixing portion. At this time, the main joining step is performed using a chamber different from the chamber used to perform the temporary joining step.

[0029] As described above, the temporary joining step can efficiently create a state within the cavity (the cavity before sealing) where the internal pressure is reduced to the target value. Therefore, in the main joining step, by only joining the cavity (the cavity before sealing), a cavity (the cavity after sealing) with the internal pressure maintained at an appropriate value (the target internal pressure value) can be easily created.

[0030] According to scheme 8 above, by using a different chamber than the one used for the temporary engagement step to perform the main engagement step, the cycle time required for processing (temporary engagement + main engagement) of a set of engagement objects (first engagement object and second engagement object) can be shortened. This is described in detail below.

[0031] Both the stacking step (which requires creating an atmosphere below a specified pressure (e.g., a high vacuum atmosphere)) and the main bonding step in the temporary bonding process are time-consuming processes. Here, if the temporary bonding step and the main bonding step are performed sequentially in the same chamber, the process for the next set of bonding objects can only proceed after the previous set has been processed. Therefore, the cycle time required for processing a set of bonding objects (temporary bonding + main bonding) becomes longer.

[0032] On the other hand, according to the above scheme 8, by using a different chamber than the chamber used to perform the main engagement step, it is possible to use multiple chambers to process these steps in parallel. As a result, the cycle time required for processing a group of engagement objects (temporary engagement + main engagement) can be shortened.

[0033] Invention Effects

[0034] According to the present invention, the internal pressure of the cavity can be efficiently reduced to the target internal pressure. Attached Figure Description

[0035] Figure 1 This is a conceptual diagram showing the temporary joining steps performed in the implementation method in the order of processing.

[0036] Figure 2 This refers to the temporary joining steps, presented in the order of processing. Figure 1 A conceptual diagram of the subsequent processing.

[0037] Figure 3 (A) and Figure 3 (B) is a top view illustrating the first and second joining objects prepared in the preparation step, respectively.

[0038] Figure 4 This is a top view illustrating the predetermined pattern of the fastener used in the temporary joining step.

[0039] Figure 5 This is a conceptual diagram showing the main joining steps performed in the implementation method in the order of processing.

[0040] Figure 6 This is a top view illustrating the predetermined pattern of the fastener used in the main joining step.

[0041] Figure 7 (A) and Figure 7 (B) is a top view showing two examples of the predetermined forming pattern of the fastener used in the temporary joining step of the first variation.

[0042] Figure 8 (A) and Figure 8 (B) is a top view showing two other examples of the predetermined forming pattern of the fastener used in the temporary joining step of the first variation.

[0043] Figure 9 This is a conceptual diagram showing the temporary joining steps performed in the second variation, arranged in the order of processing.

[0044] Figure 10 This refers to the temporary joining steps, presented in the order of processing. Figure 9 A conceptual diagram of the subsequent processing.

[0045] Figure 11 This is a conceptual diagram showing the main joining steps performed in the second variation, arranged in the order of processing. Detailed Implementation

[0046] The bonding method of the present invention is a method for bonding two bonding objects (semiconductor wafers, etc., hereinafter referred to as "first bonding object W1" and "second bonding object W2"). ​​Hereinafter, embodiments and variations of the bonding method of the present invention will be specifically described. Furthermore, the bonding method described below can be implemented using various known devices.

[0047] [1] Implementation

[0048] In the joining method of this embodiment, the steps for joining the first joining object W1 and the second joining object W2 are generally divided into two joining steps performed sequentially. Specifically, a temporary joining step S1 is performed as the first joining step, followed by a main joining step S2 as the second joining step. These joining steps will be described in detail below.

[0049] [1-1] Temporary joining step

[0050] Figure 1 and Figure 2 This is a conceptual diagram showing the temporary joining step S1 performed in this embodiment in the order of processing. In the temporary joining step S1, the preparation step S10, the stacking step S11, and the fixing part forming step S12 are performed sequentially.

