Device and calibration method for testing the internal atmosphere of a sealed, small vacuum cavity

Abstract

This invention discloses an internal atmosphere testing device and calibration method for a sealed micro-vacuum cavity. The testing device includes a calibration mechanism, a puncture mechanism, and a testing and analysis mechanism connected in sequence. It utilizes the puncture mechanism to destroy the sample, achieving advantages such as high accuracy and wide application range. It uses a leak with extremely low leakage rate and a time-of-flight mass spectrometer to build the measurement and analysis mechanism, improving the device's testing sensitivity and ability to distinguish different gas components, and expanding the device's measurable range. The calibration method involves passing a gas of known mass into the testing device to verify the accuracy of the results and derive the deviation coefficient of the test data.

Description

Technical Field

[0001] This invention belongs to the field of vacuum technology, and more specifically, it is a device and calibration method for testing the internal atmosphere of a sealed micro vacuum cavity. Background Technology

[0002] With the rapid development of vacuum technology, sealed micro-vacuum cavities have been increasingly applied to products and facilities across various fields, becoming an indispensable prerequisite. Particularly in the semiconductor industry, the development and application of semiconductor integrated circuits in recent years have placed higher demands on semiconductor devices in cutting-edge technological fields—minimal size, long-term reliability, and extended service life. The advantages of sealed micro-vacuum cavities can fully meet these requirements. A good vacuum environment can control the composition and content of gases in contact with electronic components, while also isolating heat and limiting the operating temperature range of electronic components. Therefore, more and more sealed micro-vacuum cavities are being used in semiconductor devices.

[0003] Abnormal atmosphere or excessively high levels of a certain component within a sealed, tiny vacuum cavity can severely impact the performance, lifespan, and reliability of electronic components. For example, excessive moisture content inside the cavity may cause condensation on the electronic components, leading to leakage and affecting insulation performance. Therefore, accurately measuring the pressure and gas composition inside a sealed cavity has become an essential testing method in the production and testing of semiconductor electronic components.

[0004] Current internal atmosphere testing devices for cavities have several shortcomings, including: they can only detect a limited number of samples and can only be applied to specific samples; they have low pressure detection sensitivity and low ability to distinguish different gas components; they have a limited measurement range, with most devices only able to detect samples larger than 1 cc; and they have low measurement accuracy and lack calibration experiments for the testing devices. Summary of the Invention

[0005] To overcome the aforementioned shortcomings, this invention provides an internal atmosphere testing device and calibration method for a sealed micro-vacuum cavity. By assembling a puncture unit and a support platform, precise puncture and destruction of the sealed micro-vacuum cavity is achieved. A testing and analysis mechanism is constructed using a leak with an extremely low leakage rate and a time-of-flight mass spectrometer, improving the device's testing sensitivity and ability to distinguish different gas components, and expanding the measurement range. A calibration chamber is built using two ball valves, allowing a controllable gas of known volume and pressure to be introduced into the internal atmosphere testing device, simulating the puncture detection process of the sealed micro-vacuum cavity, completing the device calibration experiment, and verifying the accuracy of the internal atmosphere testing device's test results.

[0006] To achieve its objectives, the present invention employs the following technical solution:

[0007] This invention relates to an internal atmosphere testing device for a sealed, micro-vacuum cavity, comprising a calibration mechanism, a puncture mechanism, and a testing and analysis mechanism connected in sequence. The calibration mechanism includes a pre-calibration chamber and a calibration chamber. The pre-calibration chamber has three flange interfaces: front interface A, front interface B, and front interface C. Front interface A is fitted with a first full-range vacuum gauge; front interface B is connected to a rotary vane pump via a first angle valve; and front interface C is connected to one end of the calibration chamber. The calibration chamber consists of a first ball valve, a second ball valve, and a stainless steel tube connecting the two. The volume of the calibration chamber is adjusted by installing stainless steel tubes of different lengths and inner diameters. The other end of the calibration chamber is connected to the puncture mechanism.

