Straight-through notch silane blowdown pipe for improving poly silicon uniformity and low pressure chemical vapor deposition (LPCVD) furnace tube
By setting an extended straight-through silane gas supply pipe in the LPCVD deposition furnace tube, the problem of poor polysilicon uniformity was solved, the uniformity of gas distribution on the silicon wafer surface was achieved, and the back passivation performance of the solar cell was improved.
Patent Information
- Application Number
- CN202520055013.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-10
- Publication Date
- 2026-01-30
- Estimated Expiration
- 2035-01-10
AI Technical Summary
In existing LPCVD deposition furnace tubes, the uniformity of polysilicon is poor. Silicon wafers closer to the gas outlet receive more gas, while those farther away receive less, resulting in uneven polysilicon thickness and affecting the passivation performance of the back side of the solar cell.
An extended straight-through silane gas supply pipe is installed in the LPCVD deposition furnace tube, extending its length to the center of the boat support. This reduces reactant loss, allows the reactants to be deposited uniformly on the silicon wafer surface, and improves the uniformity of polysilicon.
By using a straight-through silane gas supply pipe, the uniformity of polysilicon in the furnace was significantly improved, with inter-cell uniformity increasing from 10% to 2.62%, thus improving the back passivation performance of the solar cells.
Smart Images
Figure CN223852768U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of battery cell manufacturing technology, specifically relating to a straight-through notch silane gas supply pipe and an LPCVD deposition furnace tube for improving the uniformity of polysilicon. Background Technology
[0002] Polysilicon refers to silicon powder and hydrogen generated by the thermal decomposition of silane, deposited as a layer on the polished surface of a silicon wafer. This polysilicon layer is also called amorphous silicon. Polysilicon is deposited on an ultrathin tunneling oxide layer to increase the electron migration rate while suppressing the hole migration rate. In addition, amorphous silicon acts as a bridge for electron transport in contact with the metal. Therefore, the uniformity of polysilicon directly affects the passivation performance of the back side of the solar cell. In the LPCVD (Low Pressure Chemical Vapor Deposition) process, the material to be deposited is first placed in a reaction chamber, and one or more gases (called precursor gases) are introduced. A chemical reaction occurs under low pressure, and the chemical substances in these gases react on the surface to form the desired thin film. The existing LPCVD technology uses three gas intake methods: furnace opening, furnace middle, and furnace tail. When the gas flow enters the tube from the gas inlet outlet, the silicon wafers near the gas outlet receive more gas, while the silicon wafers far from the gas outlet (in the furnace middle) receive less gas. Increasing the gas flow at the furnace opening and tail will cause the poly silicon near the gas outlet to be thicker, making it impossible to ensure that the entire tube of silicon wafers receives the same amount of gas. The overall gas flow in the furnace body is drawn backward, and the silane in the furnace decomposes and disperses in all directions. Most of it is drawn away by the furnace tail, resulting in poor uniformity of poly silicon in the furnace.
[0003] To improve the uniformity of polysilicon deposition in the middle of the furnace tube, it is necessary to propose a straight-through silane gas supply pipe and an LPCVD deposition furnace tube to improve the uniformity of polysilicon. By lengthening a section of the straight-through silane gas supply pipe, the loss of reactants is reduced, and the reactants are deposited more concentratedly on the wafer surface. Utility Model Content
[0004] The purpose of this invention is to provide a straight-through silane inlet pipe and an LPCVD deposition furnace tube containing the silane inlet pipe to improve the uniformity of polysilicon, in order to solve the problem that in the prior art, after the silane decomposes in the furnace, it diffuses everywhere and most of it is drawn away by the furnace tail, resulting in poor uniformity of polysilicon in the furnace.
[0005] To achieve the above objectives, in one aspect, the present invention provides a straight-through silane gas supply pipe for improving the uniformity of polysilicon, which is installed in the furnace of an LPCVD deposition furnace tube. The end of the straight-through silane gas supply pipe that enters the LPCVD deposition furnace tube has at least one straight-through notch arranged along its length.
[0006] Optionally, the length of the through notch is 200mm.
[0007] Optionally, the radial height of the through notch is 3 mm.
[0008] Optionally, the length of the straight-through silane inlet pipe is 2100mm, the outer diameter is 16mm, and the inner diameter is 14mm.
[0009] Optionally, the straight-through silane inlet pipe is made of 316L steel and is integrally formed.
[0010] Optionally, the end of the straight-through silane gas supply pipe that enters the LPCVD deposition furnace tube has two straight-through notches along its length, and the two straight-through notches are located on both sides of the center of the boat support length in the LPCVD deposition furnace tube.
[0011] Optionally, the length of the through notch is 100mm.
[0012] On the other hand, this utility model also provides an LPCVD deposition furnace tube, including a furnace tube body and a boat support disposed in the furnace tube body. Several wafer boats are arranged in an array on the boat support. One end of the furnace tube body has an air inlet and the other end has an air outlet. One end of the furnace tube body is connected to an annular air inlet pipe at the furnace opening and the other end is connected to an air inlet pipe at the furnace tail. The end of the furnace tube body connected to the air inlet pipe at the furnace tail is also connected to a gas supply pipe. The gas supply pipe is a straight-through notch silane gas supply pipe for improving the uniformity of polysilicon as described in any of the above claims.
