CN217765424U - Pressure maintaining cabin and air tightness testing device - Google Patents

Abstract

The utility model provides a pressure maintaining cabin and an air tightness testing device, wherein the pressure maintaining cabin comprises a cabin body, a self-checking sealing cover, an ear type support and a plurality of fasteners; wherein the top of the cabin body is provided with an opening, and the side wall of the cabin body is provided with at least one ventilation interface; the self-checking sealing cover is arranged at the opening in an attaching mode; the ear type support is arranged on the periphery of the side wall of the cabin body close to the opening; wherein, a plurality of screw holes are arranged on the ear type support, and the direction of the screw-in opening of the screw holes is the same as the direction of the opening of the cabin body; the fastening piece is connected with the screw hole so as to fasten the self-checking sealing cover on the cabin body. Through the utility model discloses a keep warm cabin and gas tightness testing arrangement has solved among the prior art problem that the ion source leakproofness test is long consuming time, inefficiency.

Description

Pressure maintaining cabin and air tightness testing device

Technical Field

The utility model relates to a semiconductor equipment field especially relates to a pressurize cabin and gas tightness testing arrangement.

Background

An ion implantation apparatus is an apparatus essential in a semiconductor process, wherein an ion source in the ion implantation apparatus is a device that ionizes neutral atoms or molecules and extracts an ion beam from the ionized neutral atoms or molecules. Because of the requirement of the process, the ion source works in a high vacuum environment and is fixedly arranged on a sealing plate, and the sealing ring and the screw hole are arranged on the ion source sealing plate; the cavity of the ion implantation equipment is correspondingly provided with a cavity door, and the ion source is directly installed and fixed in the cavity through an ion source sealing plate.

The ion source needs to be connected with various gas pipelines and electric pipelines, such as electrode access, a cooling loop, an air supply pipeline and a solid evaporator; therefore, ion source sealing plates are provided with various flanges and interfaces. When the ion source is disassembled for maintenance, the flanges, the interfaces and the pipelines are also disassembled, and the situation of air leakage may exist after the ion source is re-assembled, which affects the tightness of the cavity, so that the airtightness test of the ion source is required.

The current process of the airtightness test after ion source maintenance comprises the following steps: firstly, after ion source maintenance and assembly are finished, appearance is checked, drying is carried out, and insulativity is checked; then, the ion source is loaded into ion implantation equipment; and vacuumizing a cavity of the ion implantation equipment, observing a vacuum reading value and preliminarily judging the sealing performance of the whole system.

Once the problem of air tightness exists, a helium detector is required to be matched with helium to spray helium, each position of the cavity is tested point by point, and the position of poor air tightness of the cavity is judged, the point-by-point testing process is extremely complicated, and the time is spent for 3-24 hours according to general experience; moreover, when the point-by-point test confirms that the air tightness of the ion source is poor, the vacuum system needs to be broken to be vacuumized to the atmospheric environment, the ion source needs to be taken out again, and the air tightness needs to be tested again after the inspection and the maintenance, so that the maintenance efficiency of the equipment is seriously influenced.

SUMMERY OF THE UTILITY MODEL

In view of the above shortcomings of the prior art, an object of the present invention is to provide a pressure-holding chamber and air tightness testing device for solving the problems of long time consumption and low efficiency in the ion source tightness test in the prior art.

In order to realize above-mentioned purpose and other relevant purposes, the utility model provides a pressurize cabin, the pressurize cabin includes: the self-checking sealing cover is arranged on the cabin body; wherein, the first and the second end of the pipe are connected with each other,

the top of the cabin body is provided with an opening, and the side wall of the cabin body is provided with at least one ventilation interface;

the self-checking sealing cover is arranged at the opening in an attaching mode;

the ear type support is arranged on the periphery of the side wall of the cabin body close to the opening; wherein, a plurality of screw holes are arranged on the ear type support, and the direction of the screw-in opening of the screw holes is the same as the direction of the opening of the cabin body;

the fastening piece is connected with the screw hole so as to fasten the self-checking sealing cover on the cabin body.

Optionally, the sealed lid of self-checking still includes the sealing washer, the sealed lid of self-checking with open-ended laminating region is provided with the recess, the sealing washer sets up in the recess.

