JP3300232B2 - High barrier film defect detection apparatus and method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for detecting defects in a high barrier film obtained by subjecting a synthetic polymer or a surface modification such as various coatings to the synthetic polymer. ^{-14 to} 10 ^-11 cm ³ (S
The present invention relates to a simple defect detection apparatus and method effective for quality control of a high barrier film having a high barrier property of TP) cm ⁻² S ⁻¹ cmHg ⁻¹ .

[0002]

2. Description of the Related Art In recent years, the development of a polymer permeable film and a gas barrier film using a novel polymer material has been actively pursued with advances in polymer synthesis technology and film formation technology. These films are becoming thinner year by year, and there is an increasing demand for uniform film thickness without defects.

[0003] In addition, evaporation on the surface of a synthetic polymer film,
Functional films having various functions can be made by performing various surface modifications such as sputtering and plasma polymerization, and these are made of electronic components, flat panel members represented by liquid crystal displays, etc., materials for the pharmaceutical packaging field, Furthermore, it is widely used in the field of industrial materials. For this,
Quality control in the process of making a thin film and the process of making a polymer film which is the base of various functional films becomes indispensable.

[0004]

Various film-making manufacturers have advanced automation and quality control of the film-forming process by introducing a computer, and the technology for the uniformity of the film thickness has been determined. In addition, various physical properties such as mechanical strength and dimensional stability are measured for each film forming lot and the quality is assured.

However, in the prior art, there is no established means for inspecting defects such as minute pinholes generated in processes such as high-speed film formation and thinning. In particular, it is often difficult to detect a relatively small pinhole or defect having a size of 0.1 μm to several μm even when examined with a microscope. In addition, there is a method of detecting a defect or the like of a film by dyeing a defective portion by using a penetrable chemical, but has a problem that it has high know-how and is difficult to quantify.

The present invention has been made in view of the above circumstances, and it is possible to reliably and easily detect a defect such as a minute pinhole of a high barrier film. An object of the present invention is to provide an apparatus and a method for detecting a defect of a high barrier film which are useful for quality control of a functional material such as a gas selective film.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention has a gas permeability coefficient of 10 ^{-14 to} 10 ^-11 cm.
A defect detector for detecting a defect of a barrier film in a range of ³ (STP) cm ^-2 S ^-1 cmHg ^-1 , comprising: a sample holder forming two sealed spaces separated by the barrier film; Vacuum evacuation means for evacuating two closed spaces of the sample holder, and selectively adjusting at least two types of gases having different molecular radii on one side of the closed space to a predetermined pressure at a constant temperature. Gas introduction means to be introduced, arranged to communicate with the other side of the closed space,
A pressure detecting means for detecting a pressure rise value per unit time of the gas permeating the barrier film and entering the closed space on the other side; and calculating a permeation coefficient of each gas based on the pressure rise value. In addition, a high barrier film defect detection device is provided which includes a calculating means for determining these transmission coefficient ratios and a defect determining means for determining a defect of the barrier film from the transmission coefficient ratio.

Further, the gas permeability coefficient is 10 ^{-14 to} 10 ^-11.
What is claimed is: ^1. A defect detector for detecting a defect of a barrier film in a range of cm ³ (STP) cm ⁻² S ⁻¹ cmHg ⁻¹ , wherein the sample holder forms two closed spaces separated by the barrier film. Vacuum evacuation means for evacuating the two closed spaces of the sample holder, and adjusting the temperature conditions while adjusting at least one type of gas having an arbitrary molecular radius on one side of the closed space to a predetermined pressure. Gas introducing means to be introduced, and pressure detecting means arranged to communicate with the other side of the closed space and detecting a pressure rise value per unit time of gas permeating the barrier film and entering the closed space on the other side. Defect determination means for calculating a permeability coefficient of the gas at each temperature based on the pressure rise value and determining a defect of the barrier film from the temperature dependence of the permeability coefficient of the gas; Are provided to constitute a defect detection device for a high barrier film.

