Constant-temperature reaction corrosion tank for silicon wafer texturing cleaning machine

Abstract

The utility model provides a constant-temperature reaction etching tank for a silicon wafer texturing cleaning machine, which comprises a reaction tank body, a flow slowing plate is supported on the reaction tank body corresponding to the upper part of a porous liquid inlet plate, a cavity is arranged in the flow slowing plate, one end of the cavity is connected with a circulating liquid inlet pipeline, and the other end of the cavity is connected with a circulating liquid outlet pipeline. The circulating liquid inlet pipeline and the circulating liquid outlet pipeline are externally connected with a circulating liquid outer cavity, and a temperature control device for adjusting the temperature of circulating liquid is arranged in the circulating liquid outer cavity. According to the utility model, the structural design is reasonable, the flow slowing plate is structurally improved, on one hand, the filling of the texturing liquid can be further buffered, and on the other hand, the cavity is designed in the flow slowing plate, and heat exchange is carried out on the texturing liquid at the flow slowing plate by utilizing liquid flowing circulation, namely, temperature control is carried out in the corrosion tank; the temperature controllability of reaction corrosion can be further maintained, the surface texturing quality of the monocrystalline silicon wafer is effectively improved, and stable, reliable and excellent product quality is ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of silicon wafer production, in particular to a constant temperature reaction etching tank for a silicon wafer texturing and cleaning machine. Background Art

[0002] In silicon wafer production, texturing involves etching the wafer surface with a chemical etchant to create a microscopic roughness. This increases the light-trapping effect on the wafer surface, thereby improving photoelectric conversion efficiency. The etching process requires strict control of parameters such as the type and concentration of the etchant, temperature, and time to ensure uniform etching and wafer surface quality. Depending on the wafer type, acidic etchants are typically used when processing multicrystalline silicon wafers due to their complex crystal arrangement. The preferential corrosion reaction between the acidic etchant and the surface defects creates a worm-like light-trapping structure. When processing single-crystalline silicon wafers, alkaline solutions are used to anisotropically etch the different crystal faces of the single-crystalline silicon wafer, creating a uniform, dense, pyramid-like texture.

[0003] When using an alkaline texturing process to prepare single-crystal silicon wafers using a wafer texturing cleaning machine, surface contaminants such as organic impurities, particles, and metal ions must first be cleaned to ensure the texturing effect and surface quality. The wafer is then placed in a reactive etching tank for etching. During the alkaline texturing process, the preparation of the texturing solution, the amount of texturing solution, the temperature of the texturing solution, and the stability of the texturing solution level all have a significant impact on the uniformity of the texturing and the quality of the wafer surface.

[0004] At present, in the above-mentioned variable control, CN201720606099.9 discloses a reaction etching tank for a silicon wafer texturing and cleaning machine, in which a liquid inlet plate, a slow-flow baffle and other structures are designed at the liquid inlet of the texturing liquid to slow down the flow rate of the texturing liquid rushing into the reaction etching tank, thereby stabilizing the liquid level. Although this structure has a slow-flow design when the texturing liquid enters the reaction etching tank, it does not involve the temperature control of the texturing liquid. Therefore, for those skilled in the art, there are still opportunities for combined improvement in the control of various variables in the alkali texturing process, and it is also necessary to further improve the design of the reaction etching tank based on these improvement directions, so that the quality of single-crystal silicon wafer products prepared by the alkali texturing process is more stable and excellent. Utility Model Content

[0005] The technical problem to be solved by the present invention is: in order to overcome the deficiencies of the prior art, the present invention provides a constant temperature reaction corrosion tank for a silicon wafer texturing and cleaning machine, which effectively reduces and alleviates the impact force of the texturing liquid entering the reaction tank, alleviates and effectively guides the flow of the liquid, and at the same time provides temperature exchange for the texturing liquid, ensuring that the temperature in the reaction tank is stable and reliable, thereby improving the surface texturing quality of single crystal silicon wafers and ensuring stable and excellent product quality.

