JP2021135239A - Leak inspection method and leak inspection device - Google Patents

Abstract

To provide a leak inspection method and a leak inspection device having a high degree of freedom for design, which are compact and easy to incorporate into an existing device, which can calculate not only the presence or absence of leak of an electronic component but also an amount of leak of the electronic component.SOLUTION: A leak inspection method comprises: arranging a crystal unit for a first predetermined time under a pressure lower than the internal pressure of the crystal unit; acquiring first impedance change (ΔZd) of the crystal unit; arranging the crystal unit for a second predetermined time under a pressure higher than the internal pressure of the crystal unit; acquiring second impedance change (ΔZu) of the crystal unit; obtaining the internal pressure of the crystal unit from the first impedance change (ΔZd) and the second impedance change (ΔZu); and calculating an amount of leak.SELECTED DRAWING: Figure 7

Description

The present invention relates to a leak inspection method and a leak inspection apparatus for calculating a leak amount of an electronic component containing a piezoelectric element and inspecting the leak.

The small electronic component in which the piezoelectric element is enclosed in the package is hermetically sealed by evacuating the inside of the package or injecting an inert gas into the package in order to maintain the performance of the circuit. Then, it is confirmed by a leak inspection that the seal is securely sealed and no leak occurs. There are two types of leak inspection: gross leak inspection, which inspects large leaks, and fine leak inspection, which inspects small leaks.

Gross leak inspection includes, for example, bubble leak inspection in which the package is submerged in hot water to expand the inside, and if the sealing is not sufficient, the expanded air becomes bubbles and leaks out visually. When a leak-free reference material and a leaky test object are placed in the two sealed containers described in Document 1 and pressurized, the pressure on the leaky test object side decreases, and the reference material This is an air leak inspection or the like that determines a leak by observing the pressure difference between the subject and the subject. In the fine leak inspection, for example, the package is pressurized in an inspection container filled with helium gas, and if there is a minute hole, helium gas is press-fitted into the package through the minute hole, and then the inside of the inspection container is depressurized to leak from the package. This is an inspection to confirm the existence of minute holes by measuring the amount of helium gas.

In the gloss leak inspection, the bubble leak inspection is visually confirmed, so that it lacks reliability, and there is a problem that even the air leak inspection cannot detect a minute leak. Helium leak inspection, which is a fine leak inspection, has the advantage of high leak detection sensitivity, but it takes time because it is performed using helium gas, and it cannot be detected when the leak hole is large, so it is a gross leak inspection. There is a drawback that it is essential to use it together with the machine. Further, in order to shorten the processing time, it is indispensable to perform a plurality of simultaneous processes, and it is difficult to individually determine the leak of the electronic component to be inspected. For example, a large number of helium leaks are inspected at the same time, and if there is a defect, the helium leaks are divided into several groups and the helium leaks are inspected again for each group. The group in which the leak was found is further divided into groups, a helium leak inspection is performed, and this re-inspection is repeated to find out the leaking electronic component. During the re-inspection, helium is not newly filled, so depending on the amount of leakage, helium may escape and defective products may not be identified, so it will be discarded together with non-defective products as a defective contamination group. .. Further, a large dedicated device is required to carry out the gross leak inspection and the fine leak inspection by one unit.

On the other hand, a leak inspection may be performed using a change in the impedance of the piezoelectric element. This inspection is an inspection method that utilizes the fact that the impedance of the piezoelectric element changes with pressure. For example, as disclosed in Patent Document 2, a piezoelectric element is arranged in an examination room to reduce the pressure from atmospheric pressure, and if there is no change in the impedance of the piezoelectric element due to the reduced pressure, it is determined that there is no leak, and there is a change in impedance. If there is a leak, it is judged. Patent Document 3 pressurizes an electronic component from atmospheric pressure, and determines that the airtightness is poor when the impedance change amount is equal to or greater than a set value. In Patent Document 4, an airtight sealing chamber and an inspection chamber are continuously provided side by side, and crystal impedance (hereinafter referred to as “CI value”) in a vacuum atmosphere after vacuum sealing and CI in an inspection chamber in a pressurized atmosphere are provided. It compares the values and checks for leaks.

JP-A-49-59692 Japanese Unexamined Patent Publication No. 11-51802 International Publication No. 2008/033833 Japanese Unexamined Patent Publication No. 2012-257152

When the leak inspection method disclosed in Patent Document 2 or Patent Document 3 is used as a leak inspection, the presence or absence of a leak can be inspected, but the leak amount cannot be accurately measured. When the piezoelectric element after vacuum sealing is released to the atmosphere, the pressure inside the piezoelectric element package gradually increases through the leak hole. When the amount of leak is extremely small, it takes a sufficiently long time for the internal pressure of the package and the external pressure to become equal, so that the internal pressure of the package and the external pressure often do not match at the start of the leak inspection. When a leak inspection is performed on a piezoelectric element in which the piezoelectric element after vacuum sealing is released to the atmosphere by the method of Patent Document 2 or Patent Document 3, the initial value of the internal pressure of the package is unknown, and the amount of leak cannot be calculated. Even when the leak inspection of the piezoelectric element is repeated, the amount of change in the CI value differs due to the difference in the internal pressure at the start of measurement in the remeasurement depending on the history of exhaust gas or pressurization, and the amount of leak cannot be calculated from the amount of change in the CI value.

In Patent Document 4, since the CI value is measured without being released to the atmosphere after vacuum sealing, the CI value measured at a known package internal pressure can be used as a reference, and the initial value of the package internal pressure can be accurately obtained. Therefore, it is possible to calculate the leak amount from the change amount of the CI value. However, it is necessary to maintain the vacuum from vacuum sealing to leak inspection, and since the vacuum sealing device and the inspection device are connected by a vacuum tank, there is a problem that the device becomes large. Further, in order to connect the sealing device and the inspection device, it is necessary to share the accommodating tray of the piezoelectric element or to provide a separate transfer machine, and it is not easy to connect the inspection device to the existing vacuum sealing device. No. Furthermore, the leakage amount measurement and remeasurement of piezoelectric elements that could not measure the CI value in vacuum due to equipment malfunction, defective returned products after shipment, etc. after being taken out under atmospheric pressure are performed in Patent Document 2 or Patent Document 3. Similarly, it becomes difficult to calculate the leak amount.

In the inspection method in which only the presence or absence of a leak is known, the electronic component having a leak is judged to be a defective product. However, even if there is a leak, the performance of the electronic component is not significantly affected as long as the leak amount is within a predetermined allowable value. If the leak amount can be calculated, the permissible value of the leak amount can be determined, and the yield of the product is improved accordingly. Therefore, it is important to calculate the leak amount.

The present invention has been made in view of the above circumstances, and is designed by a leak inspection method capable of calculating not only the presence or absence of leaks of electronic components but also the amount of leaks of electronic components, and a compact size that can be easily incorporated into an existing device. An object of the present invention is to provide a leak inspection device having a high degree of freedom.

The leak inspection method according to the first aspect of the present invention is
This is a leak inspection method that calculates the amount of leakage of electronic components in which the piezoelectric element is sealed.
The electronic component is placed in an atmosphere of a pressure lower than the internal pressure of the electronic component for a first predetermined time, a change in the first impedance of the piezoelectric element is acquired, and an atmosphere of a pressure higher than the internal pressure of the electronic component is obtained. An impedance change acquisition step of arranging the electronic component underneath for a second predetermined time and acquiring a change in the second impedance of the piezoelectric element, and
The present invention includes a leak amount calculation step of calculating the leak amount of the gas leaking from the electronic component from the change of the first impedance and the change of the second impedance.

