Be applied to the pressure detecting system of low pressure furnace tube apparatus
Technical field
The present invention relates to a kind of pick-up unit, specifically belong to a kind of pressure detecting system that is applied to low pressure furnace tube apparatus.
Background technology
In semi-conductive manufacture process, often utilize LPCVD(Low Pressure Chemical Vapor Deposition, i.e. low-pressure chemical vapor deposition) technique forms the films such as polysilicon, silicon nitride, and this technique is carried out conventionally in low pressure furnace tube apparatus.At present, in the boiler tube of low pressure furnace tube apparatus, atmospheric pressure is determined by capacitance-type pressure gage conventionally, described capacitance-type pressure gage 3 and a control module 1 form a test loop, as shown in Figure 1, in order to ensure the safety of product and quartz member, low pressure furnace tube apparatus is set with INTERLOCK(interlocking) function, that is to say, when the boiler tube internal pressure that capacitance-type pressure gage detects is held in the palm lower than 750torr() time, boat action is not fallen in the boiler tube that boat retains.
Yet, existing capacitance-type pressure gage tends to occur the defect of zero migration, if there is the situation of negative bias in pressure gauge, can extend so the time of the actual arrival of capacitance-type pressure gage atmospheric pressure, cause boat cannot exit in time boiler tube, increase the hot resume of silicon chip in stove, thereby affected the characteristic of silicon chip; If there is the situation of positively biased in pressure gauge, when capacitance-type pressure gage is shown as 760torr, the actual pressure of boiler tube inside is less than outside atmospheric pressure, falls boat action and can cause and pour in down a chimney, and then affect the particle of product, if the excessive damage that also can cause boiler tube internal fragment or quartz member of pressure reduction.
Summary of the invention
The technical problem to be solved in the present invention is to provide a kind of pressure detecting system that is applied to low pressure furnace tube apparatus, can effectively avoid low pressure furnace tube apparatus to occur because of the damage of product that the zero migration of capacitance-type pressure gage causes.
For solving the problems of the technologies described above, the pressure detecting system that is applied to low pressure furnace tube apparatus of the present invention, comprises control module, mechanical pressure switch and capacitance-type pressure gage;
Described mechanical pressure switch comprises a base, and described base has a pressure introduction port, and this pressure introduction port communicates with the corrugated tube that a top seal and bottom are opened, and the lower end of described corrugated tube is fixed on base;
The closure tip of described corrugated tube is fixed with a support bar, is arranged with a conducting strip that connects signal on described support bar;
One support cover is fixedly housed on described base, and described corrugated tube, support bar and conducting strip are all positioned at support cover inside, and two stubs are fixedly equipped with at the top of described support cover, and the top of each stub is connected with a wire;
Described mechanical pressure switch is connected in the test loop of capacitance-type pressure gage and control module formation by two wires;
When the pressure in boiler tube is not less than the threshold value of setting, the state of described corrugated tube in naturally upholding, conducting strip contacts with stub, and capacitance-type pressure gage is communicated with control module;
Pressure in boiler tube lower than set threshold value time, the state of described corrugated tube in shrinking, conducting strip is separated with stub, capacitance-type pressure gage is not communicated with control module.
In said structure, described capacitance-type pressure gage is connected with two signal wires, and wherein a signal wire is connected with control module, and another root signal wire is connected with a wire of mechanical pressure switch, another root wire connection control unit of mechanical pressure switch.
Wherein, described corrugated tube, conducting strip, support bar and support cover are stainless steel.
Preferably, described support bar is threaded rod structure, and conducting strip is fixed on support bar by upper and lower two nuts, between two nuts and conducting strip, is respectively equipped with insulating washer.Described two nuts are equipped with retainer nut away from a side of conducting strip.
Preferably, described stub is threaded rod structure, and each stub is fixedly connected with support cover by upper and lower two nuts, between nut and support cover, is respectively equipped with insulating washer.Described nut is equipped with retainer nut away from a side of support cover.
Further, the top of described corrugated tube is sealed by a top board, and described support bar is fixed on top board.Described top board is stainless steel.
In addition, be fixed with a protective cover on described base, described support cover and stub are all positioned at protective cover, and described protective cover top is provided with an opening, and two wires stretch out protective cover by this opening.The opening part of described protective cover is equipped with plastic protective sleeve.
Pressure detecting system of the present invention has increased a mechanical pressure switch on original capacitance-type pressure gage basis, this mechanical pressure switch and original capacitance-type pressure gage detect respectively the pressure condition of low pressure furnace tube apparatus, and be that in normally situation, capacitance-type pressure gage just works at mechanical pressure switch, therefore this system has not only retained the measuring ability of capacitance-type pressure gage, and again the capacitance-type pressure gage of equipment itself has been carried out to double acknowledge, the capacitance-type pressure gage that effectively reduces low pressure furnace tube apparatus itself is due to the damage of product that zero migration causes or the component such as quartzy occurring.
Accompanying drawing explanation
Fig. 1 is the existing pressure detecting system that is applied to low pressure furnace tube apparatus;
Fig. 2 is the structural representation that the present invention is applied to the pressure detecting system of low pressure furnace tube apparatus;
Fig. 3 is the structural representation of mechanical pressure switch in the present invention.
