Wafer bonding apparatus and wafer bonding method

Abstract

The embodiments of the present disclosure disclose a wafer bonding device and a wafer bonding method, wherein the wafer bonding device comprises: a first fixing device for fixing a first wafer; a first alignment mark is arranged on the first wafer; a second fixing device for fixing a second wafer; a second alignment mark is arranged on the second wafer; a reflection device is located between the first fixing device and the second fixing device; a mark reader reads position information of the first alignment mark and the second alignment mark by using the reflection device, so as to align the first wafer fixed on the first fixing device and the second wafer fixed on the second fixing device; a heating device is used for heating the first wafer to cause thermal expansion of the first wafer, so that the first alignment mark is located at the center position of the field of view of the mark reader; or the second wafer is heated to cause thermal expansion of the second wafer, so that the second alignment mark is located at the center position of the field of view of the mark reader.

Description

Technical Field

[0001] This disclosure relates to wafer packaging process technology, and more particularly to a wafer bonding apparatus and a wafer bonding method. Background Technology

[0002] Semiconductor bonding technology refers to the direct bonding of two homogeneous or heterogeneous semiconductor materials under certain conditions after surface cleaning and activation treatment. This bonding is achieved through van der Waals forces, molecular forces, and even atomic forces. In wafer bonding technology, wafer alignment accuracy and the degree of wafer distortion after bonding are crucial parameters characterizing the quality of the wafer bonding process. Defects in alignment accuracy during wafer bonding will severely affect subsequent processes, consequently impacting the connectivity and functionality of the circuits after wafer bonding and reducing wafer yield. Therefore, wafer alignment accuracy is particularly critical. Summary of the Invention

[0003] In view of this, embodiments of the present disclosure provide a wafer bonding apparatus and a wafer bonding method.

[0004] According to a first aspect of the present disclosure, a wafer bonding apparatus is provided, comprising:

[0005] A first fixing device is used to fix a first wafer; a first alignment mark is provided on the first wafer;

[0006] A second fixing device is used to fix a second wafer; a second alignment mark is provided on the second wafer; the second fixing device is disposed opposite to the first fixing device;

[0007] A reflective device is located between the first fixing device and the second fixing device;

[0008] The marker reader uses a reflective device to read the position information of the first alignment mark and the second alignment mark in order to align the first wafer fixed on the first fixing device and the second wafer fixed on the second fixing device.

[0009] A heating device is used to heat the first wafer, causing it to thermally expand so that the first alignment mark is positioned at the center of the mark reader's field of view; or...

[0010] The second wafer is heated to cause it to thermally expand, so that the second alignment mark is positioned at the center of the mark reader's field of view.

[0011] In some embodiments, the number of both the first alignment mark and the second alignment mark is greater than or equal to 2.

[0012] In some embodiments, the marker reader uses a reflective device to read the position information of the first alignment marker and the second alignment marker; including:

[0013] The detection light is incident on the first alignment mark and the second alignment mark. The first alignment mark and the second alignment mark reflect the detection light. The reflected detection light is then reflected by the reflection device and enters the mark reader to read the position information of the first alignment mark and the second alignment mark.

[0014] In some embodiments, the reflecting device includes a first reflecting surface and a second reflecting surface;

[0015] The detection light, after being reflected by the first alignment mark, enters the mark reader after being reflected by the first reflective surface.

[0016] The detection light reflected by the second alignment mark is then reflected by the second reflective surface and enters the mark reader.

[0017] In some embodiments, the reflective device is Σ-shaped.

[0018] In some embodiments, the angle between the first reflective surface and the plane of the first wafer is 45°;

[0019] The angle between the second reflective surface and the plane of the second wafer is 45°.

[0020] In some embodiments, a reflective layer is formed on the first reflective surface and the second reflective surface.

[0021] In some embodiments, it also includes:

[0022] A computing device is configured to calculate the offset between the position information of the first alignment mark and the second alignment mark read by the mark reader and the center position of the field of view of the mark reader, and to align the first wafer fixed on the first fixing device and the second wafer fixed on the second fixing device according to the calculation result.

