Plasma etching machine
Technical field
The utility model relates to a kind of dry etching equipment that is used for semiconductor technology, relates in particular to a kind of plasma etching machine.
Background technology
Plasma etching machine is used for the dry etching equipment of semiconductor technology.This equipment can be used for the etching of polysilicon in the semiconductor technology, silicon nitride and removes photoresist, and is particularly suitable for the etching of the battery circumferential doped silicon in the present solar battery sheet production, so plasma etching machine is used on the silicon solar cell production line at most.Its operation principle is that workpiece is placed vacuum cavity, feed reacting gas, make it be subjected to high frequency pumping and produce glow discharge, thereby obtain the chemism particulate, this chemism particulate produces volatile materials with the material chemically reactive that is etched, get rid of by air extractor, thereby make workpiece surface to be carved be able to etching.In the etching technics of the battery circumferential doped silicon in solar battery sheet is produced, reacting gas (carbon tetrafluoride), after being sent to reative cell, gas molecule is produced active fluoro plasma by the high-frequency electric field excitation, fluoro plasma and pasc reaction, generate the silicon tetrafluoride of gaseous state, this gaseous state product is constantly extracted by vacuum pump.Gas is sent into continuously, and silicon tetrafluoride constantly generates, and is constantly extracted by vacuum pump again, thereby the silicon periphery is constantly removed, and reaches the purpose of etching.
Existing plasma etching machine is made up of reative cell, the unit of supplying gas, the unit of bleeding, electric automatic control unit, high frequency electric source and adaptation, mainframe etc.Reative cell mainly is made up of cover plate, the even flow plate of supplying gas, upper flange, crystal reaction tube, last retainer ring, inductance coil, coil stationary frame, radome, following retainer ring, lower flange, horse back shaft, horse rotating mechanism, support bar, bleed even flow plate and horse etc.Reative cell is the core of plasma etching machine, requires electric field, distribution of gas more even in when work, and reative cell is within suitable pressure limit, and silicon wafer layer is stacked in the horse, and its center should be consistent with the center of inductance coil.The unit of supplying gas mainly is made up of electromagnetically operated valve, two mass flowmenters, stainless steel pipeline and FEP pipelines etc.Reacting gas is connected to equipment by crossing the plate joint, by the stainless steel pipeline gas is received mass flowmenter, receives electromagnetically operated valve again, receives reative cell with the FEP pipe again after compiling through threeway then.Supply gas the unit mainly by the density of flow, pressure control reaction indoor gas, will pass through accurate control suction pressure simultaneously, thus the pressure of control reative cell.The unit of bleeding is made up of stainless-steel vacuum pipeline, film rule, electronic actuators and butterfly valve, pneumatic corrugated valve, corrugated stainless steel tubing, pneumatic valve for pressure difference, private filter and mechanical pump etc.Film rule, electronic actuators and butterfly valve decomposition pressure control system are converted into the signal of telecommunication by film rule detected pressures and with pressure, and deliver to electronic actuators and control butterfly valve opening again, thus the pressure of control reative cell.The air inlet of vacuum pump is normal to adopt an electromagnetic release valve, when shutdown this valve can open automatically one with atmosphere port air inlet mutually, make pumping hole be in the same atmospheric condition in gas outlet.Control unit adopts the control of PLC+ text display, and under full-automatic functional status, except that the loading and unloading sheet needs the manual operation, all the other processes have realized unattended.High frequency electric source in the plasma etching machine, adaptation are compositions such as high frequency coil transmission line and joint, inductance coil.The mainframe of existing plasma etching machine adopts one high and one low two racks splicing modeling structure.Existing plasma etching machine mainly has the following disadvantages:
1, the reative cell inductance coil lacks the location, is difficult to guarantee consistent with the horse center; The inside and outside temperature of reative cell can raise when particularly working, and the thermal deformation meeting is softened the loosening coil stationary frame that reaches of horse intermediate plate, makes and the inductance coil displacement causes the silicon chip surface etching, influences battery quality.
