Surface treatment method of solid-state B2O3 doping source

Abstract

The invention discloses a surface treatment method for a solid-state B2O3 doping source, which belongs to the technical field of semiconductor processes, and is characterized in that a silicon wafer is used for scraping and etching the surface of a boron source without polluting a source wafer, the doped silicon wafer is not influenced when the silicon wafer is used for a diffusion source, and meanwhile, baking is beneficial to surface water vapor drying; deformation and surface local bubbling and falling caused by direct heating to the high temperature required by doping are avoided, diffusion doping uniformity can be improved, the boron diffusion source surface without a non-compact loose layer on the surface can be obtained finally, and the technological method is simple in theory, easy to understand and suitable for large-scale production. Different process technicians can perform adjustment according to different equipment and process conditions, results meeting process requirements can be obtained by following the method, and the application range is wide.

Description

Technical Field

[0001] The present invention belongs to the field of semiconductor process technology and particularly relates to a solid-state B 2 O 3 Surface treatment method of doping source. Background Art

[0002] The diffusion doping process plays an important role in semiconductor chip manufacturing. It introduces specific types of impurity atoms into silicon wafers to precisely control the electrical properties of the material, thereby meeting the performance requirements of different devices. In this process, solid sources, liquid sources or gas sources can be flexibly selected for diffusion according to the state of the doping source material. Each method has its own unique advantages and application scenarios, and solid source diffusion, especially using B 2 O 3 As a diffusion source, it has been widely used in P-type doping due to its stability and controllability.

[0003] B 2 O 3 The main advantage of (boron trioxide) as a solid diffusion source is that the boron (B) element it contains can effectively diffuse into the silicon wafer lattice, replacing some silicon atoms to form a P-type semiconductor. This process is crucial for adjusting the conductivity of the silicon wafer, controlling the carrier concentration, and optimizing device performance. However, B 2 O 3 During the preparation and storage process, the source wafer is prone to adsorb impurities and form surface particles, and there is often a loose and non-dense layer on the surface. These defects not only affect the uniform diffusion of boron atoms, but may also lead to unstable electrical properties of the final semiconductor product and even cause reliability problems.

[0004] Therefore, when using B 2 O 3 Strict surface treatment of the source wafer is an essential step. This treatment process usually includes two stages: physical cleaning and chemical etching, which aims to completely remove pollutants, particles and non-dense layers on the surface of the source wafer. Physical cleaning can remove large particles and loose materials through ultrasonic cleaning, brushing and other methods; while chemical etching uses specific chemical solutions to selectively dissolve the non-dense layer and other impurities on the surface, while ensuring that the main structure of the boron source is not damaged.

[0005] Carefully processed B 2 O 3The surface of the source wafer becomes smoother and denser, reducing the risk of cracking due to thermal stress during high-temperature diffusion, and significantly improving the uniformity and consistency of doping. This not only helps to improve the yield and performance stability of semiconductor devices, but also lays a good foundation for subsequent process steps such as lithography and etching. It is one of the key links to ensure the high quality and high efficiency of the entire semiconductor chip manufacturing process. In addition, with the continuous advancement of semiconductor technology, the B 2 O 3 The requirements for source wafer surface processing technology are also constantly increasing to meet the needs of chip manufacturing with smaller size and more complex structure. Summary of the invention

[0006] The object of the present invention is to provide a solid B 2 O 3 Surface treatment method of doping source to solve B 2 O 3 The source film will introduce surface particles during the manufacturing process, and the unused B 2 O 3 There is a technical problem that there is a non-dense layer on the surface of the source piece.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions: A solid B 2 O 3 The surface treatment method of the doping source comprises: Solid B 2 O 3 Physically erasing the surface of the doped source sheet; After physically erasing the solid state B 2 O 3 The surface of the doping source sheet is scrubbed; After scrubbing the surface, solid B 2 O 3 The doped source piece is baked to obtain the processed solid B 2 O 3 Doping source sheet; Among them, solid B 2 O 3 Physical erasure of the doped source wafer: Use a diamond knife to scratch the side of the silicon wafer to scrape the surface of the B2O3 doped source wafer until no particles fall off the surface.

[0008] Preferably, the surface is wiped with a dust-free cloth soaked in anhydrous ethanol.

[0009] Preferably, the anhydrous ethanol used for surface scrubbing is of MOS grade.

[0010] Preferably, after wiping is completed, flushing and air drying operations are performed in sequence.

[0011] Preferably, DI water is used for flushing for more than 10 minutes.