[0023] According to a second aspect of the present disclosure, a wafer bonding method is provided, using the apparatus described in any of the above embodiments, the method comprising:

[0024] The first wafer is fixed on the first fixing device; the first wafer is provided with a first alignment mark;

[0025] The second wafer is fixed on the second fixing device; the second wafer is provided with a second alignment mark; the second fixing device is disposed opposite to the first fixing device;

[0026] The reflective device is positioned between the first fixing device and the second fixing device;

[0027] The marker reader uses a reflective device to read the position information of the first alignment marker and the second alignment marker;

[0028] The first wafer is heated using a heating device, causing it to thermally expand so that the first alignment mark is positioned at the center of the mark reader's field of view; or...

[0029] The second wafer is heated to cause it to thermally expand, so that the second alignment mark is positioned at the center of the mark reader's field of view.

[0030] In some embodiments, the number of both the first alignment mark and the second alignment mark is greater than or equal to 2.

[0031] In some embodiments, the marker reader uses a reflective device to read the position information of the first alignment marker and the second alignment marker; including:

[0032] The detection light is incident on the first alignment mark and the second alignment mark. The first alignment mark and the second alignment mark reflect the detection light. The reflected detection light is then reflected by the reflection device and enters the mark reader to read the position information of the first alignment mark and the second alignment mark.

[0033] In some embodiments, the reflecting device includes a first reflecting surface and a second reflecting surface;

[0034] The detection light, after being reflected by the first alignment mark, enters the mark reader after being reflected by the first reflective surface.

[0035] The detection light reflected by the second alignment mark is then reflected by the second reflective surface and enters the mark reader.

[0036] In some embodiments, the reflective device is Σ-shaped.

[0037] In some embodiments, the angle between the first reflective surface and the plane of the first wafer is 45°;

[0038] The angle between the second reflective surface and the plane of the second wafer is 45°.

[0039] In some embodiments, a reflective layer is formed on the first reflective surface and the second reflective surface.

[0040] In some embodiments, after the marker reader reads the position information of the first alignment marker and the second alignment marker using a reflective device, the method further includes:

[0041] The offset between the position information of the first alignment mark and the second alignment mark read by the mark reader and the center position of the field of view of the mark reader is calculated using a computing device. Based on the calculation result, the first wafer fixed on the first fixing device and the second wafer fixed on the second fixing device are aligned.

[0042] In this embodiment of the present disclosure, a heating device is used to cause thermal expansion of the first wafer and the second wafer, thereby compensating for nonlinear errors during wafer alignment and improving the accuracy of wafer alignment. Attached Figure Description

[0043] Figure 1 This is a process flow diagram for wafer bonding in related technologies;

[0044] Figure 2 This is a schematic diagram illustrating several types of offset errors in the wafer bonding process of related technologies;

[0045] Figure 3 This is a schematic diagram of the structure of the wafer bonding equipment provided in the embodiments of this disclosure;

[0046] Figure 4 This is a schematic diagram of the first alignment mark in an embodiment of this disclosure;

[0047] Figure 5 A perspective view of a reflective device in a wafer bonding apparatus provided in an embodiment of this disclosure;

[0048] Figure 6 A schematic flowchart of the wafer bonding method provided in the embodiments of this disclosure;

[0049] Figures 7a to 7b This is a schematic diagram of the alignment process of the wafer bonding method in the embodiments of this disclosure.

[0050] Explanation of reference numerals in the attached figures:

[0051] 1-First fixing device; 2-Second fixing device;

[0052] 10 - First wafer; 11 - First alignment mark; 20 - Second wafer; 21 - Second alignment mark;

[0053] 3-Reflecting device; 31-First reflecting surface; 32-Second reflecting surface;

[0054] 4-Tag reader; 5-Computing device; 6-Heating device. Detailed Implementation

[0055] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the specific embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0056] In the following description, numerous specific details are set forth in order to provide a more thorough understanding of this disclosure. However, it will be apparent to those skilled in the art that this disclosure may be practiced without one or more of these details. In other instances, to avoid confusion with this disclosure, certain technical features well-known in the art have not been described; that is, not all features of actual embodiments are described herein, nor are well-known functions and structures described in detail.

