CN113324709A

CN113324709A - Leak inspection method and leak inspection apparatus

Info

Publication number: CN113324709A
Application number: CN202110225279.3A
Authority: CN
Inventors: 塩野忠久; 迹边好寿
Original assignee: Showa Shinku Co Ltd
Current assignee: Showa Shinku Co Ltd
Priority date: 2020-02-28
Filing date: 2021-03-01
Publication date: 2021-08-31
Also published as: JP2021135239A; JP7470373B2

Abstract

Provided are a leak inspection method and a leak inspection apparatus which are compact, can calculate the amount of leakage of an electronic component regardless of the presence or absence of leakage, can be easily assembled into a conventional apparatus, and have a high degree of freedom in design. In the leak inspection method, a quartz resonator is arranged at a pressure lower than the internal pressure of the quartz resonator for a 1 st predetermined time, and the change Δ Z of the 1 st impedance of the quartz resonator is acquired_dThe quartz resonator is arranged at a 2 nd predetermined time under a pressure higher than the internal pressure of the quartz resonator, and the change DeltaZ of the 2 nd impedance of the quartz resonator is obtained_uAccording to the change of the 1 st impedance Δ Z_dAnd 2 nd change in impedance Δ Z_uThe internal pressure of the quartz resonator was obtained, and the leakage amount was calculated.

Description

Leak inspection method and leak inspection apparatus

Technical Field

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

Background

In a small electronic component in which a piezoelectric element is sealed in a package, the inside of the package is evacuated or an inert gas is injected into the package to seal the package in order to maintain the performance of a circuit. And, it was confirmed by leak check that the package was surely sealed and no leak (leak) occurred. The leak check includes both a total leak check for checking a large leak and a fine leak check for checking a small leak.

As the total leakage inspection, for example, there is a bubble leakage inspection in which the package is immersed in hot water to expand the package, and when the package is insufficient, the expanded air leaks out as bubbles, or an air leakage inspection in which when a reference substance that does not leak and a test substance that leaks are added to two sealed containers described in patent document 1 and pressurized, the pressure on the side of the test substance that leaks is lowered, and the pressure difference generated between the reference substance and the test substance is observed, and the leak is determined. In addition, the fine leak inspection is an inspection in which, for example, the package is pressurized in an inspection container filled with helium gas, helium gas is pressed into the package from the small hole if there is a small hole, and then the inside of the inspection container is depressurized and the helium gas leaking from the package is measured to confirm the presence of the small hole.

In the total leak test, the bubble leak test is visually checked and lacks reliability, and there is a problem that the air leak test cannot detect a minute leak. The helium leak test, which is a fine leak test, has an advantage of high leak detection sensitivity, but has a problem of time consumption due to the use of helium gas and a disadvantage of requiring a total leak tester because the leak hole is large and cannot be detected. In addition, in order to shorten the processing time, a plurality of processes must be performed simultaneously, and it is difficult to determine leakage of an electronic component to be inspected individually. For example, when a plurality of helium leak tests are performed at the same time and there is a defect, the helium leak tests are performed for each group after dividing the helium leak tests into a plurality of groups. Groups in which no leak is found are further grouped, helium leak inspection is performed, and this recheck is repeated to find out the electronic component that is leaking. Since helium is not refilled during the re-inspection, helium may be exhausted depending on the amount of leakage, and a defective product may not be sufficiently limited, and may be discarded as a defective product mixed group together with the good product. Further, to perform the total leak inspection and the fine leak inspection by 1 apparatus, a large-sized dedicated apparatus is required.

However, the leak check may be performed using a change in the impedance of the piezoelectric element. This inspection is an inspection method using the variation of the impedance of the piezoelectric element with pressure. For example, as disclosed in patent document 2, a piezoelectric element is placed in an inspection chamber and reduced in pressure from the atmospheric pressure, and if there is no change in the impedance of the piezoelectric element due to the reduction in pressure, it is determined that there is no leak, and if there is a change in the impedance, it is determined that there is a leak. In patent document 3, when an electronic component is pressurized from the atmospheric pressure and the impedance variation is equal to or more than a set value, it is determined that the airtightness is poor. In patent document 4, an airtight sealed chamber and an inspection chamber are arranged in series, and a leak is inspected by comparing a crystal impedance (hereinafter, referred to as "CI value") in a vacuum environment after vacuum sealing with a CI value in the inspection chamber in a pressurized environment.

Documents of the prior art

Patent document

[ patent document 1 ] Japanese patent laid-open publication No. Sho 49-59692

[ patent document 2 ] Japanese patent application laid-open No. 11-51802

[ patent document 3 ] International publication No. 2008/038383

[ patent document 4 ] Japanese patent laid-open No. 2012 and 257152

When the leak inspection method disclosed in patent document 2 or patent document 3 is used as the leak inspection, the presence or absence of a leak can be inspected, but the amount of leak cannot be accurately measured. When the vacuum-sealed piezoelectric element is released from the atmosphere, the pressure inside the package of the piezoelectric element gradually rises through the leak hole. The leakage amount is extremely small and it takes a sufficiently long time until the package internal pressure and the external pressure are equal, and therefore the package internal pressure and the external pressure are often inconsistent at the start of the leak check. When the leak inspection is performed by the method of patent document 2 or patent document 3 for the piezoelectric element in which the piezoelectric element after vacuum packaging is released to the atmosphere, the initial value of the internal pressure of the package is unknown, and the leak amount cannot be calculated. Even when the leak inspection of the piezoelectric element is repeated, the internal pressure at the start of measurement differs depending on the history of the exhaust or pressurization in re-measurement, and thus the CI value change amount differs, and the leak amount cannot be calculated from the CI value change amount.

In patent document 4, since the CI value is measured without atmospheric release after vacuum packaging, the initial value of the package internal pressure can be accurately obtained with the CI value measured by the known package internal pressure as a reference, and thus the leak amount can be calculated from the CI value change amount. However, since it is necessary to maintain the vacuum from the vacuum sealing to the leak inspection, and the vacuum sealing apparatus and the inspection apparatus are connected by the vacuum tank, there is a problem that the apparatus becomes large in size. Further, in order to connect the sealing device and the inspection device, it is necessary to share a storage tray for the piezoelectric element or separately provide a conveyor, and it is not easy to connect the inspection device to the conventional vacuum sealing device. Further, it is difficult to calculate the leakage amount as in

patent document

2 or 3, for the leakage amount measurement and re-measurement after taking out once under atmospheric pressure, such as the piezoelectric element which cannot measure the CI value in vacuum due to a device failure, and the defect return after delivery.

In the inspection method in which only the presence or absence of a leak is known, an electronic component having a leak is determined to be a defective product. However, even if there is a leak, if the leak amount is a predetermined allowable value, the performance of the electronic component is not greatly affected. If the leakage amount can be calculated, the allowable value of the leakage amount can be determined, and thus the yield of the product is also improved, so that it is important to calculate the leakage amount.

Disclosure of Invention

The present invention has been made in view of the above circumstances, and an object thereof is to provide a leak inspection method capable of calculating the amount of leakage from an electronic component regardless of the presence or absence of leakage from the electronic component, and a leak inspection apparatus which is small in size, easy to assemble into a conventional apparatus, and has a high degree of freedom in design.