Further, the gas permeability coefficient is 10 ^{-14 to} 10 ^-11.
A defect detection method for detecting a defect of a barrier film in a range of cm ³ (STP) cm ⁻² S ⁻¹ cmHg ⁻¹ , wherein the two closed spaces separated through the barrier film are evacuated. A second procedure of separately introducing at least two types of gases having different molecular radii at one side of the closed space at a predetermined temperature under a predetermined pressure, and a second procedure of transmitting the gas through the barrier film on the other side. A third procedure of detecting a pressure rise value per unit time according to the permeation amount of each gas introduced into the closed space, and calculating a permeation coefficient of each gas from the pressure rise value and calculating a ratio of these permeation coefficients; A fourth aspect of the present invention is characterized in that a fourth procedure to be determined and a fifth procedure to determine a defect of the barrier film from the magnitude of the transmission coefficient ratio are sequentially performed, and a defect detection method for a high barrier film is characterized.

Further, the gas permeability coefficient is 10 ^{-14 to} 10 ^-11.
A defect detection method for detecting a defect of a barrier film in a range of cm ³ (STP) cm ⁻² S ⁻¹ cmHg ⁻¹ , wherein the two closed spaces separated through the barrier film are evacuated. A first procedure, a second procedure of introducing at least one type of gas into one side of the closed space while maintaining a predetermined pressure while changing the temperature condition, and passing the barrier film through the barrier film into the closed space on the other side. A third procedure for obtaining a pressure rise value per unit time according to the amount of the introduced gas permeation, a fourth procedure for calculating a permeability coefficient for each temperature of the gas from the pressure rise value, And a sixth procedure for determining a defect of the barrier film from the magnitude of the gradient is sequentially performed. Things.

Further, in the present invention, for example, nitrogen is used as a reference gas, and nitrogen and oxygen are used as a plurality of kinds of gases. The predetermined pressure of the gas introduced into the closed space is 0.1 kg / kg. cm ^{2 to} 10 kg / cm ² , and a temperature condition from room temperature to 60 ° C. is adopted.

If the polymer film has no defects such as pinholes, the gas permeability coefficient of the polymer film shows a smaller value as the molecular radius of the gas passing therethrough is larger. It is known that the transmission coefficient ratio between gases having different molecular radii varies depending on the type of polymer and the higher-order structure of the polymer, but takes a substantially constant value. For example, it is known that the transmission coefficient ratio between nitrogen gas and oxygen gas and between nitrogen gas and carbon dioxide is 3 to 9 times and 15 to 30 times that of nitrogen gas, respectively. Therefore, for example, nitrogen gas, oxygen gas, carbon dioxide gas, or the like is transmitted through the high barrier film under predetermined pressure conditions to determine the transmission coefficient, and the transmission coefficient ratio is calculated to determine the presence or absence of a defect such as a pinhole. be able to. When a pinhole is present in the film, a gas having a large molecular radius is easily transmitted through the pinhole similarly to a gas having a small molecular radius. Therefore, the apparent gas permeability coefficient of a gas having a large molecular radius, which is originally strongly restricted in permeation, greatly increases, and the difference from the gas permeability coefficient of a gas having a small molecular radius becomes less noticeable. Therefore, the ratio of the permeability coefficient of both gases is actually measured, and when this value is lower than the normal value, the presence of a pinhole is estimated. Further, the size and occurrence frequency of the pinhole can be estimated to some extent from the gas permeability coefficient ratio. In particular, since defect detection is performed using the relative transmission coefficient ratio between different gases, objective judgment can be made without largely depending on measurement conditions. Further, the temperature dependence of the gas permeation coefficient for a specific gas (for example, the absolute value of the activation energy (Ep) (Kcal / mol) of gas permeation)
, Pinholes and defects can be determined. In general, the gas permeation coefficient has a large temperature dependence. For example, nitrogen has a permeation coefficient that increases with an increase in temperature, and a relatively large activation energy is recognized. However, the presence of pinholes allows molecules to freely permeate regardless of the temperature, so that the temperature dependence is apparently lost. That is, when the activation energy shows a small value such as 0.5 to several (Kcal / mol), a pinhole or a defect exists.