[0051] <Preparation Step S10>

[0052] In preparation step S10, the first joining object W1 and the second joining object W2 are prepared. Figure 3 (A) and Figure 3 (B) is a top view illustrating the first joining object W1 and the second joining object W2 prepared in preparation step S10, respectively. Furthermore, Figure 1 and Figure 2 The first joining object W1 and the second joining object W2 shown represent the first joining object W1 and the second joining object W2 shown in the figure. Figure 3 (A) and Figure 3 The cross-sections of lines A1-A1 and A2-A2 are marked in (B). The same applies to the other figures showing the various steps.

[0053] In this embodiment, the first bonding object W1 has multiple device regions Rd1 that are monolithized by cutting at the cutting line Ct (see reference). Figure 3 (A)), and the second bonding object W2 has a device region Rd2 corresponding to each device region Rd1 of the first bonding object W1 (refer to...). Figure 3 (B) Furthermore, the corresponding set of device regions Rd1 and Rd2 are monolithized after bonding by being cut along the cutting line Ct, forming a single device.

[0054] Specifically, each device region Rd1 of the first bonding object W1 forms the base of the device, and each device region Rd1 has a recess 10, which serves as a sealed space (cavity) for sealing the element Ge that performs the function of the device. Here, the element Ge is a sensor (accelerometer, gyroscope, etc.), a micro-mechanical device (actuator, etc.), an electronic circuit, etc. In this embodiment, the element Ge is a component for which the internal pressure of the cavity needs to be maintained at an appropriate value to improve its performance.

[0055] In addition, each device region Rd2 of the second bonding object W2 is a region that closes the recess 10 of the corresponding device region Rd1 of the first bonding object W1, and is a part that becomes a cover in the device.

[0056] In addition, wiring, electrodes, etc. (not shown) that will be interconnected are formed in device regions Rd1 and Rd2, and they are required to be electrically connected correctly during bonding.

[0057] <Layering Step S11>

[0058] In the lamination step S11, using the first bonding object W1 and the second bonding object W2 prepared in the preparation step S10, the second bonding object W2 is overlapped with the first bonding object W1 in an atmosphere below a specified pressure Pt. Here, the specified pressure Pt is the pressure of the atmosphere used in the main bonding step S2 described later, and is not particularly limited, such as atmospheric pressure.

[0059] Specifically, the first mating object W1 and the second mating object W2 are first placed into the pressure-adjustable chamber 30. At this time, while the mating surfaces 11s and 21s of the first mating object W1 and the second mating object W2 are facing each other and spaced apart from each other, the first mating object W1 and the second mating object W2 are positioned within the chamber 30 (see reference). Figure 1 (See the upper layer diagram of S11 shown). Here, the mating surfaces 11s and 21s are the surfaces that are mated in the temporary mating step S1 and the main mating step S2, respectively, and are the surfaces exposed by the recess 10, interconnected wiring, electrodes, etc.

[0060] Next, by reducing the internal pressure of the chamber 30, an atmosphere (atmosphere below the specified pressure Pt) is formed inside the chamber 30, until the pressure is reduced to the same value or near the target internal pressure Px of the cavity (the sealed space used to seal the element Ge).

[0061] Furthermore, in this embodiment, during the stacking step S11, at least one of the first bonding object W1 and the second bonding object W2 is aligned to ensure that the positions of the corresponding device regions Rd1 and Rd2 are consistent. Specifically, by aligning, the positional relationship of wiring, electrodes, etc., formed in the corresponding device regions Rd1 and Rd2 is adjusted so that electrical connections can be correctly made during bonding.

[0062] Then, while maintaining the aligned positional relationship, the second joining object W2 is overlapped with the first joining object W1 (see reference). Figure 1 The diagram below S11 is shown.

[0063] According to this stacking step S11, by a simple method such as overlapping two joining objects (first joining object W1 and second joining object W2) in an atmosphere lower than a specified pressure Pt, the pressure inside the cavity before sealing can be made the same as the pressure of the atmosphere at that time. Moreover, by simply adjusting the pressure of the atmosphere during the stacking step S11 to the same level as the target internal pressure value Px of the sealed cavity, the pressure inside the cavity before sealing can be reduced to the same level as the target internal pressure value Px. Thus, it is possible to efficiently form a cavity (in this case, the cavity before sealing) with its internal pressure reduced to the target internal pressure (target internal pressure value Px). In this way, according to the stacking step S11, the internal pressure of the cavity before sealing can be efficiently controlled.