2, bleed the unit easy break-down, often to make cleaning maintenance and influence the part of use.Main cause is: one, and vacuum pump; Owing in the pumped gas dust and corrosive gas are arranged, both ground chip select in the running, decrease the pump case surface of internal cavity again, its usefulness of bleeding is lowered in the temperature rise meeting of pump.And the pollution of pump oil also can be lowered its usefulness of bleeding, and uses a period of time just must change oil, and has taken the utilization rate of equipment.Two, vacuum measurement; Unsettled film rule have been adopted in vacuum measurement, and this measuring component lacks the compensation that temperature is raise.And because mounting means is extremely unreasonable, make that measuring film is in vertical state, dust is if enter fine elastic deformation space like this, will be accumulated in the bottom owing to the action of gravity of dust, have influence on the bridge balance on the film, thereby can produce error, the accuracy that influence is measured.Three, dust is handled; The dust that enters the pump housing, thin film sensor can influence the use of equipment, must remove as far as possible.Four, reliability; Except dust influenced the useful life of vacuum pump, film rule, equipment is the most troublesome to be the pumping hole electromagnetic release valve.When shutdown this valve can open automatically one with atmosphere port air inlet mutually, make pumping hole be in the same atmospheric condition in gas outlet, and to block the bellows connector of connection device, and this action is by the outer solenoid outage of valve, and spool is by the elastic force driving of a concentric spring.When valve core seal ring had dust, this elastic force was too little, and the atmosphere that charges into can recoil in the pump-line of access arrangement, pollutes vacuum pipe and cavity inner wall.And the deflation sequences of pumping hole electromagnetic release valve is often unreliable, and with regard to opened blow vent, this does not just have influence on the reliability of equipment when spool blocks the bellows connector as yet.
3, the reative cell cover plate of existing plasma etching machine does not have positioner, makes that cover plate was in don't care state when cover plate was opened, and easily pollutes sealing ring, damages sealing surface and air duct.
The utility model content
For overcoming the flimsy defective of the reative cell cover plate location deficiency and the unit of bleeding, the utility model provides a kind of plasma etching machine, it is provided with positioner on the reative cell cover plate, and changes by the structure to the unit of bleeding, and can strengthen the reliability of the unit of bleeding effectively.
The utility model adopts following technical scheme to be: it comprises the reative cell that is installed in the mainframe plasma etching machine, be arranged on the electric automatic control unit on the mainframe, the supply gas unit and the unit of bleeding that are connected with reative cell, the vacuum pump that is connected with the unit of bleeding, the high frequency electric source and the adaptation of powering for reative cell ionization reaction gas.
Reaction chamber structure adopts vertical structure, and the reative cell top connects the unit of supplying gas, the below connects the unit of bleeding; At mechanical pumping hole, be provided with the reacting gas processing unit.
The reaction tube top is provided with upper flange and is connected lower flange with cover plate, below, constitutes the reactor chamber of a sealing.Lower flange is in three directions of an energy to be regulated on the mounting panel of displacement.Cover plate can separate with reaction tube, to expose reactor chamber.In the reaction tube outside, be provided with last retainer ring and the following retainer ring of fixing support bar jointly, following retainer ring is connected by screw with lower flange, and support bar is provided with inductance coil.Last retainer ring, following retainer ring and support bar constitute the fixed mount of a rigidity.
The cover plate center is provided with an aspirated joint, and aspirated joint is connected with the unit of supplying gas, and is used for the input of gas.The cover plate of reative cell top is provided with positioner, and as all connecting backstay in the cover plate both sides, backstay one end is connected on the mainframe with hinge, and the other end is connected with cover plate.Cover plate can be that axle, hinge are that move in the center of circle with the backstay.
On mounting panel, the inductance coil arranged outside has radome, and radome is formed the cavity of sealing, and it surrounds entire reaction pipe and inductance coil, and wind system runs at the radome rear portion.The horse back shaft is hollow axis body, and horse is being supported in its top, and hollow parts is connecting the unit of bleeding, and the horse back shaft is connecting the horse rotating mechanism that is positioned at reative cell below by gear, adopts the square axle to link to each other between horse back shaft and the horse.
