KR102587356B1 - Differential vacuum ionization source - Google Patents

Abstract

The differential vacuum ionization source includes an ionization region into which the sample gas is injected, a filament that emits hot electrons, a repeller that accelerates the hot electrons to the ionization region, and a vacuum cover provided on the opposite side of the filament to the repeller. has a tube shape extending along the direction of arrangement of the filament and repeller.

Description

DIFFERENTIAL VACUUM IONIZATION SOURCE}

This disclosure relates to ionization sources, and specifically to ionization sources utilizing differential vacuum.

An ionization source is a device that ionizes a sample. Ionization sources can be used in a variety of fields that require ionization of samples, such as time-of-flight mass spectrometry. In the case of an ionization source that ionizes sample gas using the energy of hot electrons emitted from a filament, there is a possibility of damage or contamination of components due to contact between the sample gas and components of the ionization source. The useful life of the ionization source may be shortened due to damage or contamination of the ionization source.

[Support task]

[Business name]

Research equipment industry development

[Detailed Project Name]

Research equipment development and advancement support project

[Identification number]

COMPA2022-SETC(N)-G-01

[Comprehensive research and development name]

Development of a simultaneous heat and gas analysis system for secondary battery materials

The problem to be solved is to provide an ionization source with a long service life.

The challenge to be solved is to provide an ionization source with reduced risk of damage and contamination.

However, the problem to be solved is not limited to the above disclosure.

In one aspect, an ionization region into which sample gas is injected; A filament that emits hot electrons; a repeller that accelerates the hot electrons into the ionization region; And a vacuum cover provided on the opposite side of the filament with respect to the repeller; wherein the vacuum cover may be provided with a differential vacuum ionization source having a tube shape extending along the arrangement direction of the filament and the repeller. .

It may further include an external cover surrounding the vacuum cover, wherein the vacuum cover may be configured such that the conductance within the vacuum cover is greater than the conductance between the external cover and the vacuum cover.

an electronic lens provided between the ionization region and the filament; And a collector provided between the electronic lens and the filament; wherein the electronic lens may be configured to apply a voltage greater than the voltage applied to the collector.

The electronic lens, the collector, and the repeller may include conductance holes.

a filament cover provided on an opposite side of the vacuum cover to the repeller; an external cover surrounding the filament cover and the vacuum cover; and a vacuum pump connected to the external cover, wherein the vacuum cover may be spaced apart from the vacuum pump.

It further includes an electronic lens provided between the ionization region and the filament, wherein the filament cover is configured to have a tube shape with one side blocked by the electronic lens, and the electronic lens has a first conductance communicating with the ionization region. May include holes.

The cross-sectional area of the area between the filament cover and the outer cover is larger than the cross-sectional area of the first conductance hole of the electronic lens, and the outer cover, the inner region of the filament cover, and the inner region of the vacuum cover may communicate with each other.

It may further include a collector provided between the electronic lens and the filament, wherein the collector may include a second conductance hole facing the first conductance hole of the electronic lens.

The present disclosure can provide an ionization source with a long shelf life.

The present disclosure can provide an ionization source with reduced potential for damage and contamination.

However, the effect of the invention is not limited to the above disclosure.

1 is a cross-sectional view of an ionization source according to an exemplary embodiment.
Figure 2 is an enlarged view of portion AA of Figure 1.
Figures 3 and 4 show fluid flow within the ionization source of Figure 1.
Figures 5 to 8 are enlarged views of portion AA of Figure 1 for explaining the driving mode of the ionization source of Figure 1.
9 shows a time-of-flight mass spectrometer according to an exemplary embodiment.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the attached drawings. In the following drawings, the same reference numerals refer to the same components, and the size of each component in the drawings may be exaggerated for clarity and convenience of explanation. Meanwhile, the embodiments described below are merely illustrative, and various modifications are possible from these embodiments.

Hereinafter, the term “on” may include not only what is directly above in contact but also what is above without contact.

Hereinafter, “top surface” may mean a surface disposed above in the drawing.

Singular expressions include plural expressions unless the context clearly dictates otherwise. Additionally, when a part "includes" a certain component, this means that it may further include other components rather than excluding other components, unless specifically stated to the contrary.

