JP2019129015A - Ion filter, ion detection device, and manufacturing method of ion filter - Google Patents

Abstract

To provide an ion filter capable of suppressing waveform sharpness of a voltage applied to between electrodes.SOLUTION: An ion filter part 200 of an embodiment 2, comprises: a support layer 203; a BOX layer 202 laminated onto the support layer 203; and an electrode layer 201 containing two comb-shaped electrodes 211 and 212 laminated on the BOX layer 202, and oppositely arranged so that a plurality of comb-shaped teeth is engaged in a surface orthogonal to a lamination direction. In an ion filter, a path where a region corresponded to one part of a gap between the comb-shaped teeth of adjacent the comb-shaped electrodes 211 and 212 in the BOX layer 202 and the support layer 203 is removed and an ion can pass to the lamination direction, and the region of the support layer 203 corresponded to one part of the electrode layer 201.SELECTED DRAWING: Figure 15

Description

  The present invention relates to an ion filter, an ion detection device, and a method of manufacturing an ion filter, and more specifically, an ion filter capable of sorting ions, an ion detection device including the ion filter, and sorts ions. The present invention relates to a method of manufacturing an ion filter.

  There is a method called field asymmetric ion mobility spectrometry (hereinafter, also referred to as "FAIMS") as one of methods for analyzing gas or vaporized chemical substance (for example, Patent Document 1) ~ 3).

  In this method, ionized gas molecules or chemical substances (hereinafter collectively referred to as "chemical substance etc.") are passed through an ion filter in which a voltage is applied between the electrodes, and they are sorted according to the difference in mobility The chemical substance or the like is identified by detection with a detector.

  In an ion filter included in a conventional analyzer (hereinafter, also referred to as “ion detector”) used in FAIMS disclosed in Patent Documents 1 to 3, regarding the suppression of waveform dullness of a voltage applied between electrodes. There was room for improvement.

  The present invention provides a support layer, an insulating layer stacked on the support layer, and a plurality of comb teeth that are stacked on the insulating layer and are engaged with each other in a plane perpendicular to the stacking direction. At least one of the gaps between the comb teeth of the adjacent first comb electrode and the comb teeth of the second comb electrode, and an electrode layer including the first and second comb electrodes, There is no region of the insulating layer and the support layer corresponding to the portion, and a passage through which ions can pass in the stacking direction is formed, and the region of the support layer corresponding to at least a part of the electrode layer is It is an ion filter characterized by not existing.

  ADVANTAGE OF THE INVENTION According to this invention, the waveform blunting of the voltage applied between electrodes can be suppressed.

It is a schematic block diagram of the ion detector which concerns on one Embodiment. It is a figure for demonstrating the electric field strength dependence of the mobility of ion. It is FIG. (1) for demonstrating the locus | trajectory of a movement of three ion (ion A, ion B, ion C) between the electrodes of an ion filter part. It is a figure for demonstrating the electric field waveform generated between the electrode A and the electrode B. FIG. It is FIG. (2) for demonstrating the movement locus | trajectory of three ion (ion A, ion B, ion C) between the electrodes of an ion filter part. It is a perspective view of an ion filter part concerning one embodiment. FIG. 7A is a diagram for explaining a rectangular signal, and FIG. 7B is a diagram for explaining a signal in which the rectangular signal is blunt. It is a figure for demonstrating the capacitor | condenser formed between two opposing comb-tooth electrodes. FIGS. 9A and 9B are views (No. 1) for explaining the capacitance between the comb electrode and the support layer, respectively. It is FIG. (2) for demonstrating the capacitance between a comb-tooth electrode and a support layer. FIG. 11A to FIG. 11C are diagrams (No. 1) for explaining the first embodiment, respectively. FIG. 12A to FIG. 12C are diagrams (No. 2) for explaining the first embodiment. 4 is a diagram for explaining three electrodes in Example 1. FIG. FIG. 14A to FIG. 14D are diagrams for explaining capacitances generated in portions other than the ion channel in the first embodiment. FIGS. 15A to 15C are diagrams (No. 1) for explaining the second embodiment. FIGS. 16A to 16C are diagrams (part 2) for describing the second embodiment. FIGS. 17A to 17C are diagrams (No. 1) for explaining the third embodiment. FIG. 18A to FIG. 18C are views (No. 2) for explaining the third embodiment. FIGS. 19A to 19C are diagrams (No. 1) for explaining the fourth embodiment. FIGS. 20A to 20C are diagrams (part 2) for explaining the fourth embodiment. It is a figure (the 1) for demonstrating the manufacturing method of an ion filter part. It is FIG. (2) for demonstrating the manufacturing method of an ion filter part. It is a figure (the 3) for demonstrating the manufacturing method of an ion filter part. It is FIG. (4) for demonstrating the manufacturing method of an ion filter part. It is FIG. (5) for demonstrating the manufacturing method of an ion filter part. It is a figure (the 6) for demonstrating the manufacturing method of an ion filter part. It is a figure (the 7) for demonstrating the manufacturing method of an ion filter part. It is FIG. (8) for demonstrating the manufacturing method of an ion filter part. It is a figure (the 9) for demonstrating the manufacturing method of an ion filter part. It is FIG. (10) for demonstrating the manufacturing method of an ion filter part. It is FIG. (11) for demonstrating the manufacturing method of an ion filter part. It is FIG. (12) for demonstrating the manufacturing method of an ion filter part. It is FIG. (13) for demonstrating the manufacturing method of an ion filter part. It is FIG. (14) for demonstrating the manufacturing method of an ion filter part. It is FIG. (15) for demonstrating the manufacturing method of an ion filter part.