[0064] Furthermore, since the positional relationship of the wiring, electrodes, etc. formed in the corresponding two device regions Rd1 and Rd2 is adjusted by the above alignment, they can be correctly electrically connected when the first bonding object W1 overlaps the second bonding object W2.

[0065] <Step S12 for forming the fixed joint>

[0066] In the fixing part forming step S12, while keeping the atmosphere inside the chamber 30 constant (in other words, keeping the air pressure adjusted in the lamination step S11), a fixing part Qs for fixing the second joint object W2 to the first joint object W1 is formed in an annular (closed annular) shape along the outer periphery 11t of the first joint object W1, thereby sealing the annular shape.

[0067] Specifically, by locally irradiating the interface (contact surface) of the mating surfaces 11s and 21s with laser (refer to...) Figure 2 (See the upper layer diagram of S12 shown). The laser-irradiated area is locally heated to melt or deform it, thereby fixing the mating surfaces 11s and 21s together at that local location (see Figure 11). Figure 2 (See the lower layer diagram of S12 shown). At this time, the first joint object W1 and the second joint object W2 can also be clamped by a quartz plate, etc., to improve the tightness of the joint surfaces 11s and 21s against each other. Then, by forming the predetermined pattern Xs along the closed annular pattern (fixed part Qs). Refer to Figure 4 A scanning laser is used to fix the mating surfaces 11s and 21s together along the pattern. This forms a closed annular fixed part Qs.

[0068] Figure 4 This is a top view illustrating the predetermined pattern Xs of the fixed joint Qs. Figure 4In the example, the first bonding object W1 is a circular plate, and a predetermined forming pattern Xs is set on its periphery Re in such a way that it becomes an annular shape along the outer periphery 11t. According to this shape, the predetermined forming pattern Xs is set as an annular shape surrounding all device regions Rd1 of the first bonding object W1.

[0069] According to the fixing part forming step S12, by forming the fixing part Qs in an annular (closed annular) shape and sealing the annular shape while maintaining the atmosphere inside the chamber 30 (in other words, while maintaining the air pressure adjusted in the lamination step S11), even when the first joint object W1 and the second joint object W2 after temporary bonding are exposed to an atmosphere of a specified air pressure Pt (atmospheric pressure, etc.) or a higher air pressure atmosphere, the air pressure inside the annular shape can be maintained at the internal pressure target value Px.

[0070] [1-2] Main joining steps

[0071] Figure 5 This is a conceptual diagram showing the main joining step S2 performed in this embodiment according to the processing sequence. In this embodiment, the first joining object W1 and the second joining object W2, after temporary joining, are removed from the chamber 30, and the main joining step S2, as described below, is performed on these joining objects at atmospheric pressure. Furthermore, in this embodiment, the main joining step S2 is performed using a different chamber than the chamber 30 used to perform the temporary joining step S1. Additionally, these chambers can be constructed within the same device or separately within different devices.

[0072] Here, according to the temporary joining step S1 described above, the annular part Qs is sealed with an air pressure at the same or similar level as the target internal pressure value Px. Therefore, by exposing the first joining object W1 and the second joining object W2 after temporary joining to atmospheric pressure, a pressure difference is generated between the air pressure inside the annulus (internal pressure) and the air pressure outside the annulus (external pressure). Using this pressure difference, the first joining object W1 and the second joining object W2 can be clamped from the back side in a region closer to the annular joining part Qs. Moreover, by using such a pressure difference for clamping, the joining surfaces 11s and 21s can be brought into close contact with each other in a region closer to the annular joining part Qs. The main joining step S2 is performed in this state where the joining surfaces 11s and 21s are brought into close contact with each other.

[0073] Then, in the main joining step S2, the first joining object W1 and the second joining object W2 are further joined in the region inside the annular fixed part Qs formed in the temporary joining step S1.

[0074] Specifically, for each corresponding device region Rd1 and Rd2 (device regions Rd1 and Rd2 whose positions are aligned with each other), a fixing portion Qt is formed to seal the cavity (cavity before sealing) formed in the region of the group. At this time, the fixing portion Qt is formed as an annular shape (closed annular shape) surrounding the recess 10 constituting each cavity.

