Leak inspection method and leak inspection method for liquid discharge head

Abstract

To provide a method by which leakage inspection in a space can be suitably performed even if the space has a minute capacity.SOLUTION: A leakage inspection method for performing leakage inspection in a space 7 includes: a step of placing a test piece 8 in the space 7; a first measurement step of measuring the physical properties or the shape of the test piece 8; a step of filling the periphery of the space 7 with fluid; a second measurement step of measuring the physical properties or the shape of the test piece 8 again; and a step of comparing a result of the measurement in the first measurement step with a result of the measurement in the second measurement step to determine the presence or absence of leakage.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a leak inspection method and a leak inspection method for a liquid ejection head.

Background Art

[0002] An inkjet printer that ejects a liquid (ink) to perform recording on a recording medium such as paper is known. An inkjet printer is provided with a piezoelectric element that generates pressure for ejecting the liquid from the ejection port. In order to suppress corrosion by the liquid, this piezoelectric element needs to be disposed in a sealed space isolated from the flow path through which the liquid flows. At this time, it may be necessary to inspect (leak inspection) whether the space in which the piezoelectric element is disposed is properly sealed.

[0003] In Patent Document 1, as a leak inspection method, a method of inspecting airtightness by pressurizing and supplying gas or liquid into the space and then inspecting the leakage from the space is disclosed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the leak inspection method in Patent Document 1, as the volume of the space becomes minute, the amount of gas or liquid that can be pressurized and supplied into the space becomes minute. Therefore, the amount of leakage from the space thereafter also becomes minute, making it difficult to inspect the leakage.

[0006] In view of the above problems, an object of the present invention is to provide a method capable of suitably performing a leak inspection in a space even when the volume of the space is minute.

Means for Solving the Problems

[0007] To solve the above problems, the present invention provides a leak inspection method for performing leak inspection in a space, comprising: a step of placing a test piece in the space; a first measurement step of measuring the physical properties or shape of the test piece; a step of filling the space with fluid; a second measurement step of measuring the physical properties or shape of the test piece again; and a step of comparing the measurement results from the first measurement step and the measurement results from the second measurement step to determine whether or not there is a leak. The fluid is used to etch the test piece. It is characterized by the following: [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a method for suitably performing leak testing in a space even when the volume of the space is minute. [Brief explanation of the drawing]

[0009] [Figure 1] Schematic diagram of the liquid dispensing head. [Figure 2] A schematic diagram illustrating a leak detection method. [Figure 3] A schematic diagram illustrating a leak detection method. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described in detail below. In the embodiments described below, specific descriptions may be made in order to fully explain the present invention, but these are merely examples of technically preferred examples and do not particularly limit the scope of the present invention.

[0011] Figure 1(a) is a schematic diagram showing the liquid discharge head 14. Figure 1(b) is a cross-sectional view taken along a-a' in Figure 1(a). The liquid discharge head 14 is composed of a first substrate 1, a second substrate 2, and a third substrate 3. The first substrate 1 has a flow path 4 through which the liquid flows and a space 7 in which a piezoelectric element 6 is housed. The second substrate 2 has a pressure chamber 15 through which pressure from the piezoelectric element 6 acts. The third substrate 3 has a discharge port 5 for discharging the liquid. By driving the piezoelectric element 6, the liquid is discharged from the discharge port 5.

[0012] Figure 2 shows the leak inspection method of this embodiment. In the leak inspection in this embodiment, first, as shown in Figure 2(a), a test piece 8 is placed in the space 7 that is to be inspected for leaks. This can be achieved by placing the test piece 8 on the second substrate 2 and then bonding the first substrate 1 to the second substrate 2. It is particularly preferable to place the test piece 8 near the location to be inspected for leaks. Figure 2(b) is a cross-sectional view of the area a-a' shown in Figure 2(a).

[0013] Next, the initial physical properties or shape of the test specimen 8 are measured (first measurement step).

[0014] Next, as shown in Figure 2(c), the space 7 is filled with a liquid such as a mixed acid or a fluid such as boron trichloride that can etch the test specimen 8. Figure 2(d) is a cross-sectional view of a-a' shown in Figure 2(c). Here, if the space 7 is kept airtight, no change occurs in the test specimen 8.