[0012] Preferably, air drying is performed using a nitrogen gun until no water droplets adhere to the surface.

[0013] Preferably, the baking tool is a horizontal furnace tube.

[0014] Preferably, the baking method is to pass saturated N 2 bake. Preferably, the baking temperature is 150°C to 200°C.

[0015] Preferably, the baking time is 20-28 hours.

[0016] Compared with the prior art, the present invention has the following beneficial effects: the present invention provides a solid B 2 O 3 The surface treatment method of the doping source uses a silicon wafer to scrape the surface of the boron source without causing contamination to the source wafer, and will not affect the doped silicon wafer when used as a diffusion source. At the same time, baking is conducive to drying of surface water vapor, avoiding deformation and local bubbling and shedding of the surface caused by directly rising to the high temperature required for doping, which is conducive to improving the uniformity of diffusion doping, and finally a boron diffusion source surface without a non-dense loose layer can be obtained. The theory of this process method is simple and easy to understand. Different process technicians can adjust it according to different equipment and process conditions. Following this method can obtain results that meet the process requirements, and it has a wide range of applications.

[0017] Further, the side of the silicon wafer cleaved by a diamond knife is scratched to form B 2 O 3 The surface of the doping source can effectively remove impurities and pollutants on the surface of the source wafer, including particles, dust, organic matter, etc., to ensure the cleanliness of the surface of the source wafer.

[0018] Furthermore, wiping the surface with a dust-free cloth soaked in anhydrous ethanol can further remove tiny particles and contaminants that may remain on the surface of the source wafer during the physical erasing process, thereby ensuring a high degree of surface cleanliness.

[0019] Furthermore, MOS-grade anhydrous ethanol has high purity and few impurities, which can ensure that no new pollutants are introduced during the scrubbing process and maintain the high cleanliness of the source wafer surface.

[0020] Furthermore, flushing with DI water (deionized water) for more than 10 min can completely remove the anhydrous ethanol residue and further clean the surface to ensure the cleanliness of the surface.

[0021] Furthermore, nitrogen is used to blow dry the surface of the source wafer until no water droplets are attached, so as to avoid water droplets leaving traces on the surface of the source wafer or causing secondary pollution, while keeping the surface of the source wafer dry.

[0022] Furthermore, low-temperature baking can completely remove the moisture remaining on the surface of the source wafer during the scrubbing process, thereby avoiding the influence of moisture on subsequent processes.

[0023] Furthermore, by selecting a low-temperature baking range of 150° C. to 200° C., the purpose of removing moisture and stabilizing the surface can be achieved without damaging the source wafer or introducing new defects due to excessively high temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A solid B 2 O 3 Flow chart of the surface treatment method of the doping source. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0026] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0028] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0029] In order to remove the non-dense loose layer on the surface of the boron source, remove surface particles, reduce the cracking of the surface of the boron source at high temperature, improve the surface integrity of the boron source, and thereby improve the doping uniformity.

[0030] like Figure 1 As shown, the present invention provides a solid B 2 O 3 A surface treatment method for a doping source, comprising: S1, physical erasure of the source chip surface; S2, scrubbing the surface of the source sheet obtained in S1; S3, low-temperature baking is performed on the source sheet obtained in S2.

[0031] Further, in S1, the surface of the source wafer is physically erased by scraping the side of the silicon wafer with a diamond knife. 2 O 3 The surface of the doping source is cleaned until no particles fall off the surface.

[0032] Using a diamond knife to scratch the side of the silicon wafer B 2 O 3 The surface of the doping source can effectively remove impurities and pollutants on the surface of the source wafer, including particles, dust, organic matter, etc., to ensure the cleanliness of the surface of the source wafer.

[0033] During the physical erasing process, the scraping action can activate the surface of the source sheet to a certain extent, increase its surface activity, and facilitate the adsorption and reaction of substances in subsequent processing steps.

[0034] Compared with the chemical cleaning method, the physical erasing method avoids the contamination and residue problems that may be caused by the use of chemical reagents, thereby ensuring the purity of the source wafer surface.

[0035] Clean surfaces help B 2 O 3 The doping source is more evenly distributed on the surface of the source piece, improving the uniformity and effect of doping.

[0036] Furthermore, in S2, the surface is scrubbed by wiping the surface with a dust-free cloth soaked in anhydrous ethanol and then rinsing and drying the surface.

