Cleaning and furnace charging: cleaning the inner wall of the whole furnace cavity and the heating coil, reflector, crystal holder, upper shaft and lower shaft, and adjusting the level of the heating coil and reflector and their alignment with the upper shaft and lower shaft; Fixing the polycrystalline material fixture in the groove at the tail of the polycrystalline material, and then installing it at the end of the upper shaft to center the polycrystalline material; Loading a seed crystal into a seed crystal chuck, and then mounting the seed crystal at the top end of the lower shaft; Close all oven doors and tighten all fastening bolts; (2) vacuumizing, inflating and preheating: opening the vacuum pump and the exhaust pipeline valve to evacuate the furnace cavity, closing the exhaust pipeline valve and the vacuum pump when the vacuum degree reaches the required value, and rapidly inflating argon into the furnace cavity; When the inflation pressure reaches the relative pressure 1bar-6bar, stop rapid inflation, switch to slow inflation, and open the exhaust valve to introduce argon; After the gas charging is completed, the polysilicon rod is preheated, using a graphite preheating ring and a current gear, the preheating setting value is 25-40%, and the preheating time is 10-20 minutes; (3) melting and seeding: melting after preheating, and switching the voltage range during melting, with the set value of the generator being 40-60%; After the polycrystalline material is melted, the seed crystal is welded with molten silicon, and after welding, the molten zone is shaped and seeded; (4) growing a thin neck: after sowing, growing a thin neck with a diameter of 2-6mm and a length of 30-60 mm; ; (5) Nitrogen filling for shoulder expansion: shoulder expansion is carried out after the neck grows, and the descending speed is slowly reduced to 3 2 mm/min, while the descending speed is continuously reduced to 8±4 rpm and the ascending speed is also slowly reduced to 65438±0.5 rpm； with the increase of shoulder expansion diameter; In order to prevent high-pressure ionization, a certain proportion of nitrogen is filled in argon protective atmosphere, and the doping proportion of nitrogen is 0.01%-5% relative to argon; (6) Turn the shoulder, hold and loosen the gripper: when the difference between the shoulder expanding diameter and the single crystal holding diameter is 3-20mm, slow down the shoulder expanding speed, turn the shoulder to the required diameter, hold the single crystal, the equal-diameter holding diameter is 75-220 mm, and the single crystal growth speed is 1mm/min-5mm/min. In the shoulder expanding process, when the shoulder of the single crystal (7) is closed and the furnace is stopped: when the single crystal is pulled to the tail, it starts to close until the diameter of the single crystal reaches φ 10-80mm and the melting zone is opened. At this time, the lower shaft continues to move down and the upper shaft moves up, while the power is maintained at 40 10%, and the crystal is slowly cooled. A Czochralski single crystal growth device belongs to the technical field of semiconductor growth equipment. It comprises a hydraulic servo system for adjusting the crucible rod; In the heating control unit, a three-phase balance transformer, a filter capacitor, a reactor and a resistor are combined and connected in parallel with a harmonic source; It also has a variable frequency inflator. The invention overcomes the defects that the existing crucible shaft lifting drive device cannot effectively ensure the stability and accuracy of production control, the existing heating control unit cannot eliminate harmonics, and the existing crucible shaft lifting drive device cannot effectively ensure the stability and accuracy of production control. 1, use
This specification is formulated in order to correctly and normatively operate the single crystal furnace and ensure normal production and operation.
2. Scope of application
Suitable for operation of TDR-70A/B and JRDL-800 single crystal furnaces.
3, single crystal furnace operation process
Operation preparation → thermal leak detection → taking single crystal and seed crystal → taking out graphite parts for cooling → cleaning vacuum filter → checking and replacing vacuum pump oil → cleaning graphite parts → cleaning single crystal furnace chamber → installing graphite parts → installing timely crucible → installing silicon material → installing seed crystal → vacuumizing for leak detection → filling argon, increasing power, melting materials → seeding, necking, shouldering and rotating shoulders → equal-diameter growth →
4. Main contents
A. homework preparation
You must wear clean work clothes and work shoes when entering the single crystal workshop.
B. Before starting the furnace, check the water, electricity and gas according to the process requirements, and start the furnace only after it is confirmed.