A leak inspection method according to a first aspect of the present invention is a leak inspection method for calculating a leak amount of an electronic component that encapsulates a piezoelectric element, the leak inspection method including:

an impedance change acquiring step of acquiring a 1 st impedance change of the piezoelectric element by disposing the electronic component for a 1 st predetermined time in an environment of a pressure lower than an internal pressure of the electronic component, and acquiring a 2 nd impedance change of the piezoelectric element by disposing the electronic component for a 2 nd predetermined time in an environment of a pressure higher than the internal pressure of the electronic component; and

and a leakage amount calculation step of calculating a leakage amount of the gas leaked from the electronic component based on the change in the 1 st impedance and the change in the 2 nd impedance.

The 1 st change in impedance is a 1 st gradient, the 1 st gradient showing the 1 st change in impedance by a gradient,

the change in the 2 nd impedance is a 2 nd gradient, the 2 nd gradient showing the change in the 2 nd impedance by a gradient,

the leakage amount of the electronic component can be calculated according to the 1 st gradient and the 2 nd gradient.

The degree of correlation between the time per unit time of the 1 st predetermined time and the change in impedance or the degree of correlation between the time per unit time of the 2 nd predetermined time and the change in impedance is obtained, and the leak amount of the electronic component can be calculated from the obtained degree of correlation.

The impedance change acquiring step includes:

an impedance change amount calculation step of forming a decompression curve formed from a relationship between a change in the 1 st impedance and time and a pressurization curve formed from a relationship between a change in the 2 nd impedance and time, and obtaining an impedance change amount (Δ Z) from a change in an impedance value at 2 points different from the decompression curve or from a change in an impedance value at 2 points equal to the impedance value at 2 points on the pressurization curve;

a time variation calculation step of obtaining a 1 st time variation (Δ t) from the time corresponding to the impedance value at the 2 points on the pressure-reduction curve_d) And obtaining a 2 nd time variation (Deltat) from the time corresponding to the impedance value at the 2 points on the pressurization curve_u) (ii) a And

a pressure gradient ratio calculation step of calculating a pressure gradient ratio based on the impedance change amount (Δ Z) and the 1 st time change amount (Δ t)_d) And the 2 nd time variation (Δ t)_u) Determining a pressure gradient ratio (gamma), toThe pressure gradient ratio (γ) is a ratio between a decompression pressure gradient showing a slope of the decompression curve and a pressurization pressure gradient showing a slope of the pressurization curve,

the leakage amount calculating step may calculate an internal pressure (P) of the electronic component from the pressure gradient ratio (γ)_s) According to the internal pressure (P)_s) And determining the leakage amount (Q) of the gas leaked from the electronic component after the time elapses.

On the decompression curve, the impedance value is from Z as the impedance value of the 2 points_xTo Z_sChange, time from and Z_xCorresponding time 1 to Z_sAt the corresponding time 2, the time of day,

on the pressure curve, the impedance value is from Z as the impedance value of the 2 points_sTo Z_xChange, time from and Z_sCorresponding time 3 to Z_xAt the corresponding time 4, the time of day,

the 2 nd time and the 3 rd time may be the same time.

Can be represented by (Δ Z/Δ t)_d)/(ΔZ/Δt_u) -calculating said pressure gradient ratio (gamma),

(Δ Z is the amount of change in impedance,. DELTA.t)_dIs the 1 st time variation, Δ t_uIs the 2 nd time variation amount)

By P_s＝(γP_h+P_l) V (γ +1) calculating the internal pressure (P)_s)，

(P_hIs the pressure value at the time of pressurization, P_lIs the pressure value at the time of decompression)

By Q ═ V.DELTA.P.P_atm/(P_s－P_l) Δ t or

Q＝VΔP·P_atm/(P_h－P_s) Δ t calculates the leakage (Q).

(V is the internal volume of the piezoelectric element, P_atmIs atmospheric pressure,. DELTA.t is elapsed time)

A leak inspection apparatus according to a second aspect of the present invention is a leak inspection apparatus for calculating a leak amount of an electronic component that encapsulates a piezoelectric element, the leak inspection apparatus including:

a decompression unit configured to decompress an inspection space in which the electronic component is disposed;

a pressurizing unit that pressurizes the inspection space in which the electronic component is disposed;

an impedance change acquiring unit that measures impedance of the piezoelectric element of the electronic component disposed in the inspection space to acquire a change in impedance, wherein the impedance of the piezoelectric element is measured to acquire a 1 st impedance change after the electronic component is disposed in the inspection space decompressed by the decompression unit for a 1 st predetermined time, and the impedance of the piezoelectric element is measured to acquire a 2 nd impedance change after the electronic component is disposed in the inspection space decompressed by the compression unit for a 2 nd predetermined time; and

and a leakage amount calculation unit that obtains a leakage amount of the gas leaking from the electronic component from the change in the 1 st impedance and the change in the 2 nd impedance acquired by the impedance change acquisition unit.

The impedance change acquiring unit includes:

an impedance change amount calculation unit that forms a decompression curve formed from a relationship between a change in the 1 st impedance and time and a pressurization curve formed from a relationship between a change in the 2 nd impedance and time, and obtains an impedance change amount from a change in an impedance value at 2 points different from the decompression curve or from a change in an impedance value at 2 points that is the same as the impedance value at 2 points on the pressurization curve;

a time change amount calculation unit that obtains a 1 st time change amount from a time corresponding to the impedance value at the 2 point on the pressure reduction curve, and obtains a 2 nd time change amount from a time corresponding to the impedance value at the 2 point on the pressure increase curve; and

a pressure gradient ratio calculation unit that obtains a pressure gradient ratio, which is a ratio between a decompression pressure gradient indicating a slope of the decompression curve and a pressurization pressure gradient indicating a slope of the pressurization curve, from the impedance change amount, the 1 st time change amount, and the 2 nd time change amount,

the leakage amount calculation unit may calculate an internal pressure of the electronic component from the pressure gradient ratio, and may calculate a leakage amount of the gas leaked from the electronic component from the internal pressure and an elapsed time.

The inspection space is formed in the same inspection chamber, and the decompression unit and the pressurization unit may be connected to the inspection chamber.

Effects of the invention

The present invention can provide a leak inspection method capable of calculating the amount of leakage from an electronic component regardless of the presence or absence of leakage from the electronic component, and a leak inspection apparatus that is small in size, easy to assemble in an existing apparatus, and has a high degree of design freedom.

Drawings

Fig. 1A is a plan view of a quartz resonator with a cover removed, showing a quartz resonator for which a leakage amount is calculated by a leakage amount calculation method according to an embodiment.

Fig. 1B is a sectional view taken along line a-a of fig. 1A.

Fig. 2 is a graph showing changes in pressure outside the quartz resonator over time in the reference example.

Fig. 3 is a graph showing a relationship between the amount of leakage and the amount of change in impedance in accordance with the standing time in the reference example.

Fig. 4 is a graph showing a relationship between an actual leak amount and a measured value of He flow rate in the helium leak inspection.

Fig. 5 is a diagram showing a change in pressure in the package of the quartz resonator when the pressure in the package is reduced for a certain period of time and then increased.

Fig. 6 is a diagram showing a change in pressure in the package of the quartz resonator when the interior of the package is pressurized for a certain period of time and then depressurized.

Fig. 7 is a diagram illustrating the principle of the leak inspection method according to the present embodiment.

Fig. 8 is a graph showing the relationship between the pressure change and the ratio of the time change to the pressure change amount, the ratio of the time change to the impedance change amount, and the pressure gradient ratio when the pressure is increased after the pressure inside the package of the quartz resonator is reduced.

Fig. 9 is a diagram illustrating another principle of the leak inspection method according to the present embodiment.

Fig. 10 is a conceptual diagram of the leak inspection apparatus.

Fig. 11 is a block diagram of the leak inspection apparatus.