[0008] The piercing mechanism includes a piercing unit and a sample carrying platform. The piercing unit has four flange interfaces: unit interface A, unit interface B, unit interface C, and unit interface D. Unit interface A is equipped with a second full-range vacuum gauge, unit interface B is connected to the sample carrying platform, unit interface C is connected to the calibration chamber, and unit interface D is connected to the testing and analysis mechanism. The piercing unit uses an all-metal angle valve shell, with the sealing copper gasket of the all-metal angle valve replaced by a tungsten carbide drill bit. The sample carrying platform is a vacuum knife-edge blind flange, with a cuboid groove at its center for supporting and positioning the sample to be tested.

[0009] The testing and analysis facility includes an analysis chamber with five flange interfaces: analysis interface A, analysis interface B, analysis interface C, analysis interface D, and analysis interface E. Analysis interface A is connected to a cold cathode ionization vacuum gauge, analysis interface B is connected to a time-of-flight mass spectrometer, analysis interface C is connected to a molecular pump assembly via a fourth angle valve, analysis interface D is connected to a second angle valve, and analysis interface E is connected to a third angle valve. The second angle valve is connected to a minimum leakage rate orifice.

[0010] Preferably, the first ball valve and the second ball valve are connected by a stainless steel pipe. Polytetrafluoroethylene (PTFE) ferrules are used to clamp the stainless steel pipe onto the ball valve connector with ferrules. A torque of 2 N·m is applied with a torque wrench to tighten the ferrules and complete the connection and installation.

[0011] Preferably, the tungsten carbide drill bit is threaded;

[0012] Preferably, the shape and depth of the cuboid groove inside the blind flange are machined according to the three-dimensional dimensions (width, height, and depth) of the sample to be tested;

[0013] Preferably, the second angle valve and the minimum leakage rate orifice are connected to form a flow path, which is used to control the flow to extend the time for the sample chamber gas to reach the analysis chamber through the pipeline, so that the time-of-flight mass spectrometer can obtain sufficient test time to sample and analyze the gas inside the sample chamber.

[0014] Preferably, the ultra-low leakage rate via is an ultra-low leakage rate vacuum via element fabricated using MEMS ultraviolet lithography and silicon-silicon direct bonding technology, with a leakage rate lower than […]. The minimum leakage rate orifice is a replaceable component, allowing the desired leakage rate to be selected by replacing different orifice components.

[0015] A calibration method for the aforementioned internal atmosphere testing device is also disclosed, comprising the following steps:

[0016] S1. Evacuate the internal atmosphere testing device and use a heating device to bake the entire device at high temperature to remove gas. After baking is completed and the device has completely cooled down, close the third angle valve, evacuate the sample chamber through a leak with a very low leakage rate, and record the readings of the second full-range vacuum gauge and the cold cathode ionization vacuum gauge;

[0017] S2. Open the first ball valve, record the reading of the first full-range vacuum gauge, close the first angle valve, start the time-of-flight mass spectrometer, open the second angle valve, and introduce gas into the internal atmosphere testing device.

[0018] S3. Record the changes in the pressure inside the sample chamber over time, and analyze the changes in the pressure, gas type, and partial pressure inside the chamber over time.

[0019] S4. After the pressure in the analysis chamber returns to its initial state, close all angle valves and pump groups of the device, process the recorded data, and obtain the calibration test results.

[0020] The theoretical calculation method for calibrating the internal atmosphere testing device is explained below.

[0021] The amount of gas released within a sealed micro-vacuum cavity was measured using the orifice conductance method. The total amount of gas passing through the orifice with the minimum leakage rate was obtained by integrating the pressure change curves at both ends using the integral method. for:

[0022]

[0023] in, For the flow conductance of the central hole of the leak with minimal leakage rate, This represents the internal pressure of the sample chamber. To analyze the indoor pressure, The calibration is the time point at which gas is introduced into the sample chamber. To analyze the time point at which the indoor pressure recovers to the ultimate pressure.

