Monocrystalline silicon wafer processing method and apparatus

Abstract

The application provides a single crystal silicon wafer processing method and device, and belongs to the technical field of semiconductor manufacturing. The single crystal silicon wafer processing device comprises: a rotating clamping structure for clamping a single crystal silicon wafer and driving the single crystal silicon wafer to rotate; a rotating table comprising a bearing plane; a protective glue container for storing protective glue; a nozzle in communication with the protective glue container through a pipeline, used for spraying the protective glue to the bearing plane; and a moving mechanism for moving and rotating the rotating table and controlling the rotating speed of the rotating table. The technical scheme of the application can improve the cleanliness of the single crystal silicon wafer.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing technology, and in particular to a method and apparatus for processing single-crystal silicon wafers. Background Technology

[0002] As the most widely used substrate for large-scale silicon semiconductor integrated circuit manufacturing, the manufacturing process of silicon wafers generally includes crystal pulling, dicing, polishing, and cleaning. Different types of wafers are required for the fabrication of different devices in the integrated circuit manufacturing field. Epitaxial wafers are silicon wafers with a thin layer of single-crystal silicon deposited on the surface of a single-crystal silicon wafer, and are mostly used in the CMOS (Complementary Metal Oxide Semiconductor) field. Polished wafers are silicon wafers that have undergone polishing, and are mostly used in NAND (Non-volatile Memory Device) / DRAM (Dynamic Random Access Memory) devices.

[0003] Whether it's an epitaxial wafer or a polished wafer, as the chip size of the wafer gets smaller and smaller, the requirements for the cleanliness of the single-crystal silicon wafer substrate are also getting higher and higher. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a method and apparatus for processing monocrystalline silicon wafers, which can improve the cleanliness of monocrystalline silicon wafers.

[0005] To achieve the above objectives, the technical solution adopted in the embodiments of the present invention is as follows:

[0006] A single-crystal silicon wafer processing apparatus, comprising:

[0007] A rotating clamping structure is used to clamp a monocrystalline silicon wafer and drive the monocrystalline silicon wafer to rotate.

[0008] A rotary table, including a bearing surface;

[0009] A protective adhesive container for storing a protective adhesive, wherein the protective adhesive is made of a hydrophobic material;

[0010] A nozzle connected to the protective adhesive container via a pipeline is used to spray the protective adhesive onto the bearing surface.

[0011] A moving mechanism for moving and rotating the rotary table and controlling the rotation speed of the rotary table.

[0012] In some embodiments, it also includes:

[0013] The valve assembly installed on the pipeline is used to control the supply speed of the protective adhesive.

[0014] In some embodiments, it also includes:

[0015] A heating component for heating the protective adhesive sprayed onto the bearing surface.

[0016] In some embodiments, the bearing plane is circular, and the diameter of the bearing plane is equal to the diameter of the single-crystal silicon wafer held by the rotating clamping structure.

[0017] In some embodiments, the protective adhesive includes a base agent and a curing agent, wherein the weight ratio of the base agent to the curing agent is 10:1 to 20:1, and the base agent is a hydrophobic material.

[0018] This invention also provides a method for processing monocrystalline silicon wafers, applied to the monocrystalline silicon wafer processing apparatus described above, the method comprising:

[0019] The nozzle is controlled to spray the protective adhesive onto the bearing surface, while the moving mechanism is controlled to rotate the rotary table.

[0020] Control the nozzle to stop spraying the protective adhesive, and control the moving mechanism to move the rotary table to a position below the monocrystalline silicon wafer held by the rotary clamping structure in the vertical direction, with the center of the bearing plane coinciding with the center of the monocrystalline silicon wafer in the vertical direction;

[0021] The moving mechanism is controlled to rotate the rotary table, and the rotary table is moved upward so that the back side of the monocrystalline silicon wafer comes into contact with the protective adhesive on the bearing plane;

[0022] The rotating clamping structure is controlled to rotate the monocrystalline silicon wafer, forming a protective film composed of the protective adhesive on the back side of the monocrystalline silicon wafer.

[0023] In some embodiments, controlling the nozzle to spray the protective adhesive onto the bearing surface while simultaneously controlling the moving mechanism to rotate the rotary table includes:

[0024] In the first protective adhesive supply stage, the supply speed of the protective adhesive is controlled by the valve assembly to be 5 ml / s and the supply time is 5s to 20s. At the same time, the moving mechanism is controlled to start rotating the rotating table. After the speed of the rotating table reaches the set speed, the rotating table rotates for 60s to cure the protective adhesive on the bearing surface.

