A quartz room temperature bonding method

Abstract

The present invention provides a room-temperature quartz bonding method, comprising: S100, cleaning the surfaces of quartz wafers; S200, depositing silicon dioxide on two quartz wafers to form a silicon dioxide bonding film on the surfaces of the quartz wafers; S300, chemically mechanically polishing the silicon dioxide bonding film; S400, cleaning the quartz wafers with a hydrofluoric acid solution; and S500, bringing the silicon dioxide bonding films of the two quartz wafers into contact with each other and bonding the quartz wafers using a bonding machine. This method can achieve high-reliability bonding between quartz wafers at room temperature.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing, and in particular to a quartz room temperature bonding method. Background Art

[0002] Due to its excellent thermal, mechanical, optical, and chemical properties, quartz is widely used in microelectromechanical systems (MEMS), optoelectronic devices, and microfluidic devices. Quartz-to-quartz bonding, as a reliable solid-state connection method, has received widespread attention worldwide and has been widely applied in a variety of fields, including aerospace, basic scientific research, and high-power lasers.

[0003] There are several methods for bonding quartz, including optical bonding, thermal bonding, and vacuum bonding. Optical bonding has relatively poor reliability. Thermal bonding requires heating the quartz, which is complex and results in low yields. Vacuum bonding requires placing the quartz in a vacuum environment, resulting in weaker bond strength. This demonstrates that traditional bonding methods limit the application range of devices, necessitating the need for new and more effective bonding methods.

[0004] The invention patent application with application publication number CN113488381A discloses a method for direct bonding of quartz and silicon. However, the use of the direct bonding method of quartz and silicon in bonding quartz to quartz will result in a large number of bubbles between the quartz sheets, that is, there will be a large number of areas between the quartz sheets where bonding is unsuccessful, resulting in poor bonding between the quartz sheets. It can be seen that the direct bonding method of quartz and silicon cannot be directly applied to bonding quartz to quartz. Summary of the Invention

[0005] The purpose of the present invention is to overcome the defects of the prior art and to provide a quartz room temperature bonding method that can achieve high reliability bonding between quartz at room temperature and pressure.

[0006] To achieve the above objectives, the present invention adopts the following specific technical solutions:

[0007] The quartz room temperature bonding method provided by the embodiment of the present invention includes:

[0008] S100, cleaning the surface of the quartz plate;

[0009] S200, depositing silicon dioxide on the two quartz plates to form a silicon dioxide bonding film on the surfaces of the quartz plates;

[0010] S300, performing chemical mechanical polishing on the silicon dioxide bonding film;

[0011] S400, cleaning the quartz plate with a hydrofluoric acid solution;

[0012] S500 , bringing the silicon dioxide bonding films of the two quartz plates into contact with each other and bonding the quartz plates together using a bonding machine.

[0013] The present invention can at least achieve the following beneficial effects: the bonding between quartz sheets is completed at room temperature and pressure, high reliability is achieved without the need for high temperature and vacuum conditions, and the present solution can be used for the production of a variety of chips because it is completed at room temperature and pressure. After the quartz sheets are ground, the quartz sheets are cleaned with a hydrofluoric acid solution to improve the bonding effect between the quartz sheets, so that there are no unbonded areas or only a small number of unbonded areas between the quartz sheets. Compared with traditional optical adhesive methods, thermal bonding and vacuum bonding methods, the present solution overcomes the defects of traditional quartz bonding technology, can achieve high reliability bonding between quartz and quartz at room temperature and pressure, does not require any intermediate layer material for auxiliary connection, and will not damage the optical properties of the quartz interface. The quartz sheets bonded using this solution show significant advantages in terms of bonding strength, temperature shock environment and adaptability to water environment.

[0014] According to some embodiments of the present invention, S200 includes depositing the silicon dioxide on the quartz wafer using a chemical vapor deposition method, and the silicon dioxide generation source is tetraethyl orthosilicate.

[0015] According to some embodiments of the present invention, the thickness of the silicon dioxide bonding film generated in S200 is 1 micrometer to 3 micrometers.

[0016] According to some embodiments of the present invention, S300 includes the following sub-steps:

[0017] S301: placing the quartz plate into a grinding chamber to grind the silicon dioxide bonding film;

[0018] S302: placing the ground quartz plate into the silicon dioxide bonding film in the polishing chamber for polishing;

[0019] S303: placing the polished quartz plate into an ultrasonic chamber for ultrasonic cleaning;

[0020] S304: placing the quartz plate after ultrasonic cleaning into a cleaning chamber for cleaning;

[0021] S305: placing the cleaned quartz plate into the drying chamber for drying.