[0075] More specifically, by locally irradiating the interface (contact surface) of the mating surfaces 11s and 21s with a laser in a region closer to the fixed joint Qs (refer to...) Figure 5 (See the upper layer diagram of S2 shown). The laser irradiation area is locally heated to melt or deform it, thereby fixing the bonding surfaces 11s and 21s together at that local location (see Figure 1). Figure 5 (See the lower layer diagram of S2 shown). At this time, the first bonding object W1 and the second bonding object W2 can also be clamped by a quartz plate, etc., so that the tightness of the bonding surfaces 11s and 21s is further improved. Then, according to each corresponding device region Rd1 and Rd2, the predetermined forming pattern Xt of the fixed part Qt is formed along the closed annular pattern (refer to the reference). Figure 6 A scanning laser is used to fix the mating surfaces 11s and 21s together along the pattern. In this way, a closed annular fixing portion Qt is formed according to each corresponding device region Rd1 and Rd2.

[0076] Figure 6 This is a top view illustrating the predetermined pattern Xt of the fixed joint Qt. Figure 6 In the example, each device region Rd1 is quadrilateral in shape (and the corresponding device region Rd2 is also quadrilateral). In this device region Rd1, the predetermined pattern Xt is set to be a ring that runs along the perimeter of the quadrilateral and surrounds the recess 10. Furthermore, the shape of the predetermined pattern Xt is not limited to a quadrilateral ring, and can be appropriately changed to other shapes (circles, polygons, etc.) depending on the perimeter shape of each device region Rd1 and the opening shape of the recess 10.

[0077] As described above, in the temporary engagement step S1, the cavity (cavity before sealing) can be efficiently formed to a state where the internal pressure is reduced to the target internal pressure value Px. Therefore, in the main engagement step S2, by simply performing the engagement to seal the cavity (cavity before sealing) as described above, a cavity (cavity after sealing) with the internal pressure maintained at an appropriate value (target internal pressure value Px) can be easily formed.

[0078] Furthermore, in this embodiment, by using a different chamber than the chamber 30 used to perform the main engagement step S2, the cycle time required for processing (temporary engagement + main engagement) of a set of engagement objects (first engagement object W1 and second engagement object W2) can be shortened. This is described in detail below.

[0079] The stacking step S11 (the step that requires forming an atmosphere below a specified pressure Pt (e.g., a high vacuum atmosphere)) and the main bonding step S2 in the temporary bonding step S1 are both time-consuming processes. Here, if the temporary bonding step S1 and the main bonding step S2 are performed sequentially within a chamber, the process for the next set of bonding objects cannot proceed until the processing of one set of bonding objects is completed, thus increasing the cycle time required for processing one set of bonding objects (temporary bonding + main bonding).

[0080] According to the manufacturing method of this embodiment, by using a chamber different from the chamber 30 used to perform the main engagement step S2, it is possible to process these steps in parallel using multiple chambers. As a result, the cycle time required for processing a group of engaged objects (temporary engagement + main engagement) can be shortened.

[0081] [2] Variations

[0082] [2-1] First variation

[0083] The predetermined pattern Xs of the fixing portion Qs used in the temporary bonding step S1 can be appropriately modified, as long as it is an annular shape that can surround multiple device regions Rd1, and is not limited to other types. Figure 4 Other ring shapes, such as the one illustrated (a ring along the outer perimeter 11t).

[0084] Figure 7 (A) and Figure 7 (B) is a top view showing two examples of the predetermined forming pattern Xs of the fastener Qs used in the temporary joining step of the first modified example. Figure 8 (A) and Figure 8 (B) is a top view showing two other examples of the predetermined forming pattern Xs of the fastener Qs used in the temporary joining step of the first variation.

[0085] exist Figure 7 In (A), the predetermined pattern Xs is set as a ring that surrounds all device regions Rd1 along the outermost edge of the first bonding object W1.

[0086] On the other hand, Figure 7 (B)~ Figure 8 In (B), multiple device regions Rd1 are divided into several groups, and a pattern Xs is pre-defined as a ring surrounding all device regions Rd1 within each group. Furthermore, in Figure 7 In (B), the predetermined pattern Xs is set to be an independent ring shape for each group. And... Figure 8 (A) and Figure 8In (B), a circular pattern Xs1 and a linear pattern Xs2 are combined and configured in such a way that a portion of the annular shape can be shared between the groups. This is described in detail below.