FIG. 12 is a flow chart diagram of a leak check method.

Fig. 13A is a diagram showing an example of use of the leak inspection apparatus according to the present embodiment, and showing an example of use of the leak inspection apparatus according to the present embodiment in a subsequent step of the vacuum sealing apparatus.

Fig. 13B is a diagram showing an example in which the leak inspection apparatus according to the comparative example is used in a subsequent step of the vacuum sealing apparatus.

Detailed Description

Hereinafter, embodiments of a leak inspection apparatus and a measurement method according to the present invention will be specifically described with reference to the drawings. The embodiments described below are merely illustrative and do not limit the scope of the present invention. Therefore, those skilled in the art can adopt an embodiment in which these respective elements or all the elements and the equivalent elements are substituted, and these embodiments are also included in the scope of the present invention.

(Structure of Quartz vibrator)

A piezoelectric element used in a leak inspection method and a leak inspection apparatus according to an embodiment of the present invention will be described with reference to a quartz resonator as an example. In the drawings, the vertical and horizontal directions are defined, but these terms are only for describing the present embodiment and do not limit the direction in which the embodiment of the present invention is actually used. The technical scope described in the claims should not be construed as being limited by these terms.

Fig. 1 is a diagram showing a quartz resonator used in the leak inspection method and the inspection apparatus according to the present embodiment, fig. 1A is a plan view showing a state where a cover of the quartz resonator is removed, and fig. 1B is a cross-sectional view taken along line a-a in a state where the cover of the quartz resonator shown in fig. 1A is provided.

The quartz resonator 1 includes a quartz piece 10 and a package 20 accommodating the quartz piece 10. The package 20 has a base 21 and a cover 22 closing an opening of an upper surface of the base 21. The opening in the upper surface of the base 21 is closed by the cover 22, thereby forming a closed space as an inspection space.

On the two opposing main surfaces of the quartz plate 10,

excitation electrodes

11a and 11b formed of a thin metal film for applying a voltage to the quartz plate 10 are formed by vapor deposition or sputtering. One end portions of the

excitation electrodes

11a and 11b are connected to

internal electrodes

211c and 211d of a susceptor 21, which will be described later, via a conductive adhesive 13 on the lower surface of the quartz plate 10. As the conductive adhesive 13, for example, an adhesive using silicone resin as a base material is used.

The susceptor 21 is made of a material such as metal, ceramic, glass, quartz, or resin, and has a space in which the quartz plate 10 is inserted, as shown in fig. 1B, and is a box-shaped member having an open upper portion. The base 21 has a bottom 211 and a wall 212 standing from the peripheral edge of the bottom 211. A pair of

external electrodes

211a and 211b for electrical connection with an external circuit board or the like are mounted on the lower surface of the bottom portion 211. A pair of

internal electrodes

211c and 211d are attached to the bottom surface of the inside of the base 21, and the internal electrode 211c and the excitation electrode 11a, and the internal electrode 211d and the excitation electrode 11b are connected to each other via a conductive adhesive 13. The

internal electrodes

211c, 211d are electrically connected to the

external electrodes

211a, 211b, and the

excitation electrodes

11a, 11b are connected to the

internal electrodes

211c, 211d, whereby the

excitation electrodes

11a, 11b are electrically connected to the

external electrodes

211a, 211b, respectively.

The lid 22 is a plate-like member made of a material such as metal, ceramic, glass, crystal, or resin, and closes an opening in the upper portion of the base 21 to form a closed space. The upper surface of the base 21, that is, the upper surface of the wall portion 212 is coated with a bonding member 23 such as silver solder, gold tin, nickel plating, or the like. The joining member 23 and the lid 22 are heat-fusion joined, whereby the base 21 and the lid 22 are joined, and the package 20 is hermetically sealed.

In the current miniaturized quartz resonator, the inside of the package 20 of the quartz resonator 1 is hermetically sealed under vacuum. As described above, there is a method for inspecting whether or not the electronic component is sealed, and whether or not there is a leak in the electronic component. However, in addition to the presence or absence of a leak, it is also important to identify the amount of leak to ensure product yield.

The principle of the leakage amount calculation method described in the present embodiment will be described with reference to the reference example. The leakage amount calculation method according to the present embodiment is a method using a characteristic that the impedance of the quartz resonator rises together with the pressure due to the friction between the quartz resonator and the gas molecules. The impedance of the quartz resonator increases in proportion to the pressure in the molecular flow region and increases in proportion to the 1/2 th power of the pressure in the viscous flow region. Therefore, a change in pressure inside the package of the quartz resonator (hereinafter referred to as "internal pressure") can be known by measuring a change in impedance, and it can be determined that a leak is occurring by recognizing the change in internal pressure.

(reference example)

As a method of checking the presence or absence of leakage based on the amount of change in the impedance of the quartz resonator, for example, there is a method of taking out a quartz piece after vacuum-sealing it in a package, measuring the CI value of the quartz, putting the package in an inspection chamber, reducing the pressure, measuring the CI value again, detecting the change in the pressure based on the change in the CI value, and determining the presence or absence of leakage (hereinafter referred to as "reference example 1"). There is also a method of taking out a quartz plate after vacuum-sealing it to a package, measuring the CI value, placing the package in an inspection chamber, pressurizing it, measuring the CI value again, detecting a pressure change based on a change in the CI value, and determining whether or not there is a leak (hereinafter referred to as "reference example 2"). These two methods of checking for the presence or absence of a leak (reference examples 1 and 2) can check for the presence or absence of a leak, but cannot measure the amount of a leak.

The reason why the leakage amount cannot be measured in reference examples 1 and 2 will be described with reference to reference example 2. Fig. 2 is a graph showing the relationship between the pressure (atmospheric pressure) outside the package and the elapsed time (t) when the quartz resonator, in which the inside of the package containing the quartz piece is sealed in vacuum, is placed at atmospheric pressure for a certain period (t1) and then the CI value is measured while being pressurized for a certain period (Δ t 2). When there is a leak in the quartz resonator, the size of the leak hole is different from each other, and therefore the internal pressure of each quartz resonator after the atmospheric pressure leaving time (t1) is also different from each other. Even when the atmospheric pressure holding time (t1) differs depending on the measurement order of the quartz resonators, the initial value of the internal pressure before pressurization differs among the quartz resonators.

FIG. 3 is a graph showing the amount of leakage (unit: Pam) corresponding to different standing times²Change amount of value of/s) and CI value (Δ Z: unit (Ω)). The internal volume V is 5E-12 m³The pressure in the package (2) was increased to 2.5E +5 Pa. The setting time (t1) was set to four patterns of 10 seconds, 60 seconds, 180 seconds, and 600 seconds, and the pressing time (Δ t2) was the same as 120 seconds. It is shown that when the leaving time (t1) is 10 seconds and 60 seconds, the CI value increases as the leakage amount increases, but the leakage amount goes to a decreasing peak value curve when it exceeds a certain value, and the leakage amount is not uniquely determined according to the change amount of the CI value. Further, even with the same leakage amount, the change amount (Δ Z) of the CI value differs for different internal pressure initial values. Even if the change amount (Δ Z) of the CI value is calculated, the leakage amount cannot be measured. This case is also the same as in reference example 1.