Optionally, the fastener comprises a plurality of screws and a plurality of L-shaped copper buttons, wherein,

the L-shaped copper buckle comprises a fixing force arm and an inner buckle force arm which are perpendicular to each other, and the fixing force arm is connected with the ear type support through the screw; and a counter bore is arranged in the fixed force arm, and the screw penetrates through the counter bore and is connected with the screw hole.

Optionally, the fastener further comprises a number of springs; the spring is arranged in the counter bore, and the screw penetrates through the spring and the counter bore and is connected with the screw hole.

Optionally, at least one positioning pin is further arranged on the ear type support, and the positioning pin is arranged on the ear type support, and the self-checking sealing cover is attached to the attaching area of the opening.

The utility model also provides an airtightness testing device, testing arrangement include preceding the pressurize chamber.

Optionally, the testing apparatus further comprises: the air pressure gauge, the pressure limiting valve and the air release valve are arranged on the side wall of the cabin body; wherein the content of the first and second substances,

the barometer, the pressure limiting valve and the deflation valve are respectively communicated with the cabin body through three different ventilation interfaces, and the rest ventilation interface is used as an inflation inlet.

Optionally, the testing apparatus further comprises: the air-pressure measuring cabin comprises a ventilation pipeline, an air pressure meter, a pressure limiting valve and an air release valve, wherein the side wall of the cabin body is provided with a ventilation interface, and the ventilation pipeline is provided with five air interfaces; wherein the content of the first and second substances,

the barometer, the pressure limiting valve, the deflation valve and the ventilation interface are respectively communicated with the ventilation pipeline through four gas interfaces, and the rest gas interface is used as an inflation inlet.

Optionally, the testing apparatus further comprises: the air-release cabin comprises a ventilation pipeline, an air pressure meter, a pressure limiting valve and an air release valve, wherein two ventilation interfaces are arranged on the side wall of the cabin body, and the ventilation pipeline is provided with four air interfaces; wherein, the first and the second end of the pipe are connected with each other,

the barometer, the pressure limiting valve, the deflation valve and one of the ventilation interfaces are respectively communicated with the ventilation pipeline through four gas interfaces, and the rest ventilation interface is used as an inflation inlet.

Optionally, the testing apparatus further comprises: the air-pressure measuring cabin comprises a ventilation pipeline, an air pressure meter, a pressure limiting valve and an air release valve, wherein the side wall of the cabin body is provided with three ventilation interfaces, and the ventilation pipeline is provided with three air interfaces; wherein, the first and the second end of the pipe are connected with each other,

and one ventilation interface is communicated with the ventilation pipeline through one gas interface, two of the barometer, the pressure limiting valve and the deflation valve are respectively communicated with the ventilation pipeline through the remaining two gas interfaces, the remaining one of the barometer, the pressure limiting valve and the deflation valve is communicated with one of the remaining two ventilation interfaces, and the last ventilation interface is used as an inflation inlet.

As above, the utility model discloses a pressurize cabin and gas tightness testing arrangement has following beneficial effect:

1. by providing the pressure-maintaining chamber, the air tightness of the ion source can be independently tested outside the cavity of the equipment, the testing mode is simple, the efficiency is high, once the air tightness of the ion source is poor, the ion source can be directly maintained without breaking vacuum of the equipment, and the ion source is repeatedly disassembled;

2. through providing the pressure-maintaining chamber, the ion source need not install the test on equipment, and its gas tightness can not influence the gas tightness of equipment, avoids staff's erroneous judgement, has improved work efficiency.

Drawings

Fig. 1 shows a schematic structural view of the pressure-holding chamber of the present invention.

Fig. 2 shows a front view of the ballast according to the present invention.

Fig. 3 shows the cabin and the ear-type support of the present invention.

Fig. 4 shows the front view of the integrated structure of the cabin and the ear-type support of the present invention.

Fig. 5 is a front view of the self-checking sealing cover of the present invention.

Fig. 6 shows a schematic structural diagram of the self-checking sealing cover of the present invention.

Fig. 7 shows a top view of the fastener of the present invention.

Fig. 8 shows a schematic structural view of the fastener of the present invention.