Additionally, terms such as “unit” used in the specification refer to a unit that processes at least one function or operation.

1 is a cross-sectional view of an ionization source according to an exemplary embodiment. Figure 2 is an enlarged view of portion AA of Figure 1. Figures 3 and 4 show fluid flow within the ionization source of Figure 1. For brevity of explanation, an enlarged view of portion AA of FIG. 1 is shown with some components omitted from portion AA of FIG. 1 .

1 and 2, an ionization source 100 may be provided. The ionization source 100 may ionize the sample gas. The ionization source 100 includes a housing 102, a vacuum pump 104, a sample gas inlet 106, a first plate 112, a second plate 114, a filament 120, a repeller 122, It may include a collector 124, an electronic lens 126, a filament cover 130, and a vacuum cover 140. Housing 102 may be configured to provide an area where sample gas is ionized. A portion of the housing 102 surrounding the filament cover 130 and the vacuum cover 140 may be referred to as the outer cover 103.

Vacuum pump 104 may be connected to housing 102. Vacuum pump 104 may provide vacuum inside housing 102. For example, the inside of the housing 102 may have an air pressure of about 10 ^-10 to 10 ^-4 Torr by the vacuum pump 104.

The sample gas injection unit 106 may supply sample gas into the housing 102. For example, the sample gas may be a process gas used in a semiconductor process (e.g., HF, NF ₃ , Cl ₂ , HCl, SF ₆ , HBr, CF ₄ , BCl ₃ , C ₃ F ₈ , SiF ₄ , C ₂ etching gas such as F ₈ ). The sample gas may be highly corrosive. Components of the ionization source 100 (eg, filament 120, collector 124, or electron lens 126) may be damaged or contaminated by the sample gas.

The first plate 112 may be disposed closer to the sample gas injection unit 106 than the second plate 114. The first plate 112 may include a gas hole 112h through which sample gas passes. For example, the sample gas may pass through the gas hole 112h of the first plate 112 and flow into the ionization region (IR) between the first plate 112 and the second plate 114. A first conductive mesh 112m may be provided in the gas hole 112h. The first conductive mesh 112m may be electrically connected to the first plate 112. Accordingly, the first conductive mesh 112m may be configured to have substantially the same voltage as the first plate 112. Sample gas may pass through the first conductive mesh (112m). The sample gas may be ionized by the filament 120 in the ionization region (IR) by a process described later. Ionized sample gas (ie, positive ions) and electrons may be formed in the ionization region (IR). The first plate 112 may be configured to apply a positive voltage. For example, the voltage applied to the first plate 112 may be 2 to 4 kV.

The second plate 114 may be arranged to face the first plate 112. For example, the second plate 114 may be disposed substantially parallel to the first plate 112. The second plate 114 may include an ion hole 114h through which positive ions pass. For example, the ion hole 114h of the second plate 114 may face the gas hole 112h of the first plate 112. The second plate 114 is configured to be applied with substantially the same voltage as the first plate 112 when performing a process for generating positive ions, and the first plate 112 is configured to apply a voltage substantially the same as that of the first plate 112 when performing a process for generating positive ions. ) may be configured to apply a voltage lower than that. For example, the voltage applied to the second plate 114 may be 2 to 4 kV. When a voltage lower than that of the first plate 112 is applied, positive ions are separated from the first plate 112 to the second plate 114 by the electric field generated by the first plate 112 and the second plate 114. Force can act in the direction toward . Positive ions may be discharged outside the ionization region (IR) through the ion hole 114h of the second plate 114. A second conductive mesh 114m may be provided in the ion hole 114h. The second conductive mesh 114m may be electrically connected to the second plate 114. Accordingly, the second conductive mesh 114m may be configured to have substantially the same voltage as the second plate 114. Cations can pass through the second conductive mesh 114m.

Filament 120 may be configured to emit hot electrons. For example, when a high voltage is applied to the filament 120, electrons may be emitted from the filament 120. The electrons emitted at this time may be referred to as hot electrons. For example, the filament 120 may include tungsten (W) or rhenium (Re).

