Silicon wafer bending core forming tool

Abstract

The utility model provides a silicon wafer bending and core forming tool, which belongs to the technical field of solar cell manufacturing, and includes two parallel clamping rods and a translation drive mechanism. A plurality of clamping grooves for clamping silicon wafers are symmetrically arranged on the inner sides of the two clamping rods relative to each other; the translation drive mechanism is arranged on the outer side of at least one of the clamping rods to drive the clamping rods to move closer to or away from each other, and to adjust the distance between the two clamping rods. The silicon wafer bending and core forming tool provided by the utility model uses the silicon wafer bending and core forming tool provided by the utility model to apply external force to the silicon wafer, and increases the pinholes and concave surfaces in the silicon oxide layer through the tensile or compressive stress caused by the bending and stretching process of the silicon wafer, thereby effectively transporting electrons, reducing resistivity, and controlling the uniform distribution of polysilicon grain size; at the same time, the bending amount of the silicon wafer is adjustable, and the number of pinholes and concave surfaces can be adjusted by adjusting the bending amount, without the need for an additional continuous high temperature process.

Description

Technical Field

[0001] The utility model belongs to the technical field of solar cell manufacturing, and in particular relates to a silicon slice bending core forming tool. Background Art

[0002] TOPCon solar cell: tunneling oxide passivation contact cell, the silicon oxide layer on the back of the cell is about 1.5nm thick, which can play the role of passivation and allow electrons to tunnel through.

[0003] TOPCon solar cells use a tunneling passivation layer to improve cell performance. The tunneling passivation layer material is usually an ultra-thin silicon oxide layer. The silicon oxide layer itself is not conductive, but when its thickness is thin, the electrons in the crystalline silicon substrate can tunnel through the silicon oxide layer and enter the conductive polysilicon layer, and are eventually collected by the electrode. In addition, if a uniform and appropriate amount of pinholes can be formed on the silicon oxide layer, the electrons in the crystalline silicon substrate can directly enter the polysilicon layer from the pinholes, and the corresponding resistivity is lower.

[0004] The polysilicon layer adjacent to the silicon oxide layer is a phosphorus-doped N-type polysilicon layer, which can transport electrons to the electrode. The better the uniformity of the grains and the larger the grain size, the fewer defects in the polysilicon layer and the better the battery performance. The number of grains is related to the number and position of nucleation points during the deposition of the polysilicon layer. When depositing the polysilicon layer, it is easier to nucleate on a concave surface than on a flat surface.

[0005] At present, the number of pinholes on the silicon oxide layer is related to the thermal stress exerted on the silicon oxide layer during the annealing process. The process of forming pinholes through thermal stress during the annealing process is relatively difficult to control and is highly dependent on temperature. Continuous high temperature may have adverse effects on the battery, so it is not conducive to the control of the number of pinholes and the nucleation of grains in the polysilicon layer. Utility Model Content

[0006] The embodiment of the utility model provides a silicon wafer bending nucleation tool, which is designed to make the silicon wafer form a slight bend when depositing the silicon oxide layer. After the deposition is completed, the bend is released to allow the silicon wafer to naturally stretch and flatten, which will form tensile or compressive stress on the silicon oxide layer, thereby forming pinholes and concave surfaces on the silicon oxide layer, which helps to increase the probability of electron pinhole transport and control the nucleation process of the polysilicon layer.

[0007] In order to achieve the above-mentioned purpose, the technical solution adopted by the utility model is: to provide a silicon wafer bending core forming tool, comprising:

[0008] Two parallel clamping rods, wherein the inner sides of the two clamping rods facing each other are symmetrically provided with a plurality of clamping grooves for clamping the silicon wafer; and

[0009] The translation driving mechanism is arranged at least on the outer side of one of the clamping rods to drive the clamping rods to move closer to or farther from each other.

[0010] In one achievable manner, the translation drive mechanism comprises an electric push rod, an end of a telescopic rod of the electric push rod is provided with an elastic buffer, and the electric push rod is connected to the outer side of the clamping rod through the elastic buffer.

[0011] In one achievable manner, the elastic buffer is a spring, a rubber block or a silicone block.

[0012] In one feasible manner, the tooling further comprises a guide rod having a guide groove arranged along the length direction of the guide rod, the same end of the two clamping rods being engaged in the guide groove, and at least one of the clamping rods slides reciprocatingly along the guide groove under the drive of the translation drive mechanism.

[0013] In one practicable manner, a limit block for limiting the travel of the clamping rod is arranged in the guide groove.

[0014] In one practicable manner, a buffer pad is provided on the side of the limit block.

[0015] In one achievable manner, rollers are provided at both ends of the clamping rod, and the rollers are in rolling engagement with the guide grooves.

[0016] In one practicable manner, the guide rods are provided at both ends of the two clamping rods, and the ends of the guide rods are provided with anti-dropping end caps.

