Bonding method and bonding equipment

Abstract

The invention provides a bonding method and bonding equipment. The method comprises the following steps: providing a first substrate and a second substrate for bonding, wherein at least one surface of the first substrate and the second substrate is an oxide surface; bonding the first substrate and the second substrate; and placing the bonded combined substrate in a vacuum environment for more than 1 hour so as to increase the bonding force. According to the invention, the bonded combined substrate is placed in a vacuum environment for more than one hour so as to increase the bonding force. The pre-bonding is directly connected together through the acting force (hydrogen bond) between atoms, and the vacuum environment can promote the diffusion of gas molecules and water molecules on the bonding interface, thereby facilitating the bonding reaction.

Description

Technical Field

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

[0002] With the development of semiconductor manufacturing technology, integrated circuits have been widely used in many fields. Among them, devices based on silicon-on-insulator (SOI) technology have the characteristics of high temperature resistance and radiation resistance, which are suitable for traditional fields such as aerospace. At the same time, their advantages such as low power consumption, high speed and high integration are the basis for the design and preparation of high-speed and low-power integrated circuits, which can be applied to emerging fields such as autonomous driving and the Internet of Things.

[0003] The use of bonding technology to prepare SOI materials is one of the most important preparation methods in the prior art. In the bonding process, if the bonding strength can be improved, the overall process yield will inevitably be improved. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a bonding method and a bonding device, which can improve the bonding strength and thus improve the overall process yield.

[0005] In order to solve the above problems, the present invention provides a bonding method, comprising: providing a first substrate and a second substrate for bonding, at least one surface of the first substrate and the second substrate being an oxide surface; bonding the first substrate and the second substrate; placing the bonded combined substrate in a vacuum environment for more than 1 hour to increase the bonding force.

[0006] Optionally, the air pressure of the vacuum environment is 1E-5 to 1E-3 torr.

[0007] Optionally, the holding time ranges from 1 to 24 hours.

[0008] Optionally, the bonding is a hydrophilic link bonding.

[0009] Optionally, the oxide is silicon oxide.

[0010] In order to solve the above problems, the present invention provides a bonding device, including a bonding control device, which is configured to perform the following steps: bonding a first substrate and a second substrate for bonding, at least one surface of the first substrate and the second substrate is an oxide surface; providing a vacuum environment for the bonded combined substrate and maintaining it for more than 1 hour to increase the bonding force.

[0011] The present invention places the bonded combined substrate in a vacuum environment for more than 1 hour to increase the bonding force. The pre-bonding is directly connected together through the force between atoms (hydrogen bonds), and the vacuum environment can promote the diffusion of gas molecules and water molecules at the bonding interface, which is beneficial to the bonding reaction. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Attached Figure 1 Shown is a schematic diagram of the implementation steps of the bonding method described in a specific embodiment of the present invention.

[0013] Attached Figure 2A To Attachment Figure 2B Shown is a process flow chart of a bonding method according to a specific embodiment of the present invention.

[0014] Attached Figure 3 Shown are the test results of the implementation of the bonding method described in a specific embodiment of the present invention.

[0015] Attached Figure 4 Shown is a schematic diagram of the implementation steps of the bonding method described in a specific embodiment of the present invention.

[0016] Attached Figure 5A To Attachment Figure 5E Shown is a process flow chart of a bonding method according to a specific embodiment of the present invention. DETAILED DESCRIPTION

[0017] The specific implementation of the bonding method provided by the present invention is described in detail below with reference to the accompanying drawings.

[0018] Attached Figure 1 The figure shows a schematic diagram of the implementation steps of the bonding method according to a specific embodiment of the present invention, which includes the following steps: step S10, providing a first substrate and a second substrate for bonding, wherein at least one surface of the first substrate and the second substrate is an oxide surface; step S11, bonding the first substrate and the second substrate; and step S12, placing the bonded combined substrate in a vacuum environment for more than 1 hour to increase the bonding force.

[0019] Attached Figure 2A As shown, referring to step S10, a first substrate 11 and a second substrate 12 for bonding are provided, and at least one surface of the first substrate 11 and the second substrate 12 is an oxide surface. The first substrate 11 and the second substrate 12 can each independently be a wafer including any common semiconductor material such as silicon, germanium, silicon carbide, GaAs, and GaN. In this specific embodiment, the first substrate 11 and the second substrate 12 are single crystal silicon substrates. In addition, the surfaces of the first substrate 11 and the second substrate 12 are oxide surfaces, that is, each includes a first oxide layer 11 and a second oxide layer 12, and the material thereof is preferably silicon oxide. The first oxide layer 11 and the second oxide layer 12 can be an oxide layer formed by a thermal oxidation process, an epitaxial process, etc., or can be a natural oxide layer formed in the air. In other specific embodiments, at least one surface of the first substrate 11 and the second substrate 12 is an oxide surface to facilitate the subsequent implementation of the bonding process.

[0020] Attached Figure 2B As shown, referring to step S11, the first substrate 11 and the second substrate 12 are bonded. At least one surface of the first substrate 11 and the second substrate 12 is an oxide surface, so the bonding is preferably a hydrophilic link bonding.