C prepare disposable cleaning gloves, high-temperature gloves, towels, paper towels, emery cloth, alcohol, vacuum brushes, vacuum tubes and dust masks.
D. Prepare pliers, wrenches and various special tools for disassembling and assembling the furnace.
E. Take the single crystal stand, graphite stainless steel trolley, crucible bottom stainless steel cylinder and silicon stainless steel trolley and clean them.
F clean the furnace body from top to bottom with a towel. When scrubbing, be careful not to break or damage all control circuits and switches, and clean the periphery of the furnace.
B. Thermal leakage detection
A. check the power-off time of the last furnace. After cooling the single crystal for 4.0 hours (TDR-70A/B single crystal furnace) and 5.0 hours (JRDL-800 single crystal furnace), turn off the argon gas (only turn off the argon gas valve, turn on the flow meters in the main chamber and the auxiliary chamber, and adjust them to 30L/Min respectively), start vacuumizing and record the time.
B. When the pressure in the furnace reaches the limit (below 3Pa), first close the ball valve in the main room, and then turn off the power supply of the leak detection vacuum pump, and make corresponding time records. If the pressure is lower than 3Pa within 0.5 hours, it should be handed over to the relevant maintenance personnel for handling. During this period, we should cooperate with relevant maintenance personnel to assemble and disassemble the furnace, and make relevant records.
C. Leak detection takes more than 3 minutes, and the leak rate is
C, taking a single crystal and a seed crystal
A. After thermal leak detection, unscrew the four screws of the auxiliary chamber door, open the argon valve to charge argon to normal pressure, close the argon, unscrew the four screws of the auxiliary chamber door, and open the auxiliary chamber door.
B. Lift the single crystal to the auxiliary chamber, and confirm that the single crystal rises to the required height from the small door of the auxiliary chamber. If there is no abnormality, cover the flap valve, turn on the hydraulic pump and lift the auxiliary chamber.
C move the safety connecting plate to the mouth of the furnace barrel, and slowly turn the auxiliary room to one side.
D, placing the single crystal taking frame directly below the furnace barrel of the auxiliary chamber, and preparing to connect the single crystals.
E, stabilize the single crystal, remove the safety tray, press the seed crystal to drop quickly, and put the single crystal into the shelf.
F, after confirming that the single crystal is completely put into the shelf, press and hold the seed crystal, and use pliers to clamp off the seed crystal from the small diameter. After clamping off the seed crystal, stabilize the heavy hammer to prevent the heavy hammer from rotating rapidly and damaging the wire rope.
G. Remove the seed crystal from the heavy hammer, put it in the designated position, and then lift the heavy hammer to an appropriate position in the auxiliary room.
H. Move the single crystal to the transit area, write down the single crystal number on the single crystal in time and accurately, and test and record all parameters of the single crystal after natural cooling.
D, taking out the graphite sheet and cooling.
A. take out the small graphite sheet
1) Turn on the power of the hydraulic pump and press the cover up button to raise the cover. After the furnace cover rises in place, rotate the furnace cover to one side.
2) Wear high-temperature gloves, take out the draft tube and the heat preservation cover in turn, and put them on the stainless steel trolley with graphite parts. Pay attention to hold it firmly and put it down gently.
3) Wear high-temperature gloves, clamp the upper part of the timely crucible with pliers, lift it to loosen it, and take out the timely crucible. If the crucible can take all the bottom materials out of the crucible and put them directly into the stainless steel cylinder; If not, first take out the timely crucible, take out the remaining crucible bottom material together with the three-petal crucible, and then put the crucible bottom material into the stainless steel cylinder. In case of suffocation in the furnace, take it out piece by piece with pliers like charging until it is completely taken out. Finally, move the stainless steel cylinder to the designated position, write the single crystal number, and naturally cool. After cooling, detect and record the weight of the material at the bottom of the crucible.
4) Wear high-temperature resistant gloves, take out the three-petal crucible and the bottom of the crucible in turn, and put them on the stainless steel trolley with graphite parts. No! The link is invalid. Pay attention to safety after putting it on.
5) Unscrew the stainless steel screw from the center hole of the crucible rod with the crucible rod wrench, take out the crucible rod wrench, and then put the crucible rod with the stainless steel screw on the stainless steel trolley, and pay attention to smooth stacking.