[0024] Background leakage and material venting within the sample chamber cannot be ignored; therefore, the leakage and venting rate within the sample chamber is crucial. for:

[0025]

[0026] in, This represents the ultimate pressure inside the sample chamber. To test the ultimate pressure inside the room.

[0027] In reality, the total amount of gas passing through the minimum leakage rate orifice includes both internal leakage within the sample chamber and material venting. Therefore, the amount of gas released from the sealed micro-vacuum chamber measured through the minimum leakage rate orifice is... for:

[0028]

[0029] The internal volume of the calibration chamber is measured using the gas expansion method, based on Boyle's law, which states that for a given mass of gas at constant temperature, pressure and volume are inversely proportional. Neglecting temperature changes, the standard volume chamber is connected to the calibration chamber to conduct a gas expansion experiment. The specific formula is as follows:

[0030]

[0031] in, The initial pressure of the standard volume chamber. The volume of a standard volume chamber. To calibrate the initial pressure of the chamber, To calibrate the internal volume of the room, This represents the average pressure within the entire chamber after gas expansion.

[0032] At this point, the internal pressure and volume of the calibration chamber are known, and the amount of gas inside the calibration chamber can be calculated. for:

[0033]

[0034] Where P2 is the initial pressure inside the calibration chamber during the calibration experiment.

[0035] The deviation coefficient of the test results of the internal atmosphere testing device can then be calculated. for:

[0036]

[0037] Compared with existing technologies, the beneficial effects of this invention are reflected in:

[0038] 1. This invention designs a puncture mechanism for sealed micro-vacuum cavities of different volumes (1cc-0.001cc). By modifying the angle valve, replacing the internal sealing copper gasket with a threaded tungsten steel drill bit, and slotting inside the blind flange, the position of the sample is supported and restricted. This enables precise puncture and destruction of samples of different sizes and with different packaging materials, improving the accuracy and success rate of destruction, and has a wide range of applications.

[0039] 2. This invention addresses the characteristic of a sealed, tiny vacuum cavity containing a very small amount of gas by designing a testing and analysis mechanism. By utilizing a leak with an extremely low leakage rate and a time-of-flight mass spectrometer, the sensitivity of the testing and analysis mechanism and its ability to distinguish different gas components are improved, the measurable range of the mechanism is expanded, and precise measurement of the amount of gas inside the sealed cavity is achieved.

[0040] 3. In this invention, a calibration chamber is used to calibrate the internal atmosphere testing device. The internal volume and pressure of the calibration chamber are controllable, allowing for multiple calibration tests over a wide volume and pressure range. This enables the correction of the device's test data and the determination of the deviation coefficient of the test results, thus optimizing the device's test data. Furthermore, this calibration method is also applicable to other testing devices. Attached Figure Description

[0041] Figure 1 This is a diagram showing the partitioning of the testing device of the present invention;

[0042] Figure 2 This is a schematic diagram of the test device structure of the present invention;

[0043] Figure 3 This is a three-dimensional view of the puncture unit portion in the testing device of the present invention;

[0044] Figure 4 This is a cross-sectional view of the sample support platform in the testing device of the present invention;

[0045] Figure 5 This is a three-dimensional view of the testing device of the present invention;

[0046] The following are the labels in the diagram: 1. Calibration mechanism; 2. Puncture mechanism; 3. Testing and analysis mechanism; 11. First full-range vacuum gauge; 12. Calibration fore-stage chamber; 13. First angle valve; 14. Rotary vane pump; 15. Calibration chamber; 151. First ball valve; 152. Second ball valve; 21. Second full-range vacuum gauge; 22. Puncture unit; 23. Sample chamber; 24. Sample support platform; 31. Second angle valve; 32. Minimal leakage rate leak hole; 33. Third angle valve; 34. Cold cathode ionization vacuum gauge; 35. Analysis chamber; 36. Time-of-flight mass spectrometer; 37. Fourth angle valve; 38. Molecular pump; 39. Fore-stage pump. Detailed Implementation

[0047] See Figure 1An internal atmosphere testing device for a sealed micro-vacuum cavity includes a calibration mechanism 1, a puncture mechanism 2, and a testing and analysis mechanism 3 connected in sequence.

