Wafer bonding alignment method and system and wafer bonding method

Abstract

The invention designs a wafer bonding alignment method and system and a wafer bonding method, and the alignment method comprises the following steps: providing a first wafer and a second wafer which are provided with gap marks, oppositely fixing the first wafer and the second wafer on a wafer bearing platform, sequentially moving the first wafer and the second wafer into a wafer bonding cavity, a first sensing detection assembly and a second sensing detection assembly in a wafer bonding cavity are used for collecting detection signals within the depth range of edge notch marks of a first wafer and a second wafer respectively, and waveforms of the detection signals collected when the first wafer and the second wafer rotate by a circle are compared; and when the waveforms of the detection signals acquired when the second wafer and the first wafer rotate for a circle are completely fitted, controlling the wafer bearing table to stop rotating. According to the invention, the two wafers to be bonded are aligned in the wafer bonding cavity of the EGV machine table by using the notch marks on the surfaces of the wafers and the sensing detection assembly in the wafer bonding cavity, so that high-precision wafer alignment is realized, and the yield of semiconductor products is ensured.

Description

Technical Field

[0001] The present invention belongs to the field of semiconductor technology, and in particular relates to a wafer bonding alignment method, system and wafer bonding method. Background Art

[0002] Wafer bonding is a key technology in semiconductor manufacturing. It uses different methods to closely bond two or more wafers together to achieve device integration and functional improvement. During the wafer bonding process, the accuracy of wafer alignment will directly affect the bonding quality, chip performance, and the performance and reliability of the final product.

[0003] Commonly used wafer alignment methods are bonding mark alignment and notch alignment bonding. Alignment by bonding mark requires pre-coating of patterned photoresist on the wafer surface or etching of silicon structure to make bonding marks, and then position compensation is performed by measuring the offset between bonding marks of different layers during the bonding process. Although this alignment method can achieve high-precision alignment, it requires additional steps to manufacture and identify bonding marks, which increases the complexity and cost of the process, and is not conducive to the efficient production of semiconductor products. At the same time, the identification of bonding marks may be affected by environmental factors such as dust and humidity, affecting the accuracy of wafer alignment.

[0004] The notch alignment bonding method can effectively avoid the defects of bonding mark alignment bonding. The existing notch alignment bonding process is usually carried out on an EVG machine. In the process of wafer bonding on the EVG machine, the two wafers to be bonded must first be pre-aligned outside the bonding chamber, and the pre-aligned wafers are moved into the bonding chamber for bonding by a robotic arm. During the transmission process by the robotic arm, it is very easy to cause the wafer to shift, resulting in the notch of the two wafers being offset, affecting the final bonding accuracy. Summary of the invention

[0005] The purpose of the present invention is to solve one of the above technical problems and to provide a wafer bonding alignment method, system and wafer bonding method.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] A wafer bonding alignment method is used to align wafers in a wafer bonding process of an EVG machine, comprising the following steps:

[0008] Providing a first wafer and a second wafer, wherein edges of the first wafer and the second wafer are both provided with notch marks;

[0009] Providing a first wafer carrier and a second wafer carrier, fixing the first wafer on the first wafer carrier, and fixing the second wafer on the second wafer carrier, after fixing, the first wafer and the second wafer are arranged opposite to each other;

[0010] A wafer bonding chamber is provided, wherein a first sensing detection component and a second sensing detection component are arranged in the wafer bonding chamber;

[0011] The first wafer carrier is driven to move to a first predetermined position in the wafer bonding chamber, rotated at the first predetermined position, and a detection signal within a depth range of an edge notch mark is collected by using a first sensing detection component during a rotation of the first wafer, and the signal is sent to a second sensing detection component;

[0012] Drive the second wafer carrier to move to a second predetermined position in the wafer bonding chamber, rotate the second wafer carrier at the second predetermined position, use the second sensing detection component to collect a detection signal within a depth range of the edge notch mark during the rotation of the second wafer, and compare the detection signal with the received detection signal within the depth range of the edge notch mark of the first wafer;

[0013] When the waveform of the detection signal collected when the second wafer rotates one circle completely matches the waveform of the detection signal collected when the first wafer rotates one circle, the second wafer carrier is controlled to stop rotating.

[0014] In some embodiments of the present invention, the notch mark is a V-shaped positioning groove.

