Disclosure of Invention
The invention aims to disclose a double-layer film wire gas-liquid mixing device and a double-layer film wire preparation method, which are used for solving the problems that in the prior art, the carbon dioxide dissolving speed of the gas-liquid mixing device is too high to exceed the expected dissolving speed, and the conductivity distribution of the dissolved carbon water is uneven, so that the requirement of a rear-end semiconductor device cleaning wafer on the conductivity of the carbonic acid water is difficult to meet.
In order to achieve the above purpose, the invention provides a double-layer membrane filament gas-liquid mixing device, which comprises a shell, wherein liquid inlet holes and liquid outlet holes are formed in two ends of the shell in the length direction, air inlet holes are formed in the side wall of the shell, the shell is connected with a first permeable membrane and a second permeable membrane with different permeation efficiencies, the second permeable membrane is arranged in a tubular shape, two ends of the second permeable membrane are respectively communicated with the liquid inlet holes and the liquid outlet holes, pure water flows into the second permeable membrane after entering the shell through the liquid inlet holes, carbon dioxide is sequentially dissolved into the pure water in the second permeable membrane through the first permeable membrane and the second permeable membrane after entering the shell through the air inlet holes, and the carbonated water after gas-liquid mixing is discharged from the shell through the second permeable membrane and the liquid outlet holes.
As a further improvement of the invention, the first permeable membranes are arranged around the inner wall of the shell, the second permeable membranes which are arranged in a tubular shape are arranged in a plurality of ways and uniformly distributed on one side of the first permeable membranes far away from the shell, and the linear distances between the axes of the second permeable membranes and the axes of the first permeable membranes are equal.
As a further improvement of the invention, the air inlet hole is connected with the membrane frame assembly, the membrane frame assembly comprises a first frame body and a second frame body, the first frame body is fixedly connected with the air inlet hole, the second frame body is detachably connected with the first frame body, and the first permeable membrane is clamped between the first frame body and the second frame body;
The second osmosis membranes which are arranged in a tubular shape are arranged in a plurality and evenly distributed around the inner diameter of the shell, and the linear distances between the axes of the second osmosis membranes and the axes of the shell are equal.
As a further improvement of the invention, the shell comprises a first cover body, a second cover body and a mixing pipeline, wherein the first cover body and the second cover body are buckled at two ends of the mixing pipeline in the length direction, the first cover body is provided with a liquid inlet hole, the second cover body is provided with a liquid outlet hole, and the air inlet hole is arranged on the side wall of the mixing pipeline.
As a further improvement of the invention, the first cover body is connected with a first liquid dividing block, a plurality of first liquid dividing holes communicated with the liquid inlet holes are uniformly distributed in the first liquid dividing block, and each first liquid dividing hole is correspondingly communicated with one second permeable membrane;
the second cover body is connected with a second liquid separation block, a plurality of second liquid separation holes communicated with the liquid outlet holes are uniformly distributed in the second liquid separation block, and each second liquid separation hole is correspondingly communicated with one second permeable membrane;
The pore size and porosity of the first permeable membrane are smaller than those of the second permeable membrane.
As a further improvement of the invention, a sealing gasket is respectively arranged between the first cover body and the end face of the mixing pipeline and between the second cover body and the end face of the mixing pipeline.
Based on the same thought, the invention discloses a double-layer film yarn preparation method, which comprises the following steps:
s1, mixing polytetrafluoroethylene resin, an extrusion aid, a super-hydrophobic fluorine-containing material and a solvent to form paste;
s2, sieving, prepressing and extrusion molding are sequentially carried out on the paste, so that a tubular primary membrane comprising an outer tube and a plurality of inner tubes nested in the outer tube is formed;
S3, performing heat treatment on the tubular primary membrane, and respectively stretching the inner tube and the outer tube at different stretching multiples and then sintering to form a double-layer membrane wire consisting of a first permeable membrane and a second permeable membrane.
