Silicon wafer alkali polishing additive and synthesis device thereof

Abstract

The invention discloses an alkali polishing additive for silicon wafers. The alkali polishing additive comprises organic amine, a complexing dispersant, inorganic salt and a surfactant. The organic amine is one or more of dichloroaniline, diethanol amine and dimethylamine, and the organic amine is 1-5 parts. The complexing dispersant is one or more of sodium benzoate, sodium alginate and sodium citrate, and the complexing dispersant is 3-8 parts. The inorganic salt is one or more of sodium sulfate, lauryl sodium sulfate, sodium pyrosulfate and sodium tartrate, and the inorganic salt is 1-5 parts. The surfactant is one or more of dodecyl dimethyl betaine, sodium alkyl naphthalene sulfonate and alkyl glycoside, and the amount of the surfactant is 5-8 parts; the additive also comprises deionized water; according to the silicon wafer alkali polishing additive, the organic amine is added, the back polishing effect of the same tower footing is obtained under the condition of low weight loss, the battery efficiency is improved, meanwhile, the additive synthesis device can stir and dissolve all the raw materials evenly, and the alkali polishing additive is obtained.

Description

Technical Field

[0001] This invention relates to the technical field of industrial processing, and in particular to a silicon wafer alkaline polishing additive and its synthesis apparatus. Background Technology

[0002] In the production of crystalline silicon solar cells, to further improve the performance and efficiency of the cells, the back surface of the silicon wafer is usually polished to make it smoother or even achieve a mirror-like effect. After polishing, the back surface of the silicon wafer is flat, which on the one hand enhances the reflection of transmitted light and reduces light transmittance, and on the other hand allows for more thorough contact between the aluminum paste and the silicon wafer surface, improving the passivation effect. Back surface polishing increases both the current (Isc) and the open-circuit voltage (Voc), thereby improving the conversion efficiency of the solar cell. Therefore, a silicon wafer alkaline polishing additive is proposed. By adding organic amines, the same back surface polishing effect is achieved with minimal weight loss, improving cell efficiency. Simultaneously, an additive synthesis device is proposed to ensure that all raw materials are stirred and dissolved uniformly. Summary of the Invention

[0003] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0004] In view of the problems existing in the above-mentioned silicon wafer alkaline polishing additives and their synthesis equipment, the present invention is proposed.

[0005] Therefore, the purpose of this invention is to provide a silicon wafer alkali polishing additive and its synthesis apparatus, which achieves the same back-side polishing effect of the tower base with low weight loss by adding organic amine, thereby improving battery efficiency. At the same time, an additive synthesis apparatus is proposed to stir and dissolve the various raw materials evenly.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a silicon wafer alkali polishing additive includes organic amine, complexing dispersant, inorganic salt and surfactant.

[0007] As a preferred embodiment of the silicon wafer alkaline polishing additive and its synthesis apparatus according to the present invention, the organic amine is one or more of dichloroaniline, diethanolamine, and dimethylamine, and the organic amine is 1 to 5 parts.

[0008] As a preferred embodiment of the silicon wafer alkali polishing additive and its synthesis apparatus according to the present invention, the complexing dispersant is one or more of sodium benzoate, sodium alginate, and sodium citrate, and the complexing dispersant is 3 to 8 parts.

[0009] As a preferred embodiment of the silicon wafer alkali polishing additive and its synthesis apparatus according to the present invention, the inorganic salt is one or more of sodium sulfate, sodium dodecyl sulfate, sodium pyrosulfate, and sodium tartrate, and the inorganic salt is 1 to 5 parts.

[0010] As a preferred embodiment of the silicon wafer alkali polishing additive and its synthesis apparatus according to the present invention, the surfactant is one or more of dodecyl dimethyl betaine, sodium alkyl naphthalene sulfonate, and alkyl glycoside, and the surfactant is 5 to 8 parts; the additive also includes deionized water.

[0011] As a preferred embodiment of the silicon wafer alkali polishing additive and its synthesis apparatus according to the present invention, the apparatus includes: a housing assembly comprising a mixing tank, a mounting frame disposed within the mixing tank, and reinforcing ribs fixed to the mounting frame; and a synthesis assembly disposed on the mixing tank, comprising a motor, a central roller connected to the motor, and mixing fins disposed on the central roller.

[0012] In a preferred embodiment of the silicon wafer alkali polishing additive and its synthesis apparatus according to the present invention, the mixing tank is provided with a mounting platform, the bottom of the mounting platform is provided with a fixing plate, and a rotating frame passes through the side wall of the mixing tank.