[0006] The technical solution adopted by the utility model to solve its technical problems is: a constant temperature reaction corrosion tank for a silicon wafer texturing and cleaning machine is arranged in the silicon wafer texturing and cleaning machine, and the single crystal silicon wafers to be processed are placed in a flower basket, and the flower basket carries the single crystal silicon wafers into the reaction corrosion tank for immersion corrosion operation, the reaction corrosion tank comprises a reaction tank body, the bottom of the reaction tank body is provided with a liquid inlet, a porous liquid inlet plate is fixed at the position of the liquid inlet, the reaction tank body is supported above the porous liquid inlet plate and a slow flow plate is provided therein, one end of the cavity is connected to a circulating liquid inlet pipeline and the other end is connected to a circulating liquid outlet pipeline, the circulating liquid inlet pipeline and the circulating liquid outlet pipeline are externally connected to a circulating liquid external cavity, and a temperature control device for adjusting the circulating liquid temperature is provided in the circulating liquid external cavity.

[0007] In the above solution, the slow-flow plate design effectively guides the texturing liquid, preventing it from rushing out, thus maintaining a stable liquid level. Furthermore, the slow-flow plate incorporates a temperature control function. By utilizing the plate's internal cavity and combining it with a circulating liquid pipeline, heat exchange between the circulating liquid and the texturing liquid can be achieved while guiding the liquid. This achieves the dual functions of stabilizing the liquid level and controlling the temperature, which helps improve the surface texturing quality of single-crystal silicon wafers.

[0008] Furthermore, the slow-flow plate reaction tank bodies are supported and connected by at least two support columns. These support columns are hollow, with their tops communicating with the internal cavity of the slow-flow plate and their bottoms communicating with the circulating liquid inlet or outlet pipes. When supporting the slow-flow plate, the support columns are designed to be hollow, thus serving as channels for the circulating liquid. This dual function of the support columns effectively supports the slow-flow plate and provides a channel for the circulation of the circulating liquid, further organically combining the guidance of the texturing liquid, the stabilization of the texturing liquid level, and the control of the texturing liquid temperature.

[0009] Furthermore, in the support column of the slow flow plate, the pipeline connected to the bottom of the support column close to the liquid inlet is the circulating liquid outlet pipeline, and the pipeline connected to the bottom of the support column away from the liquid inlet is the circulating liquid inlet pipeline.

[0010] Preferably, the slow-flow plate is an angular structure with an opening facing downward in the vertical direction, and the angle formed by the angular structure is an obtuse angle. The projections of the two corners of the angular structure on the plane of the liquid inlet extend to the outside of the liquid inlet. Due to the provision of the angular structure, when the texturing liquid passes through the porous liquid inlet plate from the liquid inlet and rushes upward into the reaction corrosion tank, the upper position is blocked by the slow-flow plate and guided by the slow-flow plate, and the liquid is drained vertically along the two corners of the slow-flow plate. When the texturing liquid enters the reaction corrosion tank through the liquid inlet, after passing through the porous liquid inlet plate, the slow-flow plate further buffers and disperses the liquid, effectively buffering the impact of the texturing liquid and avoiding excessive impact on the stability of the liquid level.

[0011] Furthermore, in the flow direction of the circulating liquid and the drainage direction of the slow flow plate, the flow direction of the flow channel formed by the circulating liquid inlet pipeline, the internal cavity of the slow flow plate and the circulating liquid outlet pipeline is opposite to the drainage direction of the texturing liquid at the lower end of the slow flow plate. Usually, the texturing liquid has been adjusted to the temperature required by the reaction corrosion process as needed before entering the reaction corrosion tank. The farther away from the liquid inlet, the greater the temperature difference between the temperature of the texturing liquid and the temperature of the liquid inlet. In order to maintain the temperature, the circulating liquid heat exchange is introduced. At this time, the heat exchange starts from the far end of the liquid inlet, which can effectively balance the temperature of the texturing liquid near the liquid inlet and far away from the liquid inlet, making the temperature of the texturing liquid in the reaction corrosion tank more stable and reliable, and reducing the difference in texturing quality caused by temperature difference.