[0017] In one achievable manner, a flexible protective layer is provided on both inner walls of the clamping groove and on the groove bottom.

[0018] In one achievable manner, the flexible protective layer is a rubber layer or a silicone layer.

[0019] Compared with the prior art, the silicon wafer bending nucleation tool provided by the utility model has the following beneficial effects: before depositing the silicon oxide layer, one of the clamping rods is pushed toward the other clamping rod by a translation driving mechanism, the distance between the clamping rods is shortened, and an external force is applied to the edge of the silicon wafer. When the distance between the two clamping rods becomes narrower, the silicon wafer clamped between the two is slightly bent; then the silicon oxide layer is deposited on the bent silicon wafer, and after the deposition is completed, the clamping rod is driven to move by the translation driving mechanism to increase the distance between the two clamping rods, and the bend is slowly released, so that the silicon wafer is naturally stretched and flattened. In this process, tensile or compressive stress is formed on the silicon oxide layer. Since the silicon oxide layer is relatively thin, the stress will form pinholes and concave surfaces in the silicon oxide layer. Better control of the pinhole density can effectively improve the electron transport process; then a polycrystalline silicon layer is deposited on the silicon oxide layer, and silicon will preferentially nucleate at the concave surface, which helps to increase the nucleation points of the polycrystalline silicon layer, make the grain size in the polycrystalline silicon layer more uniform, and ultimately help to improve the performance of the battery.

[0020] The silicon wafer bending and nucleation tooling provided by the utility model is used to apply external force to the silicon wafer, and the pinholes and concave surfaces in the silicon oxide layer are increased by the tensile or compressive stress caused during the bending and stretching of the silicon wafer, thereby effectively transporting electrons, reducing resistivity, and controlling the uniform distribution of polysilicon grain size; at the same time, the bending amount of the silicon wafer is adjustable, and the number of pinholes and concave surfaces can be adjusted by adjusting the bending amount, without the need for an additional continuous high-temperature process. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic diagram of the structure of a silicon wafer bending and core forming tooling provided in an embodiment of the utility model;

[0022] Figure 2 A schematic diagram of the structure of the guide rod provided in the embodiment of the utility model;

[0023] Figure 3 A schematic diagram of the structure of a clamping rod provided in an embodiment of the utility model;

[0024] Description of reference numerals:

[0025] 1. Guide rod; 101. Guide groove; 102. Limit block; 2. Anti-drop end cover; 3. Elastic buffer; 4. Translation drive mechanism; 5. Clamping rod; 501. Clamping groove; 502. Roller; 6. Silicon wafer. DETAILED DESCRIPTION

[0026] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0027] Please also read Figures 1 to 3 The silicon wafer bending and core forming tool provided by the utility model is now described. The silicon wafer bending and core forming tool comprises two parallel clamping rods 5 and a translation driving mechanism 4. The inner sides of the two clamping rods 5 facing each other are symmetrically provided with multiple groups of clamping grooves 501 for clamping the silicon wafer 6; the translation driving mechanism 4 is at least arranged on the outer side of one of the clamping rods 5 to drive the clamping rods 5 to move closer to or away from each other, and adjust the distance between the two clamping rods 5 so that the silicon wafer 6 is slightly bent and then flattened.

[0028] The silicon wafer 6 bending nucleation tool provided by the utility model, before depositing the silicon oxide layer, pushes one of the clamping rods 5 to move closer to the other clamping rod 5 through the translation drive mechanism 4, shortens the distance between the clamping rods 5, thereby applying external force to the edge of the silicon wafer 6, and when the distance between the two clamping rods 5 becomes narrower, the silicon wafer 6 clamped therebetween forms a slight bend; then the silicon oxide layer is deposited on the bent silicon wafer 6, and after the deposition is completed, the clamping rod 5 is driven to move by the translation drive mechanism 4 to increase the distance between the two clamping rods 5, and the bend is slowly released, so that the silicon wafer 6 naturally stretches and flattens, and tensile or compressive stress is formed on the silicon oxide layer in the process. Since the silicon oxide layer is thin, the stress will form pinholes and concave surfaces in the silicon oxide layer; then the polycrystalline silicon layer is deposited on the silicon oxide layer, and silicon will preferentially nucleate at the concave surface, which helps to increase the nucleation points of the polycrystalline silicon layer, make the grain size in the polycrystalline silicon layer more uniform, and ultimately help to improve the performance of the battery.

[0029] The silicon wafer 6 bending nucleation tool provided by the utility model is used to apply external force to the silicon wafer 6, and the pinholes and concave surfaces in the silicon oxide layer are increased by the tensile or compressive stress caused during the bending and stretching of the silicon wafer 6, thereby effectively transporting electrons, reducing resistivity, and controlling the uniform distribution of polycrystalline silicon grains; at the same time, the bending amount of the silicon wafer 6 is adjustable, and the number of pinholes and concave surfaces can be adjusted by adjusting the bending amount, without the need for an additional continuous high-temperature process.