As a further improvement of the invention, the volume fractions of the components in the paste are respectively 30% -40% of polytetrafluoroethylene resin, 20% -30% of extrusion aid, 20% -35% of super-hydrophobic fluorine-containing material and 20% -30% of solvent, wherein the crystallinity of the polytetrafluoroethylene resin is more than or equal to 98%, and the number average molecular weight is 300-900 ten thousand.
As a further improvement of the invention, the heat treatment temperature of the tubular primary membrane is 120 ℃, the stretching temperature is 90 ℃, the stretching multiple of the outer tube is 1-2 times, the stretching multiple of the inner tube is 15-20 times, and the stretched outer tube membrane and inner tube membrane are sintered for 120min at 320 ℃ to form a first permeable membrane and a second permeable membrane.
As a further improvement of the invention, the inner diameter of the first permeable membrane is 2.5 mm-4 mm, the inner diameter of the second permeable membrane is 0.4-1 mm, and the film thicknesses of the first permeable membrane and the second permeable membrane are 0.1-0.4 mm.
Compared with the prior art, the invention has the beneficial effects that firstly, the first permeable membrane and the second permeable membrane are sequentially arranged in the shell, pure water enters the second permeable membranes which are arranged in a plurality of tubular shapes through the liquid inlet holes, and carbon dioxide is dissolved into the pure water in the second permeable membranes through the first permeable membranes and the second permeable membranes after passing through the air inlet holes. Because the first osmotic membrane and the second osmotic membrane have different osmotic efficiency, when the carbon dioxide passes through the air inlet hole and permeates into the first osmotic membrane, a pressure difference is formed between the first osmotic membrane and the second osmotic membrane, compared with the prior art, the first osmotic membrane and the second osmotic membrane are matched to play an effective buffering effect between the carbon dioxide and the pure water, thereby effectively slowing down the osmotic efficiency of the pure water permeated into the second osmotic membrane by the carbon dioxide, solving the problem that the carbon dioxide is dissolved in the pure water too fast to exceed the expected dissolving rate in the prior art, and simultaneously, the carbon dioxide can permeate into the second osmotic membrane from all parts of the tubular second osmotic membrane to dissolve into the pure water after passing through the first osmotic membrane by the pure water, so that the dissolving uniformity of the carbon dioxide in the pure water is effectively improved, and the subsequent wafer cleaning requirement is met.
And secondly, through a shell formed by the first cover body, the second cover body and the mixing pipeline, the first cover body is communicated with the liquid inlet holes through the first liquid dividing block, and the second cover body is communicated with the liquid outlet holes through the second liquid dividing block, so that the purpose of fixing each second permeable membrane is achieved, and each second permeable membrane is communicated with the liquid inlet holes and the liquid outlet holes.
Finally, because the aperture and the porosity of the first permeable membrane are smaller than those of the second permeable membrane, the first permeable membrane is mainly used for adjusting the air inlet efficiency of the carbon dioxide so as to realize the purpose of slow permeation of the carbon dioxide, and the carbon dioxide passing through the first permeable membrane is dissolved into the pure water through the second permeable membrane with large aperture and large porosity. When the applied carbon dioxide concentration fluctuates, the double-layer membrane yarn formed by the first permeable membrane and the second permeable membrane can play a role of buffering, so that the concentration change of carbonated water formed by dissolving carbon dioxide into pure water is slower and smaller, and the stability of the carbonated water concentration is improved.
Detailed Description
The present invention will be described in detail below with reference to the embodiments shown in the drawings, but it should be understood that the embodiments are not limited to the present invention, and functional, method, or structural equivalents and alternatives according to the embodiments are within the scope of protection of the present invention by those skilled in the art.