6) Put the graphite parts taken out on the stainless steel trolley, hang the furnace number plate of the graphite parts next to the stainless steel trolley, move them to the designated position and naturally cool them. Pay attention to the placement of graphite parts during moving to prevent them from falling.
B take out the large stone ink sheet (usually once every five heats, and make cleaning records).
1) Take out the upper insulating cover and put it on the stainless steel trolley.
2) Remove the thermoelectric cone and put it in a proper position with the corresponding seal and glass to prevent damage and loss.
3) Turn on the oil pump switch, press and hold the furnace drum up button, raise the furnace drum to the limit, and rotate the furnace drum to lower it to a proper position.
4) Take out the middle insulating cover and put it on the stainless steel trolley.
5) Remove the heater screw cover first, then remove the heater screw with a special tool, and then remove the heater screw and the heater on the stainless steel trolley.
6) Take out the electrode sleeve, electrode timing ring, crucible rod sleeve, furnace bottom upper sheet, small graphite carbon felt, exhaust sleeve, lower heat shield, furnace bottom sheet, furnace bottom carbon felt, graphite electrode, etc. Put them on the stainless steel trolley in turn. Hang the graphite furnace number plate next to the stainless steel car, move it to the designated position and naturally cool it. Pay attention to the placement of graphite parts during exercise to prevent them from falling.
E. Cleaning the vacuum filter
A. Prepare vacuum brushes, vacuum tubes, alcohol, paper towels, wrenches, gloves and dust masks.
B use a wrench to open the screw of the vacuum filter cover and take out the filter screen.
Carefully clean the screen and volatiles in the filter with a dust brush.
D. Slowly put the cleaned filter screen into the filter.
E. Clean the filter element cover with a vacuum brush, wipe the sealing ring with a paper towel stained with alcohol, and check whether the sealing ring is completely in place to prevent it from falling off or coming out of the groove and affecting the evacuation.
F close the filter cover and tighten the filter cover with a wrench.
F. Inspection and replacement of vacuum pump oil
A. Confirm to close the ball valves of the main pump and vacuum pump, hang the inspection plate on the oil discharge single crystal furnace, put the waste oil drum under the oil discharge port of the vacuum pump, turn on the oil discharge switch of the upper and lower cavities, close the oil discharge valves of the upper and lower cavities after oil discharge, and pour the waste oil into the specified oil drum.
B clean the vacuum pump (once every 5 heats), open the side cover of the vacuum pump with a wrench, put it in a proper position, thoroughly clean the oil stains on the vacuum pump cavity, the side cover and the oil filter screen of the lower cavity with a towel, and install the filter screen and the side cover after cleaning. When opening and installing the side cover, pay attention to prevent the side cover and oil seal from being damaged and leaking oil. It is forbidden to leave scraps of paper or other foreign matter in the pump cavity, otherwise it will block the oil circuit and jam the vacuum pump. Clean up the waste of vacuum pump and put it in the designated trash can.
C. Open the oil inlet of the vacuum pump, inject the vacuum pump oil into the oil inlet hole of the vacuum pump, observe the oil level of the vacuum pump to the position of the oil level observation window12, stop oil injection, open the oil pipe valve at the pump side to discharge the oil into the lower cavity, and close the oil inlet.
D. Start the vacuum pump for 5min, then close the oil pipe valve at the pump side, check whether the oil level is in the position of the oil level observation window 1/3- 1/2, turn off the vacuum pump, and take out the maintenance card in the oil drain single crystal furnace. If it is lower than the lower limit, repeat C and D operations.
G. cleaning graphite parts
A. cleaning graphite parts
1) graphite parts must be cleaned in the designated cleaning room, and cleaning supplies (vacuum brushes, paper towels, vacuum tubes, emery cloth, special tools for removing silicon particles, cleaning vehicles for placing graphite parts, etc. ) Be prepared and wear gloves and dust masks. Clean the washing table and the surrounding environment.
2) Clean various graphite parts in turn with a vacuum brush until it is confirmed that there is no dirt. Before vacuum cleaning, parts that absorb more volatiles, such as grooves and interfaces, should be carefully polished with abrasive cloth.