The change in the first impedance is a first gradient in which the change in the first impedance is indicated by a gradient.
The change in the second impedance is a second gradient in which the change in the second impedance is indicated by a gradient.
The leak amount of the electronic component may be calculated from the first gradient and the second gradient.

The relationship between the time per unit time of the first predetermined time and the change in impedance was obtained, or the relationship between the time per unit time in the second predetermined time and the change in impedance was obtained and obtained. The leak amount of the electronic component may be calculated from the relationship.

The impedance change acquisition step is
A decompression curve formed from the relationship between the first impedance change and time and a pressurization curve formed from the relationship between the second impedance change and time are formed and differ in the decompression curve. An impedance change amount calculation step for obtaining an impedance change amount (ΔZ) based on a change in the impedance value at two points or based on a change in the impedance value at two points that are the same as the impedance value at the two points in the pressurization curve.
_{The first time change amount (Δt d} ) is obtained based on the time corresponding to the impedance values of the two points on the decompression curve, and the second time is based on the time corresponding to the impedance values of the two points on the pressurization curve. and time variation amount calculation step of calculating the time variation (Delta] t _u) of,
Since the impedance change amount ([Delta] Z) and the first time variation amount (Delta] t _d) and the second time variation amount of (Δt _u), a pressure reducing pressure gradient indicating a gradient of the decompression curve of the pressurization curve A pressure gradient ratio calculation step for obtaining a pressure gradient ratio (γ), which is a ratio to a pressure gradient indicating a gradient, is provided.
The leak amount calculation step is
_{The internal pressure (P s} ) of the electronic component may be obtained from the pressure gradient ratio (γ), and the leak amount (Q) of the gas leaking from the electronic component may be obtained from the internal pressure (P _{s) and the elapsed time.} ..

_{In the decompression curve, the impedance value changes from Z x,} which is the impedance value of the two points, to Z _s , and the time changes from the first time corresponding to _{Z x} to the second time corresponding _{to Z s.} death,
In the pressurization curve, the impedance value changes from Z _s, which is the impedance value of the two points, _{to Z x} , and the time is from the third time corresponding to _{Z s} to the fourth time corresponding _{to Z x.} Change,
The second time and the third time may be the same time.

The pressure gradient ratio (γ) is
Calculated by γ = (ΔZ / Δt _d ) / (ΔZ / Δt _u),
([Delta] Z, the impedance variation, Delta] t _d, the first time variation, Delta] t _u, the second time variation)
The internal pressure (P _s ) is
Calculated by P _s = (γP _h + P _l ) / (γ + 1)
(P _h, the pressure value of the pressurization, the pressure value of P _l is during decompression)
The leak amount (Q) is
_{Q = -VΔP · P atm / (} P s -P l) Δt or _{Q = VΔP · P atm / (} P h -P s) may be calculated by Delta] t.
(V is the internal volume of the piezoelectric element, _Patm is the atmospheric pressure, Δt is the elapsed time)

The leak inspection device according to the second aspect of the present invention is
A leak inspection device that calculates the amount of leakage of electronic components in which a piezoelectric element is sealed.
A decompression means for reducing the pressure in the inspection space where the electronic components are arranged, and
A pressurizing means for pressurizing the inspection space in which the electronic component is arranged, and a pressurizing means.
An impedance change acquisition unit that measures the impedance of the piezoelectric element of the electronic component arranged in the inspection space and acquires a change in impedance, and the electronic component is in the inspection space decompressed by the decompression means. Is placed for a first predetermined time, then the impedance of the piezoelectric element is measured to obtain a change in the first impedance, and the electronic component is placed in the inspection space pressurized by the pressurizing means for a second predetermined time. After that, the impedance change acquisition unit that measures the impedance of the piezoelectric element and acquires the change in the second impedance, and the impedance change acquisition unit.
A leak amount calculation unit for obtaining a leak amount of gas leaking from the electronic component from the first impedance change acquired by the impedance change acquisition unit and the second impedance change is provided.

The impedance change acquisition unit is
A decompression curve formed from the relationship between the first impedance change and time and a pressurization curve formed from the relationship between the second impedance change and time are formed and differ in the decompression curve. An impedance change amount calculation unit that obtains an impedance change amount based on a change in the impedance value at two points or based on a change in the impedance value at two points that are the same as the impedance value at the two points in the pressurization curve.
The first time change amount is obtained based on the time corresponding to the impedance values of the two points on the decompression curve, and the second time change amount is obtained based on the time corresponding to the impedance values of the two points on the pressure curve. Time change amount calculation unit to find
From the impedance change amount, the first time change amount, and the second time change amount, the ratio of the decompression pressure gradient indicating the inclination of the decompression curve to the pressurization pressure gradient indicating the inclination of the pressurization curve is used. A pressure gradient ratio calculation unit for obtaining a certain pressure gradient ratio is provided.
The leak amount calculation unit
The internal pressure of the electronic component may be obtained from the pressure gradient ratio, and the amount of gas leaking from the electronic component may be obtained from the internal pressure and the elapsed time.

The inspection space may be formed in the same inspection chamber, and the depressurizing means and the pressurizing means may be connected to the inspection chamber.

According to the present invention, there is provided a leak inspection method that can calculate not only the presence or absence of a leak of an electronic component but also the amount of a leak of an electronic component, and a leak inspection device that is small and easy to incorporate into an existing device and has a high degree of freedom in design. can do.

The crystal oscillator whose leak amount is calculated by the leak amount calculation method according to the embodiment is shown, (a) is a plan view of the crystal oscillator with the lid removed, and (b) is AA of (a). It is a cross-sectional view cut by a line. It is a figure which shows the pressure change of the outside of a crystal oscillator with the passage of time in a reference example. It is a figure which shows the relationship between the leakage amount and the impedance change amount corresponding to the leaving time in a reference example. It is a figure which shows the relationship between the actual leak amount and the measured value of He flow rate in a helium leak inspection. It is a figure which shows the pressure change in the package when the inside of a package of a crystal oscillator is depressurized for a certain period of time and then pressurized. It is a figure which shows the pressure change in the package when the inside of a package of a crystal oscillator is pressurized for a certain period of time and then decompressed. It is a figure which shows the principle of the leak inspection method concerning this embodiment. It is a figure which shows the relationship between the pressure change when the inside of the package of a crystal transducer is depressurized and then pressurized, the ratio of the time change and the pressure change amount, the ratio of the time change and the impedance change amount, and the pressure gradient ratio. .. It is a figure which shows the other principle of the leak inspection method concerning this embodiment. It is a conceptual diagram of a leak inspection device. It is a block diagram of a leak inspection apparatus. It is a flowchart of a leak inspection method. An example of using the leak inspection device according to the present embodiment is shown, and (a) is a diagram showing an example of using the leak inspection device according to the present embodiment in a subsequent process of the vacuum sealing device, (b). Is a diagram showing an example in which the leak inspection device according to the comparative example is used in a subsequent process of the vacuum sealing device.

Hereinafter, embodiments of the leak inspection device and the measurement method according to the present invention will be specifically described with reference to the accompanying drawings. It should be noted that the embodiments described below are for illustration purposes only and do not limit the scope of the present invention. Therefore, those skilled in the art can adopt embodiments in which each or all of these elements are replaced with equivalent ones, but these embodiments are also included in the scope of the present invention.

(Structure of crystal oscillator)
The piezoelectric element used in the leak inspection method and the leak inspection apparatus according to the embodiment of the present invention will be described by taking a crystal oscillator as an example. Although the vertical and horizontal directions are defined in the drawings, these terms are used to explain the present embodiment and do not limit the direction when the embodiment of the present invention is actually used. .. Also, these terms should not limit the technical scope of the claims.