[0025] In the second protective adhesive supply stage, the supply speed of the protective adhesive is controlled by the valve assembly to be 3 ml / s, the supply time is 5s to 20s, and the rotating table rotates at a set speed for 60s.

[0026] In some embodiments, curing the protective adhesive on the bearing surface includes:

[0027] During the first protective adhesive supply stage, the heating component is controlled to heat the protective adhesive sprayed onto the bearing surface at a temperature of 40°C to 70°C.

[0028] In some embodiments, the minimum distance d between the monocrystalline silicon wafer and the bearing plane is 0.1-1 mm.

[0029] In some embodiments, the rotation direction of the rotating clamping structure is opposite to the rotation direction of the rotating table;

[0030] The rotational speed of the rotating clamping structure and / or the rotational speed of the rotating stage are inversely proportional to the thickness of the protective film formed on the back of the monocrystalline silicon wafer.

[0031] The beneficial effects of this invention are:

[0032] In this embodiment, a protective film can be formed on the back side of the monocrystalline silicon wafer. The protective film is made of a hydrophobic material, which does not easily adsorb external impurity particles. This can protect the back side of the monocrystalline silicon wafer from contamination, thereby improving the cleanliness of the back side of the monocrystalline silicon wafer and thus improving the yield of devices made from the monocrystalline silicon wafer. Attached Figure Description

[0033] Figures 1-3 This is a schematic diagram showing the structure of a single-crystal silicon wafer processing device according to an embodiment of the present invention.

[0034] Figure Labels

[0035] 100 Rotational axis

[0036] 110 Clamping Part

[0037] 200 monocrystalline silicon wafer

[0038] 300 Rotary Table

[0039] 310 Bearing plane

[0040] 400 nozzle

[0041] 410 Protective Adhesive

[0042] 500 Protective Adhesive Container

[0043] 510 piping

[0044] 520 Valve Assembly Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention are within the scope of protection of the present invention.

[0046] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0047] During processing and testing, the defect rate caused by contamination on the back side of monocrystalline silicon wafers accounts for about 10% of the overall defect rate. Therefore, the cleanliness of monocrystalline silicon wafers can be improved by protecting the back side of the wafers, thereby increasing the yield of devices made from monocrystalline silicon wafers.

[0048] This invention provides a single-crystal silicon wafer processing apparatus, such as... Figures 1-3 As shown, it includes:

[0049] A rotating clamping structure is used to clamp a single-crystal silicon wafer and drive the single-crystal silicon wafer to rotate. The rotating clamping structure consists of a rotating shaft 100 and a clamping part 110. The clamping part 110 clamps the single-crystal silicon wafer, and the rotating shaft 100 drives the clamping part 110 to rotate.

[0050] The rotary table 300 includes a bearing surface 310;

[0051] Protective adhesive container 500, used to store protective adhesive 410;

[0052] A nozzle 400, which is connected to the protective adhesive container 500 via a conduit 510, is used to spray the protective adhesive 410 onto the bearing surface 310.

[0053] A moving mechanism is used to move and rotate the rotary table 300 and control the rotation speed of the rotary table 300.

[0054] In this embodiment, a protective film can be formed on the back side of the monocrystalline silicon wafer. The protective film is made of a hydrophobic material, which does not easily adsorb external impurity particles. This can protect the back side of the monocrystalline silicon wafer from contamination, thereby improving the cleanliness of the back side of the monocrystalline silicon wafer and thus improving the yield of devices made from the monocrystalline silicon wafer.

[0055] Silicon wafers are cut from silicon rods. The multi-layered crystal lattice on the surface of the silicon wafer is in a disrupted state, filled with unsaturated dangling bonds. These dangling bonds are highly reactive and easily attract external impurity particles, leading to surface contamination and performance degradation. Impurity particles adsorbed on the silicon wafer include particulate impurities, metal ions, organic compounds, and H2O. Particulate impurities reduce the dielectric strength of the silicon wafer, metal ions increase the reverse leakage current of the photovoltaic cell's PN junction and reduce minority carrier lifetime, organic compounds degrade the quality of the oxide layer on the silicon wafer surface, and H2O exacerbates surface corrosion. In this embodiment, a protective film is formed on the back side of the monocrystalline silicon wafer. This protective film is made of a hydrophobic material, which does not easily attract external impurity particles, thus preventing contamination of the back side of the monocrystalline silicon wafer. In this embodiment, the protective film can be formed on the back side of the polished monocrystalline silicon wafer after polishing. When the monocrystalline silicon wafer is transported to the wafer fab, ready for chip fabrication, the protective film can be removed using an acid or alkali solution before chip fabrication. In this way, during the process from polishing to transporting the monocrystalline silicon wafer to the wafer fab, the protective film can protect the back side of the monocrystalline silicon wafer from contamination, thereby preventing contamination from the back side from spreading to the front side of the monocrystalline silicon wafer and affecting the yield of devices made from the monocrystalline silicon wafer.