Further, even if a helium leak test, which is a fine leak test, is used, the leak amount cannot be accurately measured. In the helium leak test, a quartz resonator to be tested is put into a test chamber called bombing and pressurized for a certain period of time. When the quartz resonator has a leak portion due to pressurization, helium gas enters the inside of the quartz resonator from the leak portion. Hereinafter, the time for pressurizing the inside of the inspection chamber for a certain period of time to allow helium gas to enter the inside of the quartz resonator is referred to as a filling time. When the inspection chamber is evacuated by reducing the pressure in the inspection chamber, the helium gas entering the inside of the quartz resonator is released into the inspection chamber, and therefore the helium gas leaking from the quartz resonator can be measured by the helium detector.

In the helium leak test, a predetermined standing time is provided from the time when the helium gas is filled into the quartz resonator to the time when the helium detector measures the helium gas. In an area where the leakage amount of the quartz resonator is large, helium gas leaks from the quartz resonator during the standing time, and thus the flow rate of helium gas may be measured to be small. Also, in an area where the leakage amount is small, for example, in a filling time of about 60 minutes, helium gas is not sufficiently filled into the quartz resonator, and thus the flow rate of helium gas may be measured to be small. When the leak reaches 1/10, the helium fill reaches 1/10, and the helium flow measured is 1/100. The flow rate of helium becomes smaller by the square of the leakage rate.

In addition, in the helium leakage inspection, if re-inspection is performed, refilling of the quartz resonator with helium gas is required, and in an area where the leakage amount is small, the helium pressure after refilling becomes high every time refilling is performed, and the helium gas flow rate is measured to be large every time re-inspection is performed.

In order to examine the relationship between the actual leakage amount and the theoretical leakage amount, fig. 4 shows that the leakage amount of helium gas was measured after a quartz resonator was added to a container pressurized at a pressure of 0.5MPa and sealed with helium gas and left for 60 minutes. The internal volume V of the package is 1. E-10 m³. In this measurement, the time taken for measurement after the start of filling is 1 minute, and the time taken for refilling to start 60 minutes after the start of filling is 1 minute.

The graph shown in FIG. 4 shows the theoretical value of the leakage amount, the 1 st actual leakage amount, the 2 nd actual leakage amount of the helium gas refilled and measured, and the 5 th actual leakage amount of the helium gas refilled and measured, together with the helium measured value (unit: Pa · m)³S) of the first and second images. According to JIS, the actual leakage rate is expressed as the value under dry air at atmospheric pressure (unit: Pa · m)³In s). The theoretical value of the leakage amount corresponds to the amount of helium that takes a sufficiently long time to fill the helium gas so that the helium pressure inside and outside the package becomes equal and that leaks out from the inside of the package immediately after filling. Since the electric conductivity of the leak portion of the quartz resonator is the square root of the molecular weight ratio, helium gas has an electric conductivity 2.7 times that of air, and when helium gas of 5 atmospheres is filled in the package, a flow rate 13.5 times that of air (2.7 × 5 — 13.5 times) is measured. Therefore, the theoretical value of the leak amount of helium can be expressed as an air leak amount × 2.7 × 5.

As can be seen from the graph shown in fig. 4, the actual leakage amount coincides with the theoretical leakage amount value, and the range of the actual leakage amount that can be measured with high accuracy is only a very limited range, such as the range surrounded by the broken line. In this way, when the leak inspection using the CI value or the helium leak inspection is used, although the presence or absence of the leak can be determined, the leak amount cannot be accurately measured.

(principle of leakage amount calculation method according to the present embodiment)

The leakage amount calculation method according to the present embodiment is characterized in that the leakage amount can be calculated by estimating the internal pressure of the quartz resonator in a leakage inspection method using a CI value (hereinafter, also referred to as impedance).

The CI value in high vacuum is a CI value (hereinafter referred to as "Z") inherent to the quartz resonator regardless of the gas pressure₀Value ". ) And the sum of the change amount (Δ Z) with the CI value based on the pressure of the gas constitutes the CI value at a certain pressure. However, this Z₀The value differs for each quartz resonator. On the other hand, if the pressure is known as the CI value in the high vacuum or the atmospheric pressure, the pressure can be converted from the change amount of the CI value, and therefore, if the internal pressure of the quartz resonator is known, the change of the pressure can be converted from the change amount of the CI value. Thus, if the change in pressure is known, the amount of leakage can be calculated.

The applicant of the present invention has put the quartz resonator under reduced pressure for a predetermined period of time and then subject the quartz resonator to pressure, or put the quartz resonator under pressure for a predetermined period of time and then subject the quartz resonator to pressure reduction, and found the internal pressure from the difference between the pressure change at the time of pressure reduction and the pressure change at the time of pressure increase, and derived the leakage amount from the internal pressure.

The relationship between the pressure change at the time of pressure reduction and the pressure change at the time of pressure increase will be described with reference to fig. 5 and 6. Fig. 5 shows a change in pressure in the package of the quartz resonator when the quartz resonator is placed under reduced pressure for a certain period of time and the package of the quartz resonator is evacuated (reduced pressure) and then pressurized, and fig. 6 shows a change in pressure in the package of the quartz resonator when the quartz resonator is placed under pressurized for a certain period of time and the package of the quartz resonator is pressurized and then reduced pressure is applied. In fig. 5 and 6, the "constant time" when the constant pressure is reduced or increased is calculated in three modes of 7.5 minutes, 65 minutes, and 200 minutes.

As shown in fig. 5 and 6, the inclination (gradient) of a pressure curve showing a pressure change at the time of decompression (hereinafter referred to as a "decompression curve") is different from the inclination (gradient) of a pressure curve showing a pressure change at the time of pressurization (hereinafter referred to as a "pressurization curve"). As shown in fig. 5, when the internal pressure of the package with a short venting time 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 pressurization curve. When the internal pressure of the package is low during a long evacuation time, the pressure gradient of the decompression curve is smaller than that of the pressurization curve. As shown in fig. 6, when 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 depressurization curve. When the internal pressure of the package is high for a long pressurization time, the pressure gradient of the pressurization curve is smaller than that of the depressurization curve. In view of this characteristic, the internal pressure of the quartz resonator can be determined as follows.

FIG. 7 is a diagram showing the quartz resonator being placed under pressure P_lFor a predetermined time (t) in the examination room under reduced pressure_s1) The pressure in the package of the quartz resonator reaches a pressure P_sThen, the quartz resonator is placed under pressure P_hA graph of the pressure change in the package at a predetermined time in the inspection chamber under pressure. Here, P_l、P_s、P_hHaving P_l＜P_s、P_h＞P_sThe relationship (2) of (c). The horizontal axis of the graph shows the elapsed time (t), and the vertical axis shows the pressure (P) or the impedance (Z). The graph shows a decompression curve a that is decompressed and decreased for a predetermined period and a pressurization curve b that is pressurized and increased after the predetermined period. In order to determine the inclination (gradient) of the decompression curve a and the pressurization curve b in the graph, the pressure values (P) of the same pressure value on the decompression curve a and the pressurization curve b are set_x) And pressure value (P)_s) The amount of change of (b) is defined as Δ P in the decompression curve a_dDetermined as Δ P in the compression curve_u。ΔP_dAnd Δ P_uAre the same value, and Δ P as a representative value has Δ P_d＝ΔP_uA relation of Δ P. Under reduced pressureOn line a, will be at the same pressure value (P)_x) Corresponding time (t)_x1) And the same pressure value (P)_s) Corresponding time (t)_s1) The amount of change in time therebetween is defined as Δ t_d(hereinafter referred to as "1 st time variation"). On the compression curve b, the same pressure value (P) will be used_x) Corresponding time (t)_x2) And the same pressure value (P)_s) Corresponding time (t)_s2) The amount of change in time therebetween is defined as Δ t_u(hereinafter referred to as "2 nd time variation"). To make t_s1＝t_s2At t_s1The reduced pressure may be replaced with a pressurized pressure.