[0087] exist Figure 8 In (A), the predetermined pattern Xs consists of a circular pattern Xs1 that is set as an annulus along the outer perimeter 11t, and a straight line pattern Xs2 that runs through the inner side of the circular pattern Xs1. In this case, a portion of the straight line pattern Xs2 in the predetermined pattern Xs is shared between groups, resulting in the predetermined pattern Xs comprising two semi-circular annulus shapes that can surround all device regions Rd1 within each group.

[0088] exist Figure 8 In (B), the predetermined pattern Xs consists of a circular pattern Xs1 that is set in a ring shape along the outer perimeter 11t, and a pattern Xs1 that crosses the inner side of the circular pattern Xs1 and intersects with each other (in Figure 8 (B) In the example, it is composed of two straight line patterns Xs2 that are orthogonal. In this case, a portion of the straight line pattern Xs2 in the predetermined pattern Xs is also shared between groups, resulting in the predetermined pattern Xs containing four fan-shaped rings that can surround all device regions Rd1 within each group.

[0089] [2-2] Second variation

[0090] Figure 9 and Figure 10 This is a conceptual diagram showing the temporary joining step S1 performed in the second variation, arranged in the order of processing. Additionally, Figure 11 This is a conceptual diagram showing the main joining step S2 performed in the second variation, in the order of processing.

[0091] like Figure 9 As shown, in preparation step S10, a metal layer Lm can be formed on at least one of the bonding surfaces 11s of the first bonding object W1 and the bonding surfaces 21s of the second bonding object W2 (metal layer formation step). Figure 9 In the example, the formation of the fixing portions Qs and Qt is shown only on the joint surface 21s on the side of the second joint object W2 (see reference). Figure 10 and Figure 11 In the case where a metal layer Lm is formed. More specifically, the metal layer Lm is formed at a location that avoids the electrodes, wiring, etc. that are electrically connected when the first bonding object W1 and the second bonding object W2 are bonded (a location where the metal layer Lm can be formed in a non-electrically contacted state with the electrodes, wiring, etc.).

[0092] The metal layer Lm is formed to a thickness of less than 1 μm using film deposition methods such as vapor deposition, but is not particularly limited thereto. Furthermore, the main component of the metal layer Lm can be metals such as Cu, Al, Cr, Ti, Ta, and Au.

[0093] Furthermore, the metal layer Lm can also be formed on the bonding surface 11s on the side of the first bonding object W1. Alternatively, the metal layer Lm can be formed on both bonding surfaces 11s and 21s. In this case, two metal layers Lm with different main components can be formed on bonding surfaces 11s and 21s. When it is not necessary to electrically connect electrodes, wiring, etc., when the first bonding object W1 is bonded to the second bonding object W2, the metal layer Lm can also be formed on the entire surface of at least one of the bonding surfaces 11s and 21s.

[0094] Furthermore, in this modified example, the metal layer Lm is used to form step S12 (refer to) at the fixed portion. Figure 10 ) and main engagement step S2 (refer to Figure 11 In this process, fixed portions Qs and Qt are formed. Specifically, by locally irradiating the metal layer Lm located between the first bonding object W1 and the second bonding object W2 with a laser, the irradiated area of ​​the laser is locally heated, and annular fixed portions Qs and Qt are formed.

[0095] More specifically, this is achieved by laser irradiation of the metal layer Lm (refer to...). Figure 10 and Figure 11 (See the upper layer diagrams of S12 and S2 shown in the diagrams). At the laser irradiation sites (the sites where the bonding portions Qs and Qt are to be formed, and where patterns Xs and Xt are to be formed), the metal layer Lm can be melted together with the first bonding object W1 and the second bonding object W2, or the metal, which is the main component of the metal layer Lm, can diffuse into the first bonding object W1 and the second bonding object W2. As a result, at each interface between the first bonding object W1 and the second bonding object W2 and the metal layer Lm, compounds (metal silicides, etc.) or alloys (metal-Si alloys, etc.) of the main components of the first bonding object W1 and the second bonding object W2 and the metal can be formed. In other words, bonding portions Qs and Qt that firmly bond the first bonding object W1 and the second bonding object W2 can be formed (see the diagrams shown in ... Figure 10 and Figure 11 The lower layers of S12 and S2 are shown in the diagrams respectively.