1A and 1B are views showing a crystal oscillator used in the leak inspection method and the inspection apparatus according to the present embodiment, FIG. 1A is a top view of the crystal oscillator with the lid removed, and FIG. 1B is a top view. It is sectional drawing which cut at the line AA with the cover of the crystal oscillator of (a) attached.

The crystal oscillator 1 includes a crystal piece 10 and a package 20 that houses the crystal piece 10. The package 20 includes a base 21 and a lid 22 that closes an opening on the top surface of the base 21. By closing the opening on the upper surface of the base 21 with the lid 22, a closed space which is an inspection space is formed.

Excitation electrodes 11a and 11b formed of a metal thin film for applying a voltage to the crystal piece 10 are formed on both main surfaces of the crystal piece 10 facing each other by vapor deposition or sputtering. One ends of the excitation electrodes 11a and 11b are connected to the internal electrodes 211c and 211d of the base 21 described later via the conductive adhesive 13 on the lower surface of the crystal piece 10. As the conductive adhesive 13, for example, an adhesive using a silicon resin as a base material is used.

The base 21 is formed of, for example, a material such as metal, ceramic, glass, crystal, or resin, and as shown in FIG. 1 (b), has a box shape having a space for inserting the crystal piece 10 inside and an upper opening. It is a member of. The base 21 includes a bottom portion 211 and a wall portion 212 that stands up from the peripheral edge portion of the bottom portion 211. A pair of external electrodes 211a and 211b for electrically connecting to an external circuit board or the like are attached to the lower surface of the bottom portion 211. Further, a pair of internal electrodes 211c and 211d are attached to the bottom surface inside the base 21, and the internal electrodes 211c and the excitation electrode 11a and the internal electrodes 211d and the excitation electrode 11b are connected via the conductive adhesive 13. .. The internal electrodes 211c and 211d and the external electrodes 211a and 211b are electrically connected, and the excitation electrodes 11a and 11b are connected to the internal electrodes 211c and 211d so that the excitation electrodes 11a and 11b and the external electrodes 211a and 211b are connected. Each is electrically connected.

The lid 22 is a plate-shaped member made of a material such as metal, ceramic, glass, crystal, or resin, and closes the opening at the upper part of the base 21 to form a closed space. A joining member 23 such as silver wax, gold tin, or nickel plating is applied to the upper surface of the base 21, that is, the upper surface of the wall portion 212. By heat-melt joining the joining member 23 and the lid 22, the base 21 and the lid 22 are joined, and the package 20 is airtightly sealed.

The inside of the package 20 of the crystal unit 1 is hermetically sealed under vacuum in the current miniaturized crystal unit. As described above, in order to inspect whether or not the sealed state of the electronic component is maintained, there has been a method of inspecting whether or not there is a leak in the electronic component. However, it is important to recognize the amount of leak in addition to the presence or absence of leak in order to secure the yield of the product.

The principle of the leak amount calculation method described in this embodiment will be described in comparison with a reference example. The leak amount calculation method of the present embodiment utilizes the characteristic that the impedance of the crystal oscillator rises with pressure due to the friction between the crystal oscillator and the gas molecules. The impedance of the crystal unit increases in proportion to the pressure in the molecular flow region and increases in proportion to the 1/2 power of the pressure in the viscous flow region. Therefore, by measuring the change in impedance, the change in the pressure inside the crystal unit package (hereinafter referred to as "internal pressure") can be known, and by recognizing the change in the internal pressure, it can be seen that a leak has occurred. I can judge.

(Explanation of reference example)
As a method of inspecting the presence or absence of leakage from the amount of change in the impedance of the crystal oscillator, for example, a crystal piece is vacuum-sealed in a package, then taken out to atmospheric pressure, the CI value of the crystal is measured, and then the package is placed in an examination room. There is a method (hereinafter referred to as "Reference Example 1") in which the pressure is reduced, the CI value is measured again, the pressure change is detected by the change in the CI value, and it is determined whether or not there is a leak. In addition, after vacuum-sealing the crystal piece in the package, it is taken out to atmospheric pressure, the CI value is measured, then the package is placed in the examination room, pressurized, and the CI value is measured again, and the pressure change is detected by the change in the CI value. Then, there is a method of determining whether or not there is a leak (hereinafter referred to as "reference example 2"). In these two leak inspection methods (Reference Example 1 and Reference Example 2), the presence or absence of a leak can be inspected, but the amount of leak cannot be measured.

The reason why the leak amount cannot be measured in Reference Examples 1 and 2 will be described with reference to Reference Example 2. FIG. 2 shows a case where a crystal oscillator in which the inside of a package containing a crystal piece is evacuated and sealed is left at atmospheric pressure for a certain period (t1) and then pressurized for a certain period (Δt2) to measure a CI value. It is a graph which shows the relationship between the pressure (atmospheric pressure) outside a package, and the elapsed time (t). When there is a leak in the crystal unit, the size of the leak hole differs for each individual, so that the internal pressure of each crystal unit after the atmospheric pressure standing time (t1) is different. Even when the atmospheric pressure standing time (t1) is different depending on the measurement order of each crystal unit, the initial value of the internal pressure before pressurization of each crystal unit is different.

FIG. 3 is a graph showing the relationship between the amount of leakage (unit: Pam ² / s) and the amount of change in CI value (ΔZ: unit (Ω)) according to different standing times. In packages having an internal volume of V is 5E-12m ^3, pressurized with a pressure of 2.5E + 5 Pa. The leaving time (t1) is set to four patterns of 10 seconds, 60 seconds, 180 seconds, and 600 seconds, and the pressurizing time (Δt2) is the same as 120 seconds. When the standing time (t1) is 10 seconds and 60 seconds, the CI value increases as the leak amount increases, but when the leak amount exceeds a certain value, it shows a peak curve that starts to decrease, and leaks from the change amount of the CI value. The amount is not uniquely determined. Further, even if the leak amount is the same, the change amount (ΔZ) of the CI value differs depending on the initial value of the internal pressure. The leak amount cannot be measured even if the change amount (ΔZ) of the CI value is calculated. This situation is the same in Reference Example 1.

Further, even if the helium leak inspection, which is a fine leak inspection, is used, the leak amount cannot be measured accurately. In the helium leak inspection, the crystal oscillator to be inspected is placed in an inspection chamber called bombing and pressurized for a certain period of time. By pressurizing, if there is a leak point in the crystal unit, helium gas invades the inside of the crystal unit from the leak point. Hereinafter, the time during which the inspection chamber is pressurized for a certain period of time to allow helium gas to enter the inside of the crystal oscillator is referred to as a filling time. After that, when the inspection room is depressurized and the inspection room is evacuated, the helium gas that has entered the inside of the crystal oscillator is released into the inspection chamber. Therefore, the helium gas leaked from the crystal oscillator should be measured by the helium detector. Can be done.

In the helium leak inspection, there is a predetermined standing time between filling the crystal transducer with helium gas and measuring with the helium detector, and in the region where the amount of leakage of the crystal transducer is large, helium during this leaving time. Since the gas escapes from the crystal oscillator, the flow rate of helium gas may be measured small. Further, in a region where the amount of leakage is small, for example, in a filling time of about 60 minutes, the helium gas is not sufficiently filled in the crystal oscillator, so that the flow rate of the helium gas may be measured to be small. When the leak amount becomes 1/10, the helium filling amount becomes 1/10, so that the measured helium flow rate becomes 1/100. The flow rate of helium decreases with the square of the leak amount.

Further, in the helium leak inspection, when the re-inspection is performed, it is necessary to refill the crystal transducer of helium gas, and in the region where the amount of leak is small, the helium pressure after refilling increases every time the leak amount is small, and the helium pressure is refilled. The helium gas flow rate is greatly measured at each inspection.