Figure 9 shows a piping diagram for testing the air tightness by using the air tightness testing device of the present invention.

Description of the reference numerals

1. Air tightness testing device

10. Pressure-maintaining cabin

100. Cabin body

110. Ventilation interface

200. Self-checking sealing cover

210. Groove

211. Sealing ring

300. Ear type support

310. Screw hole

320. Locating pin

400. Fastening piece

410. Screw nail

420 L-shaped copper buckle

421. Counter bore

422. Fixed force arm

423. Inner buckle force arm

430. Spring

20. Air pressure meter

30. Pressure limiting valve

40. Air release valve

50. Air charging port

60. Ventilation pipeline

Detailed Description

The following embodiments of the present invention are provided by way of specific examples, and other advantages and effects of the present invention will be readily apparent to those skilled in the art from the disclosure herein. The present invention can also be implemented or applied through other different specific embodiments, and various details in the present specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

Please refer to fig. 1 to 9. It should be understood that the structure, ratio, size and the like shown in the drawings attached to the present specification are only used for matching with the content disclosed in the specification, so as to be known and read by those skilled in the art, and are not used for limiting the limit conditions that the present invention can be implemented, so that the present invention has no technical essential meaning, and any structure modification, ratio relationship change or size adjustment should still fall within the scope that the technical content disclosed in the present invention can cover without affecting the function that the present invention can produce and the purpose that the present invention can achieve. Meanwhile, the terms such as "upper", "lower", "left", "right", "middle" and "one" used in the present specification are for convenience of description, and are not intended to limit the scope of the present invention, and changes or adjustments of the relative relationship thereof may be made without substantial technical changes, and the present invention is also regarded as the scope of the present invention.

For ease of description, spatially relative terms such as "above … …", "above … …", "above … … upper surface", "above", etc. may be used herein to describe the spatial positional relationship of one device or feature to other devices or features as shown in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is turned over, devices described as "above" or "on" other devices or configurations would then be oriented "below" or "under" the other devices or configurations. Thus, the exemplary term "above … …" may include both orientations of "above … …" and "below … …". The device may be otherwise variously oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

As shown in fig. 1 to 8, the present embodiment provides a pressure-holding capsule 10, the pressure-holding capsule 10 including: the capsule body 100, the self-checking sealing cover 200, the ear type support 300 and a plurality of fasteners 400.

The cabin 100 is provided with an opening at the top and at least one ventilation port 110 at the side wall.

In this embodiment, the ion source is installed into the chamber 100 from the opening, and the chamber 100 and the sealing cover of the ion source form a closed space together to simulate a completely sealed chamber environment; the vent interface 110 is used to communicate with external piping and devices to test the sealing performance of the ion source. In practical applications, the number of the ventilation ports 110 can be flexibly adjusted according to the number of external pipes and devices. As an example, as shown in fig. 2 and 3, the cabin 100 is a cylindrical structure, and the number of the ventilation ports is 1.

The self-checking sealing cover 200 is attached to the opening.

In this embodiment, the self-checking sealing cover 200 is used to ensure the sealing performance of the capsule 100 before testing the sealing performance of the ion source, the region where the self-checking sealing cover is attached to the capsule 100 should be a finish-milled surface, and the two finish-milled surfaces are tightly attached to each other to ensure the sealing performance.

Specifically, as shown in fig. 4 and 5, the self-testing sealing cover 200 further includes a sealing ring 211, a groove 210 is disposed in a bonding region between the self-testing sealing cover 200 and the opening, and the sealing ring 211 is disposed in the groove 210 for ensuring the sealing performance of the cabin 100. The number of the seal rings 211 may be plural, and the plural seal rings can ensure the sealing performance more effectively.

The ear mount 300 is disposed on the outer periphery of the sidewall of the cabin 100 near the opening; wherein, a plurality of screw holes 310 are provided on the ear mount 300, and the screw-in direction of the screw holes 310 is the same as the opening direction of the cabin 100.