[0057] In the accompanying drawings, for clarity, the dimensions of layers, areas, and elements, as well as their relative dimensions, may be exaggerated. The same reference numerals denote the same elements throughout.

[0058] It should be understood that when an element or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, components, areas, layers, and / or portions, these elements, components, areas, layers, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, area, layer, or portion from another element, component, area, layer, or portion. Therefore, without departing from the teachings of this disclosure, the first element, component, area, layer, or portion discussed below may be referred to as a second element, component, area, layer, or portion. And the discussion of a second element, component, area, layer, or portion does not imply that the first element, component, area, layer, or portion necessarily exists in this disclosure.

[0059] Spatial relation terms such as “below,” “under,” “below,” “under,” “above,” “above,” etc., are used herein for convenience of description to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms are intended to also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, then the element or feature described as “below,” “under,” or “below” other elements or features will be oriented “above” other elements or features. Therefore, the exemplary terms “below” and “under” can include both above and below orientations. The device may be otherwise oriented (rotated 90 degrees or otherwise) and the spatial descriptive terms used herein will be interpreted accordingly.

[0060] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. When used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprise” and / or “comprising,” when used in this specification, identify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. When used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0061] To fully understand this disclosure, detailed steps and structures will be presented in the following description to illustrate the technical solutions of this disclosure. Preferred embodiments of this disclosure are described in detail below; however, other embodiments may also be implemented in addition to these detailed descriptions.

[0062] Figure 1 This is a process flow diagram for wafer bonding. During the heterogeneous bonding process, it is necessary to control the accuracy of wafer alignment. Therefore, alignment patterns (Alignment Marks) need to be designed on the alignment surfaces of the two wafers. Figure 2 This diagram illustrates several types of misalignment errors in the wafer bonding process of related technologies. These technologies use two cameras to align with the upper and lower wafers respectively, and the movement of the upper and lower wafers compensates for linear misalignment. However, this method can only compensate for linear misalignment during alignment, and cannot compensate for non-linear misalignment.

[0063] Based on this, embodiments of the present disclosure provide a wafer bonding apparatus. Figure 3 This is a schematic diagram of the structure of a wafer bonding device provided in an embodiment of this disclosure.

[0064] See Figure 3 The wafer bonding equipment includes:

[0065] A first fixing device 1 is used to fix a first wafer 10; a first alignment mark 11 is provided on the first wafer 10; a second fixing device 2 is used to fix a second wafer 20; a second alignment mark 21 is provided on the second wafer 20; the second fixing device 2 is disposed opposite to the first fixing device 1; a reflecting device 3 is located between the first fixing device 1 and the second fixing device 2; a mark reader 4 uses the reflecting device 3 to read the position information of the first alignment mark 11 and the second alignment mark 21 to align the first wafer 10 fixed on the first fixing device 1 and the second wafer 20 fixed on the second fixing device 2; a heating device 6 is used to heat the first wafer 10 to cause thermal expansion, so that the first alignment mark 11 is located at the center of the field of view of the mark reader 4; or, to heat the second wafer 20 to cause thermal expansion, so that the second alignment mark 21 is located at the center of the field of view of the mark reader 4.

[0066] In this embodiment of the present disclosure, a heating device is used to cause thermal expansion of the first wafer and the second wafer, thereby compensating for nonlinear errors during wafer alignment and improving the accuracy of wafer alignment.

[0067] Furthermore, in this embodiment of the present disclosure, there is no need to move the marker reader; alignment can be completed simply by slightly moving the wafer, which improves the stability and accuracy of wafer alignment.