Pressure gradient (Δ P/Δ t) at reduced pressure as the slope of the reduced pressure curve a_d) As shown in the following formula 1.

ΔP/Δt_d＝－C(P_s－P_l)/V(1)

Pressurization pressure gradient (Δ P/Δ t) as the slope of pressurization curve b_u) As shown in the following formula 2.

ΔP/Δt_u＝C(P_h－P_s)/V(2)

Here, V (m)³) Is the internal volume of the package of the quartz resonator, C (m)³Is the electrical conductivity of the leakage hole of the package. The decompression pressure gradient is also referred to as a 1 st gradient, and the compression pressure gradient is also referred to as a 2 nd gradient.

The ratio of the decompression pressure gradient of the decompression curve a to the compression pressure gradient of the compression curve b (hereinafter referred to as "pressure gradient ratio (γ)") is obtained by the following equation 3.

γ＝(ΔP/Δt_d)/(ΔP/Δt_u)(3)

γ＝(ΔP/Δt_d)/(ΔP/Δt_u)＝(P_s－P_l)/(P_h－P_s) The internal pressure (P) of the quartz resonator is obtained by the following equation 4_s)。

P_s＝(γP_h+P_l)/(γ+1)(4)

Here, P_h、P_lIs a known value, and P is obtained as the internal pressure by obtaining the pressure gradient ratio γ_sObtaining leakage Q as largeThe flow rate of the air pressure. That is, the conductivity C was obtained from the following expressions 5 and 6, based on

expressions

1 and 2.

C＝－VΔP/(P_s－P_l)Δt(5)

C＝VΔP/(P_h－P_s)Δt(6)

Atmospheric pressure (P)_atm) The flow rate (Q) is Q ═ CP_atmTherefore, the leakage amount (Q) is obtained by the following expression 7 or 8.

Q＝－VΔP·P_atm/(P_s－P_l)Δt(7)

Q＝VΔP·P_atm/(P_h－P_s)Δt(8)

The pressure gradient ratio (γ) can be obtained as a ratio of change in impedance at the time of decompression and at the time of pressurization. As described above, the change in the impedance of the quartz resonator corresponds to the pressure change. According to formula 3, the pressure gradient ratio (γ) is γ ═ Δ P/Δ t_d)/(ΔP/Δt_u) If the amount of change in impedance is substituted, the value is obtained by the following equation 9.

γ＝(ΔZ/Δt_d)/(ΔZ/Δt_u)＝(ΔZ_d/Δt_d)/(ΔZ_u/Δt_u)(9)

Here, let Δ Z_dReferred to as 1 st impedance variation, will be Δ Z_uReferred to as the 2 nd impedance delta. Delta Z_dAnd Δ Z_uThe pressure gradient ratio (γ) is obtained using Δ Z as a representative value.

Fig. 8 shows a pressure change in the package of the quartz resonator and a pressure gradient ratio γ (P) when the pressure is applied after the evacuation is interrupted halfway_s－P_l)/(P_h－P_s) (Δ P/Δ t) as the ratio of Δ P/Δ t_d)/(ΔP/Δt_u) And ratio of Δ Z/Δ t (Δ Z/Δ t)_d)/(ΔZ/Δt_u) The relationship between them. As shown in the figure, the pressure gradient ratio γ, the ratio Δ P/Δ t, and Δ Z/Δ t substantially match each other in the graph, and the pressure gradient ratio (γ) may be obtained by calculating the impedance change amount (Δ Z) from the graph.

Therefore, the impedance of the quartz resonator is measured, and the pressure gradient ratio (γ) is obtained by equation 9, and if the pressure gradient ratio (γ) is obtained, the pressure gradient ratio (γ) is obtainedThe internal pressure (P) of the quartz resonator is obtained from equation 4_s) As a result, the leakage amount (Q) can be calculated according to equation 7 or equation 8.

Further, as shown in FIG. 9, if the process is repeated a plurality of times of decompression-pressurization-decompression … …, a plurality of internal pressures (P) are obtained_s) The value of (c). By determining a plurality of internal pressures (P)_s) The accuracy of the leakage amount calculation is improved. As a plurality of internal pressures (P) are known_s) The amount of leakage can be determined without knowing the relationship between the amount of change in impedance (Δ Z) and the amount of change in pressure (Δ P).

Further, it is also possible to obtain that the quartz resonator is placed at the predetermined pressure P_l(P_l＜P_s) Time and internal pressure (P) of the environment of (1)_s) Obtaining a predetermined pressure P to place the quartz resonator at the predetermined pressure_h(P_h＞P_s) Time and internal pressure (P) of the environment of (1)_s) According to a plurality of internal pressures (P)_s) The leakage amount (Q) is calculated, averaged, and weighted according to conditions. Specifically, the internal pressure (P) can be obtained by obtaining the impedance value per unit time at the time of pressurization after depressurization or depressurization after pressurization, and obtaining the depressurization curve and the pressurization curve from the impedance value_s). For example, an arbitrary 2-point (Z) having different impedance values is selected from each of the decompression curve and the compression curve₁、Z₂、Z₁＞Z₂) Calculating the slave Z on the decompression curve₁Change to Z₂Time Δ t of_dAnd from Z on the compression curve₂Change to Z₁Time Δ t of_uThe impedance value is Z obtained from the pressure gradient ratio (gamma)₂Internal pressure of the cylinder. If the resistance value per unit time is acquired in advance, the arbitrary 2 points can be freely set, and thus the time and the internal pressure (P) can be known_s) The leakage amount can be continuously calculated, and fine control can be realized.

(leak inspection device)

Next, the leak inspection apparatus will be described with reference to fig. 10. Fig. 10 is a conceptual diagram of the leak inspection apparatus, which is different from the actual apparatus in size. The vertical and horizontal directions on the paper surface are referred to as "upper", "lower", "left" and "right", but these directions are merely for explanation and are not intended to limit the directions in which the embodiments of the present invention are actually used.

The leak inspection apparatus 300 includes: a platform 301 on which the quartz resonator 1 is mounted; a contact probe 302 for measuring the resonance frequency and impedance of the quartz resonator 1; a contact block 303 which holds the contact probe 302 and moves up and down; a measurement unit 304 that measures the impedance of the quartz resonator 1; a decompression unit 305 which decompresses an internal space of the inspection chamber 400 formed between the stage 301 and the contact block 303; a pressurizing unit 306 that pressurizes the internal space; a pressure gauge 400a that measures the pressure in the examination chamber 400; and a control unit 307 for controlling the overall operation of the leak inspection apparatus 300. The structure of the control portion 307 will be described later.

The quartz resonator 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 quartz resonator 1. The plurality of holes are formed in a matrix shape on the tray 14.

The stage 301 places the tray 14 accommodating the quartz resonator 1 on the upper surface. The examination chamber 400 is formed by the space formed by the platform 301 and the contact block 303.

The contact probe 302 is a member for measuring the resonance frequency and impedance of the quartz resonator 1, and has a pair of

contact pins

302a, 302b at the tip. When the contact block 303 described later moves up and down, the contact pins 302a and 302b come into contact with the

external electrodes

211a and 211b of the quartz resonator 1, and a voltage is applied to the contact pins, whereby the resonance frequency and the impedance are measured.