According to the present invention, a gas having different molecular radii is introduced into a closed space evacuated from the above, and transmitted through a barrier film to determine a transmission coefficient ratio and an activation energy to detect a defect. . The permeability coefficient can be theoretically calculated by actually measuring a pressure rise value per unit time caused by gas permeation.

In the present invention, the size of pinholes and defects of the barrier film is 0.1 μm in terms of a circle.
It is a range having a diameter of about to several hundred μm. 0.1μ
If m is smaller than m, diffusion caused by the higher-order structure of the polymer constituting the film becomes the main component of gas permeation, and the concept of the present invention is not applied. On the other hand, in the case of a defect larger than several hundred μm, 10 ^{−14 to} 10 ⁻¹¹ cm ³ (STP) c
Since it does not show a gas permeability coefficient in the range of m ⁻² S ⁻¹ cmHg ⁻¹ , it falls outside the high barrier film and is excluded from the scope of the present invention.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an apparatus and a method for detecting defects in a high barrier film according to the present invention will be described in detail with reference to the drawings. First, a schematic configuration of a defect detection apparatus for a high barrier film according to the present invention will be described with reference to FIG. As shown in FIG. 1, the defect detection apparatus is roughly classified into a barrier film 1 which is a non-inspection object.
, A gas introducing means 3, a vacuum exhaust means 4, a pressure detecting means 5, a calculating means 6, a defect determining means 7 and the like. A control unit 8 including a thermostat for controlling the temperature of the apparatus is provided.

The sample holder 2 comprises a metal holder body 9 and a lid 10 which are joined together via a seal member 11 and fastened with bolts 12 and nuts 13 as shown in FIG. . The barrier film 1 is held between the holder body 9 and the lid 10 via a packing 15 while being supported from below by a porous supporter 14 as shown in the figure. A sealed space is formed between the holder 9 and the lid 10, and the sealed space is separated by the barrier film 1 into an upper sealed space 16 and a lower sealed space 17. In addition, an inlet pipe 18 is connected to the upper sealed space 16, and a discharge pipe 19 is connected to the lower sealed space 17. The connection between the introduction pipe 18 and the discharge pipe 19 is performed by welding or sealing between Kovar and glass (bonding of metal and glass).

The gas introducing means 3 is selected from a gas reservoir 20 storing a plurality of types (a, b, c, d) of gases (for example, helium, oxygen, nitrogen, and argon) having different molecular radii, and a gas reservoir 20. And a gas selecting section 21 for selecting one type of selected gas. Specifically, the gas selector 21 includes a switching rotary valve for selecting one kind of necessary gas from the gas reservoir 20. The gas introduction means 3 and the sample holder 2 are connected by an introduction pipe 18, and a control valve 22 for adjusting the gas pressure of the introduced gas to a predetermined pressure is provided in the introduction pipe 18.
And switching valves 23 and 24 are interposed. In addition, control valve 2
No. ² adjusts the pressure of the introduced gas to about 0.1 kg / cm ^{2 to} 10 kg / cm ² (preferably several kg / cm ² or less).
The reason why the gas pressure is adjusted is that if the pressure is too high, the barrier film 1 held by the sample holder 2 is damaged.

The vacuum evacuation means 4 comprises a diffusion pump 25, a rotary pump 26 and a pipe 27 open to the atmosphere, and switching valves 28 and 29 are arranged as shown in the figure.
The suction pipe 30 connected to the diffusion pump 25 is connected to the discharge pipe 19 side, and the branch pipe 32 branched from the suction pipe 30 via the switching valve 31 is connected to the switching valve 24 on the introduction pipe 18 side.
Connect to In addition, the evacuation means 4 is the sample holder 2
The upper sealed space 16 and the lower sealed space 17 are evacuated to about 10 ^{−3 to} 10 ⁻⁴ mmHg. Also, the sample holder 2 is of course of a structure that can sufficiently withstand the above-mentioned vacuum pressure.

The pressure detecting means 5 is connected to the lower closed space 17 of the sample holder through a discharge pipe 19 having a switching valve 33.
Communicate with The pressure detecting means 5 detects the gas pressure in the lower sealed space 17 with time, and for example, a known diaphragm gauge is used.