[0015] In some embodiments of the present invention, the first sensing detection component includes multiple laser emission sources, and the multiple laser emission sources correspond to multiple detection points on the surface of the first wafer. The multiple detection points are arranged at intervals along the diameter direction of the first wafer within the depth range of the notch mark on the edge of the first wafer to collect detection signals at different positions within the depth range of the notch mark on the edge of the first wafer.

[0016] In some embodiments of the present invention, the second sensing detection component includes multiple laser emission sources; the number of laser emission sources in the second sensing detection component is the same as the number of laser emission sources in the first sensing detection component, and the positions of corresponding detection points of the laser emission sources in the second sensing detection component on the second wafer match the positions of corresponding detection points of the laser emission sources in the first sensing detection component on the first wafer.

[0017] In some embodiments of the present invention, the number of laser emission sources in the first sensing detection component is 3.

[0018] In some embodiments of the present invention, the first predetermined position is located directly above or directly below the second predetermined position.

[0019] In some embodiments of the present invention, when the first predetermined position is located directly above the second predetermined position, the first sensor detection component is installed below the second predetermined position, and the second sensor detection component is installed above the first predetermined position;

[0020] When the first predetermined position is located directly below the second predetermined position, the first sensor detection component is installed above the second predetermined position, and the second sensor detection component is installed below the first predetermined position.

[0021] In some embodiments of the present invention, after the first wafer and the second wafer are fixed and before entering the wafer bonding chamber, an alignment device of an EVG machine is used to pre-align the first wafer and the second wafer.

[0022] Some embodiments of the present invention further provide a wafer bonding alignment system, which is used to implement the above-mentioned wafer bonding alignment method, including:

[0023] A first wafer carrier, the first wafer carrier is connected to a first rotation drive assembly, and the first rotation drive assembly is used to drive the first wafer carrier to rotate;

[0024] A second wafer carrier, wherein a wafer fixing surface of the second wafer carrier is arranged opposite to a fixing surface of the first wafer carrier, and the first wafer carrier is connected to a second rotation driving assembly, and the second rotation driving assembly is used to drive the second wafer carrier to rotate;

[0025] A bonding device, used for bonding wafers, comprising a wafer bonding cavity and a first sensing detection component and a second sensing detection component installed in the wafer bonding cavity;

[0026] The conveying device includes at least two mechanical arms, which are respectively connected to the first wafer carrier and the second wafer carrier, and are used to drive the first wafer carrier and the second wafer carrier to move into or out of the wafer bonding cavity.

[0027] Some embodiments of the present invention further provide a wafer bonding method, comprising the following steps:

[0028] The first wafer and the second wafer are aligned by using the above-mentioned wafer bonding alignment method. Before the first wafer and the second wafer are aligned, the first wafer and the second wafer are pre-treated; the pre-treatment includes plasma activation of the wafer surface and hydrophilic treatment;

[0029] The first wafer and the second wafer are aligned and bonded.

[0030] The beneficial effects of the present invention are:

[0031] 1. The present invention utilizes the notch marks on the wafer surface and the sensor detection components in the wafer bonding chamber to align two wafers to be bonded in the wafer bonding chamber of the EGV machine, thereby achieving high-precision wafer alignment, ensuring the accuracy of wafer bonding, and avoiding the wafer shifting during the process of transporting the wafer to the wafer bonding chamber, resulting in a reduction in the yield rate.

[0032] 2. The sensing detection components provided by the present invention all include three laser emission sources, corresponding to multiple detection points on the wafer surface, which can collect more comprehensive signal waveforms, enhance the reliability of signal matching, and improve the accuracy of alignment.

[0033] 3. The present invention uses the alignment device of the EVG machine to pre-align the wafer to be bonded before entering the wafer bonding chamber, which can reduce the alignment time in the bonding chamber and improve the overall efficiency of wafer bonding. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the specific embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0035] Figure 1 is a flow chart of a wafer bonding alignment method;

[0036] Figure 2 A schematic diagram of a process for collecting a first wafer edge detection signal by a first sensing detection component;

[0037] Figure 3 A schematic diagram of a process for collecting a second wafer edge detection signal for a second sensing detection component;

[0038] Figure 4 This is a schematic diagram of the distribution of detection points within the depth range of the notch mark in this embodiment;

[0039] Figure 5 It is a schematic diagram of the detection result of the first wafer rotating one circle;

[0040] Figure 6 This is a schematic diagram of the detection results of the second wafer rotating one circle;

[0041] Figure 7 This is a schematic diagram comparing the inspection results of the first wafer and the second wafer after one rotation. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is described and illustrated below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application. Based on the embodiments provided in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application.

