Bonding structure and method for manufacturing the same, and semiconductor device

Abstract

The application provides a bonding structure and a preparation method thereof, and a semiconductor device. The application provides a preparation method of a bonding structure, which comprises the following steps: providing a wafer, wherein the wafer is a wafer to be bonded; in an oxygen environment, gasified tetraethyl orthosilicate and gasified phosphorus-containing compound or boron-containing compound are introduced, and reaction is carried out at a certain temperature, so that an absorption layer is grown on the surface of the wafer; the supply of the gasified phosphorus-containing compound or boron-containing compound is stopped, and only the gasified tetraethyl orthosilicate is introduced, so that a bonding layer is grown on the surface of the absorption layer, and the surface of the bonding layer serves as a bonding surface. By adopting the composite structure of the bonding layer plus the absorption layer, water molecules generated in the bonding process are absorbed, the diffusion of the water molecules generated in the bonding process into the silicon structure and the reaction of the water molecules with the silicon are effectively avoided, hydrogen is generated, the bubbles at the bonding interface are effectively reduced, the fine gaps at the bonding interface are quickly closed, and the stability of the bonding is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of semiconductor, in particular to a structure for bonding and a preparation method thereof, and a semiconductor device. BACKGROUND

[0002] Bonding process is a key process for three-dimensional integration. The bubbles generated in the wafer during the bonding process are easy to cause bonding failure, and water molecules are an important reason for the formation of bubbles. The source of water molecules in the bonding process mainly includes water molecules remaining in the bonding interface and water molecules generated by the condensation reaction of Si-OH groups during annealing process, Si-OH+HO-Si→SiO2+H2O.

[0003] In the prior art, the bonding process usually uses loose SiO2 film as a bonding medium layer, which absorbs and stores water molecules by using the loose porous characteristics of the film, thereby reducing the generation of bubbles. However, although the loose porous film can store a certain amount of water molecules, it cannot avoid the diffusion of water molecules in the pores to the silicon wafer during the heating process and the reaction: 2H2O+Si→SiO2+2H2, which may affect the performance of the wafer device and generate byproduct hydrogen. Hydrogen molecules further diffuse to the bonding interface, which is not conducive to the elimination of bubbles.

[0004] How to effectively absorb water molecules and reduce the generation of bubbles during wafer bonding has become a problem to be solved. SUMMARY

[0005] The technical problem solved by the present application is how to effectively absorb water molecules during the bonding process and reduce the generation of bubbles, and a structure for bonding and a preparation method thereof, and a semiconductor device are provided.

[0006] In order to solve the above problems, the present application provides a structure for bonding, comprising: a wafer, the wafer is a wafer to be bonded; a bonding layer, arranged on the surface of the wafer, the surface of the bonding layer as a bonding surface; an absorption layer, arranged between the wafer and the bonding layer, to absorb water molecules generated during the bonding process.

[0007] Optionally, the absorption layer can react with water molecules and generate solid products.

[0008] Optionally, the absorption layer includes phosphorus-doped silicon oxide film or boron-doped silicon oxide film.

[0009] Optionally, the wafer includes metal lines and devices.

[0010] The application further provides a preparation method of the structure for bonding, comprising: providing a wafer, which is a wafer to be bonded; in an oxygen environment, introducing vaporized tetraethyl orthosilicate and vaporized phosphorus-containing compound or boron-containing compound, and reacting at a certain temperature to grow an absorption layer on the surface of the wafer; stopping the supply of the vaporized phosphorus-containing compound or boron-containing compound, and only introducing the vaporized tetraethyl orthosilicate to grow a bonding layer on the surface of the absorption layer, the surface of the bonding layer serving as a bonding surface.

[0011] Optionally, the phosphorus-containing compound is triethyl phosphate, and the absorption layer formed is a phosphorus-doped silicon oxide film.

[0012] Optionally, the boron-containing compound is triethyl borate, and the absorption layer formed is a boron-doped silicon oxide film.

[0013] Optionally, the bonding layer comprises a silicon oxide film.

[0014] Optionally, the wafer comprises metal lines and devices.

