Method for improving disconnection step color difference of solar silicon wafer

Abstract

The application relates to a solar silicon wafer broken line step color difference improvement method, which comprises the following steps: S1. old line welding treatment is adopted; S2. according to the current wire supply amount, wire return amount, cutting direction and periodic position when the broken line occurs, the remaining periodic wire amount is calculated; S3. after the welded wire head is walked, then the corresponding parameters of the equipment are adjusted according to the calculated remaining periodic wire amount, and then the silicon wafer cutting of the remaining periodic wire amount is continuously completed and the cutting of the next stage is entered. The method adopts the old line to perform the broken line welding treatment, and combines the calculation of the remaining periodic wire amount and the corresponding parameter adjustment, so that the step line marks on the surface of the silicon wafer produced after the broken line replacement are faded, the color difference problem of the silicon wafer is improved, and the production yield of the silicon wafer is improved.

Description

Technical Field

[0001] This invention belongs to the field of solar silicon wafer technology, and particularly relates to a method for improving color difference due to broken lines and steps in solar silicon wafers. Background Technology

[0002] Solar silicon wafers are an important component of solar panels, and their performance directly affects the efficiency of solar cells. Their production is mainly achieved through a slicing process, in which silicon blocks are placed on a corresponding cutting platform, and diamond wires move back and forth in a circular motion, creating a relative grinding motion between the diamond wires and the silicon blocks being cut, thereby achieving the purpose of cutting.

[0003] The applicant discovered that wire breakage occurs during the entire cutting process due to factors such as the viscosity of the cutting fluid, the speed and tension of the steel wire, and the feed rate of the silicon block. However, the current method for resolving wire breakage is to directly use new diamond wire for wire bonding, followed by continued cutting. This method results in stepped wire marks on the produced silicon wafers, leading to severe color differences. Figure 1 As shown, the silicon wafers produced have step marks on their surface, resulting in severe color difference problems.

[0004] Moreover, with the rapid development of the photovoltaic industry, the requirements for silicon wafers are constantly increasing, and the quality requirements for their cutting are also getting higher and higher. However, the existing cutting technology may produce serious color difference problems, which can no longer meet the requirements of the current production process. Summary of the Invention

[0005] To address the aforementioned problems in the prior art, this invention provides a method for improving color difference due to broken lines and steps in solar silicon wafers.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] This invention provides a method for improving color difference due to broken lines in solar silicon wafers, comprising:

[0008] S1. Old wire welding treatment: When a diamond wire breaks during the silicon wafer cutting process, an old diamond wire is used to weld the broken wire at the break point.

[0009] S2. Calculate the remaining cycle line quantity: Calculate the remaining cycle line quantity based on the current supply quantity, return quantity, cutting direction, and cycle position at the time of the breakage;

[0010] S3. Adjust equipment parameters and continue cutting: After the welding wire ends are completed, adjust the corresponding equipment parameters according to the calculated remaining cycle line quantity, and then continue to complete the silicon wafer cutting of the remaining cycle line quantity and enter the next stage of cutting.

[0011] Furthermore, the diameter of the old diamond wire described in S1 is 1 to 2 μm smaller than that of the new diamond wire.

[0012] Furthermore, the cutting direction, cycle position, and cutting position in S2 are obtained from the equipment after a wire breakage occurs. Then, the wire supply and return quantities at the time of the wire breakage are determined based on the cutting position and cycle position.

[0013] Furthermore, the remaining periodic line quantity is calculated in S2 using the following formula:

[0014] When the cutting direction is the return line direction, the remaining periodic line quantity = return line quantity - periodic position;

[0015] When the cutting direction is the wire feeding direction, the remaining cycle wire quantity = wire supply quantity - cycle position.

[0016] Furthermore, the corresponding parameters of the equipment are adjusted according to the calculated remaining cycle line quantity. Specifically, this includes: modifying the cutting position of the current cutting step when a wire breakage occurs to the cutting position fed back in S2, modifying the wire feeding quantity to the remaining cycle line quantity calculated in S2, and increasing the cutting position of the next cutting step by a fixed value.

[0017] Beneficial effects of this invention:

[0018] By adopting the above-mentioned technical solution, this invention can effectively reduce the step marks on the surface of silicon wafers produced after wire breakage and replacement, improve the color difference problem of silicon wafers, and thus improve the production yield of silicon wafers. Attached Figure Description

[0019] Figure 1 These are photos of silicon wafers cut using a new method of direct diamond wire welding to solve the wire breakage problem.

[0020] Figure 2 This is a flowchart illustrating the method for improving color difference due to broken lines in solar silicon wafers according to the present invention.

[0021] Figure 3 This is a schematic diagram of the device interface for calculating the remaining periodic lines and adjusting parameters in an embodiment of the method for improving color difference at broken steps in solar silicon wafers according to the present invention.

[0022] Figure 4 This is a photograph of a silicon wafer cut according to an embodiment of the method for improving color difference due to broken lines and steps in solar silicon wafers as described in this invention. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0024] like Figure 2 As shown in the figure, the method for improving color difference of broken lines on solar silicon wafers according to the present invention specifically includes the following steps:

[0025] Step S1. Old wire bonding treatment: When a diamond wire breaks during the silicon wafer cutting process, an old diamond wire is used to bond the broken wire at the break point; wherein the old diamond wire is a diamond wire with a diameter 1 to 2 μm smaller than the new diamond wire.