[0022] According to some embodiments of the present invention, the thickness of the silicon dioxide bonding film after the S300 treatment is 5000 angstroms to 15000 angstroms.

[0023] According to some embodiments of the present invention, after the S300 treatment, the silicon dioxide bonding film has a profile arithmetic mean deviation Ra of less than 1 nanometer and a root mean square roughness Rq of less than 1.5 nanometers.

[0024] According to some embodiments of the present invention, the concentration of the hydrofluoric acid solution is 2%-5%.

[0025] According to some embodiments of the present invention, S500 includes: S501, the two quartz plates first enter the plasma chamber in sequence to activate plasma on the surface; S502, the quartz plates enter the cleaning chamber and undergo surface hydrophilic treatment; S503, pressure is applied to the upper quartz plate to bond the two quartz plates.

[0026] According to some embodiments of the present invention, the duration of the pressure applied to the quartz plate in S503 is 2 seconds to 20 seconds.

[0027] According to some embodiments of the present invention, the quartz room temperature bonding method further includes annealing the bonding wafer.

[0028] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments with reference to the following drawings, in which:

[0030] Figure 1 is a flow chart of a quartz room temperature bonding method according to an embodiment of the present invention;

[0031] Figure 2 is a flowchart of S300 according to an embodiment of the present invention;

[0032] Figure 3 is a flowchart of S500 according to an embodiment of the present invention;

[0033] Figure 4 Schematic diagram of the quartz room temperature bonding method according to an embodiment of the present invention, excluding the S400 quartz bond and the effect;

[0034] Figure 5 1. A schematic diagram of a quartz bond and its effect according to a quartz room temperature bonding method according to an embodiment of the present invention;

[0035] Figure 6 is a schematic diagram of a quartz room temperature bonding method according to an embodiment of the present invention;

[0036] Figure 7 is the surface roughness of the silicon dioxide bonding film after chemical mechanical polishing of the silicon dioxide bonding film according to an embodiment of the present invention.

[0037] Reference numerals:

[0038] Quartz wafer 1, silicon dioxide bonding film 2. DETAILED DESCRIPTION

[0039] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, identical modules are denoted by identical reference numerals. In the case of identical reference numerals, their names and functions are also identical. Therefore, their detailed description will not be repeated.

[0040] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not constitute a limitation of the present invention.

[0041] The quartz room temperature bonding method provided by an embodiment of the present invention includes: S100, cleaning the surface of a quartz plate 1; S200, depositing silicon dioxide on two quartz plates 1 to form a silicon dioxide bonding film 2 on the surface of the quartz plate 1; S300, performing chemical mechanical polishing on the silicon dioxide bonding film 2; S400, cleaning the quartz plate 1 with a hydrofluoric acid solution; S500, bringing the silicon dioxide bonding films 2 of the two quartz plates 1 into contact with each other and bonding the quartz plates 1 using a bonding machine.

[0042] This solution can complete the bonding between quartz plates 1 at room temperature without the need for high temperature conditions, and can be used for the production of various chips. Using a hydrofluoric acid solution to clean the quartz plates 1 after grinding can improve the bonding effect between the quartz plates 1, so that there is no unbonded area or only a small part of the unbonded area between the quartz plates 1. Compared with the traditional optical adhesive method, thermal bonding method and vacuum bonding method, this solution overcomes the defects of traditional quartz bonding technology, and can achieve high reliability of bonding between quartz and quartz at room temperature and pressure. It does not require any intermediate layer material for auxiliary connection and will not damage the optical properties of the quartz interface. The quartz plates 1 bonded using this solution show significant advantages in terms of bonding strength, temperature shock environment and adaptability to water environment.

[0043] like Figure 1 and Figure 6 As shown, the quartz room temperature bonding methods include:

[0044] S100, cleaning the surface of the quartz plate 1.

[0045] Use SC1 solution to clean and ensure the cleanliness of the surface of the quartz plate 1.

[0046] S200 , depositing silicon dioxide on two quartz plates 1 to form a silicon dioxide bonding film 2 on the surfaces of the quartz plates 1 .

[0047] Two quartz plates 1 are placed in a chemical vapor deposition device to deposit silicon dioxide so that a silicon dioxide bonding film 2, whose main component is silicon dioxide, is formed on the surface of the quartz plates 1. Since the main component of quartz is silicon dioxide, the generated silicon dioxide bonding film 2 does not affect the optical properties of quartz.

[0048] According to some embodiments of the present invention, S200 includes depositing the silicon dioxide on the quartz wafer 1 using chemical vapor deposition, wherein the silicon dioxide generation source is tetraethyl orthosilicate. The silicon dioxide is generated using tetraethyl orthosilicate, and a silicon dioxide bonding film 2 is formed on the surface of the quartz wafer 1 by chemical vapor deposition.