[0012] Furthermore, the silicon wafers are arranged in sequence along the axis of the flower basket, and the liquid inlet is located below one end of the axis of the flower basket; the cross-section of the slow flow plate along the horizontal direction is an isosceles triangle, and the liquid inlet is located on the bottom edge of the projection of the isosceles triangle, and the support columns are respectively arranged at the three corners of the isosceles triangle, wherein the support column at the top corner position is connected to the circulating liquid inlet pipeline, and the support column at the bottom corner position is connected to the circulating liquid outlet pipeline.

[0013] The beneficial effect of the present invention is that the present invention provides a constant temperature reaction corrosion tank for a silicon wafer texturing and cleaning machine, which has a reasonable structural design. On the basis of the liquid inlet plate and the slow flow plate, the slow flow plate is further structurally improved. On the one hand, it can further buffer the filling of the texturing liquid. On the other hand, a chamber is designed inside the slow flow plate, and the liquid flow circulation is used to perform heat exchange on the texturing liquid at the slow flow plate, that is, the temperature is controlled inside the corrosion tank, which can further maintain the temperature controllability of the reactive corrosion, effectively improve the surface texturing quality of the single crystal silicon wafer, and ensure that the product quality is stable, reliable and excellent. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0015] Figure 1 It is a structural schematic diagram of the optimal embodiment of the utility model (the direction of the arrow is the flow direction).

[0016] Figure 2 It is a schematic diagram of the mechanism in another direction of the optimal embodiment of the utility model (the direction of the arrow is the flow direction).

[0017] Figure 3 It is a schematic diagram of the slow flow plate in the optimal embodiment of the present utility model.

[0018] In the figure, 1, reaction tank body 2, flower basket 3, overflow port 4, overflow recovery tank 5, slow flow plate 6, porous liquid inlet plate 7, support column 8, liquid inlet 9, circulating liquid outlet pipeline 10, circulating liquid inlet pipeline. DETAILED DESCRIPTION

[0019] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams that illustrate the basic structure of the present invention only in a schematic manner. Therefore, they only show components relevant to the present invention, and directions and references (e.g., up, down, left, right, etc.) may be used solely to facilitate the description of features in the drawings. The following detailed description is therefore not to be taken in a limiting sense, and the scope of the claimed subject matter is defined solely by the appended claims and their equivalents.

[0020] like Figure 1 and Figure 2 The illustrated constant-temperature reactive etching tank for a silicon wafer texturing and cleaning machine is the preferred embodiment of the present invention. This reactive etching tank is installed within the silicon wafer texturing and cleaning machine and is used to texturize single-crystal silicon wafers. After cleaning, the single-crystal silicon wafers to be processed are placed in a basket 2. The basket 2 carries the single-crystal silicon wafers into the reactive etching tank, which is then filled with a texturing solution for immersion etching of the single-crystal silicon wafers.

[0021] Specifically, the reaction corrosion tank includes a reaction tank body 1, which has a liquid inlet 8 at the bottom, a porous liquid inlet plate 6 fixed at the position of the liquid inlet 8, and a slow flow plate 5 supported by a support column 7 above the reaction tank body 1 corresponding to the porous liquid inlet plate 6. The slow flow plate 5 has a cavity inside, and the support column 7 is an internal hollow structure. The internal cavity of the slow flow plate 5 is connected to the hollow structure of the support column 7. The texturing liquid passes through the porous liquid inlet plate 6 at the position of the liquid inlet 8 and enters the reaction tank body 1. An overflow port 3 is opened on the side of the inner wall of the reaction tank body 1 corresponding to the flower basket 2, and an overflow recovery tank 4 is designed outside the overflow port 3 to recover the overflowing texturing liquid.

