Wide-range capacitive film vacuum gauge

Abstract

The utility model relates to a wide-range capacitive film vacuum gauge, which comprises a shell provided with an accommodating cavity and an air inlet communicated with the accommodating cavity; the elastic membrane is fixed in the accommodating cavity and forms a movable electrode, the accommodating cavity is divided into a vacuum cavity and a detection cavity by the elastic membrane, and the detection cavity is communicated with the air inlet; the fixed electrodes are arranged in the vacuum cavity, the fixed electrodes comprise the first fixed electrode, the second fixed electrode and the third fixed electrode, and the first fixed electrode, the second fixed electrode and the third fixed electrode are arranged with the elastic membrane at intervals to establish a first capacitor, a second capacitor and a third capacitor; spaces are kept among the first capacitor, the second capacitor and the third capacitor; when the elastic diaphragm continuously deforms and contacts with the first fixed electrode, a corresponding signal is output, so that the second fixed electrode and the third fixed electrode are switched to form a differential capacitor pair, the measurement range is expanded, and meanwhile, the situation that multiple measurement technologies are combined into one vacuum gauge, and the measurement precision is reduced is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of measuring instruments, and in particular to a wide-range capacitive diaphragm vacuum gauge. BACKGROUND

[0002] At present, vacuum gauges are applied in various occasions. For example, in the semiconductor manufacturing process, one or more high-precision vacuum gauges are usually used in processes such as dry etching and physical vapor deposition. At present, the high-precision vacuum gauge mainly used is a capacitive diaphragm vacuum gauge. The measurement principle thereof is that gas is introduced into a detection chamber through a gas inlet pipe, the detection diaphragm is deformed due to the action of gas pressure, the distance between the detection diaphragm and a fixed electrode plate is changed, and the capacitance between the two is changed, and then the capacitance is measured by using an electrical method. According to the corresponding relationship between the capacitance change value and the gas change, the corresponding pressure value can be obtained.

[0003] However, in the actual measurement environment, there is often a demand for a larger range. In order to solve this problem, there are two methods at present. One is to use multiple capacitive diaphragm vacuum gauges with different ranges to measure in sections. The other method is to use multiple measurement technologies to form a composite vacuum gauge. The composite vacuum gauge mainly has a combination of Pirani technology and piezoresistance technology or a combination of Pirani technology and capacitive technology. The precision of these technologies is relatively poor compared with the capacitive diaphragm technology.

[0004] Therefore, it is necessary to develop a wide-range capacitive diaphragm vacuum gauge to solve the above problems. CONTENT OF THE UTILITY MODEL

[0005] The utility model aims at providing a wide-range capacitive diaphragm vacuum gauge with high detection precision and a large detection range.

[0006] In order to achieve the above-mentioned purpose, the utility model provides the following technical scheme: a wide-range capacitive diaphragm vacuum gauge, comprising:

[0007] A shell is provided with a receiving cavity and a gas inlet communicating with the receiving cavity;

[0008] An elastic diaphragm is fixed in the receiving cavity and forms a movable electrode. The elastic diaphragm divides the receiving cavity into a vacuum chamber and a detection chamber. The detection chamber is arranged in communication with the gas inlet.

[0009] A fixed electrode is arranged in the vacuum chamber. The fixed electrode comprises a first fixed electrode, a second fixed electrode and a third fixed electrode. The first fixed electrode is arranged in spaced relation with the elastic diaphragm to establish a first capacitance. The second fixed electrode is arranged in spaced relation with the elastic diaphragm to establish a second capacitance. The third fixed electrode is arranged in spaced relation with the elastic diaphragm to establish a third capacitance.

[0010] The first capacitor, the second capacitor and the third capacitor are kept apart.

[0011] Further, the first fixed electrode is located at the center of the vacuum cavity, the second fixed electrode surrounds the first fixed electrode, and the third fixed electrode surrounds the second fixed electrode.

[0012] Further, the first fixed electrode is circular, and the second fixed electrode and the third fixed electrode are annular.

[0013] Further, the shell is provided with a fixing portion, the fixing portion comprises a fixing member and a support member connected with the fixing member, the fixing member is annular, the outer end of the fixing member is abutted and fixedly connected with the inner wall of the shell, the inner side of the fixing member extends to the center of the shell and is connected with the support member, and the support member is circular and is arranged at the center of the shell.

[0014] Further, the first fixed electrode, the second fixed electrode and the third fixed electrode are all mounted on the lower surface of the support member, and the lower surface of the support member extends to the elastic diaphragm.

[0015] Further, the lower surfaces of the first fixed electrode, the second fixed electrode and the third fixed electrode are kept the same distance from the undeformed elastic diaphragm.

[0016] Further, the first fixed electrode, the second fixed electrode and the third fixed electrode are provided with an equal potential structure grounded.