In order to consider the relationship between the actual leak amount and the theoretical value of the leak amount, the crystal oscillator was placed in a container filled with helium gas pressurized at a pressure of 0.5 MPa, left for 60 minutes, and then helium gas. The measured value of the leak amount of is shown in FIG. The internal volume V of the package is 1. It is E-10m ³ . In the measurement, the time until the start of the measurement after filling was set to 1 minute, and the time until the start of refilling 60 minutes after the measurement was set to 1 minute.

The graph shown in FIG. 4 shows the theoretical value of the leak amount, the first actual leak amount, the second actual leak amount measured by refilling with helium gas, and the fifth actual leak amount measured by refilling with helium gas. The relationship between the amount of leak and the measured value of helium (unit: Pa · m ³ / s) is shown. The actual leak amount indicates a value (unit: Pa · m ³ / s) in dry air at atmospheric pressure according to JIS. The theoretical value of the leak amount corresponds to the amount of helium leaking from the inside of the package immediately after filling with helium gas for a sufficiently long time until the helium pressure inside and outside the package becomes equal. Since the conductance of the leak part of the crystal transducer is the square root of the molecular weight ratio, helium gas has a conductance of 2.7 times that of air, and when the package is filled with helium gas at 5 atm, it is 13.5 of air. Double the flow rate (2.7 x 5 = 13.5 times) is measured. Therefore, the theoretical value of the helium leak amount can be expressed as air leak amount × 2.7 × 5.

As can be seen from the graph shown in FIG. 4, the actual leak amount overlaps with the theoretical value of the leak amount, and the range of the actual leak amount that can be measured accurately is only a very limited range as surrounded by the dotted line. As described above, when the leak inspection or the helium leak inspection using the CI value described above is used, the presence or absence of the leak can be determined, but the leak amount cannot be accurately measured.

(Principle of leak amount calculation method of this embodiment)
The leak amount calculation method of the present embodiment is characterized in that the leak amount can be calculated by estimating the internal pressure of the crystal oscillator in the leak inspection method using the CI value (hereinafter, also referred to as impedance). ..

The CI value in high vacuum is the CI value peculiar to the crystal unit (hereinafter referred to as "Z ₀ value") that does not depend on the gas pressure, and is the sum of the change amount (ΔZ) of the CI value due to the gas pressure. , The CI value at a certain pressure. However, this Z ₀ value differs depending on the individual crystal unit. On the other hand, if the pressure is known like the CI value in high vacuum or atmospheric pressure, the pressure can be converted from the amount of change in the CI value. Therefore, if the internal pressure of the crystal oscillator is known, the CI value The change in pressure can be converted from the change in. If the change in pressure is known, the amount of leakage can be calculated.

Applicants place the crystal oscillator under reduced pressure for a predetermined period of time and then pressurize it, or place the crystal oscillator under pressure for a predetermined period of time and then reduce the pressure, and the difference between the pressure change during decompression and the pressure change during pressurization. The internal pressure was obtained from the internal pressure, and the amount of leakage was derived from the internal pressure.

The relationship between the pressure change during depressurization and the pressure change during pressurization will be described with reference to FIGS. 5 and 6. FIG. 5 shows the pressure change in the crystal oscillator package when the crystal oscillator is placed under reduced pressure for a certain period of time to exhaust (depressurize) the inside of the crystal oscillator package and then pressurize, and FIG. 6 shows the pressure change in the crystal oscillator package. The pressure change in the crystal oscillator package when the crystal oscillator is placed under pressure for a certain period of time to pressurize the inside of the crystal oscillator package and then depressurize is shown. In FIGS. 5 and 6, the "constant time" when depressurizing or pressurizing for a certain period of time was calculated in three patterns of 7.5 minutes, 65 minutes, and 200 minutes.

As shown in FIGS. 5 and 6, the slope of the pressure curve (hereinafter referred to as “decompression curve”) indicating the pressure change during decompression and the pressure curve (hereinafter referred to as “pressurization”) indicating the pressure change during pressurization. The slope of the "curve") is different. As shown in FIG. 5, when the exhaust time is short and the internal pressure of the package is high, the pressure gradient which is the slope of the decompression curve is larger than the pressure gradient which is the slope of the pressure curve. When the exhaust time is long and the internal pressure of the package is low, the pressure gradient of the decompression curve is smaller than the pressure gradient of the pressurization curve. As shown in FIG. 6, when the pressurization time is short and the internal pressure of the package is low, the pressure gradient which is the slope of the pressurization curve is larger than the pressure gradient which is the slope of the decompression curve. When the pressurization time is long and the internal pressure of the package is high, the pressure gradient of the pressurization curve is smaller than the pressure gradient of the decompression curve. Focusing on this characteristic, the internal pressure of the crystal unit can be obtained as follows.

7, a predetermined time a crystal oscillator to the laboratory under a reduced pressure of the pressure P _l (t _s1) and left, after the pressure in the package of the crystal oscillator becomes a pressure P _s, a pressure of the pressure P _h It is a graph which shows the pressure change in a package when a crystal unit is left for a predetermined time in the inspection room of. Here, P _l, P _{s, and} P _h have a relationship of _{P l} <P _s , _Ph > P _s. The horizontal axis of the graph shows the elapsed time (t), and the vertical axis shows the pressure (P) or impedance (Z). The graph shows a decompression curve a that is decompressed and descends for a predetermined period, and a pressurization curve b that is pressurized and ascends after a predetermined period. In order to obtain the slope of the decompression curve a and the pressure curve b of the graph, the pressure value (P _x ) and the pressure value (P _s ) having the same pressure value on the decompression curve a and the pressure curve b The amount of change is defined _{as ΔP d} on the decompression curve a and _{ΔP u on the pressurization curve.} ΔP _d and ΔP _u have the same value, and ΔP as a representative value has a relationship of _{ΔP d} = ΔP _{u = ΔP.} In the decompression curve a, the amount of change in time between the time corresponding to _{the same pressure value (P x ) (t x 1} ) and the time corresponding to the same pressure value (P _{s ) (ts 1 ) is Δt d.} (Hereinafter referred to as "first time change amount"), in the pressure curve b, it corresponds to the same pressure value (P _s ) as _{the time (t x 2 ) corresponding to the same pressure value (P x).} the amount of change in time between the time _{(t s2),} Δt u (hereinafter referred to as "second time variation amount".) and determined. You may switch from depressurization to pressurization at _{t s1} so that t _s1 = t _s2.

_{The decompression pressure gradient (ΔP / Δt d} ), which is the slope of the decompression curve a, is represented by the following equation 1.
ΔP / Δt _d = −C (P _s −P _l ) / V (Equation 1)
Slope a is applied pressure gradient pressurization curve b (ΔP / Δt _u) is represented by Formula 2 below.
_{ΔP / Δt u = C (P} h -P s) / V ( Equation 2)
Here, V (m ³ ) is the internal volume of the crystal oscillator package, and C (m ³ / s) is the conductance of the leak hole of the package. The decompression pressure gradient is also referred to as a first gradient, and the pressurization pressure gradient is also referred to as a second gradient.