The horse rotating mechanism is made up of motor, synchronous band, synchronizing wheel, magnet fluid sealing axle and gear etc., and motor is by the speed regulator control rate.During the motor rotation, to rotatablely move and pass to synchronizing wheel, be transferred to synchronous band again, be transferred to the synchronizing wheel that is fixed on the magnet fluid sealing axle again by motor shaft, thereby drive the gear movement of another section of magnet fluid sealing axle, drive the horse rotation by the horse back shaft again.The magnet fluid sealing axle is the movable sealing mode.The even flow plate of supplying gas is contained in the aspirating end of reative cell and the end of bleeding respectively with the even flow plate of bleeding.
The unit of supplying gas mainly is made up of electromagnetically operated valve, mass flowmenter, suspended body flowmeter, stainless steel pipeline and FEP pipeline etc.Reacting gas is connected to equipment by crossing pipe joint, by the stainless steel pipeline gas is received mass flowmenter, receives electromagnetically operated valve again, receives reative cell with the FEP pipe again after compiling through threeway then.Process gas adopts the accurate mass flowmenter control of control flow, and trunk line adopts EP grade stainless steel pipe, has guaranteed the purity of gas, and the pipeline that advances the reative cell part adopts the FEP pipeline to insert not only handled easily but also cleaning.The cover plate center is provided with an aspirated joint, and aspirated joint is connected with the FEP pipeline of the unit of supplying gas.
Described its structure of unit of bleeding is connecting the filer element type filter for the air extraction connector that is connected with vacuum pump by a pneumatic bellows valve, and air extraction connector is provided with vacuum solenoid; One metal bellows, one end connects the filer element type filter, and an end connects butterfly valve; Also be connected with a pneumatic bellows valve on the butterfly valve, be connected with simultaneously and start to control the electronic actuators of making usefulness, this pneumatic bellows valve links to each other with the lower end of threading a pipe of bleeding more; Bleed thread a pipe more the upper end link to each other with the lower end of reative cell, the side then is connected with an electric contact vacuum meter by the quick-release flange; Film rule clamp connector holder by the band filer element type and are fixed on to bleed and thread a pipe on the extended small pipeline in side more, and notable attribute is the corners that this extended small pipeline has one 90 degree, and it makes the fixing back maintenance of film rule vertical direction.
Film rule serve as that the basis constitutes with ultrapure ceramic sensor element chamber, and transducer and circuit case are stainless steel, are provided with the catch of maze type in measuring mouth, and shell is provided with screen.
Vacuum pump adopts water-cooled twin-stage sliding vane rotary pump, and the slide plate of vacuum pump adopts nonmetallic materials to manufacture.
Control unit adopts PLC control, and man-machine interface adopts touch display.
Power supply adopts the RF power supply of 13.56MHz, 1000W, is furnished with manual impedance matching box and coaxial high-frequency cable.Power supply can be regulated between 100W~1000W, regulates button and is divided into initial adjustment knob, fine tuning knob and vernier knob, can regulate power, power supply good stability accurately, continuously.
The utility model is owing to adopt screw between retainer ring and the lower flange, make the distance that fixing unanimity is arranged between inductance coil and the crystal reaction tube, a stabilized uniform electromagnetic field and plasma field have been guaranteed to have in the crystal reaction tube, and being provided with of even flow plate guaranteed that gas sends to uniformly and take away, thereby guaranteed the stability and the uniformity of etching; The horse back shaft drives the uniformity that the horse rotation has guaranteed battery sheet periphery etching.The cover plate both sides are provided with backstay, make cover plate open Shi Buhui and arbitrarily put, thereby avoided the sealing ring pollution.Film rule serve as that the basis constitutes with reliable ultrapure ceramic sensor element chamber; Guaranteed in harsh and corrosive atmosphere, stable and reliable and the preheating fast and the recovery time of certainty of measurement, boosted productivity long service life; Transducer and circuit case are that stainless steel is made, and effectively prevent to corrode and good interference free performance.Film rule are used the band filer element type to clamp connector holder and are fixed, and keep vertical direction in fixing back, have prevented dust adhesion to transducer, thereby have improved accuracy of measurement and repeatable accuracy the useful life that has prolonged film rule.Film rule shell is provided with screen, has improved anti-High-frequency Interference ability, prevents to disturb and causes the equipment cisco unity malfunction, has improved the reliability of equipment.Vacuum pump adopts water-cooled twin-stage sliding vane rotary pump, prolonged useful life, slide plate adopts nonmetallic materials to manufacture, fluoro-gas can not corrode slide plate, simultaneously because slide plate is nonmetallic materials, than pump housing material softer, having under the situation of dust, the wearing and tearing pump housing that can be minimum, and mainly be the wearing and tearing slide plates, and slide plate is to utilize middle spring and centrifugal force to carry out work, even there are certain wearing and tearing also can not influence vacuum degree, the low price of slide plate is changed conveniently simultaneously, thereby has prolonged the useful life of pump greatly.Air extraction connector at pumping hole is connected with filter, can prolong the drain period of vacuum pump, prolongs the cleaning cycle of vacuum pump, thereby and the wearing and tearing that reduced the pump housing can increase useful life of pump.Adopting the pneumatic bellows valve to add vacuum solenoid is valve for pressure difference, the corrosion of the anti-fluoro-gas of energy and the wearing and tearing of dust, and long service life, good reliability is difficult for gas leakage, thus the reliability that can improve equipment is keeped in repair with reducing.