[0017] Further, the outer side of the third fixed electrode is provided with other fixed electrodes, the number of the other fixed electrodes can be changed according to requirements, the other fixed electrodes are annular and surround the third fixed electrode in sequence and keep a distance from the third fixed electrode.

[0018] Compared with the prior art, the wide-range capacitive thin film vacuum gauge has the characteristics of high detection precision and large detection range, the elastic diaphragm continuously deforms and contacts the first fixed electrode, and the corresponding signal is outputted, so that the second fixed electrode and the third fixed electrode are switched to a differential capacitor pair, thereby expanding the measurement range, and multiple measurement technologies are avoided from being combined into one vacuum gauge, and the measurement precision is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical scheme in the embodiments of the present application, the drawings needed to be used in the following embodiment description will be briefly introduced, obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained without creative labor on the basis of these drawings.

[0020] Figure 1 It is a sectional view of the wide-range capacitive diaphragm vacuum gauge of the present application.

[0021] Figure 2 It is a sectional view of the wide-range capacitive diaphragm vacuum gauge of the present application. Figure 1

[0022] It is a sectional view of the wide-range capacitive diaphragm vacuum gauge of the present application. Figure 3 Figure 1 It is a sectional view of the wide-range capacitive diaphragm vacuum gauge of the present application.

[0023] Figure 4 Figure 1 It is a sectional view of the wide-range capacitive diaphragm vacuum gauge of the present application.

[0024] In the figure: 1, housing; 2, elastic diaphragm; 3, fixed electrode; 4, fixed part; 11, accommodating cavity; 12, gas inlet; 111, vacuum cavity; 112, detection cavity; 31, first fixed electrode; 32, second fixed electrode; 33, third fixed electrode; 41, fixed part; 42, support part. DETAILED DESCRIPTION

[0025] The technical scheme in the embodiments of the present application will be described clearly and completely in combination with the drawings of the embodiments of the present application, obviously, the described embodiments are only some embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0026] Please refer to Figures 1 to 4 The present application is a wide-range capacitive diaphragm vacuum gauge, which comprises a housing 1, an elastic diaphragm 2 and a fixed electrode 3 arranged in the housing 1, and a fixed part 4 supporting the fixed electrode 3.

[0027] Please refer to Figures 1 to 2 The housing 1 is internally formed with an accommodating cavity 11, and the elastic diaphragm 2 and the fixed electrode 3 are both mounted in the accommodating cavity 11. The housing 1 is further provided with a gas inlet 12, which is in communication with the accommodating cavity 11.

[0028] Please refer to Figures 1 to 2 ​​The elastic diaphragm 2 has the same shape as the cross section of the shell 1, and its outer end is fixedly connected to the inner wall of the shell 1 to divide the accommodating cavity 11 into a vacuum cavity 111 and a detection cavity 112. The fixed electrode 3 is arranged in the vacuum cavity 111, and the gas inlet 12 is communicated with the detection cavity 112.

[0029] The elastic diaphragm 2 is made of conductive material and forms a movable electrode.

[0030] Please refer to Figures 1 to 2 The fixed electrode 3 includes a first fixed electrode 31, a second fixed electrode 32 located outside the first fixed electrode 31, and a third fixed electrode 33 located outside the second fixed electrode 32. The first fixed electrode 31 is arranged in a spaced manner with the elastic diaphragm 2 to form a first capacitor. The second fixed electrode 32 is arranged in a spaced manner with the elastic diaphragm 2 to form a second capacitor. The third fixed electrode 33 is arranged in a spaced manner with the elastic diaphragm 2 to form a third capacitor.

[0031] Specifically, the first fixed electrode 31 is circular and located at the center of the vacuum cavity 111. The second fixed electrode 32 is annular and arranged around the first fixed electrode 31. The first fixed electrode 31 is spaced apart from the second fixed electrode 32 by a certain distance. The third fixed electrode 33 is annular and arranged around the second fixed electrode 32. The second fixed electrode 32 is spaced apart from the third fixed electrode 33 by a certain distance.

[0032] The fixed part 4 includes a fixed piece 41 and a support piece 42 connected to the fixed piece 41. The fixed piece 41 is annular, and its outer end is abutted and fixedly connected to the inner wall of the shell 1. The inner side extends to the center of the shell 1 and is connected to the support piece 42. The support piece 42 is circular and arranged at the center of the shell 1 and fixedly connected to the fixed piece 41. The fixed piece 41 and the support piece 42 are both parallel to the undeformed elastic diaphragm 2. The first fixed electrode 31, the second fixed electrode 32, and the third fixed electrode 33 are all mounted on the lower surface of the support piece 42. The upper surface of the support piece 42 is fixedly connected to the support piece 42, and the lower surface extends to the elastic diaphragm 2. The lower surfaces of the first fixed electrode 31, the second fixed electrode 32, and the third fixed electrode 33 are all at the same distance from the undeformed elastic diaphragm 2.