The repeller 122 may be configured to apply a lower voltage than the collector 124, which will be described later. For example, the voltage applied to the repeller 122 may be 2 to 4 kV. The repeller 122 may be configured to accelerate hot electrons in the filament 120 toward the ionization region (IR). By the repeller 122, hot electrons can have energy to ionize the sample gas. For example, hot electrons may be accelerated by the repeller 122 to have an energy of 0 to 200 eV. The repeller 122 may include a first conductance hole CH1. The first conductance hole CH1 may be configured to increase conductance within the filament cover 130 and the vacuum cover 140. Conductance can indicate gas flowability within a vacuum vessel. The higher the conductance, the more smoothly gas can move to the vacuum pump within the vacuum container, so a higher vacuum state can be created even if the same vacuum pump is used. As shown in FIGS. 3 and 4 , sample gas introduced into the vacuum cover 140 may flow through the first conductance hole CH1.

The collector 124 may be provided between the ionization region (IR) and the filament 120. The collector 124 may collect the hot electrons 1 emitted from the filament 120 so that the hot electrons 1 can be accelerated toward the ionization region IR. The collector 124 may be configured to apply a lower voltage than the electronic lens 126, which will be described later. For example, the voltage applied to the collector 124 may be 2 to 4 kV. The collector 124 may include a first electron hole 124h facing the filament 120. The first electron hole 124h of the collector 124 may be configured to allow hot electrons 1 to pass through. The collector 124 may include a second conductance hole (CH2). The second conductance hole (CH2) may face the first conductance hole (CH1). The second conductance hole CH2 may be configured to increase conductance within the filament cover 130 and the vacuum cover 140. As shown in FIGS. 3 and 4, sample gas introduced into the vacuum cover 140 may flow through the second conductance hole CH2.

An electron lens 126 may be provided between the ionization region (IR) and the collector 124. The electronic lens 126 may be configured to focus the thermal electrons 1. In one example, the focus of the electron lens 126 may be located in the ionization region (IR). The voltage applied to the electronic lens 126 may be greater than the voltage applied to the collector 124. The electronic lens 126 may include a second electron hole 126h aligned with the first electron hole 124h of the collector 124. The second electron hole 126h of the electron lens 126 may be configured to allow hot electrons 1 to pass through. The electronic lens 126 may include a third conductance hole (CH3). The third conductance hole (CH3) may face the second conductance hole (CH2). The third conductance hole CH3 may be configured to increase conductance within the filament cover 130 and the vacuum cover 140. As shown in FIGS. 3 and 4 , sample gas introduced into the vacuum cover 140 may flow through the third conductance hole CH3.

The hot electrons 1 may sequentially pass through the first electron hole 124h of the collector 124 and the second electron hole 126h of the electron lens 126 and be injected into the ionization region IR. The hot electrons 1 may collide with the sample gas in the ionization region (IR) to ionize the sample gas. In one example, hot electrons 1 may pass through the ionization region (IR) and be received in an electron trap (not shown).

A filament cover 130 may be provided on one side of the repeller 122. The filament cover 130 may surround the filament 120, the collector 124, and the electronic lens 126. One side of the filament cover 130 may be coupled to the repeller 122, and the other side of the filament cover 130 may be coupled to the first plate 112 and the second plate 114.

A vacuum cover 140 may be provided on the other side of the repeller 122. The vacuum cover 140 may have a half open tube shape. The vacuum cover 140 may include a partition wall 142 in contact with the repeller 122. The partition 142 may include a fourth conductance hole CH4. The fourth conductance hole CH4 may face the first conductance hole CH1. The fourth conductance hole CH4 may be configured to increase conductance within the filament cover 130 and the vacuum cover 140. As shown in FIGS. 3 and 4, sample gas introduced into the vacuum cover 140 may flow through the fourth conductance hole CH4. Accordingly, the sample gas may sequentially pass through the third conductance hole (CH3), the second conductance hole (CH2), the first conductance hole (CH1), and the fourth conductance hole (CH4).

