Vertical furnace tube device

Abstract

The utility model provides a vertical furnace tube device which comprises an outer tube with one end closed and the other end open; the two ends of the first inner pipe are open, and the first inner pipe is covered with the outer pipe; the two ends of the second inner pipe are open, the first inner pipe is arranged on the periphery of the second inner pipe in a sleeving mode, an interlayer space is formed between the inner periphery of the first inner pipe and the periphery of the second inner pipe, and holes are formed in different positions of the second inner pipe in the axial direction; the wafer boat is used for bearing a wafer; and the wafer boat is supported on the base, and the base is used for feeding the wafer boat into the second inner tube and sealing the open end of the outer tube. According to the utility model, through the arrangement of the first inner tube and the second inner tube, the concentration of reaction gas in each position in the furnace tube is homogenized, so that the difference of film thicknesses of all wafers in the furnace tube is reduced, the uniformity of the film thickness of a single wafer is improved, the consistency of product performance is ensured, the product yield is improved, the rejection rate is reduced, and the production cost is further saved.

Description

Technical Field

[0001] The utility model relates to the technical field of semiconductor manufacturing, in particular to a vertical furnace tube device. Background Art

[0002] In the semiconductor manufacturing process, various thin films need to be generated on the wafer to form a semiconductor structure. There are many methods for generating thin films, and chemical vapor deposition is one of the more common methods. Chemical vapor deposition mainly uses one or more gas phase compounds or single substances containing thin film elements to chemically react on the surface of the substrate to generate thin films. Commonly used equipment in chemical vapor deposition includes high-temperature vertical furnace tubes, which transport the reaction gas to the high-temperature vertical furnace tubes so that it reacts chemically with the wafers in the furnace tubes under certain conditions, thereby depositing a layer of thin film on the surface of the wafer. Since it takes a long time to grow thin films using furnace tubes, multiple wafers are generally placed in a batch and operated simultaneously to increase the yield.

[0003] The existing high-temperature vertical furnace tube includes an outer tube and an inner tube. The inner tube is used to accommodate a wafer boat loaded with multiple layers of wafers. It can be understood that the wafers are placed layer by layer in the wafer boat in the vertical direction, and there is a gap between the wafers so that the outer surface of the wafer can grow a thin film. The reaction gas is passed through the gas injection pipe between the inner tube and the wafer boat. According to the structure of the furnace tube, the gas injection pipe extends from the lower end into the inner tube and the wafer boat, so the reaction gas diffuses from the bottom of the inner tube to the top. On the one hand, it is affected by the gas diffusion rate, and on the other hand, it is blocked by the wafers in the wafer boat. A large amount of reaction gas first reacts chemically with the wafers at the bottom of the inner tube, and the reaction gas that can diffuse to the upper part of the inner tube is greatly reduced, causing the concentration of the reaction gas in the furnace tube to gradually decrease from bottom to top. The thickness of the film is proportional to the concentration of the reaction gas, so it will cause the film thickness of the wafer below to be quite different from that of the wafer above, that is, the film thickness of the wafer below is thicker and the film thickness of the wafer above is thinner, and the film thickness uniformity of the wafers is quite different.

[0004] In order to solve this problem, the temperature at the top of the furnace tube is usually increased to speed up the reaction rate between the upper wafer and the reaction gas, so that a thicker film is generated on the upper wafer in the same time, thereby improving the uniformity of the film thickness of all wafers in the wafer boat. However, this method brings new disadvantages. Since the temperature at the top of the furnace tube is increased, the reaction rate between the wafer on the upper part of the inner tube and the reaction gas is accelerated, and the reaction gas diffuses from the periphery to the center of the wafer. The high temperature and fast reaction speed will cause the film on a single wafer to be thicker on the periphery and thinner in the center, which will cause the film thickness uniformity of a single wafer to deteriorate. The deterioration of the uniformity of the film thickness of the high-temperature vertical furnace tube has become a bottleneck in the process. The difference in film thickness leads to different product performance and reduced yield. Some sensitive products may even be scrapped. Utility Model Content

[0005] The utility model aims to provide a vertical furnace tube device, which can even out the concentration of reaction gas at various locations in the furnace tube, thereby reducing the film thickness differences of all wafers in the furnace tube, ensuring the consistency of product performance, and improving the film thickness uniformity of a single wafer, thereby increasing product yield.