The ratio of the decompression pressure gradient of the decompression curve a to the pressurization pressure gradient of the pressurization curve b (hereinafter referred to as "pressure gradient ratio (γ)") is obtained by the following equation 3.
γ = (ΔP / Δt _d ) / (ΔP / Δt _u ) (Equation 3)
γ = (ΔP / Δt _d ) / (ΔP / Δt _u ) = (P _{s −} P _l ) / (P _h −P _s ), and the internal pressure (P _s ) of the crystal unit is given by the following equation 4. Desired.
P _s = (γP _h + P _l ) / (γ + 1) (Equation 4)

Here, _Ph and _Pl are known values, and the internal pressure P _s can be obtained by obtaining the pressure gradient ratio γ, and the leak amount Q can be obtained as the flow rate of atmospheric pressure. That is, from Equations 1 and 2, the conductance C is obtained by the following equations 5 and 6.
C = −VΔP / (P _s −P _l ) Δt (Equation 5)
C = VΔP / (P _h −P _s ) Δt (Equation 6)
Since the flow rate (Q) at atmospheric pressure ( _{Patm ) is Q = CP atm} , the leak amount (Q) can be obtained by the following formula 7 or formula 8.
_{Q = -VΔP · P atm / (} P s -P l) Δt ( Equation 7)
_{Q = VΔP · P atm / (} P h -P s) Δt ( Equation 8)

The pressure gradient ratio (γ) can be obtained as the ratio of changes in impedance during depressurization and pressurization. As described above, the change in impedance of the crystal unit corresponds to the change in pressure. Pressure gradient ratio (gamma) is the equation 3, a _{γ = (ΔP / Δt d)} / (ΔP / Δt u), replacing the amount of change in impedance is obtained by Equation 9 below.
γ = (ΔZ / Δt _d ) / (ΔZ / Δt _u ) = (ΔZ _d / Δt _d ) / (ΔZ _u / Δt _u ) (Equation 9)
Here, ΔZ _{d is referred} to as a first impedance change amount, and ΔZ _u is referred to as a second impedance change amount. ΔZ _d and ΔZ _u have the same value, and the pressure gradient ratio (γ) can be obtained by using ΔZ as a representative value.

FIG. 8 shows the pressure change in the package of the crystal transducer when pressurization is performed after the exhaust is interrupted in the middle, and the pressure gradient ratio γ = (P _{s −} P _l ) / (P _h −P _s ), ΔP. The relationship between (ΔP / Δt _d ) / (ΔP / Δt _u ), which is the ratio of / Δt, and (ΔZ / Δt _d ) / (ΔZ / Δt _{u), which is the ratio of the ratio of ΔZ / Δt, is shown.} As shown in the figure, the curves of the three graphs of the pressure gradient ratio γ, the ratio of ΔP / Δt, and ΔZ / Δt are almost the same, and by calculating the impedance change amount (ΔZ) from this graph as well, It can be seen that the pressure gradient ratio (γ) can be obtained.

Therefore, by measuring the impedance of the crystal oscillator, the pressure gradient ratio (γ) can be obtained by Equation 9, and if the pressure gradient ratio (γ) is obtained, the internal pressure (P _s ) of the crystal oscillator can be obtained from Equation 4. As a result, the leak amount (Q) can be calculated by the formula 7 or the formula 8.

Furthermore, as shown in FIG. 9, vacuum - pressure - over reduced pressure.. A plurality of times, repeating the process, so that the value of the plurality of internal pressure (P _s) is determined. By the values of the plurality of internal pressure (P _s) is determined to improve the accuracy of leakage amount calculation. If the relational expression between a plurality of internal pressure (P _s ) values, time, and pressure is known, it is possible to obtain the leak amount even if the relation between the impedance change amount (ΔZ) and the pressure change amount (ΔP) is not known.

Further, the crystal oscillator is arranged in an atmosphere of a predetermined pressure _Pl (P _l <P _s ) to obtain the relational expression between _{the time and the internal pressure (P s ), and the predetermined pressure Ph} (P _h > P _s ). The crystal oscillator is placed under the atmosphere of, _{the relational expression between time and internal pressure (P s} ) is obtained, the _{leak amount (Q) is calculated from the values of multiple internal pressures (P s} ), and the leak amount (Q) is calculated. ) Can be averaged, or the leak amount (Q) can be calculated by weighting according to the conditions. Specifically, the internal pressure (P. _s ) can be obtained. For example, the time required _{to select any two points (Z 1} , Z ₂ , Z ₁ > Z ₂ ) having different impedance values from each of the decompression curve and the pressurization curve and change from Z _{1 to Z 2} in the decompression curve. Calculate Δt _d and the time Δt _{u from Z 2} to Z ₁ on the pressurization curve, and obtain the internal pressure when the _{impedance value is Z 2} from the pressure gradient ratio (γ). Once you have acquired the impedance value per unit time, for the arbitrary two points can be freely set by you know the relationship between the time and the internal pressure (P _s), continuously leak amount Can be calculated, and fine control becomes possible.

(Leak inspection device)
Next, the leak inspection device will be described with reference to FIG. FIG. 10 is a conceptual diagram of the leak inspection device, which is different from the dimensions of the actual device. Further, the vertical and horizontal directions on the paper are defined as "up", "down", "left", and "right", but they are for explanation purposes only and are directions when the embodiment of the present invention is actually used. Is not limited to.

The leak inspection device 300 holds the stage 301 on which the crystal oscillator 1 is mounted, the contact probe 302 for measuring the resonance frequency and the impedance of the crystal oscillator 1, and the contact probe 302, and moves up and down the contact block 303. And the measuring unit 304 for measuring the impedance of the crystal oscillator 1, the depressurizing means 305 for depressurizing the internal space of the examination room 400 formed between the stage 301 and the contact block 303, and the addition of pressurizing the internal space. It includes a pressure means 306, a pressure gauge 400a for measuring the pressure in the inspection chamber 400, and a control unit 307 for controlling the overall operation of the leak inspection device 300. The configuration of the control unit 307 will be described later.

The crystal oscillator 1 is housed in a rectangular tray 14, and the tray 14 is placed on the stage 301. The tray 14 is formed with a plurality of holes (not shown) for accommodating the crystal oscillator 1. The plurality of holes are formed in a matrix on the tray 14.

The stage 301 places the tray 14 containing the crystal oscillator 1 on the upper surface. The examination room 400 is formed by the space formed by the stage 301 and the contact block 303.

The contact probe 302 is a member for measuring the resonance frequency and impedance of the crystal oscillator 1, and includes a pair of contact pins 302a and 302b at the tip thereof. When the contact block 303, which will be described later, moves up and down, the contact pins 302a and 302b come into contact with the external electrodes 211a and 211b of the crystal oscillator 1, and a voltage is applied to measure the resonance frequency and impedance.

The measuring unit 304 receives the signals transmitted from the external electrodes 211a and 211b and measures the impedance of the crystal oscillator 1. The measuring unit 304 uses, for example, a network analyzer. The measuring unit 304 pressurizes the inspection room 400 for a predetermined time while the crystal oscillator 1 is arranged in the inspection room 400 decompressed by the depressurizing means 305 described later for a predetermined time and by the pressurizing means 306 described later. During that time, the impedance of the crystal oscillator 1 is measured. The measuring unit 304 transmits the measured impedance value to the control unit 307.

The contact probe 302 is moved in the forward direction toward the crystal oscillator 1 or in the backward direction away from the crystal oscillator 1 by an elevating mechanism (not shown). In this embodiment, the contact probe 302 moves in the vertical direction in the drawing. A spring (not shown) is inserted in the contact pins 302a and 302b or the contact probe 302. The contact pins 302a and 302b expand and contract due to the elastic force of the spring, so that the contact pins 302a and 302b are brought into contact with the external electrodes 211a and 211b of the crystal oscillator 1 while being pressurized in the forward state. Further, the contact block 303 retracts to separate the contact pins 302a and 302b from the external electrodes 211a and 211b.

The pair of contact pins 302a and 302b of the contact probe 302 and the pair of external electrodes 211a and 211b have a one-to-one correspondence. The contact probe 302 is arranged in the same direction as any one row of the crystal oscillators 1 arranged in a matrix on the tray 14, and the same number of paired contact pins 302a and 302b as the number of the crystal oscillators arranged in the row are arranged. Will be done. The contact probe 302 may be provided so as to come into contact with all the crystal oscillators 1 arranged in a matrix.

