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Silicone Mold-Baby Bottle Silicone MoldDetailed explanation of wafer multi-wire cutting technology Silicon wafers are the main production material in the semiconductor and photovoltaic fields. Sili

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  • 型号: Silicone Mold-Baby Bottle Silicone Mold

Silicone Mold-Baby Bottle Silicone Mold


Silicone Mold-Baby Bottle Silicone Mold


Detailed explanation of wafer multi-wire cutting technology




    Silicon wafers are the main production material in the semiconductor and photovoltaic fields. Silicon wafer multi-wire cutting technology is currently the most advanced silicon wafer processing technology in the world. It is different from traditional cutting methods such as blades, saw blades and grinding wheels, and also different from advanced laser cutting and internal cutting. Its principle is through A high-speed moving steel wire drives the cutting blade material attached to the steel wire to rub the silicon rod to achieve the cutting effect. In the whole process, the steel wire is guided by more than a dozen wire wheels to form a wire web on the main wire roller, and the workpiece to be processed is fed by the lowering of the worktable. Compared with other technologies, the silicon wafer multi-wire cutting technology has the advantages of high efficiency, high productivity, and high precision. It is currently the most widely used silicon wafer cutting technology.




The multi-wire cutting technology is a landmark innovation in the silicon processing industry and the solar photovoltaic industry. It replaces the original internal circular cutting equipment. Compared with the internal circular slicing process, the sliced wafer has a bow (BOW) and a degree of warpage ( WARP) is small, the parallelism (TAPER) is good, the total thickness tolerance (TTA) is small, the cutting loss of the edge is small, the surface damage layer is shallow, the surface roughness of the wafer is small, and many other advantages.


The wire cutting mechanism of solar silicon wafers is that the machine guide wheel drives the steel wire during high-speed operation, so that the mortar mixed with polyethylene glycol and silicon carbide powder is sent to the cutting area by the steel wire, and the wire is pressed on the wire during high-speed operation of the steel wire. The workpiece is continuously rubbed to complete the cutting process.


In the entire cutting process, the main effect on the quality and yield of the silicon wafer is the viscosity of the cutting fluid, the particle type and size of the silicon carbide powder, the viscosity of the mortar, the flow rate of the mortar, the speed of the steel wire, and the tension of the steel wire. And the feed speed of the workpiece.




   One, the viscosity of the cutting fluid (PEG)


  Since the silicon carbide powder is suspended on the cutting fluid and cut by the steel wire during the entire cutting process, the cutting fluid mainly plays the role of suspension and cooling.


   1. The viscosity of the cutting fluid is an important guarantee for the suspension of silicon carbide powder. Due to the different system thinking of different machine development and design, the viscosity of the mortar is also different, that is, the viscosity of the cutting fluid is also different. For example, the Swiss wire cutting machine requires that the viscosity of the cutting fluid is not less than 55, while NTC requires 22-25, and Ernst & Young is as low as 18. Only the viscosity that meets the cutting standards required by the machine can ensure the uniform suspension of silicon carbide powder during the cutting process and the mortar to enter the cutting area through the mortar pipe and the steel wire stably.


  2. Because the steel wire with mortar will generate high temperature due to friction during the process of cutting the silicon material, the viscosity of the cutting fluid plays an important role in cooling. If the viscosity is not up to the standard, it will lead to poor fluidity of the liquid, and the temperature cannot be lowered to cause burns or breakage. Therefore, the viscosity of the cutting fluid ensures the temperature control of the entire process.




   2. Particle type and size of silicon carbide powder


  The cutting of solar silicon wafers is actually the cutting of steel wire with silicon carbide micropowder, so the grain shape and granularity of the micropowder are the key to the smoothness and cutting ability of the silicon wafer surface. With a laser scribing machine and regular grain shape, the cut silicon wafers will show a good finish; the uniform particle size distribution will improve the cutting ability of the silicon wafers.




   3. Viscosity of mortar


  The ability of the wire cutting machine to cut silicon wafers is inseparable from the viscosity of the mortar. The viscosity of the mortar depends on the viscosity of the cutting fluid of the silicon wafer laser scribing machine, the compatibility of the silicon wafer cutting fluid and the silicon carbide powder, the ratio of the silicon wafer cutting fluid to the silicon carbide powder, and the density of the mortar. Only the mortar viscosity that meets the requirements of the machine (for example, the NTC machine requires about 250) can improve the cutting efficiency and increase the yield during the cutting process.




   Fourth, the flow rate of mortar


   When the steel wire is moving at a high speed, to complete the cutting of the silicon material, the mortar must be pumped from the storage box to the sand blasting nozzle by the mortar pump, and then sprayed onto the steel wire by the sand blasting nozzle. Whether the flow of the mortar is uniform and whether the flow can meet the cutting requirements, all play a key role in the cutting ability and cutting efficiency. If the flow rate cannot keep up, the cutting ability will be severely reduced, leading to line marks, wire breakage, and even machine alarms.




   5. Steel wire speed


   Since the wire cutting machine can perform one-way routing and two-way routing according to user requirements, the requirements for wire speed are also different in the two cases. When the wire is routed in one direction, the steel wire always runs at a speed (MB and HCT can be manually adjusted at different times according to the cutting situation), which is relatively easy to control. At present, there are fewer and fewer one-way cabling operations, which are limited to MB and HCT machines.


When the wire is routed in both directions, the steel wire speed starts to accelerate from the zero point in one direction to the specified speed in 2-3 seconds. After running for a period of time, it slowly decreases to the zero point in the original direction, and then slowly stops at the zero point for 0.2 seconds. It is a periodic cutting process in which the ground is accelerated to the specified speed in the reverse direction, and then slowly reduced to the zero point in the opposite direction. In the process of bidirectional cutting, the cutting ability of the wire cutting machine increases with the speed of the steel wire within a certain range, but it cannot be lower than or exceed the cutting ability of the mortar. If it is lower than the cutting capacity of the mortar, there will be line marks or even broken lines; on the contrary, if the cutting capacity of the mortar is exceeded, the mortar flow rate may not keep up, resulting in thick flakes or even line marks.


   The current average line speed of MB can reach 13 m/s, and NTC can reach 10.5-11 m/s.




   Six, the tension of the steel wire


  The tension of the steel wire is one of the core elements in the silicon wafer cutting process. Poor tension control is an important reason for line marks, chipping, and even short threads.


  1. If the tension of the steel wire is too small, it will increase the bending of the steel wire, reduce the sanding capacity, and reduce the cutting ability. As a result, line marks and the like appear.


  2. If the tension of the steel wire is too high, it will be difficult for the silicon carbide powder suspended on the steel wire to enter the saw gap, the cutting efficiency will be reduced, the line marks will appear, etc., and the probability of wire breakage will be high.


  3. When cutting to the rubber strip, sometimes it will deviate from the zero point due to the excessive use of the tension and cause the edge to collapse.


   The general tension control of MB, NTC and other wire cutting machines is less than 1 between feeding and taking-up, only the difference between Ernst & Young is 7.5.




   Seven, the feed rate of the workpiece


  The feed speed of the workpiece is related to the wire speed, the cutting ability of the mortar, and the shape of the workpiece at different positions of the feed. The workpiece feed speed is determined by the above related factors during the entire cutting process, and it is also the least quantitative element. However, if the control is not good, there may be undesirable effects such as line marks, which affect the cutting quality and yield.


   In short, the operation of the solar wafer wire cutting machine is a delicate task with more experience than the technical process and standards. Only in actual operation, continuous summary and discussion, can control the machine with ease.