Wherein description of reference numerals is as follows:
1 is control module; 2 is mechanical pressure switch; 3 is capacitance-type pressure gage; 21 is pressure introduction port; 22 is base; 23 is corrugated tube; 24 is top board; 25 is support bar; 26 is nut; 27 is insulating washer; 28 is conducting strip; 29 is retainer nut; 210 is stub; 211 is support cover; 212 is wire; 213 is protective cover; 214 is plastic protective sleeve.
Embodiment
Below in conjunction with accompanying drawing and embodiment, the present invention is further detailed explanation.
The pressure detecting system that is applied to low pressure furnace tube apparatus provided by the invention, as shown in Figure 2, comprise control module 1, mechanical pressure switch 2 and capacitance-type pressure gage 3, described control module 1 is computing machine or single-chip microcomputer, and mechanical pressure switch 2 is connected on and between control module 1 and capacitance-type pressure gage 3, forms a test loop.
As shown in Figure 3, mechanical pressure switch 2 comprises the base 22 of a flange arrangement, base 22 has a pressure introduction port 21 that connects low pressure furnace tube apparatus, and this pressure introduction port 21 communicates with the corrugated tube 23 that a top seal and bottom are opened, and the lower end of corrugated tube 23 is fixed on base 22;
The closure tip of corrugated tube 23 is fixed with a support bar 25, is arranged with a conducting strip 28 that connects signal on support bar 25;
One support cover 211 is fixedly housed on base 22, corrugated tube 23, support bar 25 and conducting strip 28 are all positioned at support cover 211 inside, two stubs 210 are fixedly equipped with at the top of support cover 211, the top of each stub 210 is connected with a wire 212, wherein wire 212 connects a signal wire of capacitance-type pressure gages 3, another root wire 212 connection control units 1, the direct connection control unit 1 of another root signal wire of capacitance-type pressure gage 3;
When the pressure in boiler tube is not less than the threshold value (being generally 750torr) of setting, the state of corrugated tube 23 in naturally upholding, conducting strip 28 contacts conducting (now mechanical pressure switch 2 is equivalent to a closed switch) with stub 210, capacitance-type pressure gage 3 is communicated with control module 1 by mechanical pressure switch 2, whole test loop is closed, and capacitance-type pressure gage carries out pressure detection;
Pressure in boiler tube lower than set threshold value time, the state of corrugated tube 23 in shrinking, conducting strip 28 and the separated disconnection of stub 210 (now mechanical pressure switch 2 is equivalent to a not closed switch), capacitance-type pressure gage 3 and the state of control module 1 in disconnecting, capacitance-type pressure gage 3 cannot carry out pressure detection.
Preferred embodiment, the top of corrugated tube 23 is by top board 24 sealings, and support bar 25 is fixed on top board 24.Wherein, corrugated tube 23, conducting strip 28, support bar 25, support cover 211 and top board 24 are stainless steel.
Wherein, support bar 25 is threaded rod structure, and conducting strip 28 is fixed on support bar 25 by upper and lower two nuts 26, between two nuts 26 and conducting strip 28, is respectively equipped with insulating washer 27.Described two nuts 26 are equipped with retainer nut 29 away from a side of conducting strip 28.Stub 210 is also threaded rod structure, and each stub 210 is fixedly connected with support cover 211 by upper and lower two nuts 26, between nut 26 and support cover 211, is respectively equipped with insulating washer 27.Described nut 26 is equipped with retainer nut 29 away from a side of support cover 211.
In addition, be also fixed with a protective cover 213 on base 22, this support cover 211 and stub 210 are all positioned at protective cover 213, and protective cover 213 tops are provided with an opening, and opening part is equipped with 214, two wires 212 of plastic protective sleeve and stretches out protective cover 213 by this opening.
The present invention has appended a mechanical pressure switch on the original capacitance-type pressure gage of low pressure furnace tube apparatus basis, when boiler tube pressure is not less than 750torr, the corrugated tube of this mechanical pressure switch is in natural stretched condition, conducting strip is with stub for contacting conducting state, and capacitance-type pressure gage carries out pressure detection; When pressure bellows contract during lower than 750torr, conducting strip and stub are off-state, capacitance-type pressure gage cannot carry out pressure detection, during actual use, can according to the threshold value of pressure demand, adjust nut, the retainer nut of nut, retainer nut 10 or the fixed conductor rod of fixed-conductive film, make conducting strip and stub disconnect and contacting when the force value lower than needs.The capacitance-type pressure gage of mechanical pressure switch and equipment itself is installed in parallel on gas exhaust piping and uses, outside the measuring ability of capacitance-type pressure gage that has kept original equipment itself, the capacitance-type pressure gage of equipment itself is carried out to double acknowledge, the capacitance-type pressure gage that effectively reduces equipment itself is due to the loss of product that zero migration causes or the component such as quartzy occurring simultaneously.
By specific embodiment, the present invention is had been described in detail above, but these are not construed as limiting the invention.Without departing from the principles of the present invention, those skilled in the art can make many distortion and improvement to the material of the structure of mechanical pressure switch and each parts, and these also should be considered as protection scope of the present invention.