A packing 308 is attached to the peripheral edge of the lower surface of the contact block 303 to enhance the airtightness with the stage 301. When the contact block 303 descends and comes into contact with the stage 301, the examination room 400 is sealed.

The depressurizing means 305 is specifically a vacuum pump, and decompresses the inside of the inspection chamber 400 by opening and closing a gate valve (not shown) installed in the flow path of the vacuum pump.

The pressurizing means 306 is a device that sends a gas having a predetermined atmospheric pressure into the examination room 400. In this embodiment, for example, compressed nitrogen gas is introduced from the pressurizing means 306 into the laboratory 400. In the present embodiment, the pressurizing means 306 pressurizes the inside of the examination room 400 decompressed by the depressurizing means 305 for a predetermined period.

The control unit 307 includes a CPU, a storage device, and the like. For example, the CPU executes a program stored in the storage device, performs various processes based on the data stored in the storage device, and controls the overall operation of the leak inspection device 300.

As shown in FIG. 11, the control unit 307 includes an impedance change amount calculation unit 309, a time change amount calculation unit 310, a pressure gradient ratio calculation unit 311 and a leak amount calculation unit 312. The impedance change amount calculation unit 309, the time change amount calculation unit 310, and the pressure gradient ratio calculation unit 311 constitute an impedance change acquisition unit.

The impedance change amount calculation unit 309 calculates the impedance change amount based on the impedance value measured by the measurement unit 304. Specifically, the impedance change amount calculation unit 309 forms a decompression curve and a pressurization curve defined by the relationship between the impedance change and time based on the impedance value measured by the measurement unit 304. Then, the amount of change in impedance is obtained on the decompression curve and the pressurization curve. As shown in FIG. 7, the impedance change amount is determined by determining _{the impedance values (Z x} , Z _s ) of the same two points on the decompression curve a and the pressurization curve b. The reduced pressure curves a, a change in the impedance between any impedance value (Z _x), decompressed laboratory 400 to the crystal oscillator 1 for a predetermined period (t _s1) impedance value when placed with (Z _{s) Let the} amount be the first impedance change amount (ΔZ d). Further, in the pressurization curve b, the amount of change in impedance between the impedance value (Z _s ) and an arbitrary impedance value (Z _x ) when the crystal oscillator 1 is arranged in the inspection room 400 for a predetermined period ( _{ts 2).} Is the second impedance change amount (ΔZ _u ). Since the first impedance change amount (ΔZ _d ) and the second impedance change amount (ΔZ _u ) are the same value, a representative value is set as the impedance change amount (ΔZ).

The impedance change amount (ΔZ) is ideally obtained on the decompression curve a and the pressurization curve b _{with reference to the impedance values (Z x} ) (Z _s ) of the same two points, but the decompression curve a and the pressurization. In the curve b, it may be determined based on the impedance values of two points that are not the same. When the two corresponding impedance values on the decompression curve a and the pressurization curve b are close to each other, the two values are approximated to be the same impedance value (Z _x ) or (Z _s ) as the reference impedance value. And. When the two corresponding impedance values are distant values, the same impedance value (Z _x ) or (Z _s ) is obtained by using a conversion formula prepared separately, and is used as a reference impedance value.

The time change amount calculation unit 310 calculates the time change corresponding to the impedance change amount (ΔZ). The time change amount calculation unit 310 determines the time between the first time (t _x 1) and the second time ( _{ts 1) corresponding to the impedance values (Z x} , Z _{s) at two points on the decompression curve a.} a first time variation amount of the amount of change defined as (Δt _d), the pressurization curve b, the impedance value of two points _(Z x, Z _s) third time corresponding to _{(t x2)} and the fourth defined as the time the second time variation amount of transition time between the _{(t s2) (Δt u)} .

In the time corresponding to the impedance values of the two points, the second time t _s1 and the third time t _s2 may be the same time. If the same time is _{t s, t x1, t s} , using the three values of _{t x2,} be determined first time variation amount of (Delta] t _d) a second time change amount (Delta] t _u) Because it can be done, the processing can be speeded up.

Pressure gradient ratio calculating unit 311, the impedance variation and ([Delta] Z), a first time variation amount of (Delta] t _d), the second time variation amount from the (Delta] t _u), by Equation 9 pressure gradient ratio (gamma) Ask.

_{The leak amount calculation unit 312 obtains the internal pressure (P s} ) of the crystal oscillator 1 from the pressure gradient ratio (γ) from the equation 4, and from the obtained internal pressure (P _s ) and the elapsed time (Δt), the equation 7 Alternatively, the amount of leakage of the gas leaking from the crystal oscillator 1 is obtained by the equation 8.

(Calculation method of leak amount)
A method of calculating the leak amount using the leak inspection device 300 will be described with reference to the flowchart of FIG.

A tray 14 on which a plurality of crystal oscillators 1 are placed is carried into the inspection room 400 of the leak inspection device 300 shown in FIG. 10 and mounted on the stage 301. Subsequently, the contact block 303 is lowered to bring the peripheral edge portion of the contact block 303 into close contact with the upper surface of the stage 301 to form a closed space between the contact block 303 and the stage 301. Then, the contact pins 302a and 302b of the contact probe 302 are lowered and brought into contact with the external electrodes 211a and 211b of the crystal oscillator 1 to start the calculation of the leak amount.

First, the inside of the examination room 400 is decompressed by the decompression means 305, and the crystal oscillator 1 is arranged in the examination room 400 for the first predetermined time. After that, the inside of the examination room 400 is pressurized by the pressurizing means 306, and the second predetermined time crystal oscillator 1 is arranged. The pressure in the examination room 400 is monitored by the pressure gauge 400a. The measuring unit 304 measures the impedance of the crystal oscillator 1 during the first predetermined time and the second predetermined time (step S101).

Then, the impedance change amount calculation unit 309 forms a decompression curve a and a pressurization curve b based on the measured impedance, and forms a first impedance change amount (ΔZ _d ) and a second impedance change amount (ΔZ _u). ), That is, the amount of change in impedance (ΔZ) is calculated (step S102) (step of calculating the amount of change in impedance).

Time change amount calculation unit 310, the impedance variation from ([Delta] Z), a first time variation amount (Delta] t _d) and the second time variation (Delta] t _u) asking (temporal change amount calculation step), the pressure gradient ratio The calculation unit 311 obtains the pressure gradient ratio (γ) by the formula 9 (step S103) (pressure gradient ratio calculation step). The impedance change acquisition step is composed of the impedance change amount calculation step, the time change amount calculation step, and the pressure gradient ratio calculation step.

_{The leak amount calculation unit 312 calculates the internal pressure (P s} ) of the crystal transducer 1 by the equation 4 based on the pressure gradient ratio (γ) obtained by the pressure gradient ratio calculation unit 311 (step S104). The leak amount (Q) is calculated by the formula 7 or 8 based on the internal pressure (P _{s) (step S105) (leakage amount calculation step).}

(Example of using leak inspection device)
Next, an example of using the leak inspection device according to the present embodiment will be described. When manufacturing an electronic component, for example, a crystal oscillator, the leak inspection device according to the present embodiment is used, for example, after the crystal oscillator is vacuum-sealed. The features when the leak inspection device according to the present embodiment is used after the vacuum sealing step will be described with reference to comparative examples.