[0015] The application further provides a semiconductor device formed by oppositely bonding two bonding surfaces of the structure for bonding.

[0016] The application grows an absorption layer on the bonding layer to absorb water molecules generated on the bonding interface during the bonding process, avoids the hydrogen generated by the reaction between water molecules on the bonding interface and silicon from escaping to the bonding interface, reduces the bubbles on the bonding interface, promotes the rapid closure of the fine gaps, and improves the stability of the bonding. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 Fig. 1 is a schematic diagram of the structure for bonding according to an embodiment of the application.

[0018] Figure 2 Fig. 2 is a schematic diagram of the steps of the preparation method of the structure for bonding according to an embodiment of the application.

[0019] Figures 3A-3C Fig. 3 is a process schematic diagram of the preparation method of the structure for bonding according to an embodiment of the application.

[0020] Figure 4 Fig. 4 is a schematic diagram of the principle of reducing bubbles during the bonding process. DETAILED DESCRIPTION

[0021] The structure for bonding, the bonding method, and the semiconductor device according to the application are described in detail below with reference to the accompanying drawings.

[0022] The technical problem to be solved by the present application is how to effectively absorb water molecules generated on the bonding surface during the bonding process and reduce the generation of bubbles. First, the bonding structure provided by the present application is described.

[0023] Figure 1 The bonding structure provided by the present application is shown in the schematic diagram of the bonding structure in one embodiment of the present application.

[0024] Reference Figure 1 As shown, the bonding structure includes a wafer 101, which is a wafer to be bonded; a bonding layer 103, which is arranged on the surface of the wafer 101, and the surface of the bonding layer 103 serves as a bonding surface 103A during wafer bonding; and an absorption layer 102, which is arranged between the wafer 101 and the bonding layer 103 to absorb water molecules generated during wafer bonding. In one embodiment of the present application, the wafer 101 includes metal lines and devices.

[0025] Further, the absorption layer 102 can chemically react with water molecules and generate solid products. On the one hand, since the absorption layer 102 can quickly absorb water molecules on the bonding interface, it not only avoids the influence of residual water molecules on the bonding strength, but also avoids the generation of bubbles by hydrogen generated by the reaction of water molecules with silicon; on the other hand, after the absorption of water molecules, the absorption layer 102 expands in volume, so that the fine gap on the bonding interface is quickly closed, thereby improving the stability of the bonding.

[0026] In one embodiment of the present application, the absorption layer 102 includes a phosphorus-doped silicon oxide film or a boron-doped silicon oxide film. Specifically, the absorption layer 102 can use phosphorus-containing or boron-containing silicon oxide glass. After the absorption layer 102 chemically reacts with water molecules, the generated stable solid product is phosphoric acid (H3PO4) or boric acid (H3BO4).

[0027] The preparation method of the bonding structure provided by the present application is described below.

[0028] Figure 2 The preparation method of the bonding structure provided by the present application is shown in the schematic diagram of the steps of the preparation method of the bonding structure in one embodiment of the present application. The preparation method of the bonding structure includes the following steps: step S20, providing a wafer, which is a wafer to be bonded; step S21, in an oxygen environment, introducing vaporized tetraethyl orthosilicate and vaporized phosphorus-containing compounds or boron-containing compounds, and reacting at a certain temperature to grow an absorption layer on the surface of the wafer; and step S22, stopping the supply of vaporized phosphorus-containing compounds or boron-containing compounds, and only introducing vaporized tetraethyl orthosilicate to grow a bonding layer on the surface of the absorption layer, so that the wafer has a bonding surface.

[0029] Figures 3A-3CThe diagram shown is a schematic representation of the process for preparing the bonding structure according to a specific embodiment of the present invention.

[0030] Step S20, refer to Figure 3A As shown, a wafer 101 is provided. The wafer is a wafer to be bonded, and its surface is 101A. In one specific embodiment of the present invention, the wafer 101 includes metal lines and devices.