Description of drawings
Below in conjunction with drawings and Examples the utility model is described further:
Fig. 1 is the utility model structural representation;
Fig. 2 is the vertical view of Fig. 1;
Fig. 3 is the utility model reaction chamber structure schematic diagram;
Fig. 4 is the utility model cellular construction schematic diagram of bleeding;
Fig. 5 is Fig. 4 vertical view;
Fig. 6 is Fig. 4 right view.
Embodiment
Plasma etching machine as shown in Figure 1, comprise the reative cell 1 that is installed in the mainframe 5, electric automatic control unit 4 on the mainframe 5 is installed, be connected the unit 2 and be connected the unit 3 of bleeding of reative cell below of supplying gas of reative cell 1 top, the vacuum pump 6 that is connected with the unit of bleeding, for providing the high frequency electric source and the adaptation of electric energy, high frequency electric source and adaptation all to be integrated into, installs in the mainframe 5 reative cell ionization reaction gas.
This machine adopts vertical response cell structure, and supply gas on the reative cell 1, the mode of lower pumping; Radio-frequency power guarantees that by being inductively coupled to conversion zone peripheral etching is even.Vacuum system adopts the main mode of taking out and taking out combination in advance, divides two-way to bleed, and can guarantee the time that background is found time, and the atmosphere disturbance is reduced.Plenum system adopts the high solenoid control of reliability, and the high MFC of flow control accuracy has been adopted in the input of two-way reacting gas, can guarantee the repeatability of operation stability of equipment and technology.At mechanical pumping hole, be provided with the reacting gas processing unit, reduce the influence of reacting gas, with the useful life of prolonged mechanical pump to pump as far as possible.The frequency of the radio-frequency power supply of stability and high efficiency and power stability, and have impedance matching box can guarantee that radio frequency power output almost completely is coupled in the reative cell.Reliable and stable PLC and supporting touch display are adopted in the automatic control of equipment, and be easy to operate, and control stabilization has guaranteed the functional reliability of equipment.
Reaction tube 9 tops of described as shown in Figure 3 reative cell 1 connect upper flange 8 and are connected lower flange 10 with cover plate 7, below, form the reactor chamber of a sealing.In the present invention, lower flange 10 is on the mounting panel 11 of three directions adjustings of energy displacement.Lower flange 10 is used for supporting and being connected crystal reaction tube 9 and frame, opens cover plate 7 and can adorn and get horse 18.Last retainer ring 12, fix the fixed mount that 13 rings and support bar 14 are formed a rigidity down, be used for fixing inductance coil 15, adopt screw between following retainer ring 13 and the lower flange 10.Inductance coil 15 is fixed in the fixed mount of rigidity, simultaneously owing to adopting screw between retainer ring 13 and the lower flange 10 down, making has one to fix and consistent distance between inductance coil 15 and the crystal reaction tube 9, so just guaranteeing has a stabilized uniform electromagnetic field and plasma field in the crystal reaction tube 9, thereby has guaranteed the stability and the uniformity of etching.Radome 16 adopts thin aluminum sheet to curve, the radiation that produces when being used to shield inductance coil 15 work has effectively guaranteed environment and personal safety, and radome 16 is formed the cavity of base closed simultaneously, the rear portion wind system that runs in, the ozone that ionized air produced when inductance coil was worked is taken away.Horse back shaft 17 is a hollow shaft, and intermediate hollow partly is used to take out reacting gas.Horse back shaft 17 is used to support horse 18, simultaneously horse back shaft and horse rotating mechanism 21 are connected by gear, adopt the square axle to link to each other between horse back shaft 17 and the horse 18, thereby thereby horse 18 is passed in the rotation of horse rotating mechanism 21 to be driven horses and rotate.Horse rotating mechanism 21 is made up of motor, synchronous band, synchronizing wheel, magnet fluid sealing axle and gear etc., and motor is by the speed regulator control rate.During the motor rotation, to