Referring to fig. 1 to 6, in the double-layer membrane filament gas-liquid mixing device provided by the invention, compared with the gas-liquid mixing device in the prior art, an air inlet 131 is formed on a housing, carbon dioxide gas sequentially permeates through a membrane hole of a first permeable membrane 2 and a membrane hole of a second permeable membrane 3 after passing through the air inlet 131, and is dissolved into pure water flowing through the inside of the second permeable membrane 3 after entering the housing through a liquid inlet 111 to form carbonated water required for wafer cleaning. Through the setting of the different first osmotic membrane 2 of osmotic efficiency and second osmotic membrane 3, after the carbon dioxide permeated first osmotic membrane 2, form pressure differential between first osmotic membrane 2 and the second osmotic membrane 3, first osmotic membrane 2 and the mode that second osmotic membrane 3 cooperated play effectual buffering effect between carbon dioxide and pure water, thereby effectively slow down the osmotic efficiency of the pure water that carbon dioxide dissolved to in the second osmotic membrane 3, in order to solve the problem that carbon dioxide in the prior art dissolved in pure water and surpassed the expected dissolution rate too soon, simultaneously, through pure water process tubular second osmotic membrane 3, carbon dioxide can permeate in order to dissolve in the pure water by the membrane hole of tubular second osmotic membrane 3 everywhere after the carbon dioxide process first osmotic membrane 2, thereby effectively improve the dissolution uniformity of carbon dioxide in the pure water, in order to satisfy subsequent wafer cleaning demand.
Referring to fig. 1 to 6, the disclosed double-layer membrane filament gas-liquid mixing device (hereinafter referred to as gas-liquid mixing device) comprises a housing 1, wherein liquid inlet holes 111 and liquid outlet holes 121 are formed at two ends of the housing 1 in the length direction, air inlet holes 131 and air outlet holes 132 are formed on the side wall of the housing 1, the housing 1 is connected with a first permeable membrane 2 and a second permeable membrane 3 with different permeation efficiencies, and specifically, the pore diameter and the porosity of the first permeable membrane 2 are smaller than those of the second permeable membrane 3. The second permeable membrane 3 is in a tubular shape, two ends of the second permeable membrane are respectively communicated with the liquid inlet 111 and the liquid outlet 121, pure water flows into the second permeable membrane 3 after entering the shell 1 through the liquid inlet 111, carbon dioxide sequentially permeates the first permeable membrane 2 and the second permeable membrane 3 and is dissolved into the pure water in the second permeable membrane 3 after entering the shell 1 through the air inlet 131, and the carbonated water after gas-liquid mixing is discharged from the shell 1 through the second permeable membrane 3 and the liquid outlet 121.
Referring to fig. 2 to 6, the first permeable membrane 3 is disposed around the inner diameter of the casing 1, and the second permeable membranes 3 disposed in a tubular shape are disposed in a plurality of uniformly distributed manner on one side of the first permeable membrane 3 away from the casing 1, and the linear distances between the axes of the plurality of second permeable membranes 3 and the axis of the first permeable membrane 2 are equal. The casing 1 includes a first cover 11, a second cover 12, and a mixing pipe 13, where the first cover 11 and the second cover 12 are fastened to two ends of the mixing pipe 13 in a length direction, the first cover 11 is provided with a liquid inlet 111, the second cover 12 is provided with a liquid outlet 121, and the air inlet 131 is provided on a side wall of the mixing pipe 13.
