A tube diffusion oxidation furnace and a semiconductor diffusion oxidation apparatus

Abstract

The application relates to the field of semiconductor product preparation, and discloses a tubular diffusion oxidation furnace and a semiconductor diffusion oxidation equipment. The tubular diffusion oxidation furnace comprises a furnace tube body; the furnace tube body comprises a plurality of heating sections which are sequentially distributed along the length direction; a plurality of main heating strips are arranged on the tube wall of each heating section, and the length direction of each main heating strip is parallel to the length direction of the furnace tube body; an auxiliary heating ring is arranged along the tube wall in the transition section between the two adjacent heating sections; and the plane of the auxiliary heating ring is perpendicular to the length direction of the furnace tube body. In the application, the auxiliary heating ring is further arranged in the transition section between the heating sections in the tubular diffusion oxidation furnace, so that the temperature in the transition section between the two adjacent heating sections is reduced by a large amplitude, the temperature uniformity of the whole tubular diffusion oxidation furnace is improved to a certain extent, and the production quality of semiconductor cells and other products is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor preparation, in particular to a tubular diffusion oxidation furnace and a semiconductor diffusion oxidation equipment. BACKGROUND

[0002] The tubular diffusion oxidation equipment is a kind of heating oxidation equipment commonly used in the preparation process of various oxide films of semiconductors such as solar cells. The tubular diffusion oxidation equipment is used to dope N-type silicon wafers after texturing by doping impurities (BCl3) in a high temperature (900-1100 DEG C) environment. The process requires high uniformity. At present, the tubular diffusion oxidation equipment is generally provided with 5-6 temperature zones, each of which is heated independently. Although this heating method can control the heating power of a certain temperature zone independently, it cannot well guarantee the uniformity of the heating temperature of the entire tubular diffusion oxidation equipment. SUMMARY

[0003] The purpose of the present application is to provide a tubular diffusion oxidation furnace and a semiconductor diffusion oxidation equipment, which can improve the heating temperature uniformity of the battery piece during the diffusion oxidation process to some extent, and thus improve the production quality of the battery piece.

[0004] To solve the above technical problems, the present application provides a tubular diffusion oxidation furnace, which comprises a furnace tube body; the furnace tube body comprises a plurality of heating sections distributed in sequence along the length direction; a plurality of main heating strips in strip structure are arranged on the tube wall of each heating section, and the length direction of each main heating strip and the furnace tube body is parallel;

[0005] Further comprising an auxiliary heating ring in annular structure arranged along the tube wall in the transition section between two adjacent heating sections; the plane of the auxiliary heating ring is perpendicular to the length direction of the furnace tube body.

[0006] In an optional embodiment of the present application, an insulating partition strip is arranged between two adjacent main heating strips in the same heating section.

[0007] In an optional embodiment of the present application, the insulating partition strip is an alumina ceramic strip.

[0008] In an optional embodiment of the present application, the cross-sectional height of the insulating partition strip is greater than the cross-sectional height of the main heating strip.

[0009] In an optional embodiment of the present application, the heating power of the main heating strips between each heating section is independently adjustable; the heating power of the auxiliary heating rings is independently adjustable.

[0010] In an alternative embodiment of the present application, each heating section comprises three sub-heating sections along the length direction of the furnace tube body; and an insulating member is arranged between two adjacent sub-heating sections.

[0011] The heating power of the main heating strips corresponding to each sub-heating section in the same heating section is independently adjustable, and the heating power of the middle sub-heating section is smaller than that of the two side sub-heating sections.

[0012] In an alternative embodiment of the present application, the main heating strips and the auxiliary heating rings are both heating resistance wires.

[0013] In an alternative embodiment of the present application, each auxiliary heating ring comprises 5-10 turns of the heating resistance wires.

[0014] In an alternative embodiment of the present application, each auxiliary heating ring is provided with annular insulating members on both sides; and the cross-sectional height of the annular insulating members is greater than that of the auxiliary heating ring.