rotatablely move and pass to synchronizing wheel by motor shaft, be transferred to synchronous band again, be transferred to the synchronizing wheel that is fixed on the magnet fluid sealing axle again, thereby drive the gear movement of another section of magnet fluid sealing axle, drive horse 18 rotations by horse back shaft 17 again, thereby guaranteed the uniformity of battery sheet periphery etching.The magnet fluid sealing axle is advanced movable sealing mode, the rotation that can guarantee axle freely, the reative cell that held good security is air tight.The supply gas even flow plate 19 and the even flow plate 20 of bleeding is contained in the aspirating end of top of reative cell 1 and the end of bleeding of below respectively, like this gas sent to uniformly and taken away uniformly, for the uniformity of etching provides assurance.
Shown in Figure 2 as Fig. 1, cover plate 7 both sides all are connected with backstay 34, and backstay one end is connected on the mainframe 5 with hinge, and the other end is connected with cover plate 7.The positioner that backstay 34 and hinge constitute can make cover plate 7 be in level all the time.
The unit 2 of supplying gas mainly is made up of electromagnetically operated valve, mass flowmenter, suspended body flowmeter, stainless steel pipeline and FEP pipeline etc.Reacting gas is connected to equipment by crossing pipe joint, by the stainless steel pipeline gas is received mass flowmenter, receives electromagnetically operated valve again, receives reative cell with the FEP pipe again after compiling through threeway then.Process gas adopts the accurate mass flowmenter control of control flow, and trunk line adopts EP grade stainless steel pipe, has guaranteed the purity of gas, and the pipeline that advances the reative cell part adopts the FEP pipeline to insert not only handled easily but also cleaning.Cover plate 7 centers are provided with an aspirated joint 22, and aspirated joint is connected with the FEP pipeline of the unit of supplying gas.
As Fig. 4 Fig. 5 and shown in Figure 6, described its structure of unit of bleeding is connecting filer element type filter 27 for the air extraction connector 33 that is connected with vacuum pump 6 by a pneumatic bellows valve 29, and air extraction connector 33 is provided with vacuum solenoid 28; One metal bellows, 23 1 ends connect filer element type filter 27, one ends and connect butterfly valve 15; Also be connected with a pneumatic bellows valve 29 on the butterfly valve, be connected with the electronic actuators 25 of control butterfly valve 15 effect simultaneously, this pneumatic bellows valve 29 and 35 lower ends link to each other (as Fig. 4) of threading a pipe of bleeding more; Bleed 35 upper ends of threading a pipe link to each other with the lower end of reative cell 1 more, and the side then is connected with an electric contact vacuum meter 30 by quick-release flange 31; Film rule 24 clamp connector holder 32 by the band filer element type and are fixed on to bleed and thread a pipe on the extended small pipeline in 35 sides more, notable attribute is the corners that this extended small pipeline has one 90 degree, and it makes film rule 24 fixing backs keep vertical direction.
Film rule 24 have following a series of characteristics: with reliable ultrapure ceramic sensor element chamber serves as that the basis constitutes; In harsh and corrosive atmosphere, stable and reliable high accuracy pressure measurement; Preheating fast and recovery time, boost productivity; Can stand the pressure cycle period millions of times, comprise that atmospheric pressure impacts, and does not have the sign of any reduction performance; Fast quick-recovery need not isolating valve behind the exposure atmospheric pressure; Sensor element has anti-pollution protection, long service life; Transducer and circuit case are that stainless steel is made, and effectively prevent to corrode and good interference free performance.Add special mounting means simultaneously owing to the catch that is provided with maze type in measuring mouth has, effectively prevented dust adhesion to transducer, thereby prolonged the useful life of film rule 24 and improved its accuracy of measurement and repeatable accuracy.Because shell is provided with screen, has improved its anti-High-frequency Interference ability greatly, prevented to cause the equipment cisco unity malfunction owing to disturbing, improved the reliability of equipment.