FIG. 13 shows an example of use when the leak inspection device is installed in the subsequent process of the vacuum sealing device. FIG. 13A is a diagram showing a state in which the leak inspection device of the present embodiment is connected to the vacuum sealing device, and FIG. 13B is a state in which the leak inspection device of the comparative example is connected to the vacuum sealing device. It is a figure which shows. In the figure, only the state in which the vacuum sealing device and the leak inspection device are connected is shown, and the previous process of the vacuum sealing device is not shown.

In the comparative example, as shown in FIG. 13B, the vacuum sealing device 500 and the leak inspection device 503 are connected to the take-out chamber 501 via the vacuum tank 502. The vacuum sealing device 500 includes an exhaust means (not shown), and vacuum seals the crystal oscillator 1 while transporting a transport tray 504 on which a plurality of crystal oscillators 1 are mounted in a vacuum atmosphere formed by the exhaust means. Execute a stop. The vacuum sealing device 500 includes a heating and pressurizing device 505 that heats and pressurizes the crystal oscillator 1, and a cooling device 506 that cools the crystal oscillator 1. The crystal oscillator 1 is sandwiched between the heating and pressurizing members in the heating and pressurizing device 505 with the joining member 23 coated between the base 21 and the lid 22, and is heated and pressurized, and the base 21 and the lid 22 are heated and pressurized. (See FIGS. 1A and 1B for the specific structure of the crystal oscillator 1), and the package 20 of the crystal oscillator 1 is hermetically sealed. After that, the transport tray 504 is sent to the cooling device 506, and the crystal oscillator 1 is cooled.

The vacuum chamber 502 includes an exhaust means and a transfer portion (not shown), and the crystal oscillator 1 conveyed from the vacuum sealing device 500 via the take-out chamber 501 in a vacuum atmosphere is transferred from the transfer tray 504 to the inspection tray 507. Transferred to. In the case of seam welding, the crystal oscillator 1 is inverted. The crystal oscillator 1 mounted on the transport tray 504 and the inspection tray 507 is pressed by the work retainer 508 so that the transport tray 504 and the inspection tray 507 do not shift during movement.

The inspection tray 507 on which the crystal oscillator 1 is mounted is carried into the leak inspection device 503 from the transfer portion of the vacuum chamber 502. The vacuum chamber 502 includes an exhaust means (not shown), and is exhausted by the exhaust means to maintain a vacuum atmosphere.

The leak inspection device 503 includes a leak inspection unit 503a and a storage unit 503b for accommodating the leak inspection unit 503a. An exhaust means and a pressurizing means (not shown) are attached to the accommodating portion 503b. The inside of the accommodating portion 503b is created in a vacuum atmosphere by the exhaust means, and the crystal oscillator 1 mounted on the inspection tray 507 from the vacuum tank 502 is carried into the leak inspection device 503. After the inside of the accommodating portion 503b is pressurized by the pressurizing means, the CI value of the crystal oscillator 1 is measured by the leak inspection unit 503a. The inspection tray 507 for which the inspection has been completed is carried out from the leak inspection device 503.

In the comparative example, it is necessary to maintain the internal pressure of the crystal oscillator 1 vacuum-sealed by the vacuum-sealing device 500 and inspect it by the leak inspection unit 503b. Therefore, the vacuum tank 502 is required, and the capacity of the leak inspection device 503 increases in order to maintain the vacuum atmosphere. The leak inspection device 503 requires a capacity of, for example, 50 liters. Further, since the capacity of the leak inspection device 503 is large, it takes time to exhaust and pressurize the leak inspection device 503, and the tact time is extended.

Further, since it is necessary to arrange the vacuum chamber 502, the connection structure between the vacuum sealing device 500 and the leak inspection device 503 becomes complicated and large in size. When the leak inspection device 503 is added to the existing vacuum sealing device 500 later, the vacuum sealing device 500 is not designed so that it can be connected in a vacuum. It is not easy to hold it, and it may be subject to major modifications.

On the other hand, the case where the leak inspection device 300 according to the present embodiment is connected to the existing vacuum sealing device 500 is shown in FIG. 13 (a). The configuration of the vacuum sealing device 500 is the same as that of the comparative example, and the vacuum sealing device 500 includes a heating and pressurizing device 505 and a cooling device 506. The method of vacuum-sealing the package 20 of the crystal oscillator 1 with the heating and pressurizing device 505 is the same as that of the comparative example, and the description thereof will be omitted.

The transport tray 504 containing the airtightly sealed crystal oscillator 1 is carried into the take-out chamber 501 from the vacuum sealing device 500 in the same manner as in the comparative example. Then, the transport tray 504 is carried out from the take-out chamber 501, and the crystal oscillator 1 is transferred from the transport tray 504 to the inspection tray 507 under an atmospheric pressure atmosphere. If necessary, the inspection tray 507 is flipped. The inspection tray 507 is carried into the leak inspection device 300, inspected for leaks, and then carried out from the leak inspection device 300.

The leak inspection device 300 of the present embodiment corresponds to the leak inspection unit 503a of the comparative example, but does not need to be arranged in a vacuum atmosphere. Therefore, only the inside of the leak inspection device 300 corresponding to the leak inspection unit 503a needs to be evacuated and pressurized. Specifically, it is sufficient to vacuum exhaust and pressurize a minute space around the inspection tray 507, for example, an inspection chamber having a capacity of 40 ml, and the exhaust means and the pressurizing means can be miniaturized. Since the internal capacity of the leak inspection device 300 is small, the exhaust and pressurization times are short, and the tact time is shortened. The leak inspection device 300 can individually determine gross leak and fine leak by one unit at a small size and low cost.

Further, since the transfer is performed on the inspection tray 507 in an atmospheric pressure atmosphere, the degree of freedom in design is high, and the device can be easily connected to the existing vacuum sealing device 500. Further, the vacuum chamber 502 and the accommodating portion 503b are unnecessary as in the comparative example, and the connection structure between the vacuum sealing device 500 and the leak inspection device 300 can be made compact and simple. Further, since the CI value is measured by pressurizing the CI value to an atmospheric pressure or higher based on the CI value in a vacuum atmosphere, the amount of change in the CI value is large and the leak amount can be calculated with high accuracy.

According to this embodiment, not only the presence or absence of leaks but also the amount of leaks can be calculated, so that the yield of the product can be improved.

According to the present embodiment, the leak amount can be calculated from the change in the impedance of the crystal oscillator 1 under a pressure higher than the internal pressure and the change in the impedance of the crystal oscillator 1 under a pressure lower than the internal pressure. The amount of leak can be appropriately obtained by a simple method.

According to the present embodiment, the change in the impedance of the crystal oscillator 1 is regarded as a gradient, and the leak amount can be obtained from the change in the gradient. Therefore, the leak amount can be easily calculated by an existing measuring instrument, for example, a network analyzer. can do.

According to this embodiment, the leak amount can be easily calculated from the time per unit time and the change amount of impedance, and an appropriate leak inspection can be performed.

According to the present embodiment, the inspection device can be applied to both the gross leak inspection for inspecting a large leak and the fine leak inspection for inspecting a small leak, so that the inspection device can be simplified. ..

According to the present embodiment, the leak amount can be calculated by leaving the crystal oscillator 1 in a reduced pressure and pressurized atmosphere for a predetermined time (ts), so that the leak amount does not take time as in the helium leak inspection. Can be measured.

According to this embodiment, the leak amount can be calculated even when the history before the leak inspection is unknown, such as the difference in the exhaust time before the inspection or the leaving time in the atmosphere.

According to the present embodiment, since the depressurizing means 305 and the pressurizing means 306 are connected to one inspection chamber 400, it is not necessary to perform depressurizing and pressurizing in separate inspection chambers, and the apparatus becomes compact.