[0043] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0044] In the absence of conflict, the embodiments of the present invention and the features of the embodiments may be combined with each other.

[0045] The technical solution of the present invention is described in detail below in conjunction with specific embodiments and the accompanying drawings.

[0046] As attached Figure 1 - Attachment Figure 7 As shown, in an illustrative embodiment of a wafer bonding alignment method of the present invention, the wafer bonding alignment method is used to perform wafer alignment in a wafer bonding process of an EVG machine, and includes the following steps.

[0047] A first wafer and a second wafer are provided, wherein edges of the first wafer and the second wafer are provided with the same notch mark.

[0048] The notch marks on the first wafer and the second wafer are concave structures with a certain angle and depth on the edge of the wafer, which are used to determine the direction and position of the wafer in subsequent processing steps. The notch marks need to be made after the crystal rod is completed, and the notch must be cut along a specific line. The notch must be precisely cut along the predetermined crystal direction to ensure the correct positioning and identification of the wafer. For large-sized wafers, a U-shaped or V-shaped groove is generally ground on the cylindrical surface of the crystal rod as a positioning groove (Notch), and for small-sized ones, a flat edge is generally ground as a positioning edge (Flat). In this embodiment, the notch marks on the first wafer and the second wafer are V-shaped positioning grooves.

[0049] A first wafer carrier and a second wafer carrier are provided, and the wafer carrying surfaces of the first wafer carrier are arranged relative to each other; the first wafer is fixed to the wafer carrying surface of the first wafer carrier, and the second wafer is fixed to the wafer carrying surface of the second wafer carrier. After fixing, the first wafer and the second wafer are arranged relative to each other.

[0050] A wafer bonding chamber is provided for bonding wafers, wherein a first sensing detection component and a second sensing detection component are installed in the wafer bonding chamber.

[0051] The first wafer carrier is driven to move to a first predetermined position in the wafer bonding chamber, and rotates at least one circle at the first predetermined position. Figure 2 As shown, a first sensing detection component is used to collect a detection signal within a depth range of an edge notch mark during one rotation of the first wafer, and the detection signal is sent to a second sensing detection component.

[0052] The second wafer carrier is driven to move to a second predetermined position in the wafer bonding chamber, and the second wafer carrier is rotated at the second predetermined position. Figure 3 As shown, during the rotation process, the second sensing detection component is used to continuously collect the detection signal within the depth range of the second wafer edge notch mark, and the detection signal is compared with the received detection signal within the depth range of the first wafer edge notch mark.

[0053] Wherein, the first predetermined position is located directly above or directly below the second predetermined position. When the first predetermined position is located directly above the second predetermined position, the first sensing detection component is installed below the second predetermined position, and the second sensing detection component is installed above the first predetermined position. When the first predetermined position is located directly below the second predetermined position, the first sensing detection component is installed above the second predetermined position, and the second sensing detection component is installed below the first predetermined position. In this embodiment, the first predetermined position in the wafer bonding cavity is located directly below the second predetermined position.

[0054] When the waveform of the detection signal collected when the second wafer rotates one circle is completely consistent with the waveform of the detection signal collected when the first wafer rotates one circle, the second wafer carrier is controlled to stop rotating.

[0055] In order to improve the detection accuracy, in some embodiments of the present invention, the first sensing detection component includes a sensor and a receiver. The sensor includes three arranged laser emission sources for emitting a laser beam for detecting the notch. The sensor and the receiver are electrically connected. The three laser emission sources correspond to three detection points on the surface of the first wafer. The three detection points are arranged at intervals along the diameter direction of the first wafer within the depth range of the notch mark on the edge of the first wafer to collect signal waveforms at different positions within the depth range of the notch mark on the edge of the first wafer. In this embodiment, the positions of the three detection points on the surface of the first wafer are as shown in the attached figure. Figure 4 The waveforms of the three signals collected by the first sensing component after the first wafer rotates one circle are shown in the attached figure. Figure 5 shown.