[0015] However, when the inside of the space 7 is not sealed, the fluid 9 enters the space 7 from the leak location. FIG. 2(e) is a schematic diagram showing a state where the fluid 9 is entering the space 7 from the leak location 10. FIG. 2(f) is a cross-sectional view taken along a-a' shown in FIG. 2(e). When there is a leak location 10 in the space 7 and the fluid 9 enters the space 7, the test piece 8 is etched by the fluid 9. Therefore, the physical properties and shape of the test piece 8 change from the initial state. Therefore, after filling the periphery of the space 7 with the fluid 9, the state of the test piece 8 is measured again (second measurement step). Then, by comparing the measurement result in the first measurement step with the measurement result in the second measurement step, a leak inspection of the space 7 can be performed.

[0016] As described above, in the present invention, a leak inspection can be performed without pressurizing and supplying a gas or a liquid into the space. Therefore, even when the volume inside the space becomes extremely small, a leak inspection can be suitably performed.

[0017] The leak inspection may be performed in the state of a silicon wafer or after forming it into a chip state.

[0018] (Example 1) Example 1 will be described with reference to FIG. 2. The test piece 8 is made of AL. As shown in FIGS. 2(a) and 2(b), before bonding the first substrate 1 and the second substrate 2, a test piece 8 with a thickness of 1 μm is formed on the surface of the second substrate 2 on the side of the first substrate 1. Both the first substrate 1 and the second substrate 2 are silicon substrates.

[0019] After bonding the first substrate 1 and the second substrate 2, the initial shape of the test piece 8 is inspected using near-infrared light illumination with a wavelength of 1000 nm or more that penetrates the silicon substrate, a lens that transmits the wavelength, and a camera that is sensitive to the wavelength.

[0020] Next, plasma dry etching is performed using boron trichloride at 1000 W for 60 seconds.

[0021] Thereafter, the shape of the test piece 8 is inspected again using near-infrared light. As shown in FIGS. 2(e) and (f), when there is a leak location 10, the test piece 8 is etched, the shape of the test piece 8 changes, and finally it disappears. When there is no leak location 10, as shown in FIGS. 2(c) and (d), the test piece 8 is not etched and the shape does not change. Whether the test piece 8 disappears or not enables leak inspection within the space 7.

[0022] (Example 2) Example 2 is described using FIG. 3. The test piece 8 is made of AL, and a test piece 8 with a thickness of 1 μm is formed on the surface of the second substrate 2 on the side of the first substrate 1. Both the first substrate 1 and the second substrate 2 are silicon substrates. The test piece 8 is electrically connected to an electrode pad 11 formed outside the space 7 via an AL wiring 12.

[0023] After bonding the first substrate 1 and the second substrate 2, the resistance value of the test piece 8 in its initial state is measured from the electrode pad 11.

[0024] Next, as shown in FIGS. 3(a) and (b), plasma dry etching is performed using boron trichloride at 1000 W for 60 seconds. At that time, the electrode pad 11 is masked with a resist 13 so that the electrode pad 11 is not etched.

[0025] As shown in FIGS. 3(c) and (d), when there is a leak location 10, the test piece 8 is etched and finally becomes an open state. Therefore, after that, when the resistance value of the test piece 8 is measured again, the resistance value including the resistance value of the AL wiring 12 changes with respect to the resistance value in the initial state of 10 ± 1 Ω, and leak inspection within the space 7 can be performed.

[0026] Note that the test piece 8 does not have to be made of AL, and it may be formed of a conductive material.

[0027] The present invention includes the following configurations.

[0028] [Configuration ①] In a leak inspection method for performing leak inspection within a space The process of placing the test specimen in space, A first measurement step for measuring the physical properties or shape of the test specimen, A step of filling the space surrounding the aforementioned space with fluid, A second measurement step involves measuring the physical properties or shape of the test specimen again. A step of determining whether or not there is a leak by comparing the measurement results from the first measurement step and the measurement results from the second measurement step, A leak inspection method characterized by having [a certain feature].

[0029] [Configuration 2] The leak inspection method according to configuration 1, wherein the test piece is etched with the fluid.