3) When cleaning, check whether the graphite parts are damaged or stuck with silicon, and replace and handle them in time.
4) Handle with care during operation to avoid damaging graphite parts.
5) Put the cleaned graphite parts on the clean stainless steel trolley prepared in advance. It is forbidden to overlap, and the stainless steel trolley should move smoothly.
6) Put the cleaned garbage into the garbage designated place, and clean the cleaning table and surrounding environment.
B cleaning of large graphite in the furnace (applicable to small cleaning in each furnace and cleaning in the furnace when large stone ink is not taken out).
1) Use a vacuum brush to clean the residue falling from the top edge of the furnace barrel, insulation cover and heater during furnace disassembly.
2) Carefully and vigorously clean the insulation cover and the parts that can be touched by the heater with a dust brush.
3) Take out the heater screw cover and check whether the electrode screw is loose, stuck or stuck with silica gel. If it is loose, it must be tightened. If it falls off or sticks to silicon, it must be replaced. Then cover the heater screw.
4) If the thermal field moves or rotates unexpectedly when the furnace is dismantled, be sure to check whether the thermal field is symmetrical and the thermometer hole should be recalibrated. If the transverse temperature hole is deviated, it will affect the photometric signal, resulting in too small ohmmeter value, unable to automatically control the temperature in the furnace and unable to crystallize.
5) Use a dust brush to clean the dust and residue in the furnace bottom tablet, furnace bottom bellows and exhaust hole.
6) Clean the upper part of the furnace wall with a paper towel stained with alcohol.
H. Cleaning of single crystal furnace chamber
A. Cleaning and installation of auxiliary rooms
1) Prepare cleaning sticks, paper towels and alcohol.
2) Wrap the paper towel stained with alcohol on the cleaning stick, and clean the interior of the auxiliary room upward until it is confirmed that there is no dirt.
3) Put down the seed crystal chuck quickly, and carefully scrub the heavy hammer and molybdenum chuck with paper towels stained with alcohol. If necessary, remove the heavy hammer, carefully polish it with emery cloth and clean it. When removing the heavy hammer, be careful to prevent the wire rope from popping out of the groove. When cleaning the wire rope, check whether the joint part is aging or damaged. If yes, cut a section of steel wire rope to prevent the single crystal from falling down during crystal pulling. Clean the lifting hammer to a certain position. When lifting the heavy hammer, don't make the heavy hammer shake to prevent the heavy hammer from hanging on the lower edge of the auxiliary room and breaking the wire rope.
B. Cleaning of small payment rooms
1) Open the door of the payment room and scrub the attachments in the small payment room with paper towels stained with alcohol. When more volatile matter is attached, it should be treated with vacuum brush first.
2) Carefully scrub the suction port, other small holes, the periphery of the flap valve and the rotating shaft of the auxiliary room with a paper towel stained with alcohol. The groove and weld of flap valve are rolled into a shape convenient for operation with paper towels, and then carefully scrubbed.
3) Cover the flap valve with the cleaned small auxiliary chamber and close the auxiliary chamber door.
4) Cover the top of the small payment room with a clean paper towel.
C. Cleaning the furnace cover
1) First, scrub the inner wall with a paper towel (if there is too much oxide, clean it with a vacuum brush first).
2) Small holes, observation windows, Ilgen, valve ports and other interfaces, welds and other parts that are difficult to clean should be carefully scrubbed with paper towels stained with alcohol until it is confirmed that there is no dirt.
3) When the silicon powder adheres strongly or the furnace cover is partially black and white, it should be carefully polished with emery cloth until the entire inner wall of the furnace cover appears bright and free of dirt.
4) The observation window and Ilgen window should be carefully cleaned, and all small holes should be rolled up with paper towels, so that it is easier to clean them into the air holes until there is no dirt.
D. Furnace barrel cleaning
1) First, scrub the inner wall with a paper towel (if there is too much oxide, clean it with a vacuum brush first).
2) Take bare holes and carefully scrub them with paper towels stained with alcohol until it is confirmed that there is no pollution.
3) When the silicon powder is strongly attached or the furnace drum is partially black and white, it should be carefully polished with emery cloth until the whole inner wall of the furnace drum appears bright and free of dirt.