[0013] In a preferred embodiment of the silicon wafer alkali polishing additive and its synthesis apparatus according to the present invention, the mounting frame is disposed in a mixing tank, the mounting frame includes a mounting crossbar and a mounting diagonal bar, the mounting crossbar is fixed in the mixing tank, a plurality of mounting diagonal bars are disposed obliquely in the mixing tank, the mounting diagonal bars are disposed at equal intervals, one end of the reinforcing rib is fixed to the mounting crossbar, and the other end is fixed to the inner wall of the mixing tank.

[0014] In a preferred embodiment of the silicon wafer alkali polishing additive and its synthesis apparatus according to the present invention, the motor is mounted on a mounting platform, the motor output shaft is connected to a central roller, the central roller is mounted inside a rotating frame, a ball bearing is also mounted inside the rotating frame, and a fixed base is mounted outside the rotating frame.

[0015] As a preferred embodiment of the silicon wafer alkali polishing additive and its synthesis device of the present invention, wherein: the central roller is provided with a base plate at both ends in the mixing tank, and a sleeve is sleeved on the base plate; the mixing fins are provided on the sleeve; the sleeve has a square cross-section; the mixing fins are provided in several groups, each group including four sub-fins; each sub-fin has a different length and is long and narrow; each sub-fin is in contact with each surface of the sleeve, and every two adjacent sub-fins abut against each other; each group of mixing fins is embedded between two pairs of mounting inclined rods; the mixing fins do not contact the mounting inclined rods; and the shapes of every two adjacent groups of mixing fins are inconsistent.

[0016] The beneficial effects of this invention are:

[0017] The silicon wafer alkaline polishing additive of this invention achieves the same back-side polishing effect as the tower base with low weight loss by adding organic amine, thereby improving battery efficiency. At the same time, the additive synthesis device can stir and dissolve each raw material evenly to obtain the alkaline polishing additive. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0019] Figure 1 This is a schematic diagram of the overall structure of the silicon wafer alkali polishing additive and its synthesis device according to the present invention.

[0020] Figure 2 This is a side view of the overall structure of the silicon wafer alkali polishing additive and its synthesis apparatus according to the present invention.

[0021] Figure 3 This is a schematic diagram of the synthesis component structure of the silicon wafer alkali polishing additive and its synthesis device according to the present invention.

[0022] Figure 4 This is a cross-sectional view of the overall structure of the silicon wafer alkali polishing additive and its synthesis apparatus of the present invention.

[0023] Figure 5 This is an enlarged schematic diagram of point A of the silicon wafer alkali polishing additive and its synthesis apparatus according to the present invention.

[0024] Figure 6 This is an overall cross-sectional view of the silicon wafer alkali polishing additive and its synthesis apparatus of the present invention.

[0025] Figure 7 This is a schematic diagram of the sub-fin arrangement of the silicon wafer alkaline polishing additive and its synthesis device according to the present invention. Detailed Implementation

[0026] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0027] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0028] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0029] Secondly, the present invention is described in detail with reference to the schematic diagrams. When detailing the embodiments of the present invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not according to the usual scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. In addition, actual fabrication should include three-dimensional spatial dimensions of length, width, and depth.

[0030] Example 1

[0031] In a first embodiment of the present invention, a silicon wafer polishing additive is provided, comprising an organic amine, a complexing dispersant, an inorganic salt, and a surfactant. The organic amine is one or more of dichloroaniline, diethanolamine, and dimethylamine, and is present in a quantity of 1-5 parts. The complexing dispersant is one or more of sodium benzoate, sodium alginate, and sodium citrate, and is present in a quantity of 3-8 parts. The inorganic salt is one or more of sodium sulfate, sodium dodecyl sulfate, sodium pyrosulfate, and sodium tartrate, and is present in a quantity of 1-5 parts. The surfactant is one or more of dodecyl dimethyl betaine, sodium alkylnaphthalene sulfonate, and alkyl glycoside, and is present in a quantity of 5-8 parts; the additive also includes deionized water.