By providing the first permeable membrane 2 and the second permeable membrane 3, and the pore diameter and the porosity of the membrane pores of the first permeable membrane 2 are smaller than those of the second permeable membrane 3, it is possible to obtain a permeation efficiency of the first permeable membrane 2 smaller than that of the second permeable membrane 3. As shown in fig. 3 to 6, when carbon dioxide enters the mixing pipe 13 through the air inlet hole 131, it passes through the first permeable membrane 2 having a smaller permeation efficiency and is annularly distributed in the mixing pipe 13 with the first permeable membrane 2, so that the carbon dioxide entering the mixing pipe 13 uniformly and slowly permeates into the inside of the first permeable membrane 2, i.e., between the first permeable membrane 2 and the second permeable membrane 3, from everywhere outside the first permeable membrane 2, thereby first limiting the rate of carbon dioxide dissolved into pure water. And because the pure water flows into the second permeable membrane 3, after the carbon dioxide permeates between the first permeable membrane 2 and the second permeable membrane 3, the carbon dioxide permeates into the second permeable membrane 3 again to be dissolved into the pure water flowing into the second permeable membrane to form carbonated water required for wafer cleaning. It should be noted that, since the first permeable membrane 2 has made the first limitation on the permeation efficiency of carbon dioxide, the permeation rate of the second permeable membrane 3 is relatively large compared to the first permeable membrane 2, in the present application, compared to the permeable membranes 3 having a relatively large inner diameter and a relatively small number, the pure water entering the housing 1 through the liquid inlet holes 111 is equally divided into the second permeable membranes 3 communicating with the liquid inlet holes 111, carbon dioxide between the first permeable membrane 2 and the second permeable membranes 3 is uniformly permeated into the second permeable membranes 3 through the membrane holes of the respective second permeable membranes 3 and is dissolved into pure water, and the inner diameter of each second permeable membrane 3 is limited, so that carbon dioxide can be dissolved into the pure water in each second permeable membrane 3 in a uniform state, and compared to the permeable membranes having a relatively large inner diameter and a relatively small number, the problem that pure water near the axis of the permeable membranes is difficult to contact with carbon dioxide, thereby causing uneven concentration of the carbonated water and difficult to meet the wafer cleaning needs is effectively avoided, and the dissolved water is discharged from the liquid outlet holes 121. In the present embodiment, the flow direction of carbon dioxide is indicated by a dotted arrow in fig. 3 to 5, and the flow direction of pure water is indicated by a solid arrow in fig. 2 to 5. The mixing pipe 13 is also provided with an air outlet 132 for carbon dioxide to exit the mixing pipe 13. A gasket 16 is provided between the first cover 11 and the end face of the mixing pipe 13 and between the second cover 12 and the end face of the mixing pipe 13.
Referring to fig. 2 to 6, the first cover 11 is connected to the first liquid separating block 14, the first liquid separating block 14 is uniformly provided with a plurality of first liquid separating holes 141 communicated with the liquid inlet 111, each first liquid separating hole 141 is correspondingly communicated with one second permeable membrane 3, the second cover 12 is connected to the second liquid separating block 15, the second liquid separating block 15 is uniformly provided with a plurality of second liquid separating holes communicated with the liquid outlet, and each second liquid separating hole is correspondingly communicated with one second permeable membrane. With specific reference to fig. 3 to 5, the first liquid separation block 14 and the second liquid separation block 15 are respectively embedded in the first cover 11 and the second cover 12, and the annular side wall of the first liquid separation block 14 is fixed with the first cover 11 everywhere, a gap exists between the bottom surface of the first liquid separation block 14 and the first cover 11, the annular side wall of the second liquid separation block 15 is fixed with the second cover 12, and a gap exists between the top surface of the second liquid separation block 15 and the second cover 12. Referring to fig. 2 and 6, the first liquid separation block 14 has a plurality of first liquid separation holes 141 uniformly distributed around its axis, the second liquid separation block 15 has a plurality of second liquid separation holes 151 uniformly distributed around its axis, the top and bottom ends of each second permeable membrane 3 are respectively inserted between one second liquid separation hole 151 and the first liquid separation hole 141, when pure water is introduced into the liquid inlet hole 111, the pure water flows between the first liquid separation block 141 and the first cover 11, and then flows into each second permeable membrane 3 communicated with the first liquid separation hole 141, and carbonated water after carbon dioxide dissolution flows into the second liquid separation hole 151 from the other end of the second permeable membrane 3, then flows out from the liquid outlet hole 121 through between the second liquid separation block 15 and the second cover 12. The arrangement of the first liquid separation block 14 and the second liquid separation block 15 achieves the effect of communicating the liquid inlet 111, the second permeable membrane 3 and the liquid outlet 121, and simultaneously, plays a role in fixing the second permeable membrane 3. The first permeable membrane 2 may be inserted into the first and second liquid separation blocks 14 and 15, respectively, as shown in fig. 3 to 6, or may be sandwiched between only the first and second liquid separation blocks 14 and 15.