The internal cross-sectional area of the vacuum cover 140 may be smaller than the internal cross-sectional area of the external cover 103 surrounding the vacuum cover 140. The internal cross-sectional area of the vacuum cover 140 and the outer cover 103 is in a direction intersecting the extension direction of the vacuum cover 140 and the outer cover 103 in the area surrounded by the vacuum cover 140 and the outer cover 103. It can refer to the cross-sectional area along . Furthermore, the cross-sectional area of the inlet (i.e., third conductance hole (CH3)) through which fluid flows into the filament cover 130 and the vacuum cover 140 is the area between the vacuum cover 140 and the external cover 103, which allows fluid to flow into the filament cover 130 and the vacuum cover 140. may be smaller than the cross-sectional area of the inlet. Accordingly, the conductance inside the filament cover 130 and the vacuum cover 140 is outside the filament cover 130 and the vacuum cover 140 (i.e., the filament cover 130, the vacuum cover 140, and the outer cover 103). may be greater than the conductance of the area between The degree of vacuum inside the filament cover 130 and the vacuum cover 140 may be higher than the outside of the vacuum cover 140. For example, the vacuum surrounding the components of the ionization source 100 (e.g., the filament 120, the collector 124, or the electron lens 126) is lower than that around the sample gas inlet 106. It can be maintained. Accordingly, the frequency of contact between the components of the ionization source 100 (eg, the filament 120, the collector 124, or the electron lens 126) and the sample gas may be reduced. Since the likelihood of contamination or damage to the components of the ionization source 100 (e.g., the filament 120, the collector 124, or the electron lens 126) is reduced, the components of the ionization source 100 (e.g., For example, the lifespan of the filament 120, collector 124, or electronic lens 126) may be increased.

Figures 5 to 8 are enlarged views of portion AA of Figure 1 for explaining the driving mode of the ionization source of Figure 1.

Referring to FIG. 5 , sample gas 2 may be injected from the sample gas injection unit 106 into the ionization region (IR). For example, the sample gas 2 may include an etching gas such as HF, NF ₃ , Cl ₂ , HCl, SF ₆ , HBr, CF ₄ , BCl ₃ , C ₃ F ₈ , SiF ₄ , C ₂ F ₈ , etc. You can. The sample gas 2 may flow into the ionization region IR through the gas hole 112h of the first plate 112.

When a high voltage is applied to the filament 120, hot electrons 1 may be emitted from the filament 120.

Referring to FIG. 6, hot electrons 1 may be accelerated into the ionization region IR by the electric field generated between the repeller 122 and the collector 124. The collector 124 and repeller 122 may be configured such that the collector 124 has a higher voltage than the repeller 122 in the range of 2 to 4 kV.

The collector 124 may attract hot electrons 1 to be emitted from the filament 120.

A higher voltage than the collector 124 is applied to the electron lens 126, so that the hot electrons 1 can be focused. For example, a voltage of 2 to 4 kV may be applied to the electronic lens 126. In one example, the focus of the electron lens 126 may be located in the ionization region (IR).

Referring to FIG. 7, hot electrons 1 may ionize the sample gas 2 in the ionization region IR. Accordingly, positive ions 3 and electrons 4 may be generated in the ionization region IR. For example, hot electrons 1 can ionize the sample gas 2 with energy of 0 to 200 eV.

Substantially the same voltage may be applied to the first plate 112 and the second plate 114. Accordingly, the positive ions 3 can stay in the ionization region (IR).

Referring to FIG. 8 , a lower voltage may be applied to the second plate 114 than to the first plate 112 . An electric field may be generated in the ionization region IR in a direction from the first plate 112 to the second plate 114. Due to the electric field generated by the first plate 112 and the second plate 114, a force may act on the positive ions 3 in a direction from the first plate 112 to the second plate 114. Accordingly, the positive ions 3 can be accelerated by the first plate 112 and the second plate 114. Cations 3 may be emitted from the ionization region IR through the ion hole 114h of the second plate 114. A force may act on the electrons 4 in a direction from the second plate 114 to the first plate 112 . Electrons 4 may be emitted from the ionization region IR through the gas hole 114h of the first plate 114.

After the positive ions 3 are released from the ionization region IR, substantially the same voltage may be applied to the first plate 112 and the second plate 114 again.