[0031] Step S21, refer to Figure 3B As shown, in an oxygen environment, vaporized tetraethyl orthosilicate and vaporized phosphorus-containing or boron-containing compounds are introduced and reacted at a certain temperature to grow an absorption layer 102 on the surface 101A of the wafer 101. Under normal pressure, oxygen free radicals generated by the decomposition of oxygen react with tetraethyl orthosilicate and the phosphorus-containing or boron-containing compounds to grow a thin oxide film as the absorption layer 102. In this specific embodiment, the reaction is carried out at 400°C; the absorption layer 102 is grown using the PECVD method.

[0032] In one specific embodiment of the present invention, the phosphorus-containing compound is triethyl phosphate, and the grown absorber layer 102 is a phosphorus-doped silicon oxide film. Specifically, in the phosphorus-doped silicon oxide film, phosphorus is combined with silicon oxide (SiO2) in the form of phosphorus oxide (P2O5).

[0033] In another specific embodiment of the present invention, the boron-containing compound is triethyl borate, and the grown absorber layer 102 is a boron-doped silicon oxide film. Specifically, in the boron-doped silicon oxide film, boron is combined with silicon oxide (SiO2) in the form of boron oxide (B2O3).

[0034] Furthermore, since phosphorus oxide has better water absorption than boron oxide, phosphorus-doped silicon oxide films are preferred.

[0035] Step S22, refer to Figure 3C As shown, the supply of vaporized phosphorus-containing or boron-containing compounds is stopped, and only vaporized tetraethyl orthosilicate is introduced. A bonding layer 103 is grown on the surface of the absorber layer 102, and the surface of the bonding layer 103 serves as the bonding surface 103A. The bonding layer 103 is a silicon oxide film. A thin layer of ordinary oxide film is grown on the absorber layer 102 as a bonding layer, which serves to provide a bonding surface and ensure bonding strength.

[0036] The above technical solution forms a double-layer composite structure of an absorption layer and a bonding layer on the wafer, which is used to absorb water molecules generated during the bonding process. This avoids water molecules remaining at the bonding interface from affecting the bonding strength, and also avoids the generation of bubbles from hydrogen gas produced by the reaction of water molecules with silicon. This effectively reduces bubbles at the bonding interface and promotes the rapid closure of fine gaps, thereby improving the stability of the bonding.

[0037] Figure 4 The diagram illustrates the principle of reducing bubbles during wafer bonding. This invention also provides a semiconductor device employing any of the above-described bonding structures, formed by bonding the bonding surfaces of two of the bonding structures together. Please also refer to the schematic diagram of the semiconductor device. Figure 4 .

[0038] The following description uses a phosphorus-doped silicon oxide film as an example to illustrate wafer bonding using two of the above-mentioned bonding structures.

[0039] Please see Figure 4 As shown, water molecules are generated due to residual water molecules at the bonding interface, or through the condensation reaction of Si-OH groups during annealing, with the reaction formula Si-OH + HO-Si → SiO2 + H2O. During wafer bonding, water molecules 401 enter the bonding layer 103. Since the absorber layer 102 can react with water molecules, water molecules 401 continue to move in the direction indicated by the arrow, entering the absorber layer 102 and reacting chemically with it.

[0040] On the one hand, water molecules 401 react chemically with the absorber layer 102 to generate a stable solid product, phosphoric acid 402 (H3PO4). Since the absorber layer 102 can quickly absorb water molecules at the bonding interface, it avoids water molecules remaining at the bonding interface from affecting the bonding strength, and also avoids the generation of bubbles from hydrogen gas produced by the reaction of water molecules with silicon. On the other hand, after the water molecules are absorbed, the absorber layer 102 expands in volume, which allows the tiny gaps at the bonding interface to close quickly, improving the stability of the bonding.

[0041] It should be noted that all specific embodiments in this specification are described in a related manner, and the same or similar parts between the various specific embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for the embodiments of semiconductor devices, since they are basically similar to the embodiments of bonding structures, the description is relatively simple, and the relevant parts can be referred to the description of the embodiments of bonding structures.