"Overview"
Hereinafter, an embodiment of the present invention will be described based on the drawings. FIG. 1 shows a schematic configuration of an ion detector 10 according to an embodiment.

  The ion detection device 10 includes an ion generation unit 100, an ion filter unit 200, a detection unit 600, a control unit 900, and the like. Here, an XYZ three-dimensional orthogonal coordinate system is used, and the traveling direction of the molecule to be measured is the + Z direction.

  The ion generator 100 ionizes the molecule to be measured. The ion filter unit 200 selects ions from the ion generation unit 100. The detection unit 600 detects the ions sorted by the ion filter unit 200. The control unit 900 controls the entire apparatus.

  The basic detection principle of the ion detector 10 will be described.

  The ion filter unit 200 has two electrodes (electrode A and electrode B) arranged to face each other.

Ions move at a moving velocity V represented by the following equation (1) in the environment of the electric field E. Here, K is the mobility of the ions.
V = K × E (1)

  By the way, ion mobility has electric field strength dependency. And this electric field strength dependence changes with kinds of ion. FIG. 2 shows, as an example, the electric field strength dependence of the mobility of three different types of ions (ion A, ion B, and ion C). In FIG. 2, for ease of understanding, the mobility of each ion is normalized so that the electric field strength is equal to zero.

  The mobility of the three ions (ion A, ion B, and ion C) is almost unchanged at a low electric field strength of 9 kV / cm or less. As the electric field strength increases from about 10 kV / cm, characteristics specific to the type of ion appear in the mobility. The mobility of the ion A greatly increases as the electric field strength increases, and becomes maximum at Emax. The mobility of ions B increases more slowly than ions A. The mobility of ions C gradually decreases. In this way, the characteristics of the tripartite are shown. The ion filter unit 200 performs ion selection using the difference between the mobility at a low electric field strength and the mobility at a high electric field strength.

  A locus of movement of three ions (ions A, ions B, and ions C) between the electrodes of the ion filter unit 200 is shown in FIG. Here, for the sake of convenience, the electrodes A and B are parallel flat plates made of a conductor for the sake of simplicity.

  By making the waveform of the electric field generated between the electrode A and the electrode B into an asymmetric electric field waveform, only an arbitrary ion (the ion B in FIG. 3) can reach the detection unit 600.

FIG. 4 shows an example of an electric field waveform generated between the electrode A and the electrode B. In this electric field waveform, a positive high electric field (Emax) and a negative low electric field (Emin) are alternately repeated. The high electric field period (t1) is shorter than the low electric field period (t2), and the ratio of t1 to t2 is 1: 3 to 1: 5. Thus, the electric field waveform is asymmetric with respect to the upper and lower sides. This asymmetric electric field waveform is set such that the time-average electric field is zero and the following equation (2) is satisfied.
| Emax | × t1 = | Emin | × t2 (2)

  That is, the area of the region A in FIG. 4 and the area of the region B are set to coincide with each other.

In the following, as shown in the following equation (3), the value of | Emax | × t1 and the value of | Emin | × t2 are β.
| Emax | × t1 = | Emin | × t2 = β (3)

By the way, the velocity Vup at which ions move in the Y-axis direction during the high electric field period (t1) is expressed by the following equation (4). Here, K (Emax) is the mobility of ions at high electric field (Emax).
Vup = K (Emax) × | Emax | (4)

  For example, when | Emax | is about 10 kV / cm or more, the mobility of three ions (ion A, ion B, ion C) differs for each ion (see FIG. 2). Are different in three ways. That is, as shown in FIG. 5, the inclinations of the movement trajectories of the three ions are different from each other in the period (t1) of the high electric field.