[0033] In another embodiment, an equipotential structure (not shown) is arranged between the first fixed electrode 31, the second fixed electrode 32, and the third fixed electrode 33. The equipotential structure can reduce the influence between the first fixed electrode 31, the second fixed electrode 32, and the third fixed electrode 33 caused by the edge effect, thereby improving the sensitivity.

[0034] In another embodiment, other fixed electrodes (not shown) are arranged outside the third fixed electrode 33. The number of the other fixed electrodes can be changed according to requirements. The other fixed electrodes are annular and arranged around the third fixed electrode 33 in sequence and maintain a certain distance from the third fixed electrode 33.

[0035] Please refer to Figures 3 to 4 The wide-range capacitive diaphragm vacuum gauge has the characteristics of high detection precision and large detection range, the elastic diaphragm continuously deforms and contacts the first fixed electrode, corresponding signals are outputted, the second fixed electrode and the third fixed electrode are switched to form a differential capacitor pair, the measurement range is expanded, and multiple measurement technologies are avoided from being combined into one vacuum gauge, and the measurement precision is reduced.

[0036] The wide-range capacitive diaphragm vacuum gauge has the characteristics of high detection precision and large detection range, the elastic diaphragm continuously deforms and contacts the first fixed electrode, corresponding signals are outputted, the second fixed electrode and the third fixed electrode are switched to form a differential capacitor pair, the measurement range is expanded, and multiple measurement technologies are avoided from being combined into one vacuum gauge, and the measurement precision is reduced.

[0037] The wide-range capacitive diaphragm vacuum gauge has the characteristics of high detection precision and large detection range, the elastic diaphragm continuously deforms and contacts the first fixed electrode, corresponding signals are outputted, the second fixed electrode and the third fixed electrode are switched to form a differential capacitor pair, the measurement range is expanded, and multiple measurement technologies are avoided from being combined into one vacuum gauge, and the measurement precision is reduced.

Claims

1. A wide-range capacitive thin-film vacuum gauge, characterized in that, It includes: The outer casing (1) is provided with a receiving cavity (11) and an air inlet (12) communicating with the receiving cavity (11); An elastic diaphragm (2) is fixed inside the receiving cavity (11) and forms a movable electrode. The elastic diaphragm (2) divides the receiving cavity (11) into a vacuum cavity (111) and a detection cavity (112). The detection cavity (112) is connected to the air inlet (12). A fixed electrode (3) is disposed in the vacuum cavity (111). The fixed electrode (3) includes a first fixed electrode (31), a second fixed electrode (32), and a third fixed electrode (33). The first fixed electrode (31) is spaced apart from the elastic diaphragm (2) to form a first capacitor. The second fixed electrode (32) is spaced apart from the elastic diaphragm (2) to form a second capacitor. The third fixed electrode (33) is spaced apart from the elastic diaphragm (2) to form a third capacitor. The first capacitor, the second capacitor, and the third capacitor maintain a distance from each other.

2. The wide-range capacitive thin-film vacuum gauge according to claim 1, characterized in that, The first fixed electrode (31) is located at the center of the vacuum cavity (111), the second fixed electrode (32) surrounds the first fixed electrode (31), and the third fixed electrode (33) surrounds the second fixed electrode (32).

3. The wide-range capacitive thin-film vacuum gauge according to claim 2, characterized in that, The first fixed electrode (31) is circular, while the second fixed electrode (32) and the third fixed electrode (33) are both annular.

4. The wide-range capacitive thin-film vacuum gauge according to claim 1, characterized in that, The outer shell (1) is provided with a fixing part (4), the fixing part (4) includes a fixing member (41) and a support member (42) connected to the fixing member (41). The fixing member (41) is annular, its outer end abuts against and is fixedly connected to the inner wall of the outer shell (1), and its inner side extends towards the center of the outer shell (1) and is connected to the support member (42). The support member (42) is circular and is located at the center of the outer shell (1).

5. The wide-range capacitive thin-film vacuum gauge according to claim 4, characterized in that, The first fixed electrode (31), the second fixed electrode (32), and the third fixed electrode (33) are all mounted on the lower surface of the support (42), and the lower surface extends toward the elastic diaphragm (2).

6. The wide-range capacitive thin-film vacuum gauge according to claim 5, characterized in that, The lower surfaces of the first fixed electrode (31), the second fixed electrode (32), and the third fixed electrode (33) are at the same distance from the undeformed elastic diaphragm (2).

7. The wide-range capacitive thin-film vacuum gauge according to claim 1, characterized in that, A grounded equipotential structure is provided between the first fixed electrode (31), the second fixed electrode (32), and the third fixed electrode (33).

8. The wide-range capacitive thin-film vacuum gauge according to claim 1, characterized in that, Other fixed electrodes are provided on the outside of the third fixed electrode (33). The number of other fixed electrodes can be changed according to the requirements. The other fixed electrodes are in a ring shape, which surround the third fixed electrode (33) in sequence and maintain a distance from the third fixed electrode (33).

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