The measurement unit 304 receives signals from the

external electrodes

211a and 211b, and measures the impedance of the quartz resonator 1. The measurement unit 304 uses, for example, a network analyzer. The measurement unit 304 measures the impedance of the quartz resonator 1 while the quartz resonator 1 is disposed in the inspection chamber 400 depressurized by the depressurizing means 305 described later for a predetermined time and while the inspection chamber 400 is pressurized by the pressurizing means 306 described later for a predetermined time. The measurement unit 304 transmits the measured impedance value to the control unit 307.

The contact probe 302 is moved in the forward direction or the backward direction away from the quartz resonator 1 by an unshown elevating mechanism. In the present embodiment, the contact probe 302 moves in the up-down direction on the drawing. A spring, not shown, is inserted into the contact pins 302a, 302b or the contact probe 302. The contact pins 302a, 302b are extended and contracted by the elastic force of the spring, and in the advanced state, the contact pins 302a, 302b are brought into contact with the

external electrodes

211a, 211b of the quartz resonator 1 while being pressed. Then, the contact block 303 retreats, thereby separating the contact pins 302a and 302b from the

external electrodes

211a and 211 b.

A pair of

contact pins

302a, 302b of the contact probe 302 and a pair of

external electrodes

211a, 211b are in one-to-one correspondence. The contact probes 302 are arranged in the same direction as any one of the rows of the quartz resonators 1 arranged in a matrix on the tray 14, and the number of the quartz resonators arranged in a row is the same as the number of the contact pins 302a and 302b arranged in a pair. The contact probe 302 may be provided so as to be completely in contact with the quartz resonator 1 arranged in a matrix.

The peripheral edge of the lower surface of the contact block 303 is provided with a gasket 308, which enhances the sealing with the platform 301. The contact block 303 is lowered and brought into contact with the platform 301, causing the examination chamber 400 to be closed.

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

The pressurizing unit 306 is a device that sends gas of a predetermined pressure to the inspection room 400. In the present embodiment, for example, compressed nitrogen gas is introduced into the inspection chamber 400 through the pressurizing unit 306. In the present embodiment, the pressurizing unit 306 pressurizes the inside of the inspection chamber 400 depressurized by the depressurizing unit 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 data stored in the storage device, and controls the overall operation of the leak inspection apparatus 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 leakage 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 amount of change in impedance from the value of the impedance measured by the measurement unit 304. Specifically, the impedance change amount calculation unit 309 forms a decompression curve and a pressurization curve defined by a relationship between a change in impedance and time, based on the value of the impedance measured by the measurement unit 304. Then, the amount of change in impedance was determined on the decompression curve and the pressurization curve. As shown in FIG. 7, on the decompression curve a and the compression curve b, the impedance value (Z) of the same 2 points is determined_x，Z_s) The amount of change in impedance is determined. On the decompression curve a, an arbitrary impedance value (Z)_x) And a predetermined period (t) of time in the inspection room 400 after decompression_s1) Impedance value (Z) when quartz resonator 1 is disposed_s) The variation of the impedance is set as 1 st impedance variation (Δ Z)_d). On the pressurization curve b, the predetermined period (t) is set in the inspection chamber 400_s2) Impedance value (Z) when quartz resonator 1 is disposed_s) And an arbitrary impedance value (Z)_x) The variation of the impedance therebetween is set as the 2 nd impedance variation (Δ Z)_u). 1 st amount of change in impedance (Δ Z)_d) And 2 nd impedance variation (Δ Z)_u) Since the values are the same, the representative value is set as the impedance change amount (Δ Z).

Ideally, the impedance value (Z) is the same at 2 points on the decompression curve a and the compression curve b_x)(Z_s) The amount of change in impedance (Δ Z) is obtained as a reference, but may be determined from the impedance values at 2 points different from each other on the decompression curve a and the compression curve b. When the corresponding 2 impedance values on the decompression curve a and the compression curve b are close values, 2 values are approximated as the same impedance value (Z)_x) Or (Z)_s) The impedance value is set as a reference impedance value. When the corresponding 2 impedance values are far apart from each other, the same impedance value (Z) is obtained using a conversion equation prepared separately_x) Or (Z)_s) The impedance value is set as a reference impedance value.

The time change amount calculation unit 310 calculates a change over time corresponding to the impedance change amount (Δ Z). The time variation calculating unit 310 calculates the amount of time variation on the decompression curve aWill be compared to a 2-point impedance value (Z)_x，Z_s) Corresponding time 1 (t)_x1) And time 2 (t)_s1) The time variation therebetween is defined as 1 st time variation (Δ t)_d). On the compression curve b, the impedance value (Z) at 2 points is compared_x，Z_s) Corresponding time 3 (t)_x2) And time 4 (t)_s2) The amount of time change therebetween is defined as the 2 nd time change amount (Δ t)_u)。

At a time corresponding to the 2-point impedance value, the 2 nd time t_s1And a 3 rd time t_s2May be the same time. If the same time is set to t_sThen use t_x1、t_s、t_x2These 3 values enable the 1 st temporal change amount (Δ t) to be obtained_d) And 2 nd time variation amount (Δ t)_u) And thus can be processed quickly.

The pressure gradient ratio calculation unit 311 calculates the pressure gradient ratio based on the impedance change amount (Δ Z) and the 1 st time change amount (Δ t)_d) 2 nd time variation amount (Δ t)_u) The pressure gradient ratio (γ) is obtained by equation 9.

The leakage amount calculation unit 312 obtains the internal pressure (P) of the quartz resonator 1 from equation 4 based on the pressure gradient ratio (γ)_s) Based on the obtained internal pressure (P)_s) And the elapsed time (Δ t), the leakage amount of the gas leaking from the quartz resonator 1 is obtained by equation 7 or equation 8.

(method of calculating leakage amount)

A method of calculating the leakage amount using the leakage inspection apparatus 300 will be described with reference to the flowchart of fig. 12.

In an inspection chamber 400 of the leak inspection apparatus 300 shown in fig. 10, a tray 14 on which a plurality of quartz resonators 1 are placed is loaded and mounted on a platform 301. Next, the contact block 303 is lowered to bring the peripheral edge of the contact block 303 into close contact with the upper surface of the stage 301, thereby forming a sealed space between the contact block 303 and the stage 301. Then, the contact pins 302a and 302b of the contact probe 302 are lowered to contact the

external electrodes

211a and 211b of the quartz resonator 1, and calculation of the leakage amount is started.

First, the inside of the inspection chamber 400 is depressurized by the depressurization means 305, and the quartz resonator 1 is disposed in the inspection chamber 400 at the 1 st predetermined time. Then, the inside of the inspection chamber 400 is pressurized by the pressurizing means 306, and the quartz resonator 1 is arranged for the 2 nd predetermined time. The pressure in the examination room 400 is monitored by a pressure gauge 400 a. The measurement unit 304 measures the impedance of the quartz resonator 1 during the 1 st predetermined time and the 2 nd predetermined time (step S101).

The impedance change amount calculation unit 309 forms a decompression curve a and a compression curve b based on the measured impedance, and calculates the 1 st impedance change amount (Δ Z)_d) And 2 nd impedance variation (Δ Z)_u) That is, the amount of change (Δ Z) in impedance (step S102) (impedance change amount calculation step).

The time variation calculating section 310 obtains the 1 st time variation (Δ t) from the impedance variation (Δ Z)_d) And 2 nd time variation amount (Δ t)_u) (time change amount calculation step), the pressure gradient ratio calculation unit 311 obtains the pressure gradient ratio (γ) by equation 9 (step S103) (pressure gradient ratio calculation step). The impedance change acquisition step is constituted by an impedance change amount calculation step, a time change amount calculation step, and a pressure gradient ratio calculation step.