[0037] Wiping the surface with a dust-free cloth soaked in anhydrous ethanol can further remove tiny particles and contaminants that may remain on the surface of the source wafer during the physical erasing process, ensuring a high degree of surface cleanliness.

[0038] As an organic solvent, anhydrous ethanol can effectively dissolve and remove organic residues on the surface of the source wafer, preventing these residues from interfering with subsequent processes.

[0039] Anhydrous ethanol has good cleaning ability and can further remove residues on the surface, while the dust-free cloth can avoid the introduction of new contaminants and ensure the cleanliness of the surface.

[0040] Furthermore, in S2, the anhydrous ethanol used for surface scrubbing is of MOS grade.

[0041] The purity of MOS-grade anhydrous ethanol is very high, generally reaching 99.8%. This level of alcohol has extremely low impurity content. MOS-grade anhydrous ethanol has high purity and few impurities, which can ensure that no new pollutants are introduced during the scrubbing process and maintain the high cleanliness of the source wafer surface.

[0042] In the semiconductor manufacturing process, the application of MOS grade anhydrous ethanol can ensure the stability of the process and the quality of the product. Due to its extremely low impurity content and high purity, it helps to reduce contamination and defects in the process and improve the yield and performance of the chip.

[0043] Furthermore, in S2, the surface is rinsed with DI water for more than 10 minutes after being scrubbed.

[0044] Flushing with DI water (deionized water) for more than 10 minutes can completely remove the anhydrous ethanol residue and further clean the surface to ensure the cleanliness of the surface.

[0045] Furthermore, in S2, the surface is scrubbed, rinsed with DI water, and then blown dry with nitrogen until no water droplets adhere to the surface.

[0046] Use nitrogen to blow dry the surface of the source wafer until there are no water droplets attached. This can prevent water droplets from leaving traces on the surface of the source wafer or causing secondary contamination, while keeping the surface of the source wafer dry. At the same time, nitrogen, as an inert gas, will not introduce new impurities.

[0047] Further, in S3, the low temperature baking is carried out in a horizontal furnace tube, and saturated N 2 Baking, the baking temperature is 150℃~200℃.

[0048] Low-temperature baking can completely remove the moisture remaining on the surface of the source wafer during the scrubbing process, avoiding the influence of moisture on subsequent processes. The horizontal furnace tube provides a uniform and stable heating environment, which helps to remove the residual stress and moisture inside the B2O3-doped source wafer and improve the stability and reliability of the material.

[0049] By baking, the structure of the surface of the source sheet can be made more stable, reducing problems such as surface deformation or stress concentration caused by temperature changes.

[0050] During the baking process, the temperature of the source surface is moderate, which is conducive to B 2 O 3 The doping source is better attached to the surface of the source sheet, improving the firmness and uniformity of the doping.

[0051] Selecting a low-temperature baking range of 150°C to 200°C can achieve the purpose of removing moisture and stabilizing the surface without damaging the source wafer or introducing new defects due to excessively high temperature.

[0052] By low-temperature baking, the quality of the overall process can be further improved, ensuring the stability and reliability of the source wafer during subsequent processing and use.

[0053] This technology belongs to a solid source surface treatment technology in solid source diffusion. General surface treatment technologies include physical surface treatment and chemical surface treatment.2 O 3 The surface treatment method of solid-state source is a combination of physical erasing and chemical cleaning. The physical method uses recycled silicon wafers to treat B 2 O 3 The loose layer on the surface of the solid source is physically wiped off, and the chemical method used uses anhydrous ethanol and pure water to clean the surface particles, and then low-temperature baking is performed using a diffusion furnace. Compared with other solid source surface treatment technologies, the operation is simple, no other impurities are introduced, the solid source surface is intact, and the diffusion uniformity is high at high temperatures.

[0054] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0055] The following examples use conventional instruments and equipment in the art. The experimental methods in the following examples where specific conditions are not specified are usually carried out under conventional conditions or under conditions recommended by the manufacturer. The various raw materials used in the following examples are conventional commercial products unless otherwise specified, and their specifications are conventional specifications in the art. In the specification of the present invention and the following examples, unless otherwise specified, "%" means weight percentage, "part" means weight part, and ratio means weight ratio.

[0056] Embodiment 1: S1, physical erasure of the source wafer surface, using a diamond knife to scratch the side of the silicon wafer B 2 O 3 The surface of the doping source is cleaned until no particles fall off the surface.