[0015] A semiconductor diffusion oxidation equipment comprising the tubular diffusion oxidation furnace as claimed in any one of the above.

[0016] The present application provides a tubular diffusion oxidation furnace and a semiconductor diffusion oxidation equipment, the tubular diffusion oxidation furnace comprising a furnace tube body; the furnace tube body comprises a plurality of heating sections arranged along the length direction in sequence; the tube wall of each heating section is provided with a plurality of main heating strips in strip structure, and each main heating strip is parallel to the length direction of the furnace tube body; and the transition section between two adjacent heating sections is provided with an auxiliary heating ring in annular structure along the tube wall; and the plane of the auxiliary heating ring is perpendicular to the length direction of the furnace tube body.

[0017] In the present application, the transition section between each heating section in the tubular diffusion oxidation furnace is further provided with an auxiliary heating ring, and the temperature of the transition section is raised by the heating of the auxiliary heating ring, so that the temperature drop of the transition section between two adjacent heating sections is reduced to a certain extent, and the temperature uniformity of the whole tubular diffusion oxidation furnace is improved to a certain extent, thereby being beneficial to the production quality of semiconductor cells and other products. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the drawings needed in the following embodiment or prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0019] Figure 1A schematic diagram of the overall structure of a tube diffusion oxidation furnace;

[0020] Figure 2 A schematic diagram of the overall structure of a tube diffusion oxidation furnace;

[0021] Figure 3 A schematic diagram of the cross section of the heating section of the tube diffusion oxidation furnace provided in the embodiment of the present application. DETAILED DESCRIPTION

[0022] As shown in Figure 1 , Figure 1 A schematic diagram of the overall structure of a tube diffusion oxidation furnace. The tube diffusion oxidation furnace is generally in a cylindrical structure, and one end is an open end with a door closed; when it is necessary to place semiconductor cells in the tube diffusion oxidation furnace for diffusion oxidation processing, a plurality of cells are carried into the furnace of the tube diffusion oxidation furnace by a quartz boat, and the cells on the quartz boat are arranged in parallel along the length direction of the tube diffusion oxidation furnace; the tube diffusion oxidation furnace provides a high temperature environment for the diffusion oxidation of various dopants.

[0023] Because the tube diffusion oxidation furnace is provided with an opening at one end, the heat loss during the opening and closing of the end opening is relatively large, which causes the internal temperature of the tube diffusion oxidation furnace to be uneven, with one end being high and the other end being low, thereby affecting the production quality of the prepared cells. In order to improve the uniformity of the internal temperature of the tube diffusion oxidation furnace, the internal space can be divided into a plurality of heating sections along the length direction of the tube diffusion oxidation furnace, each heating section has a heating component, and the heating power of each heating section is different, the heating power of the heating section near the opening end of the furnace can be appropriately higher, and the heating power of the heating section far from the opening end can be appropriately lower; thereby improving the uniformity of the internal temperature to a certain extent.

[0024] However, in the conventional tube diffusion oxidation furnace, due to installation limitations and other reasons, the heating components of the two adjacent heating sections are not seamlessly connected, but there is a small blank transition section. This section has no heating components, so that the temperature at this position is significantly lower than that of the adjacent region during actual heating of the internal environment, that is, there is a temperature unevenness between the two heating sections. Therefore, the cells near the two ends of each heating section in the conventional tube diffusion oxidation furnace often have poor diffusion oxidation quality due to uneven heating temperature.

[0025] A technical solution is provided in the present application, which can improve the uniformity of the internal temperature of the tube diffusion oxidation furnace to a certain extent.

[0026] For those skilled in the technical field, the present application will be further described in detail below in combination with the drawings and specific embodiments. Obviously, the described embodiments are only part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0027] As Figure 2 And Figure 3 shown, Figure 2 is a partial cross-sectional structure schematic diagram of a tubular diffusion oxidation furnace provided by the present application; Figure 3 is a cross-sectional schematic diagram of the heating section of the tubular diffusion oxidation furnace provided by the present application.