[0030] The term nucleation is explained as follows: During the vapor deposition of polysilicon layers, molecules are adsorbed and accumulated at appropriate locations on the substrate surface to form nuclei. After the crystal nuclei are formed, they will gradually grow and become grains of a certain size. Compared with flat surfaces, it is easier to form nuclei on concave surfaces.

[0031] In some embodiments, Figure 1 As shown, the translation driving mechanism 4 includes an electric push rod, an elastic buffer 3 is provided at the end of the telescopic rod of the electric push rod, and the electric push rod is connected to the outer side of the clamping rod 5 through the elastic buffer 3.

[0032] For example, the clamping rod 5 on the left is controlled by an electric push rod, which pushes the clamping rod 5 on the left to translate to the right. At this time, due to the gradually narrowing distance between the two clamping rods 5, the silicon wafer 6 is bent by force, forming a slight bending of the silicon wafer 6. After the silicon oxide layer is deposited, the clamping rod 5 is moved to the left, and the external force is slowly removed. The silicon wafer 6 stretches or compresses the silicon oxide layer while slowly releasing the stress, thereby forming pinholes and pits on the silicon oxide layer. When the number of pinholes is large, the electron transport mechanism will be mainly pinhole transport, which is more effective than tunneling and can obtain a lower resistivity. In addition, when depositing a polysilicon layer, it is easier to nucleate on a concave surface than on a plane. The pits formed when stretching or compressing the silicon oxide layer can become the preferred nucleation point of polysilicon. By forming more pits by stretching or compressing the silicon oxide layer, the number of nucleation points can be increased and the grain size can be controlled, so that the grain distribution of the polysilicon layer is more uniform and the grain size is larger.

[0033] The provision of the elastic buffer 3 can alleviate the impact force of the electric push rod on the silicon wafer 6, has a buffering and shock-absorbing effect, helps the silicon wafer 6 to bend slowly, and avoids damage to the silicon wafer 6.

[0034] To explain, an electric push rod, also known as a linear drive, is an electric drive device that converts the rotational motion of an electric motor into the linear reciprocating motion of a push rod. Specifically, the motor drives a pair of lead screw nuts after being decelerated by gears or worm gears. The rotational motion of the motor is converted into linear motion, and the push rod movement is completed by using the forward and reverse rotation of the motor. For example, complex movements such as rotation and shaking can be completed through various mechanisms such as levers, rockers or connecting rods. By changing the length of the lever arm, the stroke can be increased or decreased. Worm gear transmission form of the stroke control device: the worm on the motor gear drives the worm wheel to rotate, so that the small lead screw in the worm wheel moves axially, and the connecting plate drives the limit rod to move axially accordingly. When the required stroke is reached, the stroke switch is pressed down by adjusting the limit block 102 to cut off the power, and the motor stops running. The forward and reverse control is the same.

[0035] The tooling provided by the utility model adopts a clamping rod 5 which can be made of round steel, square steel or steel plate; the guide rod 1 at the end can be made of channel steel or I-beam, and the translation drive mechanism 4 can choose linear actuators such as electric push rods, cylinders, hydraulic cylinders or linear moving slides. It is simple to make, low in production cost, simple and convenient to operate, and suitable for implementation.

[0036] In some embodiments, Figure 1 As shown, the elastic buffer 3 is a spring, a rubber block or a silicone block. The elastic buffer 3 can buffer and absorb energy to prevent the silicon chip 6 from being damaged by impact.

[0037] In some embodiments, Figure 1 and Figure 2As shown, the tooling also includes a guide rod 1, and a guide groove 101 is provided along the length direction of the guide rod 1. The same end of the two clamping rods 5 is fitted in the guide groove 101, and at least one clamping rod 5 reciprocates along the guide groove 101 under the drive of the translation drive mechanism 4. The guide rod 1 has the function of guiding and limiting the movement of the clamping rod 5, and can ensure that the clamping rod 5 translates in the same direction.

[0038] Optionally, both clamping rods 5 can slide along the guide groove 101 , and translation drive mechanisms 4 are disposed on the outer sides of both clamping rods 5 .

[0039] Optionally, each clamping rod 5 is provided with one, two or three translation drive mechanisms 4. When one translation drive mechanism 4 is provided, the translation drive mechanism 4 is provided in the middle position of the clamping rod 5; when two translation drive mechanisms 4 are provided, the two translation drive mechanisms 4 are provided at both ends of the clamping rod 5; when three translation drive mechanisms 4 are provided, they can be evenly distributed in the length direction of the clamping rod 5 to ensure the uniformity of force on each silicon wafer 6.