The calculating means 6 comprises a personal computer or the like, and calculates the transmission coefficient P based on the pressure rise value ΔP / Δt per unit time stored in the data memory in accordance with the detection result of the pressure detecting means 5. The ratio of the permeation coefficient P of each gas (permeation coefficient ratio) and the activation energy Ep (Kcal / mol) representing the temperature dependence of the permeation coefficient are obtained.

The defect judging means 7 judges the presence or absence of a defect in the barrier film 1 from the value of the transmission coefficient ratio or the activation energy Ep obtained by the calculating means 6.

The controller 8 controls the temperature of the gas in the sample holder 2 as described above. In the present invention, the gas and the film are controlled in a temperature range from room temperature (for example, 20 ° C.) to about 60 ° C. You.

The following formula shows a theoretical formula for calculating the transmission coefficient in the present invention.

[0024]

(Equation 1)

In the above equation, P is a transmission coefficient, ΔP / Δt
Is the pressure rise value per unit time, p is the introduced gas pressure (cmH
g), A is the transmission area (cm ² ), d is the thickness of the barrier film (cm), T is the temperature in the sample holder, V is the volume on the low pressure side (the volume of 17 between the lower enclosed spaces) (cm ³ ) It is. In the above, A, p, d, T, and V are known, so that ΔP / Δt
Is obtained, the transmission coefficient P is calculated.

Next, a method for detecting a defect in the barrier film 1 using the defect detection apparatus of the present invention will be described with reference to FIGS. FIG. 3 corresponds to claim 3, and FIG. 4 corresponds to claim 4 respectively.

First, the switching valves 23, 3 in FIG.
3 and 29 are closed, the switching valves 24, 31 and 28 are opened, and the rotary pump 26 of the evacuation means 4 is operated to operate the upper sealed space 16 and the lower sealed space 17 of the sample holder 2.
Is uniformly maintained in a vacuum of, for example, 10 ^{−3 to} 10 ⁻⁴ mmHg. Next, after the evacuation is stopped, a plurality of types (n) of gases having different molecular radii from the gas introducing means 3 are selected one by one, the switching valve 23 is opened, and the gas pressure is set to, for example, 0 by the adjusting valve 22. .1kg / cm ² to adjust the number Kg / cm ^2, is introduced into the upper closed space 16. The upper sealed space 16 and the lower sealed space 17 of the sample holder 2 are adjusted to a predetermined temperature, for example, 30 ° C. by the control unit 8.

The switching valve 33 is opened, and the upper sealed space 1 is opened.
6, the pressure rise value Δ per unit time for each of a plurality of types of gases that have passed through the barrier film 1 and entered the lower sealed space 17.
P / Δt is actually measured via the pressure detecting means 5.

Next, the calculation means 6 calculates ΔP / Δt.
, The transmission coefficient P is determined for each gas by the above formula. Step 100 in FIG. 3 shows the procedure.

For example, nitrogen and oxygen are selected as the gas to be introduced, and the calculation means 6 determines the transmission coefficient ratio between oxygen and nitrogen (PO ₂ / PN ₂ ). Step 101 in FIG. 3 shows this procedure.

Next, step 10 is performed by the comparison / determination means 7.
The transmission coefficient ratio obtained in step 1 is compared with a predetermined reference value (step 102 in FIG. 3). For example, if this value is smaller than 1, it is determined that there is a defect (step 103 in FIG. 3). If it is about 8, it is determined that there is no defect in the normal product (step 104 in FIG. 3). Thus, the presence or absence of a defect in the barrier film 1 is automatically determined.

Next, a method of determining a defect of the barrier film 1 based on the activation energy Ep will be described. In this case, one kind of gas is selected, and after adjusting the pressure, it is introduced into the upper sealed space 16 of the sample holder 2. However, the same measurement procedure is repeated a plurality of times while the temperature in the upper sealed space 16 is changed stepwise. As shown in step 200 of FIG. 4, the calculating means 6 calculates the permeation coefficient of each specific gas at each temperature.
Activation energy E, which is determined by
p is obtained in accordance with the illustrated equation (step 201). Next, the value of Ep is compared with the reference value by the comparing means 7 (step 202). For example, if the value of Ep is smaller than 1, the barrier film 1 is determined to be defective (step 203). If it is larger than 4, it is determined that it is normal (step 204). As described above, the defect of the barrier film 1 is automatically determined in the same manner as described above.