E. clean the suction pipe.
1) Open the cover screw on the suction pipe with a wrench and remove the cover and sealing ring.
2) Put the long rod wrapped with steel wire balls into the pipeline to twitch, and use a dust brush at the other end to suck out the volatiles in the exhaust pipeline.
3) Carefully scrub the sealing cover and sealing ring with a tissue stained with alcohol, and then install it.
First, the installation of graphite parts
A. After cleaning, install the large stone ink sheet (usually 5 heats at a time).
1) Move the cleaned large graphite stainless steel trolley to the single crystal furnace side, and the moving process should be smooth.
2) Assemble graphite electrode, furnace bottom carbon felt, furnace bottom pressing sheet and lower heat preservation cover in sequence, and exhaust pipes at both sides and furnace bottom pressing sheet lower graphite carbon felt, furnace bottom pressing sheet, crucible rod sleeve, electrode sleeve and timely electrode ring. When installing the electrode, check whether the contact surface is flat, and pad a layer of graphite paper on the upper and lower contact surfaces to prevent thermal field collision.
3) Install the cleaned heater, screw on the graphite screw and tighten it, otherwise it will cause the thermal field to catch fire, and cover the graphite screw cover.
4) Install the cleaned intermediate insulating cover and connect the bayonet. And the distance from the heater is corrected to be uniform, otherwise it needs to be adjusted.
5) Reset the furnace drum, turn on the hydraulic pump, raise the furnace drum to the upper limit, scrub the joint between the upper part of the lower furnace drum and the lower part of the furnace drum with paper towels stained with alcohol, and rotate the furnace drum to a proper position at the same time.
6) Press down the furnace drum. After the furnace barrel drops in place, check the thermometer hole to prevent the photometric signal from being too small to control the temperature.
7) Install the thermoelectric cone, and install the thermoelectric cone and the corresponding seal and glass in the original order.
8) Install the cleaned upper heat shield and connect it with bayonet.
B. install small graphite parts after cleaning.
1) Install the crucible rod with special tools. Be sure to tighten the screw of the crucible rod to prevent the liquid level from shaking due to looseness.
2) Install the crucible bottom and the three-petal crucible in turn. When installing, make sure whether the crucible rod, crucible bottom and three-petal crucible are consistent, and be careful to prevent damage to the heat preservation material or heater.
3) After installation, open the crucible and rotate it, and check whether the distance between the three-dish crucible and the heater is consistent. If it is inconsistent, it needs to be adjusted in time.
J. Installation of timely crucible
A. Scrub the outer side and periphery of the furnace tube and furnace cover with paper towels stained with alcohol, and carefully clean the ground around the furnace body.
B, take the designated timely crucible from the designated place. Wear a dust mask and clean gloves when loading.
C. Check whether the logo on the timely crucible package is consistent with the ingredient list, open the timely crucible package, and confirm whether there are cracks, dirt and bubbles under the light. If there is any abnormality, handle it in time and report to the monitor or director.
D. Install the timely crucible in the graphite three-petal crucible in the furnace, and pay attention to the uniform gap around.
E record the serial number and manufacturer of the timely crucible used in the operation record, keep the label number of the timely crucible and put it in the designated place.
K. Installation of silicon materials
A. Take stainless steel car and silicon material for feeding, carefully check whether the content of the ingredient list is consistent with the number of single crystal furnace and the ingredient material, and handle it in time if it is abnormal and report it to the monitor or supervisor.
B. replace the charging gloves. If there is a master alloy, first put it into a timely crucible. Then spread the broken materials and small materials on the bottom of the pot.
C) Put the large block in the center, fix it with medium-sized materials around the large block, and put small silicon materials in the gap. Be careful when loading, handle with care to prevent collision with the timely crucible, and don't make the material fall into the gap of the heat preservation cover to avoid ignition.
D. Be careful not to let the material out of the timely crucible when feeding, otherwise it will cause the silicon liquid to flow down during the melting process, damage the graphite parts and even stew the furnace.
E. After the charging is completed, open the crucible and rotate it to ensure that the surrounding gap is consistent, and then quickly lower the crucible to the lower limit. Stop spinning.
F clean the upper part of crucible, heater and heat preservation cover with a clean vacuum brush.