[0028] In a specific embodiment of the present application, the tubular diffusion oxidation furnace can include:

[0029] The furnace tube body 1 includes a plurality of heating sections distributed in sequence along the length direction of the furnace tube body 1; the tube wall of each heating section is paved with a plurality of main heating strips 2 in strip structure, and each main heating strip 2 is parallel to the length direction of the furnace tube body 1.

[0030] It also includes an auxiliary heating ring 3 in ring structure arranged on the tube wall of the transition section between the two adjacent heating sections; the plane where the auxiliary heating ring 3 is located is perpendicular to the length direction of the furnace tube body 1.

[0031] The furnace tube body 1 of the tubular diffusion oxidation furnace in the present embodiment is roughly the same as the structure of the conventional furnace tube body 1 in overall structure, both of which are cylindrical structure. Of course, if it is set to be cuboid structure or other cylindrical structure based on actual needs, the present application is not limited, as long as it can ensure normal heating of the battery piece opposed to it inside.

[0032] In the present embodiment, a whole circle of main heating strips 2 is uniformly paved along the inner tube wall of each heating section of the furnace tube body 1. In Figure 2 and Figure 3In the shown embodiment, each main heating strip 2 is a straight strip structure, of course, the embodiment also does not exclude that the main heating strip 2 is a wavy line strip structure or a zigzag strip structure and the like, as long as the main heating strip 2 is generally a long strip structure and the width size is not too large, so that the main heating strip 2 can be closely attached to the inner wall surface of the furnace tube body 1, and each main heating strip 2 is parallel to the center axis of the furnace tube body 1. Of course, in actual application, other shape structures of the main heating strip 2 can also be considered. However, because the inner wall surface of the furnace tube body 1 is a cylindrical surface, the straight line type structure of the main heating strip 2 can better fit the inner wall of the furnace tube body 1.

[0033] The length of each main heating strip 2 in the same heating section should be the same, and the distribution of each main heating strip 2 in the same heating section can just enclose a cylindrical heating space. The length of the main heating strip 2 between different heating sections can be set to be different according to actual needs, that is, the size of each heating section can be different, or it can be set to be the same, that is, the size of each heating section can also be the same, which is not limited in the present application.

[0034] On this basis, each main heating strip 2 in the same heating section can be connected to the same power supply circuit in series, parallel or series-parallel; correspondingly, the heating power of each main heating strip 2 in the same heating section can be the same and can be adjusted synchronously, so that the temperature field inside the furnace tube body 1 can be guaranteed to be uniform in the circumferential direction and radial direction with the center axis of the furnace tube body 1 as the center.

[0035] Although each main heating strip 2 is centrally symmetrically laid about the center axis of the furnace tube body 1, which can guarantee the uniformity of the temperature field in each heating section along the radial direction and the circumferential direction along the center axis of the furnace tube body 1, there is a transition section between the adjacent two heating sections. Even if the size of the transition section in the direction of the center axis of the furnace tube body 1 is relatively small, if the transition section is not provided with a heating member, the temperature of the space corresponding to the transition section in the furnace tube body 1 will decrease obviously, so that the temperature of each transition section corresponding to the space position will be lower than that of its adjacent space; that is to say, because the position of the transition section in the furnace tube body 1 is not provided with a heating member, the temperature distribution in the furnace tube body 1 along the length direction of the furnace tube body 1 is not uniform. When the battery piece is diffused and oxidized in the furnace tube body 1, the temperature uniformity of the environment of the battery piece located near the edge of the heating section is more obvious, so that the quality of the diffusion processing of the battery piece located at this position is obviously reduced.