In this embodiment, as shown in fig. 1, the screw holes 310 are matched with the fastening members 400 to connect and fasten the self-testing sealing cover 200 and the cabin 100. As an example, as shown in fig. 4 and 5, the ear mount 300 is a one-piece structure with the cabin 100, and surrounds the periphery of the sidewall of the cabin 100 near the opening, and the number of the screw holes 310 is 4, and they are equally spaced on the circumference of the side ear 120. As shown in fig. 4, the plane on which the upper surface of the ear mount 300 is located is flush with the plane on which the opening of the cabin 100 is located, and when the diameter of the self-testing sealing cover 200 is larger than the outer diameter of the cabin 100, the upper surface of the ear mount 300 is also attached to the opening.

Specifically, the ear mount 300 is provided with at least one positioning pin 320, and the positioning pin 320 is arranged on the ear mount 300, and the self-testing sealing cover 200 is attached to the attachment area of the opening.

In this embodiment, the positioning pin 320 plays a role in assisting positioning during the process of attaching the insulation can 100 to the ion source sealing cover; as an example, as shown in fig. 3 and 4, the ear mount 300 is provided with two positioning pins 320, which are disposed on the circumference of the ear mount 300 at an interval of 180 °, and the sealing cover of the ion source is also provided with 2 positioning holes correspondingly, which are used in cooperation with the positioning pins 320.

The fastening members 400 are coupled to the screw holes 310 to fasten the self-testing sealing cover 200 to the cabin 100.

Specifically, as shown in fig. 7 and 8, the fastening member 400 includes a plurality of screws 410 and a plurality of L-shaped copper buttons 420; the L-shaped copper buckle 420 comprises a fixing force arm 422 and an inner buckle force arm 423 which are perpendicular to each other, and the fixing force arm 422 is connected with the ear type support 300 through the screw 410; a counter bore 421 is arranged in the fixing force arm 422, and the screw 410 penetrates through the counter bore 421 and is connected with the screw hole 310.

More specifically, the fastener 400 further includes a plurality of springs 430; the spring 430 is disposed in the counterbore 421, and the screw 410 penetrates the spring 430 and the counterbore 421 and is connected with the screw hole 310.

In this embodiment, as shown in fig. 7, the screw 410, the spring 430 and the L-shaped copper buckle 420 are used in cooperation, and the screw 410 penetrates through the spring 430 and the counter bore 421 and is fixed in the screw hole 310 of the ear support 300, so that the spring 430 is pressed tightly and has a certain elastic force; after the sealing cover 200 or the sealing cover of the ion source is attached to the opening, the L-shaped copper fastener 420 is rotated to make the inner fastening arm 423 fastened above the cover, so that the sealing cover 200 can be attached to the opening of the cabin 100 tightly by the elastic force of the spring 420, and the elastic force of the spring 220 can be adjusted by adjusting the screwing depth of the screw 210.

As shown in fig. 8, the present embodiment further provides an air-tightness testing device 1, wherein the testing device 1 comprises the holding pressure chamber 10 as described above.

Specifically, the test apparatus 1 further includes: a barometer 20, a pressure limiting valve 30 and a deflation valve 40.

In this embodiment, the barometer 20 is used to monitor the gas pressure inside the ballast 10; the pressure limiting valve 30 is used to ensure that the pressure of the gas within the ballast 10 is less than a certain value, such as less than 202Kpa; the deflation valve 40 is used for actively exhausting the gas in the holding pressure chamber 10, so that the holding pressure chamber 10 is restored to the atmospheric environment.

More specifically, the present embodiment provides four examples showing the communication between the air pressure gauge 20, the pressure limiting valve 30 and the air release valve 40 with the holding pressure chamber 10.

In an example, four ventilation ports 110 are provided on the side wall of the cabin 100. The barometer 20, the pressure limiting valve 30 and the deflation valve 40 are respectively communicated with the cabin 100 through three different ventilation interfaces 110, the remaining ventilation interface 110 is used as an inflation inlet 50, and the inflation inlet 50 is used as a gas inflow port of the pressure-maintaining cabin 10.

In the second example, the testing apparatus 1 further comprises a ventilation pipeline 60, the ventilation pipeline 60 has five air interfaces 61, and in this case, the sidewall of the cabin 100 is provided with one ventilation interface 110. The ventilation interface 110, the barometer 20, the pressure limiting valve 30 and the deflation valve 40 are respectively communicated with the ventilation pipeline 60 through four gas interfaces 61, and the remaining one of the gas interfaces 61 is used as a charging port 50.