The leakage amount calculation unit 312 calculates the internal pressure (P) of the quartz resonator 1 by equation 4 based on the pressure gradient ratio (γ) obtained by the pressure gradient ratio calculation unit 311_s) (step S104) according to the internal pressure (P)_s) The leakage amount (Q) is calculated by equation 7 or equation 8 (step S105) (leakage amount calculation step).

(example of use of leak inspection device)

Next, a use example of the leak inspection device according to the present embodiment will be described. The leak inspection apparatus according to the present embodiment is used after vacuum packaging of, for example, a quartz resonator when manufacturing an electronic component such as a quartz resonator. A feature of the leak inspection apparatus according to the present embodiment when used after a vacuum sealing process will be described while showing a comparative example.

Fig. 13 shows a use example of the leak inspection apparatus provided in a subsequent step of the vacuum sealing apparatus. Fig. 13A is a diagram showing a state in which the leak inspection apparatus of the present embodiment is coupled to a vacuum sealing apparatus, and fig. 13B is a diagram showing a state in which the leak inspection apparatus of the comparative example is coupled to the vacuum sealing apparatus. In the figure, only the state of connection between the vacuum sealing apparatus and the leak inspection apparatus is shown, and the previous steps of the vacuum sealing apparatus are not shown.

In the comparative example, as shown in fig. 13B, the vacuum sealing apparatus 500 and the leak inspection apparatus 503 are connected to each other via the take-out chamber 501 and the vacuum chamber 502. The vacuum sealing apparatus 500 includes an exhaust unit, not shown, and performs vacuum sealing of the quartz resonator 1 while conveying the conveying tray 504 on which the plurality of quartz resonators 1 are mounted, in a vacuum environment formed by the exhaust unit. The vacuum sealing apparatus 500 includes a heating and pressurizing device 505 for heating and pressurizing the quartz resonator 1 and a cooling device 506 for cooling the quartz resonator 1. The quartz resonator 1 is sandwiched between the base 21 and the lid 22 by the heat and pressure members in the heat and pressure device 505 and heated and pressurized, whereby the base 21 and the lid 22 are joined to each other (see fig. 1(a) (b)) and the package 20 of the quartz resonator 1 is hermetically sealed (a specific configuration of the quartz resonator 1). Then, the conveyance tray 504 is sent to the cooling device 506, and the quartz resonator 1 is cooled.

The vacuum chamber 502 has an unillustrated evacuation unit and a transport unit, and the quartz resonator 1 transported from the vacuum packaging apparatus 500 through the take-out chamber 501 is transferred from the transport tray 504 to the inspection tray 507 in a vacuum environment. The quartz resonator 1 is reversed at the time of seam welding. The quartz resonator 1 mounted on the conveyance tray 504 and the inspection tray 507 is pressed by the workpiece pressing member 508 so as not to be displaced on the conveyance tray 504 and the inspection tray 507 during the movement.

The inspection tray 507 on which the quartz resonator 1 is mounted is carried into the leak inspection apparatus 503 from the transfer portion of the vacuum chamber 502. The vacuum chamber 502 has an unillustrated exhaust means, and is evacuated by the exhaust means to maintain a vacuum atmosphere.

The leak inspection apparatus 503 includes a leak inspection portion 503a and a housing portion 503b housing the leak inspection portion 503 a. The storage 503b is mounted with an air discharging unit and a pressurizing unit, which are not shown. The inside of the housing 503b is brought into a vacuum atmosphere by the evacuation means, and the quartz resonator 1 placed on the inspection tray 507 from the vacuum chamber 502 is carried into the leak inspection apparatus 503. After the inside of the housing 503b is pressurized by the pressurizing means, the CI value of the quartz resonator 1 is measured by the leak inspection unit 503 a. The inspection tray 507 whose inspection is completed is carried out from the leak inspection apparatus 503.

In the comparative example, it is necessary to maintain the internal pressure of the quartz resonator 1 vacuum-sealed by the vacuum sealing apparatus 500, and the leak inspection portion 503b performs inspection. This requires the vacuum chamber 502 and increases the capacity of the leak inspection apparatus 503 to maintain a vacuum environment. The leak check device 503 requires a capacity of, for example, 50 liters. Further, since the leak inspection apparatus 503 has a large capacity, it takes time to exhaust and pressurize the leak inspection apparatus 503, and the number of individual man-hours is increased.

Further, since the vacuum chamber 502 needs to be disposed, the coupling structure of the vacuum sealing apparatus 500 and the leak inspection apparatus 503 becomes complicated and large. When the leak inspection apparatus 503 is added to the conventional vacuum sealing apparatus 500, the vacuum sealing apparatus 500 is not designed to be capable of vacuum connection, and it is not easy to maintain vacuum with the leak inspection apparatus 503, and a large modification may be forced.

On the other hand, fig. 13A shows a case where the leak inspection apparatus 300 according to the present embodiment is connected to a conventional vacuum sealing apparatus 500. The vacuum packaging apparatus 500 has the same structure as the comparative example, and the vacuum packaging apparatus 500 includes a heating and pressurizing apparatus 505 and a cooling apparatus 506. The method of vacuum sealing the package 20 of the quartz resonator 1 by the heating and pressurizing device 505 is also the same as the comparative example, and the description thereof is omitted.

The transfer tray 504 containing the hermetically sealed quartz resonator 1 is loaded from the vacuum sealing apparatus 500 into the unloading chamber 501, as in the comparative example. The transfer tray 504 is then transported out of the take-out chamber 501, and the quartz resonator 1 is transferred from the transfer tray 504 to the inspection tray 507 under an atmospheric pressure. If necessary, the inspection tray 507 is inverted. The inspection tray 507 is carried into the leak inspection apparatus 300, subjected to leak inspection, and then carried out of the leak inspection apparatus 300.

The leak inspection apparatus 300 of the present embodiment corresponds to the leak inspection unit 503a of the comparative example, but need not be disposed in a vacuum environment. Therefore, the inside of the leak inspection apparatus 300 corresponding to the leak inspection portion 503a may be evacuated and pressurized. Specifically, the minute space around the inspection tray 507 can be evacuated and pressurized in an inspection chamber having a capacity of, for example, 40 ml, and the evacuation unit and the pressurization unit can be downsized. Since the internal capacity of the leak inspection apparatus 300 is small, the time for exhausting and pressurizing is short, and the man-hour for one piece is shortened. The leak inspection apparatus 300 is small and low-cost, and can determine the total leak and the fine leak by one apparatus.

Further, since the transfer to the inspection tray 507 is performed under the atmospheric pressure, the degree of freedom in design is high, and the vacuum packaging apparatus can be easily connected to the conventional vacuum packaging apparatus 500. Further, as in the comparative example, the vacuum vessel 502 and the housing part 503b are not required, and the connection structure between the vacuum sealing apparatus 500 and the leak inspection apparatus 300 can be made compact and simple. Further, since the CI value is measured while being pressurized to atmospheric pressure or higher based on the CI value in a vacuum environment, the change amount of the CI value is large, and the leakage amount can be calculated with high accuracy.

With the present embodiment, the amount of leakage can be calculated regardless of the presence or absence of leakage, and thus the yield of the product can be improved.

With the present embodiment, the leakage amount can be calculated from the change in the impedance of the quartz resonator 1 under a pressure higher than the internal pressure and the change in the impedance of the quartz resonator 1 under a pressure lower than the internal pressure, and therefore the leakage amount can be appropriately obtained by a simple method.