[0068] In this embodiment of the disclosure, the first fixing device 1 and the second fixing device 2 are heating type fixing devices. The heating device 6 first heats the first fixing device 1 or the second fixing device 2 to indirectly heat the first wafer 10 or the second wafer 20.

[0069] Figure 4 This is a schematic diagram of the first alignment mark in an embodiment of the present disclosure. The first alignment mark 11 shown in the figure is cross-shaped. In other embodiments, the shape of the first alignment mark may also be one of the following: straight, circular, or annular. Figure 4 Only the first alignment mark 11 is shown, and the second alignment mark 21 has the same shape as the first alignment mark 11. In this embodiment of the disclosure, the shapes of the first alignment mark 11 and the second alignment mark 21 are not specifically limited, and are designed according to actual needs.

[0070] The first alignment mark 11 and the second alignment mark 21 are made of metal or other materials that are sensitive to light. In this way, the photosensitivity of the first alignment mark 11 and the second alignment mark 21 is enhanced, thereby improving the accuracy of reading.

[0071] In this embodiment of the present disclosure, by moving the first wafer 10 and the second wafer 20, or by heating the first wafer 10 or the second wafer 20 to thermally expand them, the first alignment mark 11 and the second alignment mark 21 are positioned at the center of the field of view of the mark reader 4, so as to achieve the purpose of aligning the first wafer 10 fixed on the first fixing device 1 and the second wafer 20 fixed on the second fixing device 2.

[0072] In one embodiment, the marker reader 4 uses the reflection device 3 to read the position information of the first alignment marker 11 and the second alignment marker 21; this includes simultaneously reading the position information of the first alignment marker 11 and the second alignment marker 21. Simultaneously reading the position information of the first and second alignment markers improves the stability and accuracy of information reading compared to reading them separately. However, it is understood that in some other embodiments, the position information of the first and second alignment markers may be read separately.

[0073] In one embodiment, the number of both the first alignment mark 11 and the second alignment mark 21 is greater than or equal to 2. Two or more first alignment marks and second alignment marks can balance lateral and longitudinal alignment accuracy during alignment, improving the accuracy of wafer alignment.

[0074] The number of the first alignment mark 11 and the number of the second alignment mark 21 can be equal.

[0075] In this embodiment, the marker reader 4 is an optical reader. The optical reader emits light when the first fixing device 1 or the second fixing device 2 moves to a preset position to directly read the position information of the first alignment mark 11 or the second alignment mark 21. Furthermore, the light emitted by the marker reader 4 is far-infrared light. When the light emitted by the marker reader 4 is far-infrared light, the penetrating power of the light emitted by the marker reader 4 is strong, thus improving the reading capability of the marker reader 4.

[0076] Specifically, the marker reader 4 uses the reflection device 3 to read the position information of the first alignment mark 11 and the second alignment mark 21; including: a detection light is incident on the first alignment mark 11 and the second alignment mark 21, the first alignment mark 11 and the second alignment mark 21 reflect the detection light, and the reflected detection light enters the marker reader 4 after being reflected by the reflection device 3, so as to read the position information of the first alignment mark 11 and the second alignment mark 21.

[0077] The number of the tag readers 4 is greater than or equal to 2.

[0078] Figure 5 This is a perspective view of a reflective device in a wafer bonding apparatus provided in an embodiment of the present disclosure. In this embodiment, the reflective device 3 is similar to the reflective glass of an SLR camera.

[0079] In one embodiment, the reflecting device 3 includes a first reflecting surface 31 and a second reflecting surface 32; the detection light reflected by the first alignment mark 11 is reflected by the first reflecting surface 31 and enters the mark reader 4; the detection light reflected by the second alignment mark 21 is reflected by the second reflecting surface 32 and enters the mark reader 4.

[0080] See also Figure 5 The reflective device 3 is Σ-shaped.

[0081] A reflective layer is formed on the first reflective surface 31 and the second reflective surface 32. Specifically, a reflective layer is deposited on the outer surface of the first reflective surface 31 and the second reflective surface 32, so that when the detection light is reflected to the inner surface of the first reflective surface 31 and the second reflective surface 32, it will not pass directly through the first reflective surface and the second reflective surface, but will be reflected to the reader.