[0032] An alkaline polishing additive is obtained by sequentially dissolving organic amines, complexing dispersants, inorganic salts, and surfactants with deionized water in a synthesis apparatus. This alkaline polishing additive is then further formulated with 0.5%–4% inorganic alkali (sodium hydroxide or potassium hydroxide), deionized water, and 0.5%–3% of the alkaline polishing additive product. Processing these raw materials at a temperature of 60–75°C for 100–300 seconds yields an alkaline polishing bath solution. This solution can be added to the silicon wafers during the product process: silicon wafer loading – pre-cleaning – water washing – alkaline polishing to remove plating – water washing – post-cleaning – water washing – drying – unloading, for chemical polishing. The addition of organic amines to this alkaline polishing bath solution achieves the same back-side polishing effect as the substrate while reducing weight, thus improving battery efficiency. The following is a practical example of this alkaline polishing bath solution:

[0033] Case 1: 3.5% inorganic alkali (sodium hydroxide or potassium hydroxide), deionized water, 2% alkali polishing additive product. Process temperature 65℃, process time 250s. Silicon wafer weight reduction 0.2g, substrate 9µm, reflectivity 45%.

[0034] Case 2: 3.5% inorganic alkali (sodium hydroxide or potassium hydroxide), deionized water, 2% alkali polishing additive product (with added defoaming surfactant). Process temperature 65℃, process time 240s. Silicon wafer weight reduction 0.15g, substrate 9µm, reflectivity 45%.

[0035] Currently, changes in processes and additives result in weight reduction that is directly proportional to the tower base, and the ratio remains relatively stable. However, in the aforementioned case, the addition of organic amines and surfactants creates a synergistic effect, altering this ratio. This allows for the achievement of the same tower base and back-side polishing effect with even lower weight reduction, effectively improving Isc and Voc, thereby enhancing battery conversion efficiency.

[0036] Example 2

[0037] Reference Figures 1-6 This is a second embodiment of the present invention, which differs from the first embodiment in that: a silicon wafer alkali polishing additive synthesis device includes a housing assembly 100 and a synthesis assembly 200. The housing assembly 100 includes a mixing tank 101, a mounting frame 102 disposed within the mixing tank 101, and reinforcing ribs 103 fixed to the mounting frame 102. Alkali polishing additive raw materials are placed in the mixing tank 101, and the reinforcing ribs 103 reinforce the mounting frame 102 to prevent it from being unable to withstand the water flow force generated within the mixing tank 101 after stirring is started. The synthesis assembly 200, disposed on the mixing tank 101, includes a motor 201, a central roller 202 connected to the motor 201, and mixing fins 203 disposed on the central roller 202. The motor 201 provides power to the central roller 202, driving it to rotate and causing the mixing fins 203 to begin stirring and mixing.

[0038] To stabilize the rotation of the central roller 202, in this embodiment, a mounting platform 101a is provided on the mixing tank 101, and a fixing piece 101b is provided at the bottom of the mounting platform 101a. A rotating frame 101c passes through the side wall of the mixing tank 101. The mounting frame 102 is disposed inside the mixing tank 101, and the mounting frame 102 includes a mounting crossbar 102a and a mounting diagonal bar 102b. The mounting crossbar 102a is fixed inside the mixing tank 101, and several mounting diagonal bars 102b are provided. The mounting diagonal bars 102b are obliquely disposed inside the mixing tank 101 and are equidistantly arranged. One end of the reinforcing rib 103 is fixed to the mounting crossbar 102a, and the other end is fixed to the inner wall of the mixing tank 101. The fixing plate 101b and the mounting platform 101a form a triangular structure to ensure the stable installation of the motor 201. The mounting crossbar 102a is fixed to the reinforcing rib 103, and the mounting diagonal bar 102b is obliquely fixed to the inner wall of the mixing tank 101, allowing it to remain stationary with the mixing tank 101. After stirring begins, it has a good diversion effect on the disturbed processing liquid, accelerating the mixing speed. The motor 201 is mounted on the mounting platform 101a, and the output shaft of the motor 201 is connected to the central roller 202. The central roller 202 is set inside the rotating frame 101c, which also contains ball bearings 202a. A fixed base 202b is set outside the rotating frame 101c. The ball bearings 202a inside the rotating shaft can improve the kinetic energy utilization rate, while the fixed base 202b on the rotating frame 101c further stabilizes the central roller 202 during rotation.

[0039] To mix the raw materials, the central roller 202 is provided with a base plate 202c at both ends within the mixing tank 101. A sleeve 203a is fitted over the base plate 202c. The mixing fins 203 are disposed on the sleeve 203a. The sleeve 203a has a square cross-section. The mixing fins 203 are arranged in several groups, each group including four sub-fins 203b. Each sub-fin 203b is of different lengths and is elongated. Each sub-fin 203b is in contact with each surface of the sleeve 203a, and every two adjacent sub-fins 203b abut against each other. Each group of mixing fins 203 is embedded between two pairs of mounting inclined rods 102b. The mixing fins 203 do not contact the mounting inclined rods 102b. The shapes of every two adjacent groups of mixing fins 203 are not consistent. Each set of mixing fins 203 is configured to correspond to the gaps within the mounting brace 102b, allowing the mixing fins 203 to rotate freely within the gaps. Each set of mixing fins 203 includes four sub-fins 203b, which are arranged around the side wall of the central sleeve 203a to form a swastika shape. The central roller 202 is driven to rotate by the motor 201, which in turn drives the mixing fins 203 to rotate, thus agitating the raw material liquid. Since the sub-fins 203b are of different lengths and the arrangement of the sub-fins 203b within adjacent sets of mixing fins 203 is also different, the varying lengths of the stirring arms can increase the disorder in the solution, greatly increasing the mixing speed, shortening the working time, and improving efficiency.