[0013] Optionally, one end of the gas supply pipe with a straight notch extends into the middle of the furnace tube body.
[0014] Compared with the prior art, the present invention discloses at least the following beneficial effects:
[0015] This invention provides a straight-through notch silane gas supply pipe for improving the uniformity of polysilicon during LPCVD deposition. In existing low-pressure chemical vapor deposition furnace tubes, extending a section of the silane gas supply pipe, including a straight-through notch, to the center of the boat support reduces reactant loss and allows for more concentrated deposition of reactants onto the wafer surface, thereby improving poly uniformity within the furnace. After improvement, the poly thickness within the furnace is significantly increased, and the inter-wafer uniformity improves from 10% to 2.62%. Attached Figure Description
[0016] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0017] Figure 1 Axiometric measurement of the straight-through notch silane gas supply pipe for improving the uniformity of polysilicon according to this invention. Figure 1 ;
[0018] Figure 2 Axiometric measurement of the straight-through notch silane gas supply pipe for improving the uniformity of polysilicon according to this invention. Figure 1 ;
[0019] Figure 3 This is a top view of the straight-through notch silane gas supply pipe for improving the uniformity of polysilicon according to this invention;
[0020] Figure 4 This is a front view of the straight-through notch silane gas supply pipe for improving the uniformity of polysilicon according to this invention.
[0021] Figure 5 This is a right view of the straight-through notch silane gas supply pipe for improving the uniformity of polysilicon according to this invention;
[0022] Figure 6 Left view of the straight-through notch silane gas supply pipe for improving the uniformity of polysilicon according to this invention;
[0023] Figure 7 for Figure 4 Cross-sectional view at point AA;
[0024] Figure 8 This is a schematic diagram of the LPCVD deposition furnace tube provided in Embodiment 2 of this utility model.
[0025] In the diagram: 100, straight-through silane gas supply pipe; 101, gas inlet port; 102, straight-through opening; 200, furnace tube body; 300, furnace mouth annular gas inlet pipe; 400, furnace tail gas inlet pipe; 500, wafer carrier boat; 600, original furnace tube straight-through silane gas supply pipe. Detailed Implementation
[0026] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0027] LPCVD uses three gas inlets: the furnace opening, the furnace middle, and the furnace tail. When the gas flows into the tube from the outlet of the inlet pipe, the silicon wafers near the outlet receive more gas, while the silicon wafers far from the outlet (in the furnace middle) receive less gas. Increasing the gas flow at the inlet and tail will cause the poly silicon near the outlet to be thicker, making it impossible to ensure that the entire tube of silicon wafers receives the same amount of gas. After the silane in the furnace decomposes, it diffuses everywhere, and most of it is drawn away by the furnace tail, resulting in poor uniformity of the poly silicon in the furnace.
[0028] To address this, this invention designs a straight-through silane gas supply pipe leading into the furnace, extending a section of the straight-through silane gas supply pipe to reduce reactant loss and make the reactants deposit more concentrated on the surface of the wafers. The length extends to the center of the boat support, thereby improving the poly uniformity in the furnace.
[0029] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments.
[0030] Example 1:
[0031] Reference Figures 1 to 7 As shown, Embodiment 1 of this utility model provides a straight-through notch silane gas supply pipe for improving the uniformity of polysilicon, which is installed in the furnace of an LPCVD deposition furnace. The length L1 of the straight-through notch silane gas supply pipe 100 is 2100 mm, and the outer diameter of the pipe is... The inner diameter of the pipe is 16mm. The tube is 14mm thick with a 1mm wall thickness and is made of 316L steel. It must be integrally formed and welding is prohibited. The straight-through notch silane gas supply pipe 100 has an inlet port 101 at one end where it enters the furnace tube, and a straight-through notch 102 with a length L2 of 200mm is set at this end. The straight-through notch 102 is set by radially cutting off the tube wall with a height L4 of 3mm along the upper edge of the straight-through notch silane gas supply pipe 100, so that the tube wall is radially opened to form the straight-through notch 102. After cutting off 3mm of tube wall, the radial height L3 of the remaining tube wall is 13mm. In use, one end of the straight-through silane gas supply pipe 100 with the straight-through opening 102 is inserted into the middle of the furnace tube. Gas enters the furnace through the straight-through silane gas supply pipe 100 and flows evenly to the wafer carrier boat 500 through the straight-through opening 102, so that the silicon wafers placed on the wafer carrier boat 500 receive the same amount of gas. After the silane decomposes in the furnace, it can be evenly dispersed, thereby achieving the purpose of improving the poly uniformity in the furnace.
[0032] In this embodiment, the 2100mm long straight-through silane gas supply pipe 100 ensures that its length can extend to the center of the boat support length.