[0056] In some embodiments, the single-crystal silicon wafer processing apparatus further includes:

[0057] A valve assembly 520 installed on the pipeline 510 is used to control the supply speed of the protective adhesive. The supply speed of the protective adhesive can be adjusted by the valve assembly 520, thereby adjusting the supply amount of the protective adhesive.

[0058] In some embodiments, the single-crystal silicon wafer processing apparatus further includes:

[0059] A heating element is used to heat the protective adhesive sprayed onto the bearing surface, causing the adhesive to cure. The heating element can be a hot air blower or a heater.

[0060] In some embodiments, the bearing plane 310 is circular, and the diameter of the bearing plane 310 is equal to the diameter of the single-crystal silicon wafer held by the rotating clamping structure, which facilitates the alignment of the bearing plane 310 with the single-crystal silicon wafer.

[0061] In some embodiments, the protective adhesive includes a base agent and a curing agent, wherein the weight ratio of the base agent to the curing agent is 10:1 to 20:1, including weight ratios of 10:1, 12:1, 14:1, 16:1, 18:1, or 20:1. The base agent can be polydimethylsiloxane, and the base agent and curing agent can be mixed uniformly in the protective adhesive container. Of course, the base agent is not limited to polydimethylsiloxane; other hydrophobic materials can also be used.

[0062] This invention also provides a method for processing monocrystalline silicon wafers, applied to the monocrystalline silicon wafer processing apparatus described above, the method comprising:

[0063] The nozzle is controlled to spray the protective adhesive onto the bearing surface, while the moving mechanism is controlled to rotate the rotary table.

[0064] Control the nozzle to stop spraying the protective adhesive, and control the moving mechanism to move the rotary table to a position below the monocrystalline silicon wafer held by the rotary clamping structure in the vertical direction, with the center of the bearing plane coinciding with the center of the monocrystalline silicon wafer in the vertical direction;

[0065] The moving mechanism is controlled to rotate the rotary table, and the rotary table is moved upward so that the back side of the monocrystalline silicon wafer comes into contact with the protective adhesive on the bearing plane;

[0066] The rotating clamping structure is controlled to rotate the monocrystalline silicon wafer, forming a protective film composed of the protective adhesive on the back side of the monocrystalline silicon wafer.

[0067] In some embodiments, controlling the nozzle to spray the protective adhesive onto the bearing surface while simultaneously controlling the moving mechanism to rotate the rotary table includes:

[0068] In the first protective adhesive supply stage, the supply speed of the protective adhesive is controlled by the valve assembly to be 5 ml / s and the supply time is 5s to 20s. At the same time, the moving mechanism is controlled to start rotating the rotating table. After the speed of the rotating table reaches the set speed, the rotating table rotates for 60s to cure the protective adhesive on the bearing surface.

[0069] In the second protective adhesive supply stage, the supply speed of the protective adhesive is controlled by the valve assembly to be 3 ml / s, the supply time is 5s to 20s, and the rotating table rotates at a set speed for 60s.

[0070] In this embodiment, the protective adhesive sprayed by the nozzle onto the bearing surface is liquid. If the protective adhesive is sprayed onto the bearing surface and then the bearing surface comes into contact with the back of the monocrystalline silicon wafer, the liquid protective adhesive is not easy to separate from the bearing surface. Therefore, a layer of cured protective adhesive can be formed on the bearing surface first, and then a layer of liquid protective adhesive can be formed on the cured protective adhesive. Since the cured protective adhesive and the liquid protective adhesive are made of the same material, the liquid protective adhesive is easier to separate from the cured protective adhesive and adhere to the back of the monocrystalline silicon wafer.

[0071] In this embodiment, during the first protective adhesive supply stage, the nozzle is controlled to spray the protective adhesive onto the bearing surface. Under the action of centrifugal force, the protective adhesive can evenly cover the bearing surface and cure, forming a cured protective adhesive layer. During the second protective adhesive supply stage, the nozzle is controlled to spray the protective adhesive onto the bearing surface. Under the action of centrifugal force, the protective adhesive can evenly cover this cured protective adhesive layer.