In the present embodiment, the change in the impedance of the quartz resonator 1 is regarded as a gradient, and the amount of leakage can be determined from the change in the gradient, so that the amount of leakage can be easily calculated by a conventional measuring instrument such as a network analyzer.

With the present embodiment, the leak amount can be easily calculated from the time per unit time and the amount of change in impedance, and an appropriate leak check can be performed.

With the present embodiment, the inspection apparatus can be applied to both of a total leak inspection for inspecting a large leak and a fine leak inspection for inspecting a small leak, and thus the inspection apparatus can be simplified.

With this embodiment, the leakage amount can be calculated by leaving the quartz resonator 1 in a reduced-pressure and pressurized environment for a predetermined time (ts), and thus the leakage amount can be measured without taking time as in the helium leakage inspection.

With this embodiment, even when the history before the leak inspection is unknown, such as a difference in the exhaust time or the atmospheric standing time before the inspection, the leak amount can be calculated.

In the present embodiment, since the decompression unit 305 and the pressurization unit 306 are connected to one examination room 400, decompression and pressurization do not need to be performed in a separate examination room, and the apparatus becomes compact.

In the present embodiment, since the impedance is continuously measured by performing pressure reduction and pressurization in the same inspection chamber 400, the CI value is not affected by positional displacement of the contact pins 302a and 302b, or stroke change of the contact pins 302a and 302 b.

In the present embodiment, the decompression unit 305 and the pressurization unit 306 are mounted on the same inspection chamber 400, but may be mounted on separate inspection chambers.

In the present embodiment, it has been described that the contact block 303 is moved up and down, and the contact pins 302a, 302b are separated from the

external electrodes

211a, 211b, but the stage 301 may be moved up and down.

In the present embodiment, the method of calculating the leakage amount by repressurizing after depressurization has been described, but the leakage amount may be calculated by repressurizing after pressurization in the opposite mode.

The present invention is not limited to the above-described embodiments, and various modifications may be made within the scope of the claims. That is, embodiments obtained by combining technical means appropriately modified within the scope shown in the claims are also included in the technical scope of the present invention.

This application is based on Japanese patent application No. 2020-. The specification, claims and all drawings referred to in Japanese patent application No. 2020-.

[ industrial applicability ]

The present invention is applicable to a leak inspection method and a leak inspection apparatus for an electronic component.

[ Mark Specification ]

1 Quartz resonator

10 quartz plate

11a, 11b excitation electrodes

13 conductive adhesive

14 tray

20 packaging part

21 base

211 bottom

211a, 211b external electrode

211c, 211d internal electrodes

212 wall section

22 cover

23 joining member

300 leakage inspection device

301 platform

302 contact probe

302a, 302b contact pin

303 contact block

304 measuring part

305 pressure relief unit

306 pressurizing unit

307 control unit

308 liner

309 impedance change amount calculating part

310 time variation calculating part

311 pressure gradient ratio calculating section

312 leakage amount calculating part

400 inspection room

400a pressure gauge

500 vacuum packaging device

501 taking-out chamber

502 vacuum tank

503 leak inspection device

503a leak inspection section

503b receiving part

504 handling pallet

505 heating and pressurizing device

506 cooling device

507 inspection tray

508 workpiece pressing piece

Claims

1. A leak inspection method of calculating a leak amount of an electronic component that packages a piezoelectric element, wherein the leak inspection method has:

2. The leak inspection method according to claim 1,

and calculating the leakage amount of the electronic component according to the 1 st gradient and the 2 nd gradient.

3. The leak inspection method according to claim 1,

determining a degree of correlation between the time per unit time of the 1 st predetermined time and the change in impedance, or

A correlation between the time per unit time of the 2 nd predetermined time and the change in impedance is obtained, and the leakage amount of the electronic component is calculated from the obtained correlation.

4. The leak inspection method according to claim 1,

the impedance change acquiring step includes:

an impedance change amount calculation step of forming a decompression curve formed from a relationship between a change in the 1 st impedance and time and a pressurization curve formed from a relationship between a change in the 2 nd impedance and time, based on the impedance value Z at 2 different points on the decompression curve_x、Z_s、Z_x＞Z_sOr the impedance change amount Δ Z is obtained from the change in the impedance value at 2 points which is the same as the impedance value at 2 points on the pressurizing curve;

a time change amount calculation step of obtaining a 1 st time change amount Δ t from a time corresponding to the impedance value at the 2 points on the pressure-reduction curve_dThe 2 nd time variation amount Deltat is obtained from the time corresponding to the impedance value at the 2 points on the pressurizing curve_u(ii) a And

a pressure gradient ratio calculation step of calculating a pressure gradient ratio based on the impedance change amount Δ Z and the 1 st time change amount Δ t_dAnd the 2 nd time variation amount Δ t_uFinding a pressure gradient ratio γ which is a ratio between a decompression pressure gradient showing a slope of the decompression curve and a pressurization pressure gradient showing a slope of the pressurization curve,

the leakage amount calculation step obtains an internal pressure P of the electronic component from the pressure gradient ratio γ_sAccording to the internal pressure P_sAnd obtaining a leakage amount Q of the gas leaked from the electronic component with the lapse of time.

5. The leak inspection method according to claim 4,

on the pressure curve, the impedance value is from the 2 pointZ of the impedance value_sTo Z_xChange, time from and Z_sCorresponding time 3 to Z_xAt the corresponding time 4, the time of day,

the 2 nd time and the 3 rd time are the same time.

6. The leak inspection method according to claim 4 or 5,

by gamma ═ Δ Z/Δ t_d)/(ΔZ/Δt_u) The pressure gradient ratio gamma is calculated,

wherein Δ Z is the impedance change amount, Δ t_dIs the 1 st time variation, Δ t_uIs the amount of the 2 nd time variation,

by P_s＝(γP_h+P_l) V (γ +1) calculating the internal pressure P_s，

Wherein, P_hIs the pressure value at the time of pressurization, P_lIs the pressure value at the time of decompression,

by Q ═ V.DELTA.P.P_atm/(P_s－P_l) Δ t or

Q＝VΔP·P_atm/(P_h－P_s) At calculates the leakage Q and,

wherein V is an internal volume of the piezoelectric element, P_atmIs atmospheric pressure and Δ t is elapsed time.

7. A leak inspection apparatus that calculates a leak amount of an electronic component that packages a piezoelectric element, the leak inspection apparatus comprising:

and a leakage amount calculation unit that obtains a leakage amount of the gas leaking from the electronic component, based on the change in the 1 st impedance and the change in the 2 nd impedance acquired by the impedance change acquisition unit.

8. The leak inspection device according to claim 7,

the impedance change acquiring unit includes:

an impedance change amount calculation unit that forms a decompression curve formed from a relationship between a change in the 1 st impedance and time and a pressurization curve formed from a relationship between a change in the 2 nd impedance and time, and obtains an impedance change amount from a change in an impedance value at 2 points different from the decompression curve or from a change in an impedance value at 2 points that are the same as the impedance value at 2 points on the pressurization curve;

a time change amount calculation unit that obtains a 1 st time change amount from the time corresponding to the impedance value at the 2 point on the pressure reduction curve, and obtains a 2 nd time change amount from the time corresponding to the impedance value at the 2 point on the pressure increase curve; and

the leakage amount calculation unit obtains an internal pressure of the electronic component from the pressure gradient ratio, and obtains a leakage amount of the gas leaking from the electronic component from the internal pressure and an elapsed time.

9. The leak inspection apparatus according to claim 7 or 8,

the inspection space is formed in the same inspection chamber, and the decompression unit and the pressurization unit are connected to the inspection chamber.