(Experimental Example) Table 1 shows an experimental example of the defect detection method according to the procedure shown in FIG. In this case, as the barrier film 1, A, B, C of different manufacturers are used.
Were selected as samples. These barrier films 1 are made of a biaxially stretched polyester film having a thickness of 12 μm. The gas used is oxygen (O ₂ )
And nitrogen (N ₂ ). The temperature condition was set at 30 ° C.

[0034]

[Table 1]

As shown in Table 1, the transmission coefficient ratio PO ₂ / PN ₂
In Sample A, Sample A was 6.90 and Sample C was 8.67, all of which were within the normal range.
97 less than 1. Therefore, Sample B is determined to be defective with a defect. As a precautionary measure, when samples A, B, and C were randomly observed at 20 locations by SEM, respectively, it was observed that sample B had a pinhole of about 10 μm. Not observed.

(Experimental Example) Table 2 shows an experimental example of the defect detection method according to the procedure shown in FIG. In this case, three types of samples A, B, and C were similarly selected as the barrier films 1. Each of the barrier films 1 of A, B, and C is made of a biaxially stretched polyester film having a thickness of 12 μm, and oxygen (O ₂ ) and nitrogen (N ₂ ) are used as gases.
Was used. The temperature conditions are 30 ° C., 40 ° C., 5 ° C.
The same experiment was carried out under four temperature settings of 0 ° C. and 60 ° C. under each temperature condition.

[0037]

[Table 2]

As shown in Table 2, the activation energy Ep of the sample A is 6.7 and the sample C is 6.6, but the Ep value of the sample B is as low as 0.49. From the above, it was determined that Sample B had a defect as in the above-described experimental example.

[0039]

According to the present invention, the following remarkable effects are obtained. That is, a gas permeability coefficient of 10 ^{−14 to} 10 ⁻¹¹ cm ³ (S
TP) The presence or absence of minute pinholes in the high barrier film of cm ⁻² S ⁻¹ cmHg ⁻¹ can be automatically and reliably determined by a relatively simple structure and method. As a result, it is possible to perform quality control of a functional material such as an ultra-thin film or a gas-selective film, which has not existed conventionally.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of a defect detection device for a high barrier film according to the present invention.

FIG. 2 is a sectional view showing a detailed structure of a sample holder according to the present invention.

FIG. 3 is a flowchart illustrating an example of a method for detecting a defect in a high barrier film according to the present invention.

FIG. 4 is a flowchart for explaining another example of the defect detection method of the high barrier film of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Barrier film 2 Sample holder 3 Gas introduction means 4 Evacuation means 5 Pressure detection means 6 Calculation means 7 Defect judgment means 8 Control part 9 Main body 10 Cover 11 Sealing member 12 Bolt 13 Nut 14 Supporter 15 Packing 16 Upper sealed space 17 Lower Sealed space 18 Inlet pipe 19 Discharge pipe 20 Gas reservoir 21 Gas selector 22 Adjusting valve 23 Switching valve 24 Switching valve 25 Diffusion pump 26 Rotary pump 27 Atmospheric release pipe 28 Switching valve 29 Switching valve 30 Suction pipe 31 Switching valve 32 Branch pipe 33 Switching valve

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Mitsuru Kano 1-5-1, Taito, Taito-ku, Tokyo Toppan Printing Co., Ltd. (58) Field surveyed (Int. Cl. ⁷ , DB name) G01N 15/08 B01D 65/10 G01M 3/00-3/40

Claims (9)