In the third example, the testing apparatus 1 further includes a ventilation pipeline 60, the ventilation pipeline 60 has four air interfaces 61, and in this case, two ventilation interfaces 110 are disposed on the side wall of the cabin 100. One of the ventilation ports 110, the barometer 20, the pressure limiting valve 30 and the air release valve 40 is respectively communicated with the ventilation pipeline 60 through four of the gas ports 61, and the remaining one of the ventilation ports 110 is used as an inflation port 50.

In the fourth example, the testing apparatus 1 further includes a ventilation pipeline 60, the ventilation pipeline 60 has three air ports 61, and in this case, the side wall of the chamber 100 is provided with three ventilation ports 110.

One of the ventilation ports 110 is communicated with the ventilation pipeline 60 through one of the gas ports 61, two of the barometer 20, the pressure limiting valve 30 and the air release valve 40 are respectively communicated with the ventilation pipeline 60 through the remaining two of the gas ports 61, the remaining one of the barometer 20, the pressure limiting valve 30 and the air release valve 40 is communicated with one of the remaining two of the ventilation ports 110, and the last ventilation port 110 is used as the air charging port 50.

Next, referring to fig. 1 to 9, a process of testing the airtightness of the ion source by the ballast 10 and the airtightness testing apparatus 1 according to this embodiment will be described.

As an example thereof, the procedure for testing the airtightness of the ion source using the pressure holding chamber 10 is as follows:

s1: attaching the self-checking sealing cover 200 to the cabin body 100, and fastening the cabin body 100 and the self-checking sealing cover 200 through a fastening piece 400 to ensure the sealing property of the ballast 10;

s2: introducing high-pressure gas through the ventilation interface 110, observing the barometer 20, and if the gas pressure in the pressure maintaining chamber 10 can be between 150Kpa and 202Kpa, performing the next operation, otherwise, checking the self-sealing performance of the gas tightness testing device 1;

s3: opening the ventilation interface 110 to restore the normal pressure of the pressure maintaining cabin 10, and taking out the self-checking sealing cover 200;

s4: putting the side of the ion source which needs to be put into the chamber into the ballast 10, and fastening the cabin 100 and the sealing cover of the ion source by a fastener 400 to ensure the sealing performance of the ballast 10;

s5: the vent 110 is connected to a helium detector, and the pressure-maintaining chamber 10 is evacuated to a certain pressure, such as 1 × 10 ^-3 mbar；

S6: helium was spot-sprayed outside the holding tank 10 using a helium spray gun to measure leak rates at different locations.

As another example, the flow of testing the airtightness of the ion source using the airtightness testing apparatus 1 is as follows:

k1: attaching the self-checking sealing cover 200 to the cabin body 100, and fastening the cabin body 100 and the self-checking sealing cover 200 through a fastening piece 400 to ensure the sealing property of the ballast 10;

k2: introducing high-pressure gas through the charging port 50, observing the barometer 20, and if the gas pressure in the pressure maintaining chamber 10 can be between 150Kpa and 202Kpa, performing the next operation, otherwise, checking the self-sealing performance of the gas tightness testing device 1;

k3: opening the air release valve 40 to restore the normal pressure of the pressure maintaining cabin 10, and taking out the self-checking sealing cover 200;

k4: putting the side of the ion source which needs to be put into the chamber into the pressure-holding chamber 10, and fastening the chamber body 100 and the ion source sealing cover through a fastener 400 to ensure the sealing property of the pressure-holding chamber 10;

k5: closing the deflation valve 40, introducing compressed gas through the inflation inlet 50 to enable the pressure value in the pressure maintaining cabin 100 to be 202Kpa, then closing the inflation inlet 50 and starting timing;

k6: and observing the reading of the barometer 20 after ten minutes, if the reading is unchanged, the airtightness of the ion source is proved to be good, and if the pressure is observed to be reduced, a leakage point is checked and the ion source is overhauled.