[0040] The remaining structure is the same as that in Example 1.

[0041] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A silicon wafer alkaline polishing additive, characterized in that: This includes organic amines, complexing dispersants, inorganic salts, and surfactants.

2. The silicon wafer alkaline polishing additive as described in claim 1, characterized in that: The organic amine is one or more of dichloroaniline, diethanolamine, and dimethylamine, and the organic amine is present in 1 to 5 parts.

3. The silicon wafer alkaline polishing additive as described in claim 2, characterized in that: The complexing dispersant is one or more of sodium benzoate, sodium alginate, and sodium citrate, and the amount of the complexing dispersant is 3 to 8 parts.

4. The silicon wafer alkaline polishing additive as described in claim 3, characterized in that: The inorganic salt is one or more of sodium sulfate, sodium dodecyl sulfate, sodium pyrosulfate, and sodium tartrate, and the amount of the inorganic salt is 1 to 5 parts.

5. The silicon wafer alkaline polishing additive as described in claim 4, characterized in that: The surfactant is one or more of dodecyl dimethyl betaine, sodium alkylnaphthalene sulfonate, and alkyl glycoside, and the surfactant is present in 5 to 8 parts; the additive also includes deionized water.

6. A synthesis apparatus using the silicon wafer alkali polishing additive as described in claim 5, characterized in that: include, The housing assembly (100) includes a mixing tank (101), a mounting bracket (102) disposed in the mixing tank (101), and a reinforcing rib (103) fixed to the mounting bracket (102); The synthesis component (200) is disposed on the mixing tank (101) and includes a motor (201), a central roller (202) connected to the motor (201), and mixing fins (203) disposed on the central roller (202).

7. The apparatus for synthesizing silicon wafer alkali polishing additives as described in claim 6, characterized in that: The mixing tank (101) is provided with a mounting platform (101a), the bottom of the mounting platform (101a) is provided with a fixing plate (101b), and a rotating frame (101c) passes through the side wall of the mixing tank (101).

8. The apparatus for synthesizing silicon wafer alkali polishing additives as described in claim 7, characterized in that: The mounting bracket (102) is disposed in the mixing tank (101). The mounting bracket (102) includes a mounting crossbar (102a) and a mounting diagonal bar (102b). The mounting crossbar (102a) is fixed in the mixing tank (101). Several mounting diagonal bars (102b) are provided. The mounting diagonal bars (102b) are obliquely disposed in the mixing tank (101) and are equidistantly disposed. One end of the reinforcing rib (103) is fixed to the mounting crossbar (102a), and the other end is fixed to the inner wall of the mixing tank (101).

9. The apparatus for synthesizing silicon wafer alkali polishing additives as described in claim 8, characterized in that: The motor (201) is mounted on the mounting platform (101a). The output shaft of the motor (201) is connected to the central roller (202). The central roller (202) is located inside the rotating frame (101c). The rotating frame (101c) is also equipped with ball bearings (202a). A fixed base (202b) is located outside the rotating frame (101c).

10. The apparatus for synthesizing silicon wafer alkali polishing additives as described in claim 9, characterized in that: The central roller (202) is located within the mixing tank (101) and has base plates (202c) at both ends. A sleeve (203a) is fitted over the base plate (202c). Mixing fins (203) are mounted on the sleeve (203a). The sleeve (203a) has a square cross-section. Several groups of mixing fins (203) are provided, each group including four sub-fins (203b). Each sub-fin (203b) is [length missing]. The sub-fins (203b) are of varying lengths and are elongated. Each sub-fin (203b) is in contact with each surface of the sleeve (203a), and every two adjacent sub-fins (203b) abut against each other. Each group of mixed fins (203) is embedded between two mounting inclined rods (102b). The mixed fins (203) do not contact the mounting inclined rods (102b), and the shapes of every two adjacent groups of mixed fins (203) remain inconsistent.

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