G. install insulation cover and draft tube in turn. The installation of heat shield and diversion should be consistent, and the diversion pipe should be carefully installed. If it comes into contact with silicon material, the position of silicon material should be adjusted to prevent silicon from sticking during melting.
Length seed installation
A. Scrub the sealing ring at the joint between the furnace cover and the furnace barrel with a paper towel stained with alcohol, and then rotate the furnace cover to the upper part of the furnace barrel.
B. Turn on the power supply of the hydraulic pump, press the furnace cover lowering button, and lower the furnace cover. After the furnace cover is lowered in place, confirm whether the furnace cover is closed properly to prevent air leakage.
C, scrub the joint between the lower part of the auxiliary chamber and the upper part of the furnace cover with paper towels stained with alcohol, rotate the auxiliary chamber, and lower the furnace combined with the furnace cover. Turn the auxiliary chamber slowly to prevent the heavy hammer from colliding with the inner wall of the auxiliary chamber.
D. Take out the corroded seeds from the designated place, and carefully scrub the seeds with paper towels stained with alcohol. Be careful not to touch the seed crystal directly with your hands to prevent sweat from polluting the seed crystal.
E. lower the seed crystal chuck to a certain position, install the seed crystal on the chuck from the small door of the auxiliary room, and install the molybdenum pin. Pull down the seed crystal hard to make it firm. After the seed crystal is stable, press the crystal to rise quickly to make it rise to a suitable position.
F scrub the sealing ring and joint of the auxiliary door with a paper towel stained with alcohol, close the auxiliary door, screw on the auxiliary door screw and open the flap valve.
Meter (abbreviation for meter)) evacuation and leak detection
A. turn on the vacuum pump.
B. slowly open the ball valve in the main room.
C. after evacuation, the pressure in the furnace reaches
D. Wait for the pressure in the furnace
E. if the air leakage rate of the furnace >; 0.67Pa/min, it is necessary to repeat steps a, b, c and d for leak detection. If it is still unqualified, report it to the maintenance personnel for handling. And make corresponding records.
Argon filling, pressure boosting and melting
A. after the leak detection is qualified, turn on the vacuum pump power supply.
B. Open the ball valve slowly.
C. open the argon charging system, adjust the argon flow rate in the auxiliary room to 20~30L/Min, and keep the pressure in the furnace at 1000~ 1500Pa.
D. turn on the heating switch.
E gradually increase the power through the ohmmeter according to the following table. Each heating should be recorded accordingly. When using the continental meter, be careful to prevent the power from increasing sharply, the transformer from instantaneous overload, or the whole heating circuit from instantaneous overload, causing fire or damage. Heating should be carried out in strict accordance with the heating sequence, otherwise the temperature may suddenly rise, resulting in cracking and silicon leakage of the crucible.
Time power
0 minutes 50 kilowatts
30 minutes 70 kilowatts
60 minutes & lt 100 kW
F. Observe the situation in the furnace at any time during the melting process. If there is no abnormal material collapse, give the crucible a rotation speed of 2r/min and raise the appropriate crucible position. And make corresponding records. When lifting the crucible, be careful not to let the silicon level touch the lower edge of the drainage tube. After the crucible is lifted, it can only be completed if the crucible has no action, otherwise, the diversion pipe will stick to silicon and jump silicon.
G, after the materials are melted, reducing the heating power to the seed crystal temperature (corresponding to furnace charging). Turn the given crucible to 5~7r/min and record accordingly.
H. When the ohmmeter value drops to the value corresponding to the seeding temperature, it will automatically open, and the crucible will rise to a stable seeding position, that is, the distance from the drainage tube to the liquid level is about15 mm. The position of the seed tank can also be determined according to the increase/decrease of the feeding amount based on the charging in the upper furnace. For details, please refer to the reference table of seed position change in Appendix A ... and make corresponding records.
O. Seed introduction, necking, shoulder setting and shoulder turning
A. resistivity measurement and sampling
1) After the temperature is automatically turned on, press the seed crystal quick drop, lower the seed crystal to the position just visible in the main observation window, and turn on the crystal rotation power supply, and give the crystal rotation 10~ 12r/min.