[0048] See Figure 2 , Figure 3 , Figure 4 and Figure 5 The calibration mechanism 1 is equipped with a pre-calibration chamber 12 and a calibration chamber 15. The pre-calibration chamber 12 has three flange interfaces: one for installing a first full-range vacuum gauge 11, the other for connecting to a rotary vane pump 14 via a first angle valve 13, and the third for connecting to the calibration chamber 15. The calibration chamber 15 consists of a first ball valve 151, a second ball valve 152, and a stainless steel pipe connecting the two. The volume of the calibration chamber is adjusted by installing stainless steel pipes of different lengths and inner diameters. The other end of the calibration chamber 15 is connected to the piercing mechanism 2.

[0049] The piercing mechanism 2 is equipped with a piercing unit 22 and a sample carrying platform 24. The piercing unit 22 adopts the shell of an all-metal angle valve, and the sealing copper gasket of the all-metal angle valve is replaced with a threaded tungsten carbide drill bit. The piercing unit 22 has four flange interfaces, one of which is used to install the second full-range vacuum gauge 21, the second is connected to the sample carrying platform 24, and the other two are connected to the calibration chamber 15 and the testing and analysis mechanism 3, respectively. The testing and analysis mechanism 3 is equipped with an analysis chamber 35. The sample carrying platform 24 is a vacuum knife-edge blind flange, and a cuboid groove for supporting and positioning the sample to be tested is opened at the center of its interior. The shape and depth of the groove are machined according to the three-dimensional dimensions of the sample to be tested.

[0050] The analysis chamber 35 has five flange interfaces. One is connected to the cold cathode ionization vacuum gauge 34, the second is connected to the time-of-flight mass spectrometer 36, the third is connected to the molecular pump assembly via the fourth angle valve 37, and the last two are connected to the second angle valve 31 and the third angle valve 33, respectively. The second angle valve 31 is connected to the minimum leak rate orifice 32, which together form a flow path. This is used to control the flow rate to extend the time it takes for the gas in the sample chamber 23 to reach the analysis chamber 35 through the pipeline, ensuring that the time-of-flight mass spectrometer 36 has sufficient testing time to sample and analyze the gas inside the sample chamber 23. The minimum leak rate orifice 32 is a replaceable component, allowing the desired leak rate to be selected by replacing different orifice components.

[0051] The testing of the internal atmosphere of a sealed micro-vacuum cavity using the testing device of this invention is carried out according to the following steps:

[0052] First, open the second angle valve 31, the third angle valve 33, and the fourth angle valve 37; close the first angle valve 13, the first ball valve 151, and the second ball valve 152; open the second full-range vacuum gauge 21; and turn on the forepump 39 to evacuate the puncture mechanism 2 and the testing and analysis mechanism 3. Observe the reading of the second full-range vacuum gauge 21. When the reading is less than 0.1 Pa, turn on the molecular pump 38 and the cold cathode ionization vacuum gauge 34 to observe the pressure reading, evacuating both mechanisms to their ultimate pressure. Close the second full-range vacuum gauge 21 and the cold cathode ionization vacuum gauge 34, and use a heating device to bake the entire device at high temperature to remove gas.

[0053] The second step is to wait until the baking is complete and the device has cooled down completely, then open the second full-range vacuum gauge 21 and the cold cathode ionization vacuum gauge 34. Close the third angle valve 33, record the reading change curves of the second full-range vacuum gauge 21 and the cold cathode ionization vacuum gauge 34, calculate the background gas release of the sample chamber 23, and open the third angle valve 33 to re-evacuate the puncture mechanism 2 to the ultimate pressure.