[0057] S2, scrub the surface of the source wafer obtained in S1, wipe the surface with a dust-free cloth soaked in MOS-grade anhydrous ethanol, rinse with water for 20 minutes, and then use a nitrogen gun to blow dry until there are no water droplets attached to the surface.

[0058] S3, the source sheet obtained in S2 is baked at low temperature, the source sheet is clamped into a horizontal furnace tube, and saturated N 2 Bake at 150°C for 24 hours.

[0059] Embodiment 2: S1, physical erasure of the source wafer surface, using a diamond knife to scratch the side of the silicon wafer B 2 O 3 The surface of the doping source is cleaned until no particles fall off the surface.

[0060] S2, scrub the surface of the source wafer obtained in S1, wipe the surface with a dust-free cloth soaked in MOS-grade anhydrous ethanol, rinse with water for 15 minutes, and then use a nitrogen gun to blow dry until there are no water droplets attached to the surface.

[0061] S3, the source sheet obtained in S2 is baked at low temperature, the source sheet is clamped into a horizontal furnace tube, and saturated N 2 Bake at 180°C for 20 hours.

[0062] Embodiment 3: S1, physical erasure of the source wafer surface, using a diamond knife to scratch the side of the silicon wafer B 2 O 3 The surface of the doping source is cleaned until no particles fall off the surface.

[0063] S2, scrub the surface of the source wafer obtained in S1, wipe the surface with a dust-free cloth soaked in MOS-grade anhydrous ethanol, rinse with water for 12 minutes, and then use a nitrogen gun to blow dry until there are no water droplets attached to the surface.

[0064] S3, the source sheet obtained in S2 is baked at low temperature, the source sheet is clamped into a horizontal furnace tube, and saturated N 2 Bake at 200°C for 28 hours.

[0065] In summary, using silicon wafers to scrape the surface of the boron source will not cause contamination to the source wafer, and will not affect the doped silicon wafer when used as a diffusion source. At the same time, baking is conducive to drying of surface water vapor, avoiding deformation and local bubbling and shedding of the surface caused by directly rising to the high temperature required for doping, which is beneficial to improving the uniformity of diffusion doping. Finally, a boron diffusion source surface with no non-dense loose layer on the surface can be obtained. The theory of this process method is simple and easy to understand. Different process technicians can adjust it according to different equipment and process conditions. Following this method can obtain results that meet the process requirements, and it has a wide range of applications.

[0066] Although the embodiments of the present invention are described above in conjunction with the accompanying drawings, the present invention is not limited to the above-mentioned specific embodiments and application fields, and the above-mentioned specific embodiments are only illustrative and instructive, rather than restrictive. Under the guidance of the specification, a person skilled in the art can also make many forms without departing from the scope of protection of the claims of the present invention, all of which belong to the scope of protection of the present invention.

Claims

1. A surface treatment method for a solid B2O3 doping source, characterized in that: include: The surface of the solid-state B2O3-doped source wafer is physically erased; Scrubbing the surface of the solid B2O3 doped source sheet after physical erasure; The solid B2O3 doping source sheet after surface scrubbing is baked to obtain a processed solid B2O3 doping source sheet; The solid-state B2O3 doped source sheet is physically erased by using a diamond knife to scratch the side of the silicon sheet to scrape the surface of the B2O3 doped source sheet until no particles fall off the surface.

2. The surface treatment method of a solid B2O3 doping source according to claim 1, characterized in that: Wipe the surface with a dust-free cloth soaked in anhydrous ethanol.

3. The surface treatment method of a solid B2O3 doping source according to claim 2, characterized in that: The anhydrous ethanol used for surface scrubbing is MOS grade.

4. The surface treatment method of a solid B2O3 doping source according to claim 2, characterized in that: After wiping, rinse and air dry in sequence.

5. The surface treatment method of a solid B2O3 doping source according to claim 4, characterized in that: Use DI water for flushing for more than 10 minutes.

6. The surface treatment method of a solid B2O3 doping source according to claim 4, characterized in that: Air Dry Use a nitrogen gun to blow dry until no water droplets adhere to the surface.

7. The surface treatment method of a solid B2O3 doping source according to claim 1, characterized in that: The baking tool is a horizontal furnace tube.

8. The surface treatment method of a solid B2O3 doping source according to claim 7, characterized in that: The baking method is to pass saturated N2 baking.

9. The surface treatment method of a solid B2O3 doping source according to claim 7, characterized in that: The baking temperature is 150℃~200℃.

10. The surface treatment method of a solid B2O3 doping source according to claim 7, characterized in that: The baking time is 20-28h.

Images