[0036] To this end, in order to further improve the uniformity of the temperature distribution inside the furnace tube body 1, an auxiliary heating ring 3 is arranged in the transition section between the two adjacent heating sections in the furnace tube body 1. Unlike the main heating strip 2, the auxiliary heating ring 3 is in a ring structure, and the specific shape of the ring structure should be the same as the cross-sectional shape of the inner wall of the furnace tube body 1; for example, if the inner wall of the furnace tube body 1 is in a cylindrical structure, the auxiliary heating ring 3 can be in a circular ring structure that well fits the surface of the inner wall of the furnace tube body 1. It can be understood that the heating power between the auxiliary heating rings 3 corresponding to each transition section is independently adjustable. In actual application, each auxiliary heating ring 3 can be provided with a separate power supply circuit, thereby ensuring that the heating power of each auxiliary heating ring 3 is more flexible to adjust. Moreover, the heating power of each auxiliary heating ring 3 can be smaller than the heating power of each main heating strip 2 of the two adjacent heating sections, thereby avoiding the problem of excessively high temperature in the transition section.

[0037] In addition, for the main heating strip 2 and the auxiliary heating ring 3, heating resistance wire, heating lamp tube or other similar heating components can be used, and the application does not make specific limitations as long as it can ensure that the temperature of the furnace tube body 1 is stably heated to the required temperature.

[0038] Moreover, for the auxiliary heating ring 3, the auxiliary heating ring 3 corresponding to each transition section can include 5-10 turns of heating resistance wire in a circular ring structure, and each turn of heating resistance wire is arranged in sequence along the length direction of the furnace tube body 1, thereby ensuring that the auxiliary heating ring 3 can provide sufficient heating heat to a certain extent.

[0039] For the traditional tubular diffusion oxidation furnace, because the temperature distribution inside the furnace tube body 1 is not uniform, it will cause the sheet resistance of the battery sheet at different positions to be uneven, the junction depth to be inconsistent, the contact to be poor in some places during the sintering silver paste penetration process, and some places to be possibly overburned, resulting in low VOC; at the same time, it will cause the series resistance of the battery sheet to increase and the ISC to be low, directly leading to large fluctuations in the working efficiency of the final product battery sheet.

[0040] The tubular diffusion oxidation furnace provided in the embodiment can improve the uniformity of the temperature inside the furnace tube body 1 to a certain extent, thereby optimizing the uniformity of the sheet resistance of the battery sheet and widening the process debugging window. In theory, the tubular diffusion oxidation furnace in the embodiment can achieve a 3%-5% improvement in the uniformity of the sheet resistance, thereby improving the working efficiency of the battery sheet.

[0041] Based on the above discussion, further considering that when the heating resistance wire is used as the main heating strip 2, if the adjacent two main heating strips 2 contact each other, the entire heating loop may be short-circuited, and the actual heating power is increased, therefore, in another optional embodiment of the present application, the following can also be included:

[0042] The insulating partition strip 4 is arranged between the adjacent two main heating strips 2 in the same heating section.

[0043] Referring to Figure 2 and Figure 3 , the main heating strip 2 and the insulating partition strip 4 in the same heating section can be alternately arranged along the inner wall of the furnace pipe body 1, and through the insulation effect of the insulating partition strip 4, short circuit between the adjacent two main heating strips 2 is avoided.

[0044] The insulating partition strip 4 can specifically use an alumina ceramic strip, and the main component of the alumina ceramic is Al2O3, and the content is generally greater than 45%. The alumina ceramic has various excellent properties, for example, high temperature resistance, generally can be used for 1600℃ for a long time; corrosion resistance; high strength, the strength is 2-3 times of ordinary ceramic, and the high one can reach 5-6 times. Therefore, in the embodiment, the alumina ceramic strip is used as the insulating partition strip 4, which can ensure that the adjacent main heating strips 2 are insulated from each other, and also can ensure that the alumina ceramic strip can withstand the high temperature inside the furnace pipe body 1.