[0022] During the alkaline texturing process, the single-crystal silicon wafers to be processed are arranged sequentially within basket 2 along its axis. Basket 2 is positioned within the reaction tank body 1 of the reaction etching tank. The positioning structure between basket 2 and reaction tank body 1 can employ, but is not limited to, a bracket snap-on connection. Based on this, the position and structure of liquid inlet 8 and slow-flow plate 5 are further determined and designed.

[0023] like Figure 3 As shown, in this embodiment, the liquid inlet 8 is preferably positioned below one end of the flower basket 2's axis. The slow-flow plate 5 has an isosceles triangle cross-section along the horizontal direction, with the liquid inlet 8 located at the base of the isosceles triangle's projection. Support columns 7 are positioned at the three corners of the isosceles triangle, with the support columns 7 at the top corners communicating with the circulating liquid inlet pipe 10 and the support columns 7 at the bottom corners communicating with the circulating liquid outlet pipe 9. The circulating liquid inlet pipe 10 and the circulating liquid outlet pipe 9 are connected to a circulating liquid external cavity, which houses a temperature control device for adjusting the circulating liquid temperature. The temperature control device can be a commercially available heating wire, heating rod, or the like.

[0024] The slow-flow plate 5 is an obtuse, downward-opening, angled structure in the vertical direction. The projections of the two corners of the angled structure onto the plane of the liquid inlet 8 extend beyond the liquid inlet 8. This angled structure ensures that when the texturing liquid flows upward from the liquid inlet 8 through the porous liquid inlet plate 6 and into the reaction and etching tank, it is blocked and guided vertically along the two corners of the slow-flow plate 5. As the texturing liquid enters the reaction and etching tank through the liquid inlet 8 and the porous liquid inlet plate 6, it is further buffered and dispersed by the slow-flow plate 5. This effectively mitigates the impact of the texturing liquid and prevents it from significantly affecting the stability of the liquid level.

[0025] The provision of the slow-flow plate 5 not only buffers and drains the texturing liquid entering the reaction tank body 1, facilitating liquid level stability within the tank, but also effectively controls the temperature of the texturing liquid within the tank through the design of the internal cavity and the direction of the circulating liquid's movement. In the design of the circulating liquid flow and the drainage direction of the slow-flow plate 5, the flow path formed by the circulating liquid inlet pipe 10, the internal cavity of the slow-flow plate 5, and the circulating liquid outlet pipe 9 is opposite to the drainage direction of the texturing liquid from the lower end of the slow-flow plate 5. Typically, the texturing liquid is adjusted to the required temperature for the reactive etching process before entering the reactive etching tank. The further away from the liquid inlet 8, the greater the temperature difference between the texturing liquid and the liquid inlet 8. To maintain the temperature, circulating liquid is introduced for heat exchange. In this embodiment, the circulating liquid is introduced at the distal end of the liquid inlet 8, i.e., at the vertex of the isosceles triangle, to initiate heat exchange. The circulating liquid passes through the thickness of the slow-flow plate 5 and exits at the two corners of the base of the isosceles triangle. By flowing the texturing liquid in the opposite direction to the slow flow plate 5, the temperature of the texturing liquid near the liquid inlet 8 and the temperature of the texturing liquid far away from the liquid inlet 8 can be effectively balanced, so that the temperature of the texturing liquid in the reaction corrosion tank is further stabilized and reliable, and the difference in texturing quality caused by temperature difference is reduced.

[0026] When supporting and setting the slow flow plate 5, the support column 7 is designed to be hollow, so that it is used as a flow channel for the circulating liquid, so that the support column 7 has a dual function. On the one hand, it can effectively support the slow flow plate 5, and on the other hand, it can also provide a flow channel for the circulation of the circulating liquid, further organically combining the guidance of the texturing liquid, the stabilization of the texturing liquid level and the control of the texturing liquid temperature.