As shown in Figure 2, vacuum pump 6 adopts the special water-cooled twin-stage sliding vane rotary pump of manufacturing, and has prolonged the useful life of pump to greatest extent.The slide plate of vacuum pump 6 adopts the corrosion-resistant nonmetallic materials to manufacture, fluoro-gas can not corrode slide plate, because slide plate is nonmetallic materials,, having under the situation of dust simultaneously than pump housing material softer, the wearing and tearing pump housing that can be minimum, and mainly be the wearing and tearing slide plates, and slide plate is to utilize middle spring and centrifugal force to carry out work, even there are certain wearing and tearing also can not influence vacuum degree, the low price of slide plate is changed conveniently simultaneously, thereby has prolonged the useful life of pump greatly.33 places are provided with filer element type filter 27 at the pumping hole air extraction connector, can prolong the drain period of vacuum pump 6, prolong the cleaning cycle of vacuum pump, thereby and the wearing and tearing that reduced the pump housing can increase useful life of pump.
Adopting pneumatic bellows 28 valves to add vacuum solenoid 29 is valve for pressure difference, the corrosion of the anti-fluoro-gas of energy and the wearing and tearing of dust, and long service life, good reliability is difficult for gas leakage, thus the reliability and the minimizing that can improve equipment are keeped in repair.The valve of inflation adopts the special-purpose vacuum valve of the stainless steel of import, can use under adverse circumstances for a long time and air tight, thereby can improve the reliability of equipment and reduce maintenance.
Control unit 4 adopts PLC control, and man-machine interface adopts touch display, has automatic/hand control handoff functionality.Under the full-automatic functional status, except that the loading and unloading sheet needs the manual operation, all the other processes have realized unattended, have guaranteed the repeatability and the accuracy of technology, have improved product processing quality greatly.But single-step operation when manually controlling is very convenient during maintenance.The PLC software function is powerful, technical process according to this for take out in advance, main do not take out, supply gas, aura, six steps such as clean, supply gas, each step is all undertaken by the time of preestablishing, simultaneously go on foot all interlocking functions at each, when condition does not satisfy, just not carry out next step, effectively guaranteed equipment, personnel's safety.Whether open as when taking out in advance, detecting vacuum pump 6,, just can't open and take out in advance and report to the police as not opening; Whether detected pressures arrives the safe pressure scope when main taking out, and has effectively prevented the too quickly damage to crystal reaction tube 9 of the excessive draft of pressure reduction; Whether detected pressures is lower than the value of setting before supplying gas, if just carry out next step, if not just reporting to the police, prompt facility may leak gas, thereby has ensured the personal security that the back gas leakage of supplying gas causes, and has also prevented simultaneously because the technological effect that gas leakage causes is bad; Whether detected pressures is at zone of reasonableness before aura, and whether gas flow is normal, effectively guaranteed the accuracy of technological parameter; Adopt repeatedly the mode of " supply gas---find time " during cleaning, the reacting gas of remnants is thoroughly drained only, for operating personnel's safety provides guarantee; Time and the pressure back technology that all satisfies condition of supplying gas finishes, and equipment alarm prompting staff gets horse.The running status of display device visually on the color touch display screen, and can realize that authority ground revises and set technological process, technological parameter etc.
Mainframe 5 is mainly used to place various parts, is made up of frame and door etc., and is highly reasonable, easy to operate.Incorporate moulded, roomy operating table surface, very convenient operation.
Adopt the high-quality RF power supply of 13.56MHz, 1000W, be furnished with manual impedance matching box and coaxial high-frequency cable.Power supply can be regulated arbitrarily between 100W~1000W, regulates button and is divided into initial adjustment knob, fine tuning knob and vernier knob, can regulate power, power supply good stability accurately, continuously.
Etching technics software adopts touch-screen and graphic operation interface, makes easy and simple to handle, reliable.For this reason, must adopt specialized etching technics software.