[0045] In addition, during the process that the main heating strip 2 is powered to provide heating heat for the furnace pipe body 1, the main heating strip 2 itself also has a higher temperature; if the semiconductor battery piece placed in the furnace pipe body 1 and the main heating strip 2 are in contact with each other, the battery piece will inevitably be damaged, therefore, in another optional embodiment of the present application, the following can also be further included:

[0046] The cross-sectional height of the insulating partition strip 4 is greater than the cross-sectional height of the main heating strip 2.

[0047] As shown in Figure 2 and Figure 3 , because the height of the insulating partition strip 4 is greater than the height of the main heating strip 2, a space for accommodating the main heating strip 2 can be formed between the adjacent two insulating partition strips 4, which can block the battery piece from directly contacting the main heating strip 2 to a certain extent, and has a protection effect on the battery piece.

[0048] Further considering that the adjacent main heating strips 2 in the same heating section need to be insulated from each other, the auxiliary heating ring 3 and the main heating strips 2 in the adjacent two heating sections should also be insulated. Therefore, in another optional embodiment of the present application, the following can also be further included:

[0049] The auxiliary heating ring 3 is provided with an annular insulating member 5 on both sides, and the cross-sectional height of the annular insulating member 5 is greater than that of the auxiliary heating ring 3.

[0050] The annular insulating member 5 and the insulating partition 4 can be made of the same material, that is, the annular insulating member 5 in the embodiment can also be an alumina ceramic member. The cross-sectional height of the annular insulating member 5 can be the same as that of the insulating partition 4, that is, the mutual contact between the battery piece and the auxiliary heating ring 3 can be avoided to a certain extent.

[0051] In addition, further considering that although the auxiliary heating ring 3 is arranged between the two adjacent heating sections, for a single heating section, the temperature in the space corresponding to the middle section of the heating section can be higher than that in the space corresponding to the two end sections of the heating section. Therefore, in another optional embodiment of the present application, further comprising:

[0052] Each heating section sequentially comprises three sub-heating sections along the length direction of the furnace tube body 1, and an insulating member is arranged between the two adjacent sub-heating sections.

[0053] The heating power of the main heating strip 2 corresponding to each sub-heating section in the same heating section is independently adjustable, and the heating power of the sub-heating section located in the middle of the same heating section is smaller than that of the sub-heating sections located on both sides.

[0054] In the embodiment of the present application, each heating section is further divided into three smaller sub-heating sections, and correspondingly, three circles of main heating strips 2 are sequentially arranged in each heating section along the direction parallel to the center axis of symmetry of the furnace tube body 1. It can be understood that, compared with the embodiment in which the same heating section is not divided into sub-heating sections, the length of the main heating strip 2 in each sub-heating section in the present embodiment is only one third of the length of the whole heating section along the length direction of the center axis of symmetry of the furnace tube body 1. Of course, in order to insulate the main heating strips 2 between the two adjacent sub-heating sections, the main heating strips 2 in the two adjacent sub-heating sections and the insulating partitions 4 can be arranged in a staggered manner, that is, the main heating strip 2 in one sub-heating section corresponds to the insulating partition in another sub-heating section. Of course, an annular insulating member 5 can also be arranged between the two adjacent sub-heating sections, which is not limited in the present application.

[0055] In addition, the heating power of the main heating strip 2 between the sub-heating sections in the same heating section is independently adjustable. In order to avoid the temperature of the middle section being higher than that of the two end sections in the same heating section, the heating power of the main heating strip 2 corresponding to the sub-heating section located in the middle position should be appropriately lower than that of the main heating strips 2 corresponding to the other two sub-heating sections.

[0056] To sum up, the transition section between each heating section in the tube type diffusion oxidation furnace in the present application is further provided with an auxiliary heating ring, the temperature of the transition section is raised by the heating of the auxiliary heating ring, so that the temperature drop of the transition section between two adjacent heating sections is reduced to a certain extent, that is, the temperature uniformity of the whole tube type diffusion oxidation furnace is improved to a certain extent, thereby being beneficial to the production quality of semiconductor cells and the like.