[0056] In order to further improve the detection accuracy, in some embodiments of the present invention, the second sensing detection component also includes a sensor and a receiver. The sensor includes three arranged laser emission sources for emitting laser beams for detecting the gap, and the sensor and the receiver are electrically connected. The position of the corresponding detection point of the laser emission source in the second sensing detection component on the second wafer matches the corresponding detection point of the laser emission source in the first sensing detection component on the first wafer. The waveforms of the three signals collected by the second sensing detection component when the second wafer rotates one circle are shown in the attached figure. Figure 6 shown.

[0057] The results of comparing the waveform of the detection signal collected when the second wafer rotates one circle with the waveform of the detection signal collected when the first wafer rotates one circle are shown in the attached figure. Figure 7 As shown, when the waveforms of the two groups of signals are completely fitted, it is determined that the notch marks of the two wafers are aligned, and the support tables carrying the two wafers are controlled to stop rotating.

[0058] In order to reduce the time required for aligning the first wafer and the second wafer in the wafer bonding chamber and improve the alignment and bonding efficiency, in some embodiments of the present invention, after the first wafer and the second wafer are fixed on the carrier and before entering the wafer bonding chamber, a high-precision alignment device provided by the EVG machine, such as the EVG SmartView NT aligner, is used to pre-align the first wafer and the second wafer.

[0059] Some embodiments of the present invention further provide a wafer bonding alignment system for implementing the above-mentioned wafer bonding alignment method, comprising a first wafer carrier, a second wafer carrier, a bonding device and a conveying device.

[0060] Wherein, the first wafer carrying platform is connected to a first rotation driving assembly, and the first rotation driving assembly is used to drive the first wafer carrying platform to rotate;

[0061] The wafer fixing surface of the second wafer carrying platform is arranged opposite to the fixing surface of the first wafer carrying platform, and the first wafer carrying platform is connected to a second rotation driving assembly, and the second rotation driving assembly is used to drive the second wafer carrying platform to rotate;

[0062] The bonding device is used to bond wafers, and includes a wafer bonding cavity and a first sensing detection component and a second sensing detection component installed in the wafer bonding cavity;

[0063] The conveying device includes at least two robotic arms, which are respectively connected to the first wafer carrier and the second wafer carrier, and are used to drive the first wafer carrier and the second wafer carrier to move into or out of the wafer bonding cavity.

[0064] Some embodiments of the present invention further provide a wafer bonding method, comprising the following steps:

[0065] The first wafer and the second wafer are aligned by using the above-mentioned wafer bonding alignment method. Before the first wafer and the second wafer are aligned, the first wafer and the second wafer are pre-treated; the pre-treatment includes activating the wafer surface and performing hydrophilic treatment.

[0066] The specific method of activating the wafer surface and hydrophilizing the wafer is to use N2 plasma to treat the wafer, forming highly active dangling bonds on the wafer surface to absorb water molecules in the air and forming hydrophilic Si-OH groups on the wafer surface, making the wafer surface hydrophilic, thereby enhancing its bonding ability. Plasma treatment will form a disordered surface structure, making the oxide layer loose and porous, increasing the diffusion rate of water molecules, and reducing the possibility of interface voids, thereby improving the bonding strength.

[0067] After alignment, the first wafer and the second wafer are bonded.

[0068] Among them, bonding specifically includes the following three stages:

[0069] Pre-bonding stage: After plasma treatment, the surface of the wafer is covered with a water film several molecular layers thick. The two wafers are attached at room temperature and pre-bonded through van der Waals forces and hydrogen bonds. At this time, the bonding strength is relatively low.

[0070] Room temperature pressurization stage: Pressurization at room temperature before annealing can accelerate the rearrangement of water molecules, reduce the thickness of the water film between the interfaces, shorten the distance between the wafer surfaces on both sides, and improve the bonding strength.

[0071] Annealing stage after bonding: The increased temperature accelerates the diffusion movement of water molecules and the polymerization dehydration reaction of Si-OH, thereby increasing the bonding strength.

[0072] Finally, it should be noted that: the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0073] The above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or some technical features can be replaced by equivalents without departing from the spirit of the technical solution of the present invention, which should be included in the scope of the technical solution for protection of the present invention.