[0026] Step S2. Calculate the remaining cycle line quantity: Based on the current wire supply, return wire quantity, cutting direction, and cycle position at the time of the wire breakage, calculate the remaining cycle line quantity. Specifically, this can be done as follows: First, obtain the cutting direction, cycle position, and cutting position (feed position) at the time of the wire breakage. Then, based on the cutting position and cycle position, determine the wire supply and return wire quantities at the time of the wire breakage. Finally, calculate the remaining cycle line quantity based on the feedback cutting direction and the following corresponding formula:

[0027] When the cutting direction is the return line direction, the remaining periodic line quantity = return line quantity - periodic position;

[0028] When the cutting direction is the wire feeding direction, the remaining cycle wire quantity = wire supply quantity - cycle position.

[0029] The cutting direction, cycle position, and cutting location, as well as the wire supply and return wire quantities, can be obtained manually or automatically. Specifically:

[0030] (1) Manual method:

[0031] When a wire breakage occurs, first manually check the equipment to confirm the cutting direction, cycle position, and cutting location. Then, manually open the reference formula (process condition table or formula list) in the equipment and find the corresponding wire supply and return quantities from the reference formula based on the cutting location and cycle position.

[0032] (2) Automatic mode:

[0033] When a wire breakage occurs, the equipment automatically retrieves and feeds back data information on the cutting direction, cycle position, and cutting position. Then, it retrieves the equipment's reference formula and automatically finds the corresponding wire supply and return quantities from the reference formula based on the data information of the cutting position and cycle position.

[0034] Step S3. Adjust equipment parameters and continue cutting: After the welding wire ends are completed, adjust the corresponding equipment parameters according to the calculated remaining cycle wire quantity, and then continue to cut the silicon wafer with the remaining cycle wire quantity and proceed to the next stage of cutting. Specifically, adjusting the corresponding equipment parameters according to the calculated remaining cycle wire quantity includes: modifying the cutting position of the current cutting step when a wire breakage occurs to the cutting position fed back in S2; modifying the wire feed amount to the remaining cycle wire quantity calculated in S2; and increasing the cutting position of the next cutting step by a fixed value (this increase is determined by modifying the cutting depth parameter, e.g., 140mm, increasing by 0.3mm, is equivalent to modifying it to 140.3mm).

[0035] This invention effectively mitigates the stepped wire marks present in silicon wafers produced using traditional methods after wire breakage by employing existing wires for wire bonding processing, combined with calculations of remaining cycle wire quantity and corresponding parameter adjustments (see [link]). Figure 1 and Figure 4 Specifically, this is because: 1. Diamond wire wears down during cutting, reducing its diameter. Using older, smaller-diameter wire for bonding minimizes the inconsistency between the used and broken wire diameters, reducing the appearance of step marks on the silicon wafer surface. The more inconsistent the wire diameters, the more likely step marks will appear. 2. The silicon block is cut back and forth. By calculating the remaining cycle wire quantity and adjusting the wire feed accordingly, the step marks can be minimized. Therefore, this invention improves the color difference problem of silicon wafers, thereby increasing the production yield.

[0036] The following examples further illustrate the method for improving color difference in broken lines of solar silicon wafers according to the present invention.

[0037] The first step is to solder the old wire at the breakage point when the diamond wire breaks during the silicon wafer cutting process.

[0038] The second step, as Figure 3 As shown, first confirm the cycle position ①, cutting direction ②, and cutting position ③. Based on the cutting position and cycle position, confirm the supply and return wire quantities ④ in the reference formula, and then calculate the remaining cycle wire quantity; as shown in the table below.

[0039] Cutting position / mm Period position / mm Cutting direction Cable feed / m Loop length / m Remaining periodic line quantity after relay line / m 151 -337 Return direction 920 800 800-337＝463

[0040] The third step is to wait until the lead wire has finished running, then restart the machine normally to complete the remaining cycle length, and then adjust the equipment process parameters. For example... Figure 3As shown, if the wire breaks at 151.86, then change the cutting position in step 10 of the formula to 151.86, and change the wire feed position to the remaining cycle wire amount (463) according to the direction of the wire break. Change the cutting position in step 11 to 151.2 (increase by 0.3 mm), and keep everything else unchanged.

[0041] like Figure 4 As shown, the method for improving color difference of broken lines on solar silicon wafers described in this invention effectively reduces the appearance of stepped lines on the silicon wafer surface and improves the color difference problem.

[0042] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A method for improving color difference due to broken lines in solar silicon wafers, characterized in that, include: S1. Old wire welding treatment: When a diamond wire breaks during the silicon wafer cutting process, an old diamond wire is used to weld the broken wire at the break point; the diameter of the old diamond wire is 1 to 2 μm smaller than that of the new diamond wire. S2. Calculate the remaining cycle line quantity: Calculate the remaining cycle line quantity based on the current supply quantity, return quantity, cutting direction, and cycle position at the time of the breakage; S3. Adjust equipment parameters and continue cutting: After the welding wire ends are completed, adjust the corresponding equipment parameters according to the calculated remaining cycle line quantity, and then continue to complete the silicon wafer cutting of the remaining cycle line quantity and enter the next stage of cutting; Adjust the corresponding parameters of the equipment according to the calculated remaining cycle line quantity, specifically including: modifying the cutting position of the current cutting step when a wire breakage occurs to the cutting position fed back in S2, modifying the wire feed quantity to the remaining cycle line quantity calculated in S2, and increasing the cutting position of the next cutting step by a fixed value.

2. The method according to claim 1, characterized in that, The cutting direction, cycle position, and cutting position in S2 are obtained from the equipment after a wire breakage occurs. Then, based on the cutting position and cycle position, the amount of wire supplied and returned when the wire breakage occurs is determined.

3. The method according to claim 2, characterized in that, The remaining periodic line quantity is calculated in S2 using the following formula: When the cutting direction is the return line direction, the remaining periodic line quantity = return line quantity - periodic position; When the cutting direction is the wire feeding direction, the remaining cycle wire quantity = wire supply quantity - cycle position.

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