To sum up, the pressure maintaining cabin and the air tightness testing device of the utility model can realize the independent test of the air tightness of the ion source outside the cavity of the device by providing the pressure maintaining cabin, have simple testing mode and high efficiency, can be directly maintained once the air tightness of the ion source is poor, do not need to break the vacuum of the device, and repeatedly disassemble the ion source; in addition, the ion source does not need to be installed on equipment for testing, the air tightness of the equipment cannot be affected by the air tightness of the ion source, misjudgment of workers is avoided, and the working efficiency is improved. Therefore, the utility model effectively overcomes various defects in the prior art and has high industrial utilization value.

The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Modifications and variations can be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which may be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.

Claims (10)

1. A pressure-holding chamber, characterized in that the pressure-holding chamber comprises: the self-checking sealing cover is arranged on the cabin body; wherein, the first and the second end of the pipe are connected with each other,

the top of the cabin body is provided with an opening, and the side wall of the cabin body is provided with at least one ventilation interface;

the self-checking sealing cover is arranged at the opening in an attaching mode;

the ear type support is arranged on the periphery of the side wall of the cabin body close to the opening; wherein, a plurality of screw holes are arranged on the ear type support, and the direction of the screw-in opening of the screw holes is the same as the direction of the opening of the cabin body;

the fastening piece is connected with the screw hole so as to fasten the self-checking sealing cover on the cabin body.

2. The pressure maintaining cabin of claim 1, wherein the self-checking sealing cover further comprises a sealing ring, a groove is formed in an attaching area of the self-checking sealing cover and the opening, and the sealing ring is arranged in the groove.

3. The capsule according to claim 1, characterized in that the fasteners comprise a number of screws and a number of L-shaped copper buttons, wherein,

the L-shaped copper buckle comprises a fixing force arm and an inner buckle force arm which are perpendicular to each other, and the fixing force arm is connected with the ear type support through the screw; and a counter bore is arranged in the fixed force arm, and the screw penetrates through the counter bore and is connected with the screw hole.

4. The ballast of claim 3, wherein the fastener further comprises a plurality of springs;

the spring is arranged in the counter bore, and the screw penetrates through the spring and the counter bore and is connected with the screw hole.

5. The holding pressure cabin according to claim 1, wherein the ear support is further provided with at least one positioning pin, and the positioning pin is arranged on the ear support in an attaching area of the self-checking sealing cover and the opening.

6. An airtightness testing apparatus, characterized in that the testing apparatus comprises the holding chamber according to any one of claims 1 to 5.

7. The airtightness testing apparatus according to claim 6, further comprising: the air pressure gauge, the pressure limiting valve and the air release valve are arranged on the side wall of the cabin body; wherein the content of the first and second substances,

the barometer, the pressure limiting valve and the deflation valve are respectively communicated with the cabin body through three different ventilation interfaces, and the rest ventilation interface is used as an inflation inlet.

8. The airtightness testing apparatus according to claim 6, further comprising: the side wall of the cabin body is provided with a ventilation interface, and the ventilation pipeline is provided with five gas interfaces; wherein the content of the first and second substances,

the barometer, the pressure limiting valve, the deflation valve and the ventilation interface are respectively communicated with the ventilation pipeline through four gas interfaces, and the rest gas interface is used as an inflation inlet.

9. The airtightness testing apparatus according to claim 6, further comprising: the air-release cabin comprises a ventilation pipeline, an air pressure meter, a pressure limiting valve and an air release valve, wherein two ventilation interfaces are arranged on the side wall of the cabin body, and the ventilation pipeline is provided with four air interfaces; wherein the content of the first and second substances,

the barometer, the pressure limiting valve, the deflation valve and one of the ventilation interfaces are respectively communicated with the ventilation pipeline through four gas interfaces, and the rest ventilation interface is used as an inflation inlet.

10. The airtightness testing apparatus according to claim 6, further comprising: the side wall of the cabin body is provided with three ventilation ports, and the ventilation pipeline is provided with three gas ports; wherein the content of the first and second substances,

and one ventilation interface is communicated with the ventilation pipeline through one gas interface, two of the barometer, the pressure limiting valve and the deflation valve are respectively communicated with the ventilation pipeline through the remaining two gas interfaces, the remaining one of the barometer, the pressure limiting valve and the deflation valve is communicated with one of the remaining two ventilation interfaces, and the last ventilation interface is used as an inflation inlet.

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