Claims

1. A wafer bonding alignment method, used for wafer alignment in a wafer bonding process of an EVG machine, characterized in that: The following steps are involved: Providing a first wafer and a second wafer, wherein edges of the first wafer and the second wafer are both provided with notch marks; Providing a first wafer carrier and a second wafer carrier, fixing the first wafer on the first wafer carrier, and fixing the second wafer on the second wafer carrier, after fixing, the first wafer and the second wafer are arranged opposite to each other; A wafer bonding chamber is provided, wherein a first sensing detection component and a second sensing detection component are arranged in the wafer bonding chamber; The first wafer carrier is driven to move to a first predetermined position in the wafer bonding chamber, rotated at the first predetermined position, and a detection signal within a depth range of an edge notch mark is collected by using a first sensing detection component during a rotation of the first wafer, and the signal is sent to a second sensing detection component; Drive the second wafer carrier to move to a second predetermined position in the wafer bonding chamber, rotate the second wafer carrier at the second predetermined position, use the second sensing detection component to collect a detection signal within a depth range of the edge notch mark during the rotation of the second wafer, and compare the detection signal with the received detection signal within the depth range of the edge notch mark of the first wafer; When the waveform of the detection signal collected when the second wafer rotates one circle completely matches the waveform of the detection signal collected when the first wafer rotates one circle, the two wafer carriers are controlled to stop rotating.

2. The wafer bonding alignment method according to claim 1, characterized in that: The notch is marked as a V-shaped positioning groove.

3. The wafer bonding alignment method according to claim 1 or 2, characterized in that: The first sensing detection component includes multiple laser emission sources, which correspond to multiple detection points on the surface of the first wafer. The multiple detection points are arranged at intervals along the diameter direction of the first wafer within the depth range of the notch mark on the edge of the first wafer to collect detection signals at different positions within the depth range of the notch mark on the edge of the first wafer.

4. The wafer bonding alignment method according to claim 3, characterized in that: The second sensing detection component includes multiple laser emission sources; the number of laser emission sources in the second sensing detection component is the same as the number of laser emission sources in the first sensing detection component, and the positions of corresponding detection points of the laser emission sources in the second sensing detection component on the second wafer match the positions of corresponding detection points of the laser emission sources in the first sensing detection component on the first wafer.

5. The wafer bonding alignment method according to claim 3, characterized in that: The number of laser emission sources in the first sensing detection component is 3.

6. The wafer bonding alignment method according to claim 1, characterized in that: The first predetermined position is located directly above or directly below the second predetermined position.

7. The wafer bonding alignment method according to claim 6, characterized in that: When the first predetermined position is located directly above the second predetermined position, the first sensor detection component is installed below the second predetermined position, and the second sensor detection component is installed above the first predetermined position; When the first predetermined position is located directly below the second predetermined position, the first sensor detection component is installed above the second predetermined position, and the second sensor detection component is installed below the first predetermined position.

8. The wafer bonding alignment method according to claim 1, wherein: After the first wafer and the second wafer are fixed, before entering the wafer bonding chamber, an alignment device of an EVG machine is used to pre-align the first wafer and the second wafer.

9. A wafer bonding alignment system, used to implement the wafer bonding alignment method according to any one of claims 1 to 8, characterized in that: include: A first wafer carrying platform, wherein the first wafer carrying platform is connected to a first rotation driving component, and the first rotation driving component is used to drive the first wafer carrying platform to rotate; A second wafer carrier, wherein a wafer fixing surface of the second wafer carrier is arranged opposite to a fixing surface of the first wafer carrier, and the first wafer carrier is connected to a second rotation driving assembly, and the second rotation driving assembly is used to drive the second wafer carrier to rotate; A bonding device, used for bonding wafers, comprising a wafer bonding cavity and a first sensing detection component and a second sensing detection component installed in the wafer bonding cavity; The conveying device includes at least two robotic arms, which are respectively connected to the first wafer carrier and the second wafer carrier, and are used to drive the first wafer carrier and the second wafer carrier to move into or out of the wafer bonding cavity.

10. A wafer bonding method, characterized in that: The following steps are involved: Adopting the wafer bonding alignment method according to any one of claims 1 to 8 to align a first wafer and a second wafer, and before aligning the first wafer and the second wafer, pre-processing the first wafer and the second wafer; The pretreatment includes plasma activation of the wafer surface and hydrophilic treatment; The first wafer and the second wafer are aligned and bonded.

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