The displacement yup (see FIG. 5), which is the distance that the ions have moved in the Y-axis direction during the high electric field period (t1), is expressed by the following equation (5).
yup = Vup × t1 (5)

On the other hand, the velocity Vdown at which ions move in the Y-axis direction during the low electric field period (t2) is expressed by the following equation (6). Here, K (Emin) is the mobility of ions at a low electric field (Emin).
Vdown = −K (Emin) × | Emin | (6)

  For example, when | Emin | is about 5 kV / cm or less, the mobility of three ions (ion A, ion B, and ion C) is almost the same (see FIG. 2), so the movement speed Vdown of the three ions Are almost identical. That is, as shown in FIG. 5, in the low electric field period (t2), the inclinations of the movement trajectories of the three ions are substantially the same.

The displacement ydown (see FIG. 5), which is the distance that the ions have moved in the Y-axis direction during the low electric field period (t2), is expressed by the following equation (7).
ydown = Vdown × t2 (7)

  In one cycle (T) of the asymmetric electric field waveform, the ions move in the + Y direction, move in the + Y direction during the period t1, and move in the -Y direction during the period t2.

  Therefore, as shown in FIG. 5, the one moving toward the electrode A while repeating the zigzag movement (ion A), the one moving toward the electrode B while repeating the zigzag movement (ion C), the displacement in the + Y direction, and the -Y direction Is balanced with the displacement (ion B) toward the detection unit.

By the way, the average displacement ΔyRF in the Y-axis direction of ions in one cycle (T) in the asymmetric electric field waveform is expressed by the following equation (8).
ΔyRF = yup + ydown
= K (Emax) * | Emax | * t1-K (Emin) * | Emin | * t2 (8)

And said (8) Formula can be represented like the following (9) Formula using said (3) Formula.
ΔyRF = β {K (Emax) −K (min)} (9)

Here, when K (Emax) −K (min) is set to ΔK, the above equation (9) is expressed as the following equation (10).
ΔyRF = βΔK (10)

  β is a constant determined by the asymmetric electric field applied between the electrode A and the electrode B. Therefore, the displacement of the ions per cycle (T) of the asymmetric electric field waveform in the Y-axis direction depends on ΔK which is the difference between the mobility in the low electric field (Emin) and the mobility in the high electric field (Emax).

Assuming that only the carrier gas transports ions in the Z-axis direction, the displacement Y of the ions in the Y-axis direction when the ions stay between the electrode A and the electrode B is the following (11) It becomes an expression. Here, tres is an average time during which ions stay between the electrode A and the electrode B (average ion stay time).

The average ion residence time tres is expressed by the following equation (12). Here, A is the cross-sectional area of the ion filter portion, L is the electrode length (electrode depth) in the Z-axis direction (see FIG. 5), and Q is the volumetric flow rate of the carrier gas. V is the volume (= AL) of the ion filter section.

The above formula (11) can be expressed as the following formula (13) using the above formula (12) and the above formula (3). Here, D is the duty of the asymmetric electric field waveform, and D = t1 / T.

  When the same value is used for all ion species for the high electric field Emax in the asymmetric electric field waveform, the volume V of the ion filter section, the duty D of the asymmetric electric field waveform, and the volume flow rate Q of the carrier gas, the above equation (13) From the above, it can be seen that the displacement Y is proportional to the difference ΔK between the mobility in the low electric field (Emin) specific to the ion species and the mobility in the high electric field (Emax).

  In FIG. 5, only the ion B has the smallest displacement Y and can reach the detection unit 600, but by changing the duty D, ions having a ΔK different from the ion B reach the detection unit 600. It can be done. Furthermore, by changing the duty D little by little, it is possible to detect the presence or amount of various ions with different ΔK.

  In addition, as a method for detecting various ion species having different ΔK in the ion detector 10, there is a method of superimposing a low-intensity DC electric field on an asymmetric electric field waveform. According to this method, the amount of displacement in the Y-axis direction during the period t1 and the period t2 can be changed. Therefore, the ion species that can reach the detection unit 600 without contacting the electrode A or the electrode B can be continuously changed. The DC electric field superimposed on the asymmetric electric field waveform is called compensation voltage (CV: compensation voltages). In this method, the presence / absence and amount of various ion species having different ΔK are detected by sweeping the compensation voltage.

  By the way, the ions that have contacted the electrode A or the electrode B before reaching the detection unit 600 are neutralized and are not detected.

  In addition, since the control part 900 is substantially the same as the control part in the conventional ion detection apparatus, detailed description about operation | movement of the control part 900 is abbreviate | omitted here.