[0072] In some embodiments, curing the protective adhesive on the bearing surface includes:

[0073] During the first protective adhesive supply stage, the heating component is controlled to heat the protective adhesive sprayed onto the bearing surface at a temperature of 40°C to 70°C.

[0074] In some embodiments, the minimum distance d between the monocrystalline silicon wafer and the supporting plane is 0.1-1 mm. The minimum distance d between the monocrystalline silicon wafer and the supporting plane is the vertical distance between the back surface of the monocrystalline silicon wafer and the supporting plane. If the minimum distance between the monocrystalline silicon wafer and the supporting plane is too large, the protective adhesive on the supporting plane cannot contact the monocrystalline silicon wafer; if the minimum distance between the monocrystalline silicon wafer and the supporting plane is too small, the thickness of the protective film formed on the monocrystalline silicon wafer is too small, and it cannot effectively protect the back surface of the monocrystalline silicon wafer.

[0075] The thickness of the protective film on the back of the monocrystalline silicon wafer needs to be precisely controlled by the rotation speed of the rotating clamping structure and the rotating stage. In some embodiments, the rotation direction of the rotating clamping structure is opposite to the rotation direction of the rotating stage.

[0076] The rotational speed of the rotating clamping structure and / or the rotational speed of the rotating stage are inversely proportional to the thickness of the protective film formed on the back of the monocrystalline silicon wafer.

[0077] In one specific example, the rotational speed of the rotating clamping structure is 600 r / min, the rotational speed of the rotating stage is 1500 r / min, d is 0.1 mm, and the thickness of the protective film formed on the back of the single crystal silicon wafer is approximately 8000 angstroms.

[0078] The rotational speed of the rotating clamping structure is 800 r / min, the rotational speed of the rotating stage is 2500 r / min, d is 0.4 mm, and the thickness of the protective film formed on the back of the single crystal silicon wafer is approximately 6000 angstroms.

[0079] The rotational speed of the rotating clamping structure is 1000 r / min, the rotational speed of the rotating stage is 3500 r / min, d is 0.7 mm, and the thickness of the protective film formed on the back of the single crystal silicon wafer is approximately 4000 angstroms.

[0080] The rotational speed of the rotating clamping structure is 1200 r / min, the rotational speed of the rotating stage is 4500 r / min, d is 0.7 mm, and the thickness of the protective film formed on the back of the single crystal silicon wafer is approximately 3000 angstroms.

[0081] Therefore, the rotational speed of the rotary clamping structure and the rotational speed of the rotary table can be adjusted according to the thickness of the protective film to be formed.

[0082] In a specific example, such as Figures 1-3 As shown, the silicon wafer processing method of this embodiment includes the following steps:

[0083] like Figure 1 As shown, in the first protective adhesive supply stage, the control nozzle 400 sprays protective adhesive 410 onto the bearing surface 310. The supply speed of the protective adhesive is controlled to be 5 ml / s by the valve assembly 520 set on the pipeline 510, and the supply time is 5s to 20s. At the same time, the moving mechanism starts to rotate the rotating table 300. After about 10s, the rotation speed of the rotating table 300 reaches the set speed of 1500r / min to 5000r / min. The rotating table 300 rotates for 60s. During the rotation of the rotating table 300, the protective adhesive on the bearing surface 310 is cured by hot air.

[0084] In the second protective adhesive supply stage, the control nozzle 400 sprays protective adhesive 410 onto the bearing surface 310. The supply speed of the protective adhesive is controlled by the valve assembly 520 set on the pipeline 510 to be 3 ml / s and the supply time is 5s to 20s. The rotating table 300 continues to rotate at a set speed of 1500 r / min to 5000 r / min. At this time, it is not necessary to cure the protective adhesive.

[0085] like Figure 2As shown, the rotary table 300 is moved below the monocrystalline silicon wafer 200 held by the rotary clamping structure. The center of the monocrystalline silicon wafer 200 coincides with the center of the bearing plane 310 in the vertical direction. The rotary table 300 rotates while moving upwards at a speed of 0.01 mm / s to 0.10 mm / s. The rotary table 300 has a limit, and the minimum distance d between the monocrystalline silicon wafer and the bearing plane is 0.1-1 mm. The protective adhesive coated on the bearing plane 310 contacts the back side of the monocrystalline silicon wafer 200. The rotary clamping structure drives the monocrystalline silicon wafer 200 to rotate in the opposite direction to the rotation of the rotary table 300. Through the rotation of the rotary table 300 and the monocrystalline silicon wafer 200, the protective adhesive can be evenly coated on the back side of the monocrystalline silicon wafer 200.