[0049] According to some embodiments of the present invention, the thickness of the silicon dioxide bonding film 2 generated in S200 is 1 micron to 3 microns. The thickness of the silicon dioxide bonding film 2 is 1 micron to 3 microns to prevent the silicon dioxide bonding film 2 from being completely removed in subsequent processes.

[0050] S300 , chemical mechanical polishing is performed on the silicon dioxide bonding film 2 .

[0051] The shape and thickness of the generated silicon dioxide bonding film 2 are often difficult to meet the bonding requirements, so the silicon dioxide bonding film 2 needs to be subjected to chemical mechanical polishing treatment to make the silicon dioxide bonding film 2 meet the bonding conditions.

[0052] According to some embodiments of the present invention, Figure 2 As shown, S300, chemical mechanical polishing is performed on the silicon dioxide bonding film 2, including:

[0053] S301 , placing the quartz plate 1 into a grinding chamber to grind the silicon dioxide bonding film 2 .

[0054] The silicon dioxide bonding film 2 is ground to a thickness that satisfies bonding conditions.

[0055] S302, placing the ground quartz plate 1 into the polishing chamber and polishing the silicon dioxide bonding film 2.

[0056] The surface roughness of the ground silica bonding film 2 is relatively large, which affects the optical properties of the quartz plate 1 and also affects the bonding effect of the quartz plate 1 . Therefore, the silica bonding film 2 is polished.

[0057] S303, placing the polished quartz plate 1 into an ultrasonic cavity for ultrasonic cleaning.

[0058] S304, placing the quartz plate 1 after ultrasonic cleaning into a cleaning chamber for cleaning.

[0059] S303 and S304 clean the quartz plate 1 to remove impurities generated by grinding and polishing.

[0060] S305 , placing the cleaned quartz plate 1 into a spin-drying chamber for spin-drying to remove the cleaning liquid on the quartz plate 1 .

[0061] According to some embodiments of the present invention, the thickness of the silicon dioxide bonding film 2 after chemical mechanical polishing is 5000 angstroms to 15000 angstroms. When the thickness of the silicon dioxide bonding film 2 is 5000 angstroms to 15000 angstroms, the bonding effect of the quartz plate 1 is better.

[0062] According to some embodiments of the present invention, after the processing in S300 , the silicon dioxide bonding film 2 has a profile arithmetic mean deviation Ra of less than 1 nanometer and a root mean square roughness Rq of less than 1.5 nanometers.

[0063] The surface roughness of the silicon dioxide bonding film 2 affects the bonding effect. The bonding effect is better when the profile arithmetic mean deviation Ra is less than 1 nanometer and the root mean square roughness Rq is less than 1.5 nanometers.

[0064] Figure 7 The arithmetic mean deviation and root mean square roughness of the profile of the quartz plate 1 after chemical mechanical polishing are actually measured, where "Slot" is the measurement position, "AFM" represents the type of surface roughness, and "CMP" is chemical mechanical polishing. Figure 7 As shown, the surface roughness of the silicon dioxide bonding film 2 after chemical mechanical polishing treatment meets the bonding requirements.

[0065] In some cases, there is a demand for the surface roughness of the quartz plate 1, and the surface of the quartz plate 1 is subjected to chemical mechanical grinding, such as Figure 7 As shown, the arithmetic mean deviation Ra of the profile of the quartz plate 1 is less than 1 nanometer, and the root mean square roughness Rq is less than 1.5 nanometers.

[0066] S400: Cleaning the quartz plate 1 with a hydrofluoric acid solution.

[0067] Using hydrofluoric acid solution to clean the quartz plate 1 can greatly improve the bonding effect between the quartz plates 1. Figure 4 and Figure 5 As shown, the white area is the bubble area. By comparison Figure 4 and Figure 5 It can be seen that if the quartz plate 1 is not cleaned with hydrofluoric acid solution, there will be bubbles in a large area after the quartz plate 1 is bonded, and there will also be bubbles in the middle of the quartz plate 1. If the quartz plate 1 is cleaned with hydrofluoric acid solution, there will only be some small bubbles at the edge after the quartz plate 1 is bonded.