In the present embodiment, the first permeable membrane 2 having a small pore diameter and a small pore diameter is used as the outer layer tube, and the second permeable membrane 3 having a large pore diameter and a large pore diameter is used as the outer layer tube, so that the purpose of adjusting the intake efficiency of carbon dioxide and realizing slow permeation of carbon dioxide can be achieved, and at the same time, carbon dioxide can be dissolved in pure water. When the speed of the air inlet 131 applying carbon dioxide fluctuates, the double-layer membrane formed by the first permeable membrane 2 and the second permeable membrane 3 can realize the buffer function, part of carbon dioxide is remained between the first permeable membrane 2 and the mixing pipeline 13, the carbon dioxide slowly passes through the first permeable membrane 2 with the permeation efficiency, and the concentration change of the carbonated water is slower and smaller, so as to improve the concentration stability of the carbonated water.
In accordance with henry's law, p=hx, where P is the partial pressure of gas, H is the henry constant, and x is the molar fraction solubility of gas, and p=hx in the case of a monolayer film. When the double-layer membrane structure with different permeation efficiencies is adopted in the present embodiment, a buffer area is formed between the first permeation membrane 2 and the second permeation membrane 3, carbon dioxide is permeated and dissolved into pure water through the second permeation membrane 3 with higher permeation efficiency, but carbon dioxide is supplemented into the buffer area through the first permeation membrane 2 with lower permeation efficiency, and finally, the pressure of the buffer area between the first permeation membrane 2 and the second permeation membrane 3 in the equilibrium state is P1, P1 is smaller than P, and at this time x1< x. In the state of the single-layer membrane, when the P value changes, the Hunling constant is unchanged, so that the gas mole fraction solubility x of the carbon dioxide and the P value change in a positive correlation, while the double-layer membrane in the embodiment can keep the pressure of a buffer area between the first permeable membrane 2 and the second permeable membrane 3 to be P1, and when the P value changes, the pressure in the buffer area can still be kept to be P1, so that the gas mole fraction solubility x1 of the carbon dioxide is kept unchanged, and the concentration stability of the carbonated water is further kept.
Referring to fig. 7 and 8, a modified embodiment of the double-layer membrane filament gas-liquid mixing device disclosed by the invention is different from the previous embodiment in that the gas inlet 111 is connected with the membrane frame assembly 41, the membrane frame assembly 41 comprises a first frame 411 and a second frame 412, the first frame 411 is fixedly connected with the gas inlet 131, the second frame 412 is detachably connected with the first frame 411, the first permeable membrane 4 is clamped between the first frame 411 and the second frame 412, the second permeable membranes 5 which are arranged in a tubular shape are arranged in a plurality and uniformly distributed around the inner wall of the shell 1, and the linear distances between the axes of the second permeable membranes 4 and the axis of the shell 1 are equal.
In the present embodiment, the first permeable membrane 4 still has a lower permeation efficiency than the second permeable membrane 5, and since the first permeable membrane 4 is held by the first frame 411 and the second frame 412 at the air inlet 131, the first permeable membrane 4 covering the air inlet 131 can still have the purpose of allowing the carbon dioxide gas to slowly enter the housing and permeate into the second permeable membrane 5 to dissolve in pure water when carbon dioxide is introduced into the housing through the air inlet 131. In this embodiment, the housing is still composed of the first cover 11, the second cover 12 and the mixing pipe 13, and the mixing pipe 13 is provided with the air outlet 132, so as to avoid a large amount of carbon dioxide escaping from the air outlet 132, and therefore, the air outlet 132 also clamps a piece of the first permeable membrane 4 through the first frame 411 and the second frame 412.
Based on the same thought, the invention discloses a preparation method of a double-layer film yarn, which is shown in a reference chart 9 and comprises the following steps of:
s1, mixing polytetrafluoroethylene resin, an extrusion aid, a super-hydrophobic fluorine-containing material and an optional solvent to form a paste.
And S2, sieving, prepressing and extrusion molding the paste in sequence to form a tubular primary membrane comprising an outer tube and a plurality of inner tubes nested in the outer tube.
S3, performing heat treatment on the tubular primary membrane, and respectively stretching the inner tube and the outer tube at different stretching multiples and then sintering to form the double-layer membrane yarn consisting of the first permeable membrane and the second permeable membrane.