[0096] Furthermore, in the temporary bonding step S1, by forming such a fixed part Qs in an annular (closed annular) shape under an atmosphere below the specified pressure Pt, the annular part can be reliably sealed while maintaining the state below the specified pressure Pt.

[0097] [2-3] Third variation

[0098] The main joining step S2 is not limited to being performed at atmospheric pressure; it can also be performed in a pressurized atmosphere within the chamber. This structure increases the pressure difference between the internal and external air pressures within the annulus, resulting in a greater clamping force on the first joining object W1 and the second joining object W2 in the region closer to the annular fixing portion Qs. Consequently, even if either the first joining object W1 or the second joining object W2 is deformed, this deformation can be corrected, ensuring that the joining surfaces 11s and 21s are tightly pressed together.

[0099] [2-4] Fourth variation

[0100] The above-described joining method is not limited to joining two objects (first joining object W1 and second joining object W2) for the purpose of forming a cavity, but can also be applied to joining two objects for various other purposes. In this case, the pressure difference between the air pressure inside the annulus (internal pressure) and the air pressure outside the annulus (external pressure) can be used to make the first joining object W1 and the second joining object W2 fit tightly together. In addition, by using a chamber different from the chamber 30 used to perform the main joining step S2, the cycle time required for processing a set of joining objects (temporary joining + main joining) can be shortened.

[0101] Furthermore, the above-described bonding method can also be applied to bonding two objects for which no device regions Rd1 and Rd2 are defined. In this case, the two objects can be brought into close contact, reducing cycle time.

[0102] [2-5] Fifth variation

[0103] In the joining method of the above embodiment, in order to efficiently form a state in which the internal pressure of the cavity is reduced to the target internal pressure (target internal pressure value Px), in the lamination step S11, a process is performed to overlap the two joining objects (first joining object W1 and second joining object W2) in an atmosphere lower than the specified gas pressure Pt. Instead, in this modified example, in order to efficiently form a state in which the cavity is filled with the desired gas (mainly inert gases such as nitrogen, neon, and argon), the following process is performed in the temporary joining step S1.

[0104] In the temporary joining step S1 of this modified example, after performing the same preparation step S10 as in the above embodiment, the replacement step S31, the stacking step S32, and the fixing part forming step S33 are executed sequentially.

[0105] <Displacement Step S31>

[0106] In the replacement step S31, the first mating object W1 and the second mating object W2 are first placed into a chamber 30 capable of injecting gas and adjusting the internal pressure. At this time, the first mating object W1 and the second mating object W2 are positioned in the chamber 30 while the mating surfaces 11s and 21s of the first mating object W1 and the second mating object W2 are facing each other and while the first mating object W1 and the second mating object W2 are spaced apart from each other (see reference). Figure 1 The diagram above S11 is shown.

[0107] Next, the internal pressure of chamber 30 is reduced to create a vacuum (the pressure is lowered to the required vacuum level). Then, a gas identical to the gas used to fill the cavity (mainly inert gases such as nitrogen, neon, and argon) is injected into chamber 30 (hereinafter referred to as the "specified gas"), replacing the atmosphere of chamber 30 with that specified gas. At this point, the internal pressure of chamber 30 can be adjusted; it can be adjusted to a negative pressure below atmospheric pressure or a positive pressure above atmospheric pressure.

[0108] According to this replacement step S31, by evacuating the chamber 30 and then injecting a specified gas, the chamber 30 can be easily replaced with an atmosphere mainly composed of the specified gas.

[0109] <Layering Step S32>

[0110] In the stacking step S32, the first bonding object W1 is overlapped with the second bonding object W2 in an atmosphere filled with a specified gas. Furthermore, similar to the embodiment described above, at least one of the first bonding object W1 and the second bonding object W2 is aligned so that the corresponding device regions Rd1 and Rd2 are aligned with each other. Then, while maintaining the aligned positional relationship, the first bonding object W1 is overlapped with the second bonding object W2 (see reference...). Figure 1 The diagram below S11 is shown.