[0068] According to some embodiments of the present invention, S400 also includes drying the quartz plate 1 after being cleaned with the hydrofluoric acid solution. After using the hydrofluoric acid solution to clean the quartz plate 1, the hydrofluoric acid solution is removed to avoid interference with subsequent steps. According to some embodiments of the present invention, the concentration of the hydrofluoric acid solution is 2%-5%. Using a low-concentration hydrofluoric acid solution to clean the quartz plate 1 can achieve better results. The best effect is when the concentration of the hydrofluoric acid solution is 2%-5%. Since the main component of quartz is silicon dioxide, when the concentration of the hydrofluoric acid solution is higher than 5%, the hydrofluoric acid solution will corrode the quartz plate 1. When the concentration of the hydrofluoric acid solution is lower than 2%, the cleaning effect on the quartz plate 1 and the effect of improving the bonding effect between the quartz plates 1 are relatively small.

[0069] S500: The silicon dioxide bonding films 2 of the two quartz plates 1 are brought into contact with each other and bonded together using a bonding machine. After the pre-processing, the silicon dioxide bonding films 2 between the two quartz plates 1 can be directly bonded together using a bonding machine.

[0070] According to some embodiments of the present invention, Figure 3 As shown, S500 includes:

[0071] In step S501, two quartz plates 1 are first placed in a plasma chamber in sequence to activate plasma on the surface, so that the silicon dioxide bonding film 2 can connect with more hydroxyl groups.

[0072] S502: The quartz wafer 1 enters the cleaning chamber and is subjected to surface hydrophilic treatment, so that the surface of the silicon dioxide bonding film 2 is connected to hydroxyl groups.

[0073] S503: Apply pressure to the upper quartz plate 1 to bond the two quartz plates 1. Chemical bonds are generated between the two silicon dioxide bonding films 2 to connect the two quartz plates 1.

[0074] According to some embodiments of the present invention, the duration of the pressure applied to the quartz plate 1 in S503 is 2 seconds to 20 seconds. If the pressure duration is less than 2 seconds, the reaction between the two silica bonding films 2 is incomplete, and if the pressure duration is greater than 20 seconds, the bonding effect between the quartz plates 1 may be affected.

[0075] According to some embodiments of the present invention, the room temperature quartz bonding method further includes annealing the bonding sheet. The successfully bonded bonding sheet is placed in an oven for annealing to improve the surface bonding strength, remove moisture from the bonding surface, and completely bond the two quartz sheets 1 together.

[0076] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0077] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

[0078] The above specific embodiments of the present invention do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. A quartz room temperature bonding method, characterized in that: include: S100, using SC1 solution to clean the surface of the quartz plate; S200, using chemical vapor deposition to deposit silicon dioxide on the two quartz plates to form a silicon dioxide bonding film on the surfaces of the quartz plates; the silicon dioxide generation source is ethyl orthosilicate; the thickness of the generated silicon dioxide bonding film is 1 micron to 3 microns to prevent the silicon dioxide bonding film from being completely removed in subsequent processes; S300, performing chemical mechanical polishing on the silicon dioxide bonding film; after the processing in S300, the silicon dioxide bonding film has a profile arithmetic mean deviation Ra of less than 1 nanometer and a root mean square roughness Rq of less than 1.5 nanometers; S400, cleaning the quartz plate with a hydrofluoric acid solution, and drying the quartz plate after cleaning with the hydrofluoric acid solution; the concentration of the hydrofluoric acid solution is 2%-5%; S500, bringing the silicon dioxide bonding films of the two quartz plates into contact with each other and bonding the quartz plates together using a bonding machine; comprising the following sub-steps: S501, the two quartz plates first enter the plasma chamber in sequence, and the surface of the plasma is activated; S502, the quartz plate enters the cleaning chamber and undergoes surface hydrophilic treatment; S503, applying pressure to the upper quartz plate to bond the two quartz plates; The bonding between quartz can be achieved at room temperature and pressure without damaging the optical properties of the quartz interface.

2. The quartz room temperature bonding method according to claim 1, wherein: The S300 includes the following sub-steps: S301, placing the quartz plate into a grinding chamber to grind the silicon dioxide bonding film; S302, placing the ground quartz plate into the silicon dioxide bonding film in the polishing chamber for polishing; S303, placing the polished quartz plate into an ultrasonic chamber for ultrasonic cleaning; S304, placing the quartz plate after ultrasonic cleaning into a cleaning chamber for cleaning; S305: placing the cleaned quartz plate into a drying chamber for drying.

3. The quartz room temperature bonding method according to claim 2, wherein: The thickness of the silicon dioxide bonding film after the S300 treatment is 5000 angstroms to 15000 angstroms.

4. The quartz room temperature bonding method according to claim 3, wherein: The duration of the pressure applied to the quartz plate in S503 is 2 seconds to 20 seconds.

5. The quartz room temperature bonding method according to claim 1, wherein: The quartz room temperature bonding method further includes annealing the bonding sheet.

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