[0033] In some optional embodiments, the through-hole 102 is set as at least one segment, such as a continuous through-hole 102 with a length of 200 mm in this embodiment; it can also be multiple through-holes 102 spaced apart along the axial direction, such as two through-holes 102 with a length of 100 mm, the two through-holes 102 being located on both sides of the center of the boat support length in the LPCVD deposition furnace tube.
[0034] Example 2:
[0035] Reference Figure 8 As shown in Embodiment 2 of this utility model, an LPCVD deposition furnace tube is provided, including a furnace tube body 200 and a boat support disposed within the furnace tube body 200. Several wafer boats 500 are arranged in an array on the boat support, as shown in Figure 1 to 12. One end of the furnace tube body 200 has an air inlet and the other end has an air outlet. One end of the furnace tube body 200 is connected to the furnace inlet annular air inlet pipe 300, and the other end is connected to the furnace tail air inlet pipe 400. The end of the furnace tube body 200 connected to the furnace tail air inlet pipe 400 is also connected to a gas replenishment pipe. The gas replenishment pipe is the straight-through notch silane gas replenishment pipe for improving polysilicon uniformity as described in Embodiment 1.
[0036] In an optional embodiment, the furnace tube body 200 further includes the original furnace tube straight-through silane gas supply pipe 600; that is, the present invention can improve upon the existing LPCVD deposition furnace tube by adding a straight-through notch silane gas supply pipe 100.
[0037] In an optional embodiment, one end of the gas supply pipe with a straight through notch 102 extends into the middle of the furnace tube body 200 of the LPCVD deposition furnace tube.
[0038] In this embodiment, the 200mm long straight opening 102 at the end of the straight opening silane gas supply pipe 100 helps to form a uniform diffusion flow of gas.
[0039] In one specific embodiment, such as Figure 8 As shown, F represents the gas flow direction in the furnace tube. In the existing LPCVD deposition furnace tube, a section of straight-through silane gas supply pipe 100 is extended, ensuring that the length extends to the center of the boat support length during installation. The improved LPCVD deposition furnace tube significantly increases the poly thickness, and the inter-wafer uniformity increases from 10% to 2.62%, as detailed in Table 1.
[0040] Table 1
[0041]
[0042] The parts not described in this utility model are conventional technical means well known to those skilled in the art.
[0043] In the description of this utility model, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model 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 this utility model.
[0044] The embodiments described above are merely preferred embodiments of the present utility model and are not intended to limit the scope of the present utility model. Various modifications and improvements made to the technical solutions of the present utility model by those skilled in the art without departing from the spirit of the present utility model should fall within the protection scope defined by the claims of the present utility model.
Claims
1. A through-wafer gap silane fill tube for improving poly silicon uniformity, disposed in a furnace of an LPCVD deposition furnace tube, characterized in that, The straight-through notch silane air supplement pipe (100) is provided with at least one straight-through notch (102) along the length direction at one end of the pipe entering the LPCVD deposition furnace tube.
2. The in-line gap silane refill tube to improve poly silicon uniformity of claim 1, wherein, The length of the straight-through notch (102) is 200 mm.
3. The in-line gap silane refill tube to improve poly silicon uniformity of claim 2, wherein, The radial height of the straight-through notch (102) is 3 mm.
4. The in-line gap silane refill tube to improve poly silicon uniformity of claim 2, wherein, The length of the straight-through notch silane air supplement pipe (100) is 2100 mm, the outer diameter of the pipe is 16 mm, and the inner diameter of the pipe is 14 mm.
5. The in-line gap silane refill tube to improve poly silicon uniformity of claim 4, wherein, The straight-through notch silane air supplement pipe (100) is made of 316L steel and is integrally formed.
6. The in-line gap silane refill tube to improve poly silicon uniformity of claim 1, wherein, The straight-through notch silane air supplement pipe (100) is provided with two straight-through notches (102) along the length direction at one end of the pipe entering the LPCVD deposition furnace tube, and the two straight-through notches (102) are respectively located on the two sides of the length center of the boat support in the LPCVD deposition furnace tube.
7. The in-line gap silane refill tube to improve poly silicon uniformity of claim 6, wherein, The length of the straight-through notch (102) is 100 mm.
8. A LPCVD deposition furnace tube, comprising a furnace tube body (200) and a boat support arranged in the furnace tube body (200), a plurality of wafer boats (500) are arranged in an array on the boat support, the furnace tube body (200) has a gas inlet at one end and a gas outlet at the other end, characterized in that, One end of the furnace tube body (200) is connected with a furnace mouth annular air inlet pipe (300), the other end is connected with a furnace tail air inlet pipe (400), and the end of the furnace tube body (200) connected with the furnace tail air inlet pipe (400) is also connected with an air supplement pipe, and the air supplement pipe is the straight-through notch silane air supplement pipe for improving the uniformity of poly silicon according to any one of claims 1 to 7.
9. The LPCVD deposition furnace tube of claim 8, wherein, The end of the air supplement pipe provided with the straight-through notch (102) extends into the middle part of the furnace tube body (200).