According to this embodiment, since the impedance is continuously measured by depressurizing and pressurizing in the same inspection room 400, the positions of the contact pins 302a and 302b are displaced, and the strokes of the contact pins 302a and 302b are changed. It does not affect the CI value by doing so.

In the present embodiment, the depressurizing means 305 and the pressurizing means 306 are attached to the same examination room 400, but may be attached to different examination rooms.

In the present embodiment, it has been described that the contact block 303 moves up and down and the contact pins 302a and 302b come into contact with the external electrodes 211a and 211b, but the stage 301 may move up and down.

In the present embodiment, the method of calculating the leak amount by depressurizing and then pressurizing has been described, but the leak amount may be calculated by depressurizing and then depressurizing, which is the opposite pattern.

The present invention can be used in a leak inspection method and a leak inspection device for electronic components.

1 Crystal transducer 10 Crystal pieces 11a, 11b Excitation electrode 13 Conductive adhesive 14 Tray 20 Package 21 Base 211 Bottom 211a, 211b External electrodes 211c, 211d Internal electrodes 212 Wall 22 Lid 23 Joint member 300 Leak inspection device 301 Stage 302 Contact probe 302a, 302b Contact pin 303 Contact block 304 Measuring unit 305 Pressure reducing means 306 Pressurizing means 307 Control unit 308 Packing 309 Impedance change amount calculation unit 310 Time change amount calculation unit 311 Pressure gradient ratio calculation unit 312 Leakage amount calculation unit 400 Inspection Room 400a Pressure gauge 500 Vacuum sealing device 501 Extraction room 502 Vacuum tank 503 Leak inspection device 503a Leak inspection unit 503b Storage unit 504 Transport tray 505 Heating and pressurizing device 506 Cooling device 507 Inspection tray 508 Work holder

Claims (9)

This is a leak inspection method that calculates the amount of leakage of electronic components in which the piezoelectric element is sealed.
The electronic component is placed in an atmosphere of a pressure lower than the internal pressure of the electronic component for a first predetermined time, a change in the first impedance of the piezoelectric element is acquired, and an atmosphere of a pressure higher than the internal pressure of the electronic component is obtained. An impedance change acquisition step of arranging the electronic component underneath for a second predetermined time and acquiring a change in the second impedance of the piezoelectric element, and
A leak amount calculation step of calculating the leak amount of the gas leaking from the electronic component from the change of the first impedance and the change of the second impedance is provided.
Leak inspection method. The change in the first impedance is a first gradient in which the change in the first impedance is indicated by a gradient.
The change in the second impedance is a second gradient in which the change in the second impedance is indicated by a gradient.
The leak amount of the electronic component is calculated from the first gradient and the second gradient.
The leak inspection method according to claim 1. The relationship between the time per unit time of the first predetermined time and the change in impedance was obtained, or the relationship between the time per unit time in the second predetermined time and the change in impedance was obtained and obtained. Calculate the leak amount of the electronic component from the relationship,
The leak inspection method according to claim 1. The impedance change acquisition step is
A decompression curve formed from the relationship between the first impedance change and time and a pressurization curve formed from the relationship between the second impedance change and time are formed and differ in the decompression curve. Impedance change amount based on the change of the impedance value (Z _x , Z _s , Z _x > Z _s ) of the two points, or based on the change of the impedance value at the same two points as the impedance value of the two points in the pressurization curve. Impedance change amount calculation process to obtain (ΔZ) and
_{The first time change amount (Δt d} ) is obtained based on the time corresponding to the impedance values of the two points on the decompression curve, and the second time is based on the time corresponding to the impedance values of the two points on the pressurization curve. and time variation amount calculation step of calculating the time variation (Delta] t _u) of,
Since the impedance change amount ([Delta] Z) and the first time variation amount (Delta] t _d) and the second time variation amount of (Δt _u), a pressure reducing pressure gradient indicating a gradient of the decompression curve of the pressurization curve A pressure gradient ratio calculation step for obtaining a pressure gradient ratio (γ), which is a ratio to a pressure gradient indicating a gradient, is provided.
The leak amount calculation step is
_{The internal pressure (P s} ) of the electronic component is obtained from the pressure gradient ratio (γ), and the leak amount (Q) of the gas leaking from the electronic component is obtained from the internal pressure (P _{s) and the elapsed time.}
The leak inspection method according to claim 1. _{In the decompression curve, the impedance value changes from Z x,} which is the impedance value of the two points, to Z _s , and the time changes from the first time corresponding to _{Z x} to the second time corresponding _{to Z s.} death,
In the pressurization curve, the impedance value changes from Z _s, which is the impedance value of the two points, _{to Z x} , and the time changes from the third time corresponding to Z s to the fourth time corresponding to Z x. ,
The second time and the third time are the same time.
The leak inspection method according to claim 4. The pressure gradient ratio (γ) is
Calculated by γ = (ΔZ / Δt _d ) / (ΔZ / Δt _u),
([Delta] Z, the impedance variation, Delta] t _d, the first time variation, Delta] t _u, the second time variation)
The internal pressure (P _s ) is
Calculated by P _s = (γP _h + P _l ) / (γ + 1)
_{(P h,} the pressure value of the pressurization, the pressure value of _{P l} is during decompression)
The leak amount (Q) is
Q = calculated by _{-VΔP · P atm / (P s} -P l) Δt or _{Q = VΔP · P atm / (} P h -P s) Δt,
(V is the internal volume of the piezoelectric element, _Patm is the atmospheric pressure, Δt is the elapsed time)
The leak inspection method according to claim 4 or 5. A leak inspection device that calculates the amount of leakage of electronic components in which a piezoelectric element is sealed.
A decompression means for reducing the pressure in the inspection space where the electronic components are arranged, and
A pressurizing means for pressurizing the inspection space in which the electronic component is arranged, and a pressurizing means.
An impedance change acquisition unit that measures the impedance of the piezoelectric element of the electronic component arranged in the inspection space and acquires a change in impedance, and the electronic component is in the inspection space decompressed by the decompression means. Is placed for a first predetermined time, then the impedance of the piezoelectric element is measured to obtain a change in the first impedance, and the electronic component is placed in the inspection space pressurized by the pressurizing means for a second predetermined time. After that, the impedance change acquisition unit that measures the impedance of the piezoelectric element and acquires the change in the second impedance, and the impedance change acquisition unit.
A leak amount calculation unit for obtaining a leak amount of a gas leaking from an electronic component from a change in the first impedance acquired by the impedance change acquisition unit and a change in the second impedance is provided.
Leak inspection equipment. The impedance change acquisition unit is
A decompression curve formed from the relationship between the first impedance change and time and a pressurization curve formed from the relationship between the second impedance change and time are formed and differ in the decompression curve. An impedance change amount calculation unit that obtains an impedance change amount based on a change in the impedance value at two points or based on a change in the impedance value at two points that are the same as the impedance value at the two points in the pressurization curve.
The first time change amount is obtained based on the time corresponding to the impedance values of the two points on the decompression curve, and the second time change amount is obtained based on the time corresponding to the impedance values of the two points on the pressure curve. Time change amount calculation unit to find
From the impedance change amount, the first time change amount, and the second time change amount, the ratio of the decompression pressure gradient indicating the inclination of the decompression curve to the pressurization pressure gradient indicating the inclination of the pressurization curve is used. A pressure gradient ratio calculation unit for obtaining a certain pressure gradient ratio is provided.
The leak amount calculation unit
The internal pressure of the electronic component is obtained from the pressure gradient ratio, and the amount of gas leaking from the electronic component is obtained from the internal pressure and the elapsed time.
The leak inspection device according to claim 7. The inspection space was formed in the same inspection chamber, and the depressurizing means and the pressurizing means were connected to the inspection chamber.
The leak inspection device according to claim 7 or 8.

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