[0006] In order to achieve the above object, the utility model provides a vertical furnace tube device, which includes:

[0007] an outer tube, one end of which is closed and the other end of which is open;

[0008] A first inner tube, both ends of which are open, and the outer tube covers the first inner tube;

[0009] A second inner tube, both ends of the second inner tube are open, the first inner tube is sleeved on the outer circumference of the second inner tube, and a sandwich space is formed between the inner circumference of the first inner tube and the outer circumference of the second inner tube, and holes are provided at different axial positions of the second inner tube;

[0010] A wafer boat, which is used to carry wafers;

[0011] A base is provided on which the wafer boat is supported. The base is used to deliver the wafer boat into the second inner tube and to close an open end of the outer tube.

[0012] Optionally, the outer tube, the first inner tube and the second inner tube are coaxially arranged.

[0013] Optionally, the holes are evenly distributed on the second inner tube.

[0014] Optionally, a heating assembly is provided around the outer tube.

[0015] Optionally, a lifting assembly is installed on the base to drive the base to move along the axial direction of the outer tube.

[0016] Optionally, an exhaust port is provided on the outer tube.

[0017] Optionally, the closed end of the outer tube is in the shape of a convex arc surface.

[0018] Optionally, two ends of the first inner tube and two ends of the second inner tube are flush with each other.

[0019] Optionally, the outer tube, the first inner tube and the second inner tube are all quartz tubes or silicon carbide tubes.

[0020] Optionally, in the axial direction of the second inner tube, the length of the wafer boat is smaller than the length of the second inner tube.

[0021] As configured above, the vertical furnace tube device of the utility model includes: an outer tube, a first inner tube, a second inner tube, a wafer boat and a base. One end of the outer tube is closed, and the other end of the outer tube is open. Both ends of the first inner tube are open, and the outer tube covers the first inner tube. Both ends of the second inner tube are open, the first inner tube is sleeved on the outer circumference of the second inner tube, and a sandwich space is formed between the inner circumference of the first inner tube and the outer circumference of the second inner tube, and holes are provided at different axial positions of the second inner tube. The wafer boat is used to carry wafers. The wafer boat is supported on the base, and the base is used to send the wafer boat into the second inner tube and close the open end of the outer tube.

[0022] When the device is working, the base delivers the wafer boat into the second inner tube, and closes the open end of the outer tube so as to carry out a chemical reaction in the furnace tube. The reaction gas first enters the interlayer space between the first inner tube and the second inner tube, and then diffuses to the wafer boat through the holes on the second inner tube to react with the wafer. Since the reaction gas diffuses unimpeded in the interlayer space, the reaction gas can diffuse quickly and evenly into the entire furnace tube, so that the concentration of the reaction gas at various places in the furnace tube is uniform and tends to be consistent, which can avoid adjusting the film thickness difference of the wafers at the upper and lower parts of the furnace tube by temperature, and improve the uniformity of the film thickness of a single wafer. Compared with the single-layer inner tube of the prior art, the utility model evens out the concentration of the reaction gas at various places in the furnace tube by setting the first inner tube and the second inner tube, thereby reducing the film thickness difference of all wafers in the furnace tube and improving the uniformity of the film thickness of a single wafer, ensuring the consistency of product performance, improving product yield, reducing scrap rate, and thus saving production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Those skilled in the art should understand that the drawings are provided for a better understanding of the present invention and do not constitute any limitation on the scope of the present invention.

[0024] Figure 1 It is a schematic diagram of a vertical furnace tube device according to an embodiment of the utility model.

[0025] The reference numerals are as follows:

[0026] 11-outer tube; 12-first inner tube; 13-second inner tube;

[0027] 2- Crystal Boat;

[0028] 3-base; 31-lifting assembly;

[0029] 4- Wafer. DETAILED DESCRIPTION

[0030] In this document, unless otherwise specified, the terms "upper", "lower", "left", "right", "inside", "outside", "front", "back", "top", "bottom", etc. are used to indicate directions or positional relationships based on the drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction and operation. Therefore, they cannot be understood as limiting the present invention.

[0031] The following will describe the specific implementation of the utility model in more detail with reference to the schematic diagram. The advantages and features of the utility model will become clearer according to the following description. It should be noted that the drawings are all in a very simplified form and are not in exact proportions, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the utility model.

[0032] The preferred embodiments of the present utility model are given below in conjunction with the accompanying drawings and described in detail.

[0033] Figure 1 This is a schematic diagram of a vertical furnace tube device according to an embodiment of the utility model. Figure 1 The embodiment of the utility model provides a vertical furnace tube device, including an outer tube 11, a first inner tube 12, a second inner tube 13, a wafer boat 2 and a base 3. In this embodiment, the outer tube 11, the first inner tube 12 and the second inner tube 13 are preferably coaxially arranged.