[0082] The angle between the first reflective surface and the plane of the first wafer is 45°; the angle between the second reflective surface and the plane of the second wafer is 45°.

[0083] Specifically, see Figure 5 The angle between the first reflective surface 31 and the plane of the first wafer 10 is α1 in the figure, and the angle between the second reflective surface 32 and the plane of the second wafer 20 is α2 in the figure. Setting α1 and α2 to 45° allows the detected light to be reflected horizontally to the marker reader when it is perpendicularly reflected to the first and second reflective surfaces, ensuring the accuracy of the read position information and improving the alignment precision.

[0084] In one embodiment, the wafer bonding apparatus further includes a computing device 5, configured to calculate the position information of the first alignment mark 11 and the second alignment mark 21 read by the mark reader 4, and align the first wafer 10 fixed on the first fixing device 1 and the second wafer 20 fixed on the second fixing device 2 according to the calculation result.

[0085] Specifically, the computing device 5 calculates the offset between the position information of the first alignment mark 11 and the second alignment mark 21 read by the mark reader 4 and the center position of the field of view of the mark reader 4, and moves the first fixing device 1 or the second fixing device 2 according to the calculation result to align the first wafer 10 and the second wafer 20.

[0086] This disclosure also provides a wafer bonding method using the equipment described in any of the above embodiments. Please refer to the appendix for details. Figure 6 As shown in the figure, the method includes the following steps:

[0087] Step 601: Fix the first wafer onto the first fixing device; the first wafer is provided with a first alignment mark;

[0088] Step 602: Fix the second wafer onto the second fixing device; the second wafer is provided with a second alignment mark; the second fixing device is disposed opposite to the first fixing device;

[0089] Step 603: Place the reflective device between the first fixing device and the second fixing device;

[0090] Step 604: The marker reader uses a reflective device to read the position information of the first alignment marker and the second alignment marker;

[0091] Step 605: Heat the first wafer using a heating device to cause thermal expansion, so that the first alignment mark is located at the center of the field of view of the mark reader; or, heat the second wafer to cause thermal expansion, so that the second alignment mark is located at the center of the field of view of the mark reader.

[0092] The wafer bonding method provided in this disclosure will be further described in detail below with reference to specific embodiments.

[0093] Figures 7a to 7b This is a schematic diagram of the alignment process of the wafer bonding method in the embodiments of this disclosure.

[0094] First, see Figure 7aThen, execute steps 601 to 602. Fix the first wafer 10 on the first fixing device 1; the first wafer 10 is provided with a first alignment mark 11; fix the second wafer 20 on the second fixing device 2; the second wafer 20 is provided with a second alignment mark 21; the second fixing device 2 is disposed opposite to the first fixing device 1.

[0095] Figure 4 This is a schematic diagram of the first alignment mark in an embodiment of the present disclosure. The first alignment mark 11 shown in the figure is cross-shaped. In other embodiments, the shape of the first alignment mark may also be one of the following: straight, circular, or annular. Figure 4 Only the first alignment mark 11 is shown, and the second alignment mark 21 has the same shape as the first alignment mark 11. In this embodiment of the disclosure, the shapes of the first alignment mark 11 and the second alignment mark 21 are not specifically limited, and are designed according to actual needs.

[0096] The first alignment mark 11 and the second alignment mark 21 are made of metal or other materials that are sensitive to light. In this way, the photosensitivity of the first alignment mark 11 and the second alignment mark 21 is enhanced, thereby improving the accuracy of reading.

[0097] In this embodiment of the present disclosure, by moving the first wafer 10 and the second wafer 20, or by heating the first wafer 10 or the second wafer 20 to thermally expand them, the first alignment mark 11 and the second alignment mark 21 are positioned at the center of the field of view of the mark reader 4, so as to achieve the purpose of aligning the first wafer 10 fixed on the first fixing device 1 and the second wafer 20 fixed on the second fixing device 2.