[0054] The third step involves closing the third angle valve 33, using the puncture unit 22 to destroy the sample, observing and recording the changes in the readings of the second full-range vacuum gauge 21 and the cold cathode ionization vacuum gauge 34, and simultaneously turning on the time-of-flight mass spectrometer 36 to analyze the gas composition.

[0055] The above operations can complete the experiment of testing the internal atmosphere of a sealed micro vacuum cavity, and the data obtained from the experiment can be processed to obtain the internal pressure and gas composition analysis results of the cavity.

[0056] The calibration method for the aforementioned internal atmosphere testing device in this embodiment includes the following steps: Figure 2 As shown:

[0057] S1. Evacuate the internal atmosphere testing device and use a heating device to bake the entire device at high temperature to remove gas. After baking is completed and the device has completely cooled down, close the third angle valve 33, use the minimum leakage rate leak hole 32 to evacuate the sample chamber 23, and record the readings of the second full-range vacuum gauge 21 and the cold cathode ionization vacuum gauge 34.

[0058] S2. Open the first ball valve, record the reading of the first full-range vacuum gauge 11, close the first angle valve 13, start the time-of-flight mass spectrometer 36, open the second angle valve 31, and introduce gas into the internal atmosphere testing device.

[0059] S3. Record the changes in pressure in sample chamber 23 over time, as well as the changes in pressure, gas type, and partial pressure in analysis chamber 35 over time.

[0060] S4. After the pressure in the analysis chamber 35 returns to its initial state, close all angle valves and pump groups of the device, process the recorded data, and obtain the calibration test results.

[0061] The above operations can complete the internal atmosphere calibration experiment of the sealed micro vacuum cavity. By processing the experimental data, the deviation between the known pressure and gas composition in the calibration chamber 15 and the results measured by the device can be compared, and the measurement deviation coefficient of the device can be obtained.

[0062] This article describes specific embodiments of the present invention, but it should be understood that the present invention is not limited to the specific embodiments, and all inventions created based on the present invention are within the scope of protection.

Claims

1. A device for testing the internal atmosphere of a sealed, tiny vacuum cavity, characterized in that: It includes a calibration mechanism (1), a puncture mechanism (2), and a test and analysis mechanism (3) connected in sequence. The calibration mechanism (1) is provided with a calibration pre-stage chamber (12) and a calibration chamber (15); the calibration pre-stage chamber (12) has three flange interfaces, namely front interface A, front interface B and front interface C. The front interface A is equipped with a first full-range vacuum gauge (11), the front interface B is connected to a rotary vane pump (14) through a first angle valve (13), and the front interface C is connected to one end of the calibration chamber (15); the calibration chamber (15) is composed of a first ball valve (151), a second ball valve (152) and a stainless steel pipe connected between the two. The spatial volume of the calibration chamber (15) is adjusted by installing stainless steel pipes of different lengths and inner diameters; the other end of the calibration chamber (15) is connected to a piercing mechanism (2). The piercing mechanism (2) is equipped with a piercing unit (22) and a sample carrying platform (24); the piercing unit (22) has four flange interfaces, namely unit interface A, unit interface B, unit interface C and unit interface D. The second full-range vacuum gauge (21) is installed in unit interface A, unit interface B is connected to the sample carrying platform (24), unit interface C is connected to the calibration chamber (15), and unit interface D is connected to the testing and analysis mechanism (3); wherein, the piercing unit (22) adopts the shell of an all-metal angle valve, and the sealing copper gasket of the all-metal angle valve is replaced with a tungsten steel drill bit inside; the sample carrying platform (24) is a vacuum knife-edge blind flange, and a cuboid groove for carrying and positioning the sample to be tested is opened in the center of its interior; The testing and analysis unit (3) is equipped with an analysis chamber (35); the analysis chamber (35) has five flange interfaces, namely analysis interface A, analysis interface B, analysis interface C, analysis interface D and analysis interface E. The analysis interface A is connected to the cold cathode ionization vacuum gauge (34), the analysis interface B is connected to the time-of-flight mass spectrometer (36), the analysis interface C is connected to the molecular pump group through the fourth angle valve (37), the analysis interface D is connected to the second angle valve (31), and the analysis interface E is connected to the third angle valve (33); the second angle valve (31) is connected to the minimum leakage rate orifice (32).