[0027] This design of a constant-temperature reaction etching tank for a silicon wafer texturing and cleaning machine utilizes a liquid inlet plate and a slow-flow plate 5, with further structural improvements to the slow-flow plate 5. This not only buffers the inflow of texturing liquid, but also incorporates a chamber within the slow-flow plate 5, utilizing liquid circulation to exchange heat with the texturing liquid at the slow-flow plate 5. This combination of a slow-flow, stable liquid surface, and a constant temperature within the slow-flow plate 5 and support column 7 effectively improves the surface texturing quality of single-crystal silicon wafers and ensures stable, reliable, and superior product quality.

[0028] Based on the above-mentioned ideal embodiment of the present invention, and in accordance with the above description, relevant personnel can make various changes and modifications without departing from the technical scope of the present invention. The technical scope of the present invention is not limited to the content of the specification, but must be determined according to the scope of the claims.

Claims

1. A constant temperature reaction etching tank for a silicon wafer texturing and cleaning machine, which is arranged in the silicon wafer texturing and cleaning machine, wherein the single crystal silicon wafer to be processed is placed in a flower basket (2), and the flower basket (2) carries the single crystal silicon wafer into the reaction etching tank for immersion etching operation, characterized in that: The invention comprises a reaction tank body (1), wherein the bottom of the reaction tank body (1) is provided with a liquid inlet (8), a porous liquid inlet plate (6) is fixed at the position of the liquid inlet (8), and a slow flow plate (5) is supported above the reaction tank body (1) corresponding to the porous liquid inlet plate (6), wherein the slow flow plate (5) has a cavity, one end of the cavity is connected to a circulating liquid inlet pipeline (10), and the other end is connected to a circulating liquid outlet pipeline (9), the circulating liquid inlet pipeline (10) and the circulating liquid outlet pipeline (9) are externally connected to a circulating liquid external cavity, and a temperature control device for adjusting the temperature of the circulating liquid is provided in the circulating liquid external cavity.

2. The constant temperature reaction etching tank for a silicon wafer texturing and cleaning machine according to claim 1, characterized in that: The slow flow plate (5) and the reaction tank body (1) are supported and connected by at least two support columns (7). The support columns (7) are hollow inside and the top is connected to the internal cavity of the slow flow plate (5), and the bottom is connected to the circulating liquid inlet pipeline (10) or the circulating liquid outlet pipeline (9).

3. The constant temperature reaction etching tank for a silicon wafer texturing and cleaning machine according to claim 2, characterized in that: In the support column (7) of the slow flow plate (5), the pipeline connected to the bottom of the support column (7) near the liquid inlet (8) is the circulating liquid outlet pipeline (9), and the pipeline connected to the bottom of the support column (7) away from the liquid inlet (8) is the circulating liquid inlet pipeline (10).

4. The constant temperature reaction etching tank for a silicon wafer texturing and cleaning machine according to claim 1, characterized in that: The slow flow plate (5) is an angular structure with an opening facing downward in the vertical direction, and the angle formed by the angular structure is an obtuse angle. The projections of the two corner edges of the angular structure on the plane of the liquid inlet (8) extend to the outside of the liquid inlet (8).

5. The constant temperature reaction etching tank for a silicon wafer texturing and cleaning machine according to claim 4, characterized in that: The flow direction of the flow channel formed by the circulating liquid inlet pipeline (10), the internal cavity of the slow flow plate (5) and the circulating liquid outlet pipeline (9) is opposite to the drainage direction of the texturing liquid at the lower end of the slow flow plate (5).

6. The constant temperature reaction etching tank for a silicon wafer texturing and cleaning machine according to claim 5, characterized in that: The silicon wafers are arranged in sequence along the axis of the flower basket (2), and the liquid inlet (8) is located below one end of the axis of the flower basket (2); the slow flow plate (5) has an isosceles triangle cross section along the horizontal direction, and the liquid inlet (8) is located on the bottom edge of the projection of the isosceles triangle; the support columns (7) are respectively arranged at the positions of the three corners of the isosceles triangle, wherein the support columns (7) at the top corner positions are connected to the circulating liquid inlet pipeline (10), and the support columns (7) at the bottom corner positions are connected to the circulating liquid outlet pipeline (9).

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