[0098] In one embodiment, the number of both the first alignment mark 11 and the second alignment mark 21 is greater than or equal to 2. Two or more first alignment marks and second alignment marks can balance lateral and longitudinal alignment accuracy during alignment, improving the accuracy of wafer alignment.

[0099] The number of the first alignment mark 11 and the number of the second alignment mark 21 can be equal.

[0100] See also Figure 7a Proceed to step 603. Place the reflector 3 between the first fixing device 1 and the second fixing device 2.

[0101] Figure 5 This is a perspective view of a reflective device in a wafer bonding apparatus provided in an embodiment of the present disclosure. In this embodiment, the reflective device 3 is similar to the reflective glass of an SLR camera.

[0102] In one embodiment, the reflective device 3 is Σ-shaped.

[0103] See also Figure 5 The reflecting device 3 includes a first reflecting surface 31 and a second reflecting surface 32.

[0104] A reflective layer is formed on the first reflective surface 31 and the second reflective surface 32. Specifically, a reflective layer is deposited on the outer surface of the first reflective surface 31 and the second reflective surface 32, so that when the detection light is reflected to the inner surface of the first reflective surface 31 and the second reflective surface 32, it will not pass directly through the first reflective surface and the second reflective surface, but will be reflected to the reader.

[0105] The angle between the first reflective surface and the plane of the first wafer is 45°; the angle between the second reflective surface and the plane of the second wafer is 45°.

[0106] Specifically, see Figure 5 The angle between the first reflective surface 31 and the plane of the first wafer 10 is α1 in the figure, and the angle between the second reflective surface 32 and the plane of the second wafer 20 is α2 in the figure. Setting α1 and α2 to 45° allows the detected light to be reflected horizontally to the marker reader when it is perpendicularly reflected to the first and second reflective surfaces, ensuring the accuracy of the read position information and improving the alignment precision.

[0107] See also Figure 7a Step 604 is executed. The marker reader 4 uses the reflection device 3 to read the position information of the first alignment mark 11 and the second alignment mark 21.

[0108] In one embodiment, the marker reader 4 uses the reflection device 3 to read the position information of the first alignment marker 11 and the second alignment marker 21; this includes simultaneously reading the position information of the first alignment marker 11 and the second alignment marker 21. Simultaneously reading the position information of the first and second alignment markers improves the stability and accuracy of information reading compared to reading them separately. However, it is understood that in some other embodiments, the position information of the first and second alignment markers may be read separately.

[0109] In this embodiment, the marker reader 4 is an optical reader. The optical reader emits light when the first fixing device 1 or the second fixing device 2 moves to a preset position to directly read the position information of the first alignment mark 11 or the second alignment mark 21. Furthermore, the light emitted by the marker reader 4 is far-infrared light. When the light emitted by the marker reader 4 is far-infrared light, the penetrating power of the light emitted by the marker reader 4 is strong, thus improving the reading capability of the marker reader 4.

[0110] Specifically, the marker reader 4 uses the reflection device 3 to read the position information of the first alignment mark 11 and the second alignment mark 21; including: the detection light is incident on the first alignment mark 11 and the second alignment mark 21, the first alignment mark 11 and the second alignment mark 21 reflect the detection light, and the reflected detection light enters the marker reader 4 after being reflected by the reflection device 3, so as to read the position information of the first alignment mark 11 and the second alignment mark 21.

[0111] The number of the tag readers 4 is greater than or equal to 2.

[0112] In one embodiment, the detection light reflected by the first alignment mark 11 is reflected by the first reflective surface 31 and enters the mark reader 4; the detection light reflected by the second alignment mark 21 is reflected by the second reflective surface 32 and enters the mark reader 4.