2. The internal atmosphere testing device for a sealed micro-vacuum cavity according to claim 1, characterized in that: The first ball valve (151) and the second ball valve (152) are connected by a stainless steel pipe. Polytetrafluoroethylene (PTFE) ferrules are used for the front and rear fittings. The stainless steel pipe is clamped onto the ball valve fitting with the ferrules, and a torque wrench is applied. The torque tightens the ferrule, completing the connection and installation.

3. The internal atmosphere testing device for a sealed micro-vacuum cavity according to claim 1, characterized in that: The tungsten carbide drill bit is threaded.

4. The internal atmosphere testing device for a sealed micro-vacuum cavity according to claim 1, characterized in that: The shape and depth of the cuboid groove inside the blind flange are machined according to the three-dimensional dimensions (width, height, and depth) of the sample to be tested.

5. The internal atmosphere testing device for a sealed micro-vacuum cavity according to claim 1, characterized in that: The second angle valve (31) and the minimum leakage rate orifice (32) are connected to form a flow path, which is used to control the flow to extend the time for the sample chamber gas to reach the analysis chamber through the pipeline, so that the time-of-flight mass spectrometer (36) can obtain sufficient test time to sample and analyze the gas inside the sample chamber.

6. The internal atmosphere testing device for a sealed micro-vacuum cavity according to claim 1, characterized in that: The extremely low leakage rate via (32) is a vacuum via element fabricated using MEMS ultraviolet lithography and silicon-silicon direct bonding technology, with a leakage rate lower than [missing information]. The minimum leakage rate orifice (32) is a replaceable element, allowing the desired leakage rate to be selected by replacing different orifice elements.

7. A calibration method for a sealed micro-vacuum cavity, characterized in that: The internal atmosphere testing device for a sealed micro-vacuum cavity as described in any one of claims 1-6 is used, and the following steps are performed: S1. The assembled internal atmosphere testing device is completely sealed. The internal atmosphere testing device is roughly evacuated and the entire device is baked and degassed using a heating belt. After baking is completed and the device is naturally cooled to room temperature, the third angle valve is closed, so that the molecular pump group pumps gas into the sample chamber only through the leak with a very small leakage rate. The initial pressure readings of the second full-range vacuum gauge and the cold cathode ionization vacuum gauge are recorded. These readings are the background pressure values ​​of the calibration chamber and the analysis chamber. S2. Open the first ball valve and record the reading of the first full-range vacuum gauge. This is the pressure value of the calibration gas subsequently introduced into the calibration chamber. Close the first ball valve, start the time-of-flight mass spectrometer, and open the second ball valve. Record the change in the pressure reading of the second full-range vacuum gauge. This is the change in the pressure in the sample chamber over time. At the same time, record the change in the pressure reading of the cold cathode ionization vacuum gauge and the pressure monitoring curves of each gas component in the analysis chamber by the mass spectrometer. This is the change in the pressure, gas type, and partial pressure in the analysis chamber over time. S3. After the pressure in the analysis chamber returns to the initial pressure reading, close all angle valves and pump groups of the device; acquire the pressure reading change data recorded by the second full-range vacuum gauge and the cold cathode ionization vacuum gauge, and perform integral calculation on the data to obtain the test result value of the total amount of gas inside the calibration chamber; compare the test result value with the initial calibration gas total amount to obtain the calibration experiment result.

Images