2) After 20 minutes, drop the seed crystal to make it contact with the liquid surface, adjust the temperature through the ohmmeter, and start to put the shoulder.
3) Lift the shoulder to a diameter of 50~60mm, lift it from the liquid level to the auxiliary chamber, open the argon in the auxiliary chamber, cover the flap valve, open the argon in the main furnace chamber, and adjust the flow rate until the furnace pressure is consistent with the original.
4) Increase the argon flow rate in the auxiliary room. Loosen the auxiliary chamber door screw. When the auxiliary chamber pressure gauge indicates 0, open the auxiliary chamber door and close the argon gas.
5) Slowly adjust the crystal to 0 r/min and turn off the crystal.
6) Take out the seed crystal with pliers and put it on your shoulder. Be careful when taking the seed crystal. Do not touch the seed crystal directly with your hands to prevent burns. Measure the resistivity after cooling.
7) After the seed crystal is cooled, scrub it with a paper towel and close the door of the auxiliary room.
B. Pay the pump to spend time working
1) Close the auxiliary chamber furnace tube or the auxiliary chamber door, and then turn on the auxiliary pump power supply.
2) Slowly open the suction ball valve at the back of the auxiliary room until it is fully opened.
3) When the pressure gauge in the auxiliary room is pumped to -0.05 ~-0. 1 MPa, open the argon valve in the auxiliary room and close the ball valve of the auxiliary pump at the same time.
4) When the pressure gauge in the auxiliary room is charged to 0 ~-0.05 MPa, close the argon valve in the auxiliary room and open the ball valve of the auxiliary pump at the same time.
5) Repeat steps 3 and 4 three times.
6) Finally, according to the pressure gauge pointer, confirm that the air pressure in the auxiliary chamber is consistent with that in the main chamber, close the ball valve in the auxiliary chamber, and then turn off the power supply of the auxiliary pump.
7) Open the flap valve slowly. Open the flap valve slowly to prevent damage or squeezing of the valve port sealing ring.
8) Open the argon valve in the auxiliary room to normal flow, and close the argon valve in the main room.
C. Supplementing master alloy
1) If the resistivity test result is within the target range, the next step of preheating contact seeding can be carried out; If there is any deviation, the master alloy must be supplemented, and the group leader shall calculate the type and quantity of the master alloy according to the resistivity test results and the feeding amount, take it out, weigh it, supplement it, and make corresponding records.
2) The doping process is the same as resistivity sampling, except that the shoulder is placed at 100~ 150mm, and the shoulder is as flat as possible.
3) After opening the furnace chamber door, put the weighed master alloy on the flat shoulder, and do not remove the seed crystal. Be careful when placing the master alloy, and don't touch the seed crystal directly with your hands to avoid scalding.
4) Vacuum pump B to do work, then adjust the melting temperature of silicon properly, and lower the seed crystal and master alloy to the liquid level to make them melt and mix.
5) repeat the resistivity sampling in A, vacuumize in B, and replenish the master alloy in C until the resistivity test is qualified, and then enter the next process.
D. Preheating contacts
After the resistivity of 1) is qualified, according to the rapid decline of the seed crystal, lower the seed crystal to the position just visible in the main observation window, turn on the crystal rotation power supply, and give the crystal rotation of 10~ 12r/min.
2) After 20 minutes, press the seed crystal quick drop button to drop the seed crystal to the position 10mm away from the silicon liquid level, and preheat it for 20 minutes. Make corresponding records. It must be preheated, otherwise the seed crystal will be dislocated from the low temperature zone to the high temperature zone and from the fixed to the liquid state.
3) The rapid rising or falling position of the seed crystal must be determined before the lifting operation can be completed, otherwise the seed crystal will be dissolved when it is lifted to the upper limit or even fall into the dissolved silicon by heavy hammer, resulting in silicon leakage or the whole charge being completely scrapped and unable to be reused.
4) dropping the seed crystal into contact with the silicon liquid surface, soaking for 20 minutes, melting off the thinner part of the seed crystal, determining whether the seeding temperature is appropriate according to the shape of the contact hole, and starting seeding if it is appropriate; If it is not suitable, adjust the temperature for 20 minutes by an ohmmeter before sowing. The temperature should not be too low.