[0057] The present application also provides an embodiment of a semiconductor diffusion oxidation equipment, which can comprise the tube type diffusion oxidation furnace according to any one of the above.

[0058] It can be understood that, in addition to the tube type diffusion oxidation furnace, the semiconductor diffusion oxidation equipment in the present application should also comprise other structural components in the semiconductor diffusion oxidation equipment, for example, a power supply assembly for controlling and adjusting the heating power of the main heating strips and the auxiliary heating ring in the tube type diffusion oxidation furnace, and various support members for supporting and fixing the tube type diffusion oxidation furnace, and the like, and specific reference can be made to the conventional semiconductor diffusion oxidation equipment, and the present application does not make specific limitations thereto.

[0059] It should be noted that, in the present application, the relationship terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between the entities or operations. Moreover, the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements is inherent. Without more limitations, the element defined by the statement "including a" does not exclude the presence of another identical element in the process, method, article or equipment including the element. In addition, the above technical solutions provided by the embodiments of the present application have not been described in detail, in order not to be too verbose.

[0060] The principles and implementation modes of the present application are described by using specific examples in the present application, and the above description of the embodiments is only used to help understand the method of the present application and its core idea. It should be pointed out that, for ordinary skilled in the art, without departing from the principles of the present application, the present application can be improved and modified in several ways, and these improvements and modifications also fall within the protection scope of the claims of the present application.

Claims

1. A tubular diffusion oxidation furnace, characterized in that, It includes a furnace tube body; the furnace tube body includes multiple heating sections distributed sequentially along the length direction of the furnace tube body; multiple strip-shaped main heating strips are attached to the tube wall of each heating section, and each main heating strip is parallel to the length direction of the furnace tube body; It also includes an auxiliary heating ring with an annular structure attached to the tube wall of the transition section between two adjacent heating sections; the plane of the auxiliary heating ring is perpendicular to the length direction of the furnace tube body. An insulating spacer is provided between two adjacent main heating bars within the same heating zone; Each of the auxiliary heating rings is provided with annular insulating elements on both sides; and the cross-sectional height of the annular insulating elements is greater than the cross-sectional height of the auxiliary heating rings.

2. The tubular diffusion oxidation furnace as described in claim 1, characterized in that, The insulating spacer is an alumina ceramic strip.

3. The tubular diffusion oxidation furnace as described in claim 1, characterized in that, The cross-sectional height of the insulating spacer is greater than that of the main heating strip.

4. The tubular diffusion oxidation furnace as described in claim 1, characterized in that, Each of the main heating bars in the same heating section is a heating element connected to the same power supply circuit and whose heating power is synchronously adjustable; Each of the main heating bars and auxiliary heating rings in each of the different heating sections is connected to a different power supply circuit, so that the heating power of the main heating bars and the heating power of the auxiliary heating rings in each of the different heating sections are independently adjustable.

5. The tubular diffusion oxidation furnace as described in claim 1, characterized in that, Each heating section includes three sub-heating sections along the length of the furnace tube body; an insulating element is provided between two adjacent sub-heating sections; The heating power of the main heating bar corresponding to each sub-heating section within the same heating zone is independently adjustable; and the heating power of the middle sub-heating section within the same heating zone is less than that of the sub-heating sections on both sides.

6. The tubular diffusion oxidation furnace as described in claim 1, characterized in that, Both the main heating bar and the auxiliary heating ring are heating resistance wires.

7. The tubular diffusion oxidation furnace as described in claim 6, characterized in that, Each of the auxiliary heating rings includes 5 to 10 turns of the heating resistance wire.

8. A semiconductor diffusion oxidation apparatus, characterized in that, Including the tubular diffusion oxidation furnace as described in any one of claims 1 to 7.

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