[0111] In the past, the following method has been used to fill the cavity with the desired gas:

[0112] (1) First, align the positions of the two joining objects and then overlap them;

[0113] (2) Next, a temporary engagement is performed to maintain the adjusted positional relationship;

[0114] (3) Then, the two objects to be joined are placed in the chamber and the chamber is then evacuated.

[0115] (4) Then, fill the chamber with the same gas as the required gas (the specified gas).

[0116] (5) Finally, the main engagement for sealing the cavity is performed in the cavity.

[0117] In this existing method, by evacuating the chamber into a vacuum in (3), the air inside the cavity is allowed to flow out through the gap between the joint surfaces of the two joint objects (the part other than the temporarily joined part) using the differential pressure generated at this time (the state where the internal pressure is greater than the external pressure), thereby making the inside of the cavity also a vacuum. However, as mentioned above, after the two joint objects are overlapped, even if a differential pressure is generated, the flow resistance in the gap between the joint surfaces will increase, so it is considered difficult to make the air flow out through the gap between the joint surfaces.

[0118] In addition, by filling the cavity with a specified gas in (4), the gas in the cavity is made to flow into the interior through the gap between the joint surfaces of the two joint objects (the part other than the temporarily joined part) by utilizing the differential pressure generated at this time (the state where the external pressure is greater than the internal pressure), thereby filling the cavity with the specified gas. However, in this case, since the flow resistance in the gap between the joint surfaces increases, it is considered difficult for the gas to flow into the interior through the gap between the joint surfaces.

[0119] According to the lamination step S32 of this modified example, by a simple method such as overlapping the two joining objects (first joining object W1 and second joining object W2) in an atmosphere filled with a specified gas, the cavity formed before sealing can be filled with a gas identical to the atmosphere at that time. Moreover, by simply selecting the appropriate type of gas filling the filling chamber 30, the cavity before sealing can be filled with the desired gas. Thus, it is possible to efficiently form a cavity (in this case, the cavity before sealing) filled with the desired gas. In this way, according to the lamination step S32, the internal state of the cavity before sealing can be efficiently controlled.

[0120] <Step S33 for forming the fixed joint>

[0121] In the fixing part forming step S33, while maintaining the atmosphere inside the chamber 30 unchanged (in other words, while maintaining an atmosphere filled with a specified gas), similarly to the above embodiment, a fixing part Qs for fixing the second joint object W2 to the first joint object W1 is formed in an annular (closed annular) shape along the outer periphery 11t of the first joint object W1, thereby sealing the inner annular shape (see reference). Figure 2 The lower layer diagram of S12 shown below, Figure 4 ).

[0122] According to the fixing part forming step S33, by forming the fixing part Qs in an annular (closed annular) shape while maintaining the atmosphere inside the chamber 30 (in other words, while maintaining an atmosphere filled with a specified gas) and sealing the inside of the annular shape, even when the first joint object W1 and the second joint object W2 after temporary jointing are exposed to air, it is possible to keep the inside of the annular shape filled with the required gas.

[0123] Furthermore, the structures of the first to fourth modifications described above can also be applied to this modification.

[0124] [2-6] Other variations

[0125] The metal layer formation step, which is part of the preparation step S10, can also be performed in the chamber 30 where the lamination step S11 is performed.

[0126] In cases where there is no need to shorten the cycle time, or where there is a high necessity to complete the process (temporary engagement + main engagement) in the same chamber, the main engagement step S2 may also be performed in the same chamber 30 as the chamber used to perform the temporary engagement step S1.

[0127] In cases where the wiring, electrodes, etc., connected during bonding are not formed on the bonding object, or where device regions Rd1 and Rd2 are not set, and where the positional relationship between the two bonding objects is not required to be highly precise during bonding, the above bonding method can be appropriately modified to a method of bonding without performing the alignment bonding in the stacking step S11.

[0128] The above description of embodiments and modifications should be considered illustrative rather than restrictive in all respects. The scope of the invention is defined not by the above embodiments and modifications, but by the claims. Furthermore, the scope of the invention is intended to include all changes within the meaning and scope equivalent to the claims.

[0129] Furthermore, based on the above embodiments and modifications, as the object of the invention, several steps constituting the joining method can be extracted in part, or each step can be extracted individually. For example, the temporary joining step S1 and the main joining step S2 can also be extracted as objects of the invention.