[0034] One end of the outer tube 11 is closed, and the other end of the outer tube 11 is open. The closed end of the outer tube 11 is in a convex arc shape. The outer tube 11 is also provided with an exhaust port, which is used to exhaust gas when a chemical reaction occurs in the furnace tube.

[0035] Both ends of the first inner tube 12 are open, and the outer tube 11 covers the first inner tube 12 inside.

[0036] Both ends of the second inner tube 13 are open. It is understood that the first inner tube 12 and the second inner tube 13 are both tubular. The first inner tube 12 is sleeved on the outer periphery of the second inner tube 13, and an interlayer space is formed between the inner periphery of the first inner tube 12 and the outer periphery of the second inner tube 13, and the interlayer space is used to inject the reaction gas. Holes are provided at different axial positions of the second inner tube 13. It is understood that there are multiple holes. Preferably, the holes are evenly distributed on the second inner tube 13, that is, the holes are evenly distributed circumferentially and axially on the side wall of the second inner tube 13, so that the concentration of the reaction gas at various locations in the second inner tube 13 is more uniform. Further, the two ends of the first inner tube 12 and the two ends of the second inner tube 13 are flush with each other.

[0037] The wafer boat 2 is used to carry the wafer 4. It can be understood that the wafer boat 2 is a storage box or storage rack for the wafer, and is a device for storing, transporting or processing the wafer. Since the wafer is very thin and fragile, the wafer boat is to protect the wafer from damage during transportation, transfer and processing. Usually, the wafer boat 2 has a plurality of wafer placement slots, and each wafer placement slot can be used to place a wafer.

[0038] The wafer boat 2 is supported on the base 3, and the base 3 is used to send the wafer boat 2 into the second inner tube 13 and close the open end of the outer tube 11, so as to facilitate the chemical reaction of growing thin films in the furnace tube. In this embodiment, in the axial direction of the second inner tube 13, the length of the wafer boat 2 is less than the length of the second inner tube 13, that is, when the furnace tube is working, the wafer boat 2 is located within the axial range of the second inner tube 13. It can be understood that the outer tube 11, the first inner tube 12 and the second inner tube 13 are all kept in a fixed position without moving, and a lifting assembly 31 is installed on the base 3 to drive the base 3 to move along the axial direction of the outer tube. Since the furnace tube of this embodiment is a vertical furnace tube, the lifting assembly 31 can drive the base 3 to move up and down, thereby moving the wafer boat 2 into or out of the second inner tube 13. It can be understood that the lifting assembly 31 can adopt a variety of mechanical structures, such as a mechanical structure using a cylinder as a power source.

[0039] Furthermore, a heating assembly is provided around the outer tube 11 to provide the required temperature for the chemical reaction of forming a thin film on the surface of the wafer 4. The heating assembly controls the temperature inside the furnace tube by heating the outer tube 11, rather than directly heating the first inner tube 12 and the second inner tube 13. This heating method controls the temperature more stably and accurately, and can ensure that the temperature inside the furnace tube is relatively uniform. In addition, the heating assembly is provided around the outer tube 11, which can control the temperature more uniformly.

[0040] As configured above, when the device is working, the base 3 delivers the wafer boat 2 into the second inner tube 13, and closes the open end of the outer tube 11, so as to carry out a chemical reaction in the furnace tube. The reaction gas first enters the interlayer space between the first inner tube 12 and the second inner tube 13, and then diffuses to the wafer boat 2 through the holes on the second inner tube 13 to react with the wafer 4. Since the reaction gas diffuses unimpeded in the interlayer space, the reaction gas can diffuse quickly and evenly into the entire furnace tube, so that the concentration of the reaction gas at various places in the furnace tube is uniform and tends to be consistent, which can avoid adjusting the film thickness difference of the wafers at the upper and lower parts of the furnace tube by temperature, and improve the uniformity of the film thickness of a single wafer. Compared with the single-layer inner tube of the prior art, the utility model evens out the concentration of the reaction gas at various places in the furnace tube by setting the first inner tube 12 and the second inner tube 13, thereby reducing the film thickness difference of all wafers in the furnace tube and improving the uniformity of the film thickness of a single wafer, ensuring the consistency of product performance, improving product yield, reducing scrap rate, and thus saving production costs.

[0041] In this embodiment, the outer tube 11, the first inner tube 12 and the second inner tube 13 are all made of the same material. In this embodiment, the outer tube 11, the first inner tube 12 and the second inner tube 13 are all quartz tubes or silicon carbide tubes.