(57) [Claims] 1. A gas permeability coefficient of 10 ^{-14 to} 10 ^-11 cm ³
(STP) A defect detector for detecting a defect of a barrier film in a range of cm ⁻² S ⁻¹ cmHg ⁻¹ , a sample holder forming two closed spaces separated by the barrier film, Vacuum evacuation means for evacuating two closed spaces of the sample holder, and selectively introducing at least two types of gases having different molecular radii to one side of the closed space at a predetermined pressure by adjusting the pressure to a predetermined value. Pressure detecting means disposed in communication with the other side of the closed space, and detecting a pressure increase value per unit time of gas permeating the barrier film and entering the closed space on the other side. Calculating means for calculating a transmission coefficient of each gas based on the pressure rise value and calculating a transmission coefficient ratio thereof; and a defect determination for determining a defect of the barrier film from the transmission coefficient ratio. Defect detecting apparatus of a high barrier film which is characterized by providing a stage. 2. A gas permeability coefficient of 10 ^{-14 to} 10 ^-11 cm ³
(STP) A defect detector for detecting a defect of a barrier film in a range of cm ⁻² S ⁻¹ cmHg ⁻¹ , a sample holder forming two closed spaces separated by the barrier film, Vacuum evacuation means for evacuating two closed spaces of the sample holder, and introducing at least one kind of gas having an arbitrary molecular radius to one side of the closed space at a predetermined pressure and changing temperature conditions. Gas introduction means, pressure detection means arranged to communicate with the other side of the closed space, and detecting a pressure rise value per unit time of gas permeating the barrier film and entering the closed space on the other side, Defect determining means for calculating a permeability coefficient of the gas at each temperature based on the pressure rise value and determining a defect of the barrier film from a temperature dependency of the permeability coefficient of the gas. Defect detecting apparatus of a high barrier film, wherein the kick. 3. A gas permeability coefficient of 10 ^{-14 to} 10 ^-11 cm ³
(STP) A defect detection method for detecting a defect of a barrier film in a range of cm ⁻² S ⁻¹ cmHg ⁻¹ , wherein a first closed space separated by the barrier film is evacuated. A second step of separately introducing at least two types of gases having different molecular radii at one side of the closed space at a predetermined temperature under a predetermined pressure, and a second step of transmitting the barrier film through the barrier film and the other side. A third procedure of detecting a pressure rise value per unit time in accordance with the permeation amount of each gas introduced into the second step; and calculating a transmission coefficient of each gas from the pressure rise value and calculating a transmission coefficient ratio of these gases. 4. A method of detecting defects in a high barrier film, comprising sequentially performing step 4 and a fifth step of determining a defect in the barrier film from the magnitude of the transmission coefficient ratio. 4. A gas permeability coefficient of 10 ^{-14 to} 10 ^-11 cm ³
(STP) A defect detection method for detecting a defect of a barrier film in a range of cm ⁻² S ⁻¹ cmHg ⁻¹ , wherein a first closed space separated by the barrier film is evacuated. A second procedure of introducing at least one type of gas into one side of the sealed space while changing the temperature condition while maintaining the gas at a predetermined pressure, and introducing the gas into the closed space on the other side through the barrier film. A third procedure for obtaining a pressure rise value per unit time according to the permeation amount of the gas, a fourth procedure for calculating a permeability coefficient for each temperature of the gas from the pressure rise value, A method for detecting a defect in a high barrier film, comprising sequentially performing a fifth procedure for obtaining a coefficient gradient and a sixth procedure for determining a barrier film defect from the magnitude of the gradient. 5. The high barrier film defect detection apparatus or method according to claim 1, wherein at least standard nitrogen is used as a gas type. 6. In addition to nitrogen, helium,
4. The defect detecting apparatus or method for a high barrier film according to claim 1, wherein a gas selected from oxygen or argon is used. 7. The method according to claim 1, wherein the predetermined pressure of the gas introduced into the one closed space is 0.1 kg / cm ^{2 to} 10 kg / cm ² . An apparatus or method for detecting a defect of a high barrier film. 8. The defect detection of a high barrier film according to claim 2, wherein a temperature condition of the gas introduced into the closed space is set stepwise within a range from room temperature to 60 ° C. Apparatus or method. 9. The defect of a high barrier film according to claim 1, wherein the enclosed space is evacuated in advance to a range of 10 ^{−3 to} 10 ⁻⁴ mmHg before introducing the gas. Detection device or method.