[0130] Explanation of reference numerals in the attached figures

[0131] 10 concavity

[0132] 11s and 21s mating surfaces

[0133] 11t peripheral edge

[0134] 30 chambers

[0135] Ct cutting line

[0136] Ge element

[0137] Lm metal layer

[0138] Pt specified air pressure

[0139] Px internal pressure target value

[0140] Rd1, Rd2 device regions

[0141] Qs and Qt fixed joints

[0142] Re Periphery

[0143] W1 First Joining Object

[0144] W2 Second Joining Object

[0145] Xs and Xt are pre-defined to form patterns.

[0146] Xs1 circular pattern

[0147] Xs2 Linear Pattern

[0148] S1 Temporary Joining Step

[0149] S2 Main Joining Step

[0150] S10 Preparation Steps

[0151] S11 Stacking Steps

[0152] S12 Fixed Joint Formation Step

[0153] S31 Replacement Steps

[0154] S32 Stacking Steps

[0155] S33 Fixed joint formation step.

Claims

1. A joining method, characterized in that, include: The layering step involves overlapping a second bonding object onto a first bonding object in an atmosphere below a specified pressure. and In the fastening step, after the lamination step, while maintaining the atmosphere, a fastening portion is formed in a ring shape along the outer periphery of the first joining object to fasten the second joining object to the first joining object, thereby sealing the ring.

2. A joining method, characterized in that, include: In the stacking step, a second bonding object is overlapped on a first bonding object having multiple device regions in an atmosphere below a specified pressure. and In the fastening step, after the lamination step, while maintaining the atmosphere, a fastening portion is formed in a ring shape that surrounds the plurality of device regions, thereby fastening the second bonding object to the first bonding object and sealing the inner ring.

3. The joining method according to claim 2, characterized in that: In each device region of the first bonding object, a recess forming a cavity is formed. In the stacking step, an atmosphere is used as the atmosphere to reduce the pressure to the same value as or near the target internal pressure of the cavity.

4. A joining method, characterized in that, include: The replacement step involves injecting a specified gas into the chamber containing the first and second mating objects after creating a vacuum, thereby replacing the chamber with an atmosphere filled with the specified gas. The lamination step involves overlapping the second bonding object onto the first bonding object in an atmosphere filled with the specified gas; and In the fixing part forming step, after the lamination step, while maintaining an atmosphere filled with the specified gas, a fixing part is formed in a ring shape along the outer periphery of the first joint object to fix the second joint object to the first joint object, thereby sealing the inner ring.

5. A joining method, characterized in that, include: The replacement step involves injecting a specified gas into a chamber containing a first bonding object and a second bonding object with multiple device regions after the chamber has been evacuated, thereby replacing the chamber with an atmosphere filled with the specified gas. The lamination step involves overlapping the second bonding object onto the first bonding object in an atmosphere filled with the specified gas; and In the fastening step, after the lamination step, while maintaining an atmosphere filled with the specified gas, a fastening portion is formed in such a ring-like manner that it fastens the second bonding object to the first bonding object, thereby sealing the inner ring.

6. The joining method according to any one of claims 2, 3 and 5, characterized in that: The second bonding object has a device region corresponding to the device region of the first bonding object. In the stacking step, at least one of the first bonding object and the second bonding object is aligned so that the corresponding device regions are aligned with each other, and the second bonding object is overlapped with the first bonding object after the alignment is performed.

7. The joining method according to any one of claims 1 to 6, characterized in that: The process also includes a metal layer forming step, wherein, prior to the lamination step, a metal layer is formed on at least one of the mating surfaces of the first mating object and the second mating object. In the fixed joint forming step, the annular fixed joint is formed by locally irradiating the metal layer located between the first bonding object and the second bonding object with a laser, thereby locally heating the irradiated area of ​​the laser.

8. A joining method, characterized in that, include: The temporary joining step involves temporarily joining the first joining object and the second joining object using the joining method described in any one of claims 1 to 7. and In the main joining step, after the temporary joining step, the first joining object and the second joining object are further fixed in a region inside the annular fixing portion. The main engagement step is performed using a different chamber than the one used to perform the temporary engagement step.

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