9 shows a time-of-flight mass spectrometer according to an exemplary embodiment. For brevity of explanation, content substantially the same as that described with reference to FIGS. 1 and 2 may not be described.

Referring to FIG. 9, a time-of-flight mass spectrometer 1000 may be provided. The time-of-flight mass spectrometer 1000 may include an ionization source 100, an ion separation unit 200, and an ion detection unit 300. The ionization source 100 may be substantially the same as the ionization source 100 described with reference to FIGS. 1 and 2 .

The ion separation unit 200 may provide an area where positive ions emitted from the ionization source 100 are separated. The ion separation unit 200 shares an internal space with the ionization source 100 and may be in a vacuum state. In one example, the internal space of the ion separator 200 may have a pressure of about 10 ^-10 to 10 ^-4 Torr. The moving speed of cations 3 with a relatively small mass may be faster than the moving speed of cations with a relatively large mass. Therefore, cations 3 with a relatively small mass can pass through the ion separator 200 faster than cations 3 with a relatively large mass.

The ion detection unit 300 can detect positive ions that have passed through the ion separation unit 200. The ion detection unit 300 shares an internal space with the ionization source 100 and the ion separation unit 200, and may be in a vacuum state. In one example, the internal space of the ion detection unit 300 may have a pressure of about 10 ^-10 to 10 ^-4 Torr. In one example, the ion detection unit 300 may include a microchannel plate (not shown) and/or an electron multiplier (not shown). For example, positive ions can be injected into a microchannel plate and/or electron multiplier to induce electrons. Electrons may be amplified within the microchannel plate and/or electron multiplier and detected by detection circuitry (not shown). When a cation with a relatively small mass and a cation with a relatively large mass enter the ion separation unit 200 at the same time, the cation with a relatively small mass enters the ion detection unit 300 before the cation with a relatively large mass. can be detected. The longer the length of the ion separation unit 200, the greater the difference in time at which ions with different masses are detected can be.

The ionization source 100 described with reference to FIGS. 1 to 4 can be applied to various devices that require ionization of samples in addition to a time-of-flight mass spectrometer.

The above description of embodiments of the technical idea of the present disclosure provides examples for explaining the technical idea of the present disclosure. Therefore, the technical idea of the present disclosure is not limited to the above embodiments, and various modifications and changes can be made by combining the above embodiments by those skilled in the art within the technical idea of the present disclosure. This possibility is obvious.

Claims (8)

an ionization region into which sample gas is injected;
A filament that emits hot electrons;
a repeller that accelerates the hot electrons into the ionization region;
a vacuum cover provided on the opposite side of the filament to the repeller;
an electronic lens provided between the ionization region and the filament; and
Including a collector provided between the electronic lens and the filament,
The vacuum cover has a tube shape extending along the arrangement direction of the filament and the repeller,
The electronic lens is a differential vacuum ionization source configured to apply a voltage greater than the voltage applied to the collector. According to claim 1,
It further includes an external cover surrounding the vacuum cover,
The vacuum cover is configured such that the conductance within the vacuum cover is greater than the conductance between the outer cover and the vacuum cover. delete According to claim 1,
The electron lens, the collector, and the repeller include conductance holes. According to claim 1,
a filament cover provided on an opposite side of the vacuum cover to the repeller;
an external cover surrounding the filament cover and the vacuum cover; and
It further includes a vacuum pump connected to the external cover,
The vacuum cover is a differential vacuum ionization source spaced apart from the vacuum pump. According to claim 5,
The filament cover is configured to have a tube shape with one side blocked by the electronic lens,
A differential vacuum ionization source wherein the electron lens includes a first conductance hole in communication with the ionization region. According to claim 6,
The cross-sectional area of the area between the filament cover and the outer cover is larger than the cross-sectional area of the first conductance hole of the electronic lens,
A differential vacuum ionization source wherein the outer cover, the inner region of the filament cover, and the inner region of the vacuum cover are in communication with each other. According to claim 7,
The differential vacuum ionization source wherein the collector includes a second conductance hole facing the first conductance hole of the electron lens.