[0113] See also Figure 7a Execute step 605. Heat the first wafer 10 using the heating device 6 to cause the first wafer 10 to thermally expand, so that the first alignment mark 11 is located at the center of the field of view of the mark reader 4; or, heat the second wafer 20 to cause the second wafer 20 to thermally expand, so that the second alignment mark 21 is located at the center of the field of view of the mark reader 4.

[0114] Specifically, the first fixing device 1 and the second fixing device 2 are heating type fixing devices. The heating device 6 first heats the first fixing device 1 or the second fixing device 2 to indirectly heat the first wafer 10 or the second wafer 20.

[0115] After the marker reader 4 uses the reflection device 3 to read the position information of the first alignment mark 11 and the second alignment mark 21, the method further includes:

[0116] The computing device 5 calculates the offset between the position information of the first alignment mark 11 and the second alignment mark 21 read by the mark reader 4 and the center position of the field of view of the mark reader 4. Based on the calculation result, the first fixing device 1 or the second fixing device 2 is moved to align the first wafer 10 and the second wafer 20.

[0117] In this embodiment, the first fixing device or the second fixing device is moved along the X or Y direction to align the first wafer and the second wafer. Figure 7a As shown, taking the movement of the second fixing device 2 along the X direction as an example, the alignment process of the first wafer 10 and the second wafer 20 is explained.

[0118] like Figure 7a As shown, when the marker reader 4 reads that the first alignment mark 11 is located at the center of the field of view of the marker reader 4, and the position of the second alignment mark 21 is offset to the right along the X direction of the field of view of the marker reader 4, the computing device 5 calculates the offset between the position information of the second alignment mark 21 read by the marker reader 4 and the center position of the field of view of the marker reader 4. According to the calculation result, the second fixing device 2 is moved to the left along the X direction until the second alignment mark 21 is located at the center position of the field of view of the marker reader 4. At this time, the first wafer 10 and the second wafer 20 complete the alignment process, the reflective device 3 is removed, and the first wafer 10 and the second wafer 20 are bonded.

[0119] It should be noted that, in Figure 7a The example shown only illustrates the movement of the second fixing device along the X direction, but the alignment process of the first wafer and the second wafer also includes the process of moving the first fixing device and the second fixing device along the Y direction.

[0120] like Figure 7b As shown, taking the nonlinear offset of the second wafer 20 as an example, the alignment process between the first wafer 10 and the second wafer 20 is explained.

[0121] like Figure 7bAs shown, when the marker reader 4 reads that the first alignment mark is located at the center of the field of view of the marker reader 4, and along the X direction, the position of the second alignment mark 21 located to the left of the second wafer 20 is biased to the right of the field of view of the marker reader 4, and the position of the second alignment mark 21 located to the right of the second wafer 20 is biased to the left of the field of view of the marker reader 4, the computing device 5 calculates the offset between the position information of the second alignment mark 21 read by the marker reader 4 and the center position of the field of view of the marker reader 4. According to the calculation result, the second wafer 20 is heated to cause the second wafer to thermally expand until the second alignment mark 21 is located at the center position of the field of view of the marker reader 4. At this time, the first wafer 10 and the second wafer 20 complete the alignment process, the reflective device 3 is removed, and the first wafer 10 and the second wafer 20 are bonded.

[0122] The above description is merely a preferred embodiment of this disclosure and is not intended to limit the scope of protection of this disclosure. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure.

Claims

1. A wafer bonding apparatus, characterized by comprising: include: A first fixing device is used to fix a first wafer; a first alignment mark is provided on the first wafer; The second fixing device is used to fix the second wafer; The second wafer is provided with a second alignment mark; the second fixing device is disposed opposite to the first fixing device; A reflective device is located between the first fixing device and the second fixing device; The marker reader uses a reflective device to read the position information of the first alignment mark and the second alignment mark in order to align the first wafer fixed on the first fixing device and the second wafer fixed on the second fixing device. A heating device is used to heat the first wafer, causing it to thermally expand so that the first alignment mark is positioned at the center of the mark reader's field of view; or... The second wafer is heated to cause it to thermally expand, so that the second alignment mark is positioned at the center of the mark reader's field of view.