[0021] Referring to step S12, the bonded combined substrate is placed in a vacuum environment for more than 1 hour to increase the bonding force. In this specific implementation, the pressure of the vacuum environment is preferably 1E-5 to 1E-3 torr, and the holding time range is 1 to 24 hours. Figure 3 The figure shows the principle of chemical changes at the interface during the heat preservation process. The pre-bonding is directly connected through the force between atoms (hydrogen bonds), and the vacuum environment can promote the diffusion of gas molecules and water molecules at the bonding interface, which is beneficial to the bonding reaction.

[0022] Attached Figure 4 The figure shows a schematic diagram of the implementation steps of the bonding method described in another specific embodiment of the present invention. The above method is particularly suitable for the preparation of SOI materials. When it is applied to the preparation of SOI materials, its specific implementation includes: step S20, providing a device substrate and a support substrate; step S21, forming an oxide layer on the surface of at least one of the device substrate and the support substrate; step S22, injecting bubbling ions into the device substrate; step S23, bonding the device substrate and the support substrate; step S24, placing the bonded combined substrate in a vacuum environment for more than 1 hour to increase the bonding force; step S25, annealing to peel off the device substrate at the position where the bubbling ions were injected to form an SOI substrate.

[0023] Attached Figure 5A As shown, referring to step S20, a device substrate 21 and a support substrate 22 are provided. The device substrate 21 and the support substrate 22 can be wafers of any common semiconductor material including silicon, germanium, silicon carbide, GaAs, and GaN. In this specific embodiment, the device substrate 21 and the support substrate 22 are single crystal silicon substrates.

[0024] Attached Figure 5B As shown, referring to step S21, an oxide layer is formed on the surface of at least one of the device substrate 21 and the support substrate 22. The purpose of generating the oxide layer is to form a buried oxide of the SOI structure later. In this specific embodiment, oxide layers 23 and 24 are formed on both the device substrate 21 and the support substrate 22. The method of forming the oxide layer can be epitaxy or thermal oxidation. In this specific embodiment, the device substrate 21 and the support substrate 22 are single crystal silicon substrates, so the oxide layer can be formed by thermal oxidation, including dry oxygen and wet oxygen.

[0025] Attached Figure 5CAs shown, referring to step S22, bubbling ions are implanted into the device substrate 21. The bubbling ion implantation region 25 formed by the implantation is used for subsequent stripping operations. The bubbling ions are selected from one or a combination of H ions and He ions, and a suitable energy and dose range are selected according to the implantation depth. The surface portion of the implantation region 25 will be retained after stripping as the device layer of the final SOI substrate.

[0026] Attached Figure 5D As shown, referring to step S23, the device substrate 21 and the support substrate 22 are bonded. The bonding can be performed by any common bonding process such as normal pressure bonding and vacuum bonding, and the bonding surface is treated by plasma activation or the like before bonding to improve the quality of the bonding process. After bonding, a high temperature reinforcement process or the like can also be performed to enhance the bonding strength.

[0027] Step S24, placing the bonded combined substrate in a vacuum environment for more than 1 hour to increase the bonding force. In this specific implementation, the vacuum environment preferably has a pressure of 1E-5 to 1E-3 torr, and the holding time range is 1 to 24 hours. The pre-bonding is directly connected together through the force between atoms (hydrogen bonds), and the vacuum environment can promote the diffusion of gas molecules and water molecules at the bonding interface, which is beneficial to the bonding reaction.

[0028] Attached Figure 5E As shown, referring to step S25, annealing is performed to peel off the device substrate 21 at the position where the bubbling ions are implanted to form an SOI substrate. The SOI substrate formed after peeling includes a support substrate 22, an oxide buried layer 30 formed by the oxide layers 23 and 24 on the surface of the support substrate, and a device layer 40 retained after peeling.

[0029] Also provided below is a specific embodiment of a bonding device, comprising a bonding control device, which is configured to perform: bonding a first substrate and a second substrate for bonding, wherein at least one surface of the first substrate and the second substrate is an oxide surface; providing a vacuum environment for the bonded combined substrate and maintaining it for more than 1 hour to increase the bonding force.

[0030] The above is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A bonding method, characterized in that: include: providing a first substrate and a second substrate for bonding, wherein at least one surface of the first substrate and the second substrate is an oxide surface; bonding the first substrate to the second substrate; The bonded combined substrate is placed in a vacuum environment for more than 1 hour to increase the bonding force.

2. The method according to claim 1, characterized in that The air pressure of the vacuum environment is 1E-5 to 1E-3 torr.

3. The method according to claim 1, characterized in that The holding time ranges from 1 to 24 hours.

4. The method according to claim 1, characterized in that: The bonding is a hydrophilic link bonding.

5. The method according to claim 1, characterized in that The oxide is silicon oxide.

6. A bonding device, comprising a bonding control device, characterized in that: The device is configured to perform the following steps: bonding a first substrate and a second substrate for bonding, wherein at least one surface of the first substrate and the second substrate is an oxide surface; A vacuum environment is provided for the bonded combined substrate and maintained for more than 1 hour to increase the bonding force.

7. The device according to claim 6, characterized in that The air pressure of the vacuum environment is 1E-5 to 1E-3 torr.

8. The device according to claim 6, characterized in that The holding time ranges from 1 to 24 hours.

9. The device according to claim 6, characterized in that The bonding is a hydrophilic link bonding.

10. The device according to claim 6, characterized in that The oxide is silicon oxide.

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