[0042] When the device is working, the base 3 is driven to rise by the lifting assembly 31, the crystal boat 2 is sent into the second inner tube 13 and the open end of the outer tube is closed, and then the reaction gas is introduced into the furnace tube. In this embodiment, a gas injection pipe is used to introduce the reaction gas into the interlayer space between the first inner tube 12 and the second inner tube 13. For example, the gas injection pipe can pass through the bottom of the first inner tube 12 and extend into the interlayer space. In other embodiments, the number of gas injection pipes is not limited, and it is also possible to use multiple gas injection pipes. Figure 1 The arrow in the middle indicates the airflow direction. Figure 1 Since there is no shielding, the reaction gas can quickly fill the interlayer space, and then diffuse to the wafer boat 2 through the holes on the second inner tube 13 to contact the wafer 4, so that the contact time between the wafer 4 in the axial direction of the wafer boat 2 and the reaction gas is roughly the same, and the concentration of the reaction gas in the entire furnace tube can also be made more uniform. When the chemical reaction of forming a thin film is carried out in the furnace tube, the gas injection pipe continuously introduces the reaction gas into the furnace tube, and the gas is continuously discharged from the exhaust port on the outer tube 11.

[0043] It should be noted that references to "one embodiment", "an embodiment", "a specific embodiment", "some embodiments", etc. in the specification only indicate that the described embodiment may include a particular feature, structure or characteristic. Moreover, such phrases do not necessarily refer to the same embodiment. In addition, when a particular feature, structure or characteristic is described in conjunction with an embodiment, whether or not explicitly described, it is within the knowledge of a person skilled in the relevant art to implement such feature, structure or characteristic in conjunction with other embodiments.

[0044] It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same or similar parts between the various embodiments can be referred to each other. For the system disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part description.

[0045] It should also be noted that, although the present invention has been disclosed as a preferred embodiment, the above embodiment is not intended to limit the present invention. For any technician familiar with the art, without departing from the scope of the technical solution of the present invention, the above disclosed technical content can be used to make many possible changes and modifications to the technical solution of the present invention, or modified into equivalent embodiments of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of protection of the technical solution of the present invention.

[0046] It should also be understood that, unless otherwise specified or indicated, the terms "first", "second", "third", etc. in the specification are merely used to distinguish between the various components, elements, steps, etc. in the specification, and are not used to indicate the logical relationship or sequential relationship between the various components, elements, steps, etc.

[0047] It should also be recognized that the terms described herein are only used to describe specific embodiments and are not used to limit the scope of the utility model. It must be noted that the singular forms "one" and "a kind" used herein and in the appended claims include plural references unless the context clearly indicates the opposite meaning. For example, a reference to "a step" or "a device" means a reference to one or more steps or devices, and may include secondary steps and secondary devices. All conjunctions used should be understood in the broadest sense. And, the word "or" should be understood to have a logical "or" definition, rather than a logical "exclusive or" definition, unless the context clearly indicates the opposite meaning. In addition, the implementation of the method and / or device in the embodiment of the utility model may include performing the selected task manually, automatically, or in combination.

Claims

1. A vertical furnace tube device, characterized in that: include: an outer tube, one end of which is closed and the other end of which is open; A first inner tube, both ends of which are open, and the outer tube covers the first inner tube; A second inner tube, both ends of the second inner tube are open, the first inner tube is sleeved on the outer circumference of the second inner tube, and a sandwich space is formed between the inner circumference of the first inner tube and the outer circumference of the second inner tube, and holes are provided at different axial positions of the second inner tube; A wafer boat, which is used to carry wafers; A base is provided on which the wafer boat is supported. The base is used to deliver the wafer boat into the second inner tube and to close an open end of the outer tube.

2. The vertical furnace tube device according to claim 1, characterized in that: The outer tube, the first inner tube and the second inner tube are coaxially arranged.

3. The vertical furnace tube device according to claim 1, characterized in that: The holes are evenly distributed on the second inner tube.

4. The vertical furnace tube device according to claim 1, characterized in that: A heating assembly is arranged around the outer tube.

5. The vertical furnace tube device according to claim 1, characterized in that: A lifting assembly is installed on the base to drive the base to move along the axial direction of the outer tube.

6. The vertical furnace tube device according to claim 1, characterized in that: The outer tube is provided with an exhaust port.

7. The vertical furnace tube device according to claim 1, characterized in that: The closed end of the outer tube is in the shape of a convex arc surface.

8. The vertical furnace tube device according to claim 1, characterized in that: Two ends of the first inner tube and two ends of the second inner tube are flush with each other.

9. The vertical furnace tube device according to claim 1, characterized in that: The outer tube, the first inner tube and the second inner tube are all quartz tubes or silicon carbide tubes.

10. The vertical furnace tube device according to claim 1, characterized in that: In the axial direction of the second inner tube, the length of the wafer boat is smaller than the length of the second inner tube.

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