[0040] In some embodiments, Figure 2 As shown, a limit block 102 for limiting the travel of the clamping rod 5 is provided in the guide groove 101. The limit block 102 is a mechanical limit, which can avoid limiting the limit position of the movement of the clamping rod 5 when the translation drive mechanism 4 fails to control, thereby protecting the silicon wafer 6 from damage. When the clamping rods 5 can slide, two limit blocks 102 are provided for the travel of each clamping rod 5.

[0041] In some embodiments, Figure 2 As shown, a buffer pad (not shown in the figure) is provided on the side of the limit block 102. When the clamping rod 5 contacts the limit block 102, the clamping rod 5 is evenly buffered and vibration-reduced to avoid damage to the silicon wafer 6 caused by hard impact.

[0042] In some embodiments, Figure 3 As shown, rollers 502 are provided at both ends of the clamping rod 5, and the rollers 502 are rollingly matched with the guide grooves 101. Through the design of the rollers 502, rolling friction is formed between the clamping rod 5 and the guide rod 1, thereby reducing friction loss.

[0043] In some embodiments, Figure 1 As shown, both ends of the two clamping rods 5 are provided with guide rods 1, and the ends of the guide rods 1 are provided with anti-dropout end caps 2. At this time, the anti-dropout end caps 2 can also serve as the outer limit blocks 102 of the clamping rods 5.

[0044] The anti-drop end cover 2 can prevent the clamping rod 5 from slipping off the guide rod 1 and facilitates the installation of the clamping rod 5 and the guide rod 1. For example, the anti-drop end cover 2 and the guide rod 1 are connected by bolts.

[0045] In some embodiments, a flexible protective layer (not shown) is disposed on both inner walls and the bottom of the clamping groove 501. The clamping groove 501 may be a toothed groove directly processed on the clamping rod 5, and the clamping groove 501 may be rectangular or trapezoidal.

[0046] In order to avoid damage to the silicon wafer 6 and facilitate micro-bending of the silicon wafer 6, chamfers are provided on both sides of the notch of the clamping groove 501. The chamfers may be arc transition angles. Figure 1 and Figure 3 as shown in .

[0047] Optionally, the clamping groove 501 may also be composed of two strips welded to the clamping rod 5 .

[0048] In some embodiments, the flexible protective layer is a rubber layer or a silicone layer. The flexible protective layer in the clamping groove 501 contacts the silicon chip 6 to avoid damage caused by direct contact between the silicon chip 6 and the rigid clamping rod 5 .

[0049] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0050] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A silicon wafer bending and core forming tool, characterized in that: include: Two parallel clamping rods (5), wherein the inner sides of the two clamping rods (5) facing each other are symmetrically provided with a plurality of clamping grooves (501) for clamping the silicon wafer (6); and The translation driving mechanism (4) is arranged at least on the outside of one of the clamping rods (5) to drive the clamping rods (5) to move closer to or farther from each other.

2. The silicon wafer bending and core forming tool as claimed in claim 1, characterized in that: The translation drive mechanism (4) comprises an electric push rod, the end of the telescopic rod of the electric push rod is provided with an elastic buffer (3), and the electric push rod is connected to the outer side of the clamping rod (5) through the elastic buffer (3).

3. The silicon wafer bending and core forming tool as claimed in claim 2, characterized in that: The elastic buffer (3) is a spring, a rubber block or a silicone block.

4. The silicon wafer bending and core forming tool as claimed in claim 1, characterized in that: The tooling also includes a guide rod (1), a guide groove (101) is provided along the length direction of the guide rod (1), the same end of the two clamping rods (5) is engaged in the guide groove (101), and at least one of the clamping rods (5) slides reciprocatingly along the guide groove (101) under the drive of the translation drive mechanism (4).

5. The silicon wafer bending and core forming tool as claimed in claim 4, characterized in that: A limit block (102) for limiting the travel of the clamping rod (5) is arranged in the guide groove (101).

6. The silicon wafer bending and core forming tool as claimed in claim 5, characterized in that: A buffer pad is provided on the side of the limiting block (102).

7. The silicon wafer bending and core forming tool as claimed in claim 4, characterized in that: Rollers (502) are provided at both ends of the clamping rod (5), and the rollers (502) are in rolling engagement with the guide grooves (101).

8. The silicon wafer bending and core forming tool as claimed in claim 4, characterized in that: The two ends of the two clamping rods (5) are provided with the guide rods (1), and the ends of the guide rods (1) are provided with anti-dropping end covers (2).

9. The silicon wafer bending and core forming tool as claimed in claim 1, characterized in that: A flexible protective layer is provided on both inner walls of the clamping groove (501) and on the groove bottom.

10. The silicon wafer bending and core forming tool as claimed in claim 9, characterized in that: The flexible protective layer is a rubber layer or a silicone layer.

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