The volume fraction of each component in the paste formed in the step S1 is 30% -40% of polytetrafluoroethylene resin, 20% -30% of extrusion aid, 20% -35% of super-hydrophobic fluorine-containing material and 20% -30% of solvent, wherein the crystallinity of the polytetrafluoroethylene resin is more than or equal to 98%, and the number average molecular weight is 300-900 ten thousand. The super-hydrophobic fluorine-containing material is one or more of fluoroalkyl acrylate polymers with the fluorine content of 5% -50%, fluoroalkyl methacrylate polymers with the fluorine content of 5% -50%, perfluoroalkyl acrylate polymers with the fluorine content of 5% -50% and perfluoroalkyl acrylate polymers with the fluorine content of 5% -50%. Wherein, the volume fractions of the components in the paste in the embodiment are respectively 32 percent of polytetrafluoroethylene resin, 26 percent of extrusion aid, 27 percent of super-hydrophobic fluorine-containing material and 22 percent of solvent,
And S2, sieving, prepressing and finally feeding the paste formed in the step S1 into paste extrusion equipment for extrusion molding to form a tubular primary film comprising an outer pipe and a plurality of inner pipes nested in the outer pipe, wherein one end of the outer pipe perpendicular to the length direction of the inner pipe is adhered, the outer pipe is not contacted with the inner pipe in all positions in the length direction, in the embodiment, the inner diameter of the outer pipe is 2.5 mm-4 mm, the inner diameter of the inner pipe is 0.4-1 mm, and the film thicknesses of the outer pipe and the inner pipe are 0.1-0.4 mm. Specifically, the inner diameter of the outer tube is set to be 2.8mm, the inner diameter of the inner tube is set to be 0.7mm, and the film thicknesses of the outer tube and the inner tube are all set to be 0.25mm.
And S3, carrying out heat treatment on the tubular primary membrane formed in the step S2, wherein the heat treatment temperature is 120 ℃, the stretching temperature is 90 ℃, the stretching multiple of the outer tube is 1-2 times, the stretching multiple of the inner tube is 15-20 times, and sintering the stretched outer tube membrane and inner tube membrane at 320 ℃ for 120min to form a first permeable membrane and a second permeable membrane. The porosity of the first and second permeable membranes and the pore size and the stretching ratio are in a forward relation, when the stretching ratio of the outer tube is 1-2 times, the porosity of the first permeable membrane is 20% -35%, the pore size is 1-2um, in the embodiment, the stretching ratio of the outer tube is 2 times, the porosity of the first permeable membrane is 35%, the pore size is 2um, when the stretching ratio of the inner tube is 15-20 times, the porosity of the second permeable membrane is 40% -55%, the pore size is 4-6um, in the embodiment, the stretching ratio of the inner tube is 20 times, and the porosity of the second permeable membrane is 55%. The pore size was 6um.
Referring to fig. 10 and 11, which are respectively electron microscopic views of the first and second permeable membranes at a magnification of 2000 times, it is understood from comparison of fig. 10 and 11 that the number of permeable pores and the permeable pore diameter of membrane filaments formed by the treated first permeable membrane are smaller than those of membrane filaments formed by the second permeable membrane, so that when carbon dioxide is permeated, the pressure difference between the first and second permeable membranes is more easily formed, thereby achieving the effect of uniformly and slowly dissolving carbon dioxide into pure water to form carbonated water having a certain conductivity in the foregoing embodiments.
The above list of detailed descriptions is only specific to practical embodiments of the present invention, and they are not intended to limit the scope of the present invention, and all equivalent embodiments or modifications that do not depart from the spirit of the present invention should be included in the scope of the present invention.
It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.
Furthermore, it should be understood that although the present disclosure describes embodiments, not every embodiment is provided with a separate embodiment, and that this description is provided for clarity only, and that the disclosure is not limited to the embodiments described in detail below, and that the embodiments described in the examples may be combined as appropriate to form other embodiments that will be apparent to those skilled in the art.