2. The wafer bonding equipment according to claim 1, characterized in that, The number of the first alignment mark and the number of the second alignment mark are both greater than or equal to 2.

3. The wafer bonding equipment according to claim 1, characterized in that, The marker reader, utilizing a reflective device, reads the position information of the first alignment marker and the second alignment marker; including: The detection light is incident on the first alignment mark and the second alignment mark. The first alignment mark and the second alignment mark reflect the detection light. The reflected detection light is then reflected by the reflection device and enters the mark reader to read the position information of the first alignment mark and the second alignment mark.

4. The wafer bonding equipment according to claim 3, characterized in that, The reflecting device includes a first reflecting surface and a second reflecting surface; The detection light, after being reflected by the first alignment mark, enters the mark reader after being reflected by the first reflective surface. The detection light reflected by the second alignment mark is then reflected by the second reflective surface and enters the mark reader.

5. The wafer bonding equipment according to claim 4, characterized in that, The reflective device is Σ-shaped.

6. The wafer bonding equipment according to claim 4, characterized in that, The angle between the first reflective surface and the plane of the first wafer is 45°; The angle between the second reflective surface and the plane of the second wafer is 45°.

7. The wafer bonding equipment according to claim 4, characterized in that, A reflective layer is formed on the first reflective surface and the second reflective surface.

8. The wafer bonding apparatus of claim 1, wherein, Also includes: A computing device is configured to calculate the offset between the position information of the first alignment mark and the second alignment mark read by the mark reader and the center position of the field of view of the mark reader, and to align the first wafer fixed on the first fixing device and the second wafer fixed on the second fixing device according to the calculation result.

9. A wafer bonding method, characterized by, The method, using the device as described in any one of claims 1-8, comprises: The first wafer is fixed on the first fixing device; the first wafer is provided with a first alignment mark; The second wafer is fixed on the second fixing device; the second wafer is provided with a second alignment mark; the second fixing device is disposed opposite to the first fixing device; The reflective device is positioned between the first fixing device and the second fixing device; The marker reader uses a reflective device to read the position information of the first alignment marker and the second alignment marker; The first wafer is heated using a heating device, causing it to thermally expand so that the first alignment mark is positioned at the center of the mark reader's field of view; or... The second wafer is heated to cause it to thermally expand, so that the second alignment mark is positioned at the center of the mark reader's field of view.

10. The method according to claim 9, characterized in that, The number of the first alignment mark and the number of the second alignment mark are both greater than or equal to 2.

11. The method according to claim 9, characterized in that, The marker reader uses a reflective device to read the position information of the first alignment marker and the second alignment marker; including: The detection light is incident on the first alignment mark and the second alignment mark. The first alignment mark and the second alignment mark reflect the detection light. The reflected detection light is then reflected by the reflection device and enters the mark reader to read the position information of the first alignment mark and the second alignment mark.

12. The method according to claim 11, characterized in that, The reflecting device includes a first reflecting surface and a second reflecting surface; The detection light, after being reflected by the first alignment mark, enters the mark reader after being reflected by the first reflective surface. The detection light reflected by the second alignment mark is then reflected by the second reflective surface and enters the mark reader.

13. The method according to claim 12, characterized in that, The reflective device is Σ-shaped.

14. The method according to claim 13, characterized in that, The angle between the first reflective surface and the plane of the first wafer is 45°; The angle between the second reflective surface and the plane of the second wafer is 45°.

15. The method according to claim 13, characterized in that, A reflective layer is formed on the first reflective surface and the second reflective surface.

16. The method of claim 9, wherein, After the marker reader uses a reflective device to read the position information of the first alignment marker and the second alignment marker, the method further includes: The offset between the position information of the first alignment mark and the second alignment mark read by the mark reader and the center position of the field of view of the mark reader is calculated using a computing device. Based on the calculation result, the first wafer fixed on the first fixing device and the second wafer fixed on the second fixing device are aligned.

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