[0042] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A structure for bonding, characterized by, The application relates to a structure for wafer bonding. The structure comprises: a wafer to be bonded; a bonding layer arranged on the surface of the wafer, the surface of the bonding layer serving as a bonding surface; 2. The structure for bonding according to claim 1, wherein an absorption layer arranged between the wafer and the bonding layer to absorb water molecules generated in the bonding process, the absorption layer chemically reacting with the water molecules and generating a solid product, the absorption layer comprising a phosphorus-doped silicon oxide film or a boron-doped silicon oxide film.

3. A method for producing a structure for bonding, characterized by, The wafer comprises metal circuits and devices. The application relates to a method for wafer bonding. The method comprises: providing a wafer to be bonded; 4. The method of claim 3, wherein, in an oxygen environment, introducing vaporized tetraethyl orthosilicate and vaporized phosphorus-containing or boron-containing compounds to react at a certain temperature to grow an absorption layer on the surface of the wafer, the absorption layer chemically reacting with water molecules and generating a solid product, the absorption layer comprising a phosphorus-doped silicon oxide film or a boron-doped silicon oxide film; 5. The method of claim 3, wherein, stopping the supply of the vaporized phosphorus-containing or boron-containing compounds and only introducing vaporized tetraethyl orthosilicate to grow a bonding layer on the surface of the absorption layer, the surface of the bonding layer serving as a bonding surface.

6. The method of claim 3, wherein, The phosphorus-containing compound is triethyl phosphate, and the grown absorption layer is a phosphorus-doped silicon oxide film.

7. The method of claim 3, wherein, The boron-containing compound is triethyl borate, and the grown absorption layer is a boron-doped silicon oxide film.

8. A semiconductor device, characterized by comprising: The bonding layer comprises a silicon oxide film. The wafer comprises metal circuits and devices. The application relates to a structure for wafer bonding. The structure comprises: a wafer to be bonded; a bonding layer arranged on the surface of the wafer, the surface of the bonding layer serving as a bonding surface; an absorption layer arranged between the wafer and the bonding layer to absorb water molecules generated in the bonding process, the absorption layer chemically reacting with the water molecules and generating a solid product, the absorption layer comprising a phosphorus-doped silicon oxide film or a boron-doped silicon oxide film. The wafer comprises metal circuits and devices. The application relates to a method for wafer bonding. The method comprises: providing a wafer to be bonded; in an oxygen environment, introducing vaporized tetraethyl orthosilicate and vaporized phosphorus-containing or boron-containing compounds to react at a certain temperature to grow an absorption layer on the surface of the wafer, the absorption layer chemically reacting with water molecules and generating a solid product, the absorption layer comprising a phosphorus-doped silicon oxide film or a boron-doped silicon oxide film; stopping the supply of the vaporized phosphorus-containing or boron-containing compounds and only introducing vaporized tetraethyl orthosilicate to grow a bonding layer on the surface of the absorption layer, the surface of the bonding layer serving as a bonding surface. The phosphorus-containing compound is triethyl phosphate, and the grown absorption layer is a phosphorus-doped silicon oxide film. The boron-containing compound is triethyl borate, and the grown absorption layer is a boron-doped silicon oxide film. The bonding layer comprises a silicon oxide film. The wafer comprises metal circuits and devices. The application relates to a structure for wafer bonding. The structure comprises: a wafer to be bonded; a bonding layer arranged on the surface of the wafer, the surface of the bonding layer serving as a bonding surface; an absorption layer arranged between the wafer and the bonding layer to absorb water molecules generated in the bonding process, the absorption layer chemically reacting with the water molecules and generating a solid product, the absorption layer comprising a phosphorus-doped silicon oxide film or a boron-doped silicon oxide film. The wafer comprises metal circuits and devices. The application relates to a structure for wafer bonding. The structure comprises: a wafer to be bonded; a bonding layer arranged on the surface of the wafer, the surface of the bonding layer serving as a bonding surface; an absorption layer arranged between the wafer and the bonding layer to absorb water molecules generated in the bonding process, the absorption layer chemically reacting with the water molecules and generating a solid product, the absorption layer comprising a phosphorus-doped silicon oxide

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