[0030] [Configuration 3] The aforementioned test specimen is made of a conductive material, The test specimen is electrically connected via wiring to an electrode pad formed outside the space, The leak inspection method according to configuration 1 or 2, wherein the resistance value of the test piece is measured in the first measurement step and the second measurement step.

[0031] [Structure 4] The aforementioned space is formed by multiple silicon substrates, The leak inspection method according to configuration 1 or 2, wherein in the first measurement step and the second measurement step, the shape of the test piece is measured by near-infrared light transmitted through the silicon substrate.

[0032] [Composition 5] A method for inspecting a leak in a space of a liquid discharge head having a discharge port for discharging liquid, a piezoelectric element for generating pressure to discharge liquid from the discharge port, and a space for housing the piezoelectric element, The steps include: placing a test specimen in the aforementioned space; A first measurement step for measuring the physical properties or shape of the test specimen, A step of filling the space surrounding the aforementioned space with fluid, A second measurement step involves measuring the physical properties or shape of the test specimen again. A step of determining whether or not there is a leak by comparing the measurement results from the first measurement step and the measurement results from the second measurement step, A method for inspecting leaks in the space of a liquid discharge head, characterized by having the following:

[0033] [Composition 6] A method for inspecting a leak in the space of a liquid discharge head according to configuration 5, wherein the fluid is used to etch the test piece.

[0034] [Composition 7] The aforementioned test specimen is made of a conductive material, The test specimen is electrically connected via wiring to an electrode pad formed outside the space, A method for inspecting a leak in the space of a liquid discharge head according to configuration 5 or 6, wherein the first measurement step and the second measurement step involve measuring the resistance value of the test piece.

[0035] [Structure 8] The aforementioned space is formed by multiple silicon substrates, A method for inspecting a leak in the space of a liquid discharge head according to configuration 5 or 6, wherein the shape of the test piece is measured by near-infrared light transmitted through the silicon substrate in the first measurement step and the second measurement step. [Explanation of symbols]

[0036] 5 Outlet 7 Space 8 test specimens 9 fluid 14 Liquid dispensing head 15 Pressure Chamber

Claims

1. In a leak testing method that performs leak testing in a space, The process of placing the test specimen in space, A first measurement step for measuring the physical properties or shape of the test specimen, A step of filling the space surrounding the aforementioned space with fluid, A second measurement step involves measuring the physical properties or shape of the test specimen again. A step of determining whether or not there is a leak by comparing the measurement results from the first measurement step with the measurement results from the second measurement step, It has, A leak inspection method characterized by etching the test piece with the fluid.

2. The aforementioned test specimen is made of a conductive material, The test specimen is electrically connected via wiring to an electrode pad formed outside the space, The leak inspection method according to claim 1, wherein the resistance value of the test piece is measured in the first measurement step and the second measurement step.

3. The aforementioned space is formed by multiple silicon substrates, The leak inspection method according to claim 1, wherein in the first measurement step and the second measurement step, the shape of the test piece is measured by near-infrared light transmitted through the silicon substrate.

4. A method for inspecting a leak in a space of a liquid discharge head having a discharge port for discharging liquid, a piezoelectric element for generating pressure to discharge liquid from the discharge port, and a space for housing the piezoelectric element, The steps include: placing a test specimen in the aforementioned space; A first measurement step for measuring the physical properties or shape of the test specimen, A step of filling the space surrounding the aforementioned space with fluid, A second measurement step involves measuring the physical properties or shape of the test specimen again. A step of determining whether or not there is a leak by comparing the measurement results from the first measurement step with the measurement results from the second measurement step, It has, A method for inspecting a leak in the space of a liquid discharge head, characterized by etching the test piece with the fluid.

5. The aforementioned test specimen is made of a conductive material, The test specimen is electrically connected via wiring to an electrode pad formed outside the space, The method for inspecting a leak in the space of a liquid discharge head according to claim 4, wherein the resistance value of the test piece is measured in the first measurement step and the second measurement step.

6. The aforementioned space is formed by multiple silicon substrates, The method for inspecting a leak in the space of a liquid discharge head according to claim 4, wherein in the first measurement step and the second measurement step, the shape of the test piece is measured by near-infrared light transmitted through the silicon substrate.

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