[0086] like Figure 3 As shown, the protective adhesive coated on the bearing plane 310 contacts the back side of the monocrystalline silicon wafer 200 for a certain period of time, such as 60 seconds. After that, the rotating stage 300 is removed. The back side of the monocrystalline silicon wafer 200 is coated with a layer of protective adhesive. This layer of protective adhesive can be heated to cure it and form a protective film. Alternatively, the protective adhesive can be left unheated and allowed to stand for a period of time to cure and form a protective film. This protective film can protect the back side of the monocrystalline silicon wafer from contamination, thereby improving the cleanliness of the back side of the monocrystalline silicon wafer and thus improving the yield of devices fabricated from the monocrystalline silicon wafer.

[0087] It should be noted that the various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, since the embodiments are basically similar to the product embodiments, the descriptions are relatively simple, and the relevant parts can be referred to the descriptions of the product embodiments.

[0088] In the description of the above embodiments, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0089] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. A method for processing single-crystal silicon wafers, characterized in that, A single-crystal silicon wafer processing device is used to process single-crystal silicon wafers. The device includes: a rotating clamping structure for clamping and rotating the single-crystal silicon wafer; a rotating table including a bearing plane; a protective adhesive container for storing a hydrophobic material; a nozzle connected to the protective adhesive container via a pipeline for spraying the protective adhesive onto the bearing plane; a moving mechanism for moving and rotating the rotating table and controlling its rotation speed; and a valve assembly on the pipeline for controlling the supply speed of the protective adhesive. The method includes: The nozzle is controlled to spray the protective adhesive onto the bearing surface, while the moving mechanism is controlled to rotate the rotary table. Control the nozzle to stop spraying the protective adhesive, and control the moving mechanism to move the rotary table to a position below the monocrystalline silicon wafer held by the rotary clamping structure in the vertical direction, with the center of the bearing plane coinciding with the center of the monocrystalline silicon wafer in the vertical direction; The moving mechanism is controlled to rotate the rotary table, and the rotary table is moved upward so that the back side of the monocrystalline silicon wafer comes into contact with the protective adhesive on the bearing plane; The rotating clamping structure is controlled to rotate the monocrystalline silicon wafer, forming a protective film composed of the protective adhesive on the back of the monocrystalline silicon wafer; The process of controlling the nozzle to spray the protective adhesive onto the bearing surface, while simultaneously controlling the moving mechanism to rotate the rotary table, includes: In the first protective adhesive supply stage, the supply speed of the protective adhesive is controlled by the valve assembly to be 5ml / s and the supply time is 5s~20s. At the same time, the moving mechanism is controlled to start rotating the rotating table. After the speed of the rotating table reaches the set speed, the rotating table rotates for 60s to cure the protective adhesive on the bearing surface. In the second protective adhesive supply stage, the supply speed of the protective adhesive is controlled by the valve assembly to be 3 ml / s, the supply time is 5s~20s, and the rotating table rotates at a set speed for 60s.

2. The method for processing single-crystal silicon wafers according to claim 1, characterized in that, The single-crystal silicon wafer processing apparatus further includes: A heating component for heating the protective adhesive sprayed onto the bearing surface.

3. The method for processing single-crystal silicon wafers according to claim 2, characterized in that, Curing the protective adhesive on the bearing surface includes: During the first protective adhesive supply stage, the heating component is controlled to heat the protective adhesive sprayed onto the bearing surface at a temperature of 40°C to 70°C.

4. The method for processing single-crystal silicon wafers according to claim 1, characterized in that, The bearing plane is circular, and the diameter of the bearing plane is equal to the diameter of the single-crystal silicon wafer held by the rotating clamping structure.

5. The method for processing single-crystal silicon wafers according to claim 1, characterized in that, The protective adhesive includes a main agent and a curing agent, and the weight ratio of the main agent to the curing agent is 10:1 to 20:

1. The main agent is made of a hydrophobic material.

6. The method for processing single-crystal silicon wafers according to claim 1, characterized in that, The minimum distance d between the monocrystalline silicon wafer and the bearing plane is 0.1-1 mm.

7. The method for processing single-crystal silicon wafers according to claim 1, characterized in that, The rotation direction of the rotating clamping structure is opposite to the rotation direction of the rotating table; The rotational speed of the rotating clamping structure and / or the rotational speed of the rotating stage are inversely proportional to the thickness of the protective film formed on the back of the monocrystalline silicon wafer.

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