"Details"
The ion detector 10 detects ions by utilizing the fact that the mobility varies depending on the ion species when the electric field strength is 10 kV / cm or more. In the example of FIG. 2, the ion species is separated by generating an electric field strength of about 20 kV as Emax between the electrodes in the ion filter unit 200. For example, assuming that the distance between electrodes in the ion filter unit 200 is 1 mm (0.1 cm), the voltage Vmax applied between the electrodes to generate an electric field of 20 kV / cm is expressed by the following equation (14) Thus, it becomes 2 kV.
Vmax = 20 kV / cm × 0.1 cm = 2 kV (14)

  In the case of using the ion detection device as a facility and fixing the installation location, there is no problem in terms of voltage and power consumption since an AC power supply can be used. In addition, if the installation location can be secured, there is no problem even if the outer shape is somewhat large. However, if the conventional ion detection device is driven by a battery and is to be realized as a small portable device, several tens to several hundreds of volts as an AC voltage Vd must be generated from a battery power source of several tens to several tens of volts. Therefore, it is necessary to use a booster circuit and high-voltage components, which has been an obstacle to downsizing the device and reducing power consumption.

  In order to achieve the same electric field strength at a low voltage, the distance between the electrodes in the ion filter portion may be reduced. For example, when the distance between the electrodes is 1 μm (0.0001 cm), an electric field strength of 20 kV / cm can be realized at a voltage of 2 V.

  By the way, Patent Document 1 describes that an electrode was prototyped by a LIGA (Lithographie Galvanoforming Abforming) process. On the other hand, in this embodiment, an electrode is realized using a wafer called SOI (Silicon On Insulator) used in semiconductor manufacturing.

  If the distance between the electrodes is reduced while the aspect ratio, which is the ratio between the distance between the electrodes and the electrode depth L, is kept constant, the electrode depth L may be reduced. For example, when the electrode spacing is 1 μm and the aspect ratio 10 is maintained, the electrode depth L is 10 μm, and the etching amount is small with respect to the conventional example of the aspect ratio 10 where the electrode spacing is 100 μm and the electrode depth L is 1000 μm. It will be finished. This is a value that is sufficiently possible to etch silicon using a deep reactive ion etching (DRIE) technique used in semiconductor manufacturing.

  In addition, in the case of using a comb electrode as the electrode and arranging two comb electrodes opposite to each other so that the comb teeth alternately mesh with each other, the ion channel which is a flow path through which ions pass in a certain fixed chip area In order to increase the area, the width of the comb teeth needs to be as small as possible, for example, 1 μm.

  In the conventional ion filter portion, for example, when the length of the comb teeth is 1000 μm, the aspect ratio of one comb tooth is 1000, and the shape is very vulnerable to stress or impact. In this case, in the processes such as resist coating, etching, conveyance, and cleaning necessary for manufacturing, force is applied to the comb teeth, the comb teeth are deformed, contact with adjacent comb teeth, or comb teeth remain in contact with each other. There is a risk of so-called sticking phenomenon in which the sticking occurs, or in the worst case, destruction.

  In operation, a pulse signal for generating an asymmetric electric field waveform is applied to the electrodes. At that time, the comb teeth may vibrate due to electrostatic force. The present embodiment solves the above disadvantages.

  FIG. 6 shows an ion filter unit 200 according to an embodiment of the present invention. The ion filter unit 200 is manufactured using a wafer substrate called SOI (Silicon On Insulator). This wafer substrate is mainly made of silicon (Si) and is also used for manufacturing LSI (Large Scale Integrated Circuit). In FIG. 6, the pad electrode portion is omitted. Further, in FIG. 6, the number of the comb teeth in each comb electrode is three, but this is for the purpose of avoiding complexity and making the description easy to understand, and is not limited to three.

The ion filter unit 200 includes an electrode layer 201, a BOX (Buried Oxide) layer 202, and a support layer 203. The electrode layer 201 is a layer in which silicon (Si) is doped with impurities such as phosphorus (P) and boron (B) in advance to reduce electric resistance (high electric conductivity). The BOX layer 202 is an insulating film made of a silicon oxide film (SiO ₂ ) and has a very high electric resistance. The support layer 203 is a layer made of silicon (Si). Note that it is preferable that the support layer 203 has a higher electrical resistance because the influence of parasitic capacitance is reduced.

  Here, the stacking direction of the three layers is the c-axis direction, the direction orthogonal to the c-axis direction is the a-axis direction, and the direction orthogonal to both the c-axis direction and the a-axis direction is the b-axis direction Do.

  In the electrode layer 201, the comb-tooth electrode 211 and the comb-tooth electrode 212 are separately formed in the ab plane. Note that the comb electrode 211 and the comb electrode 212 are partly in contact with the BOX layer 202. Since the BOX layer 202 is an insulating film, the comb electrode 211 and the comb electrode 212 are electrically separated, and no current flows even if different voltages are applied to the both. The BOX layer 202 is in contact with the support layer 203, and the relative positions of the comb electrode 211 and the comb electrode 212 are fixed.

  Although hidden in FIG. 6, the BOX layer 202 and the support layer 203 thereunder are removed in part of the gap between the comb electrode 211 and the comb electrode 212, and ions pass in the c-axis direction. The flow path (ion channel) is formed.

  The comb-tooth electrode 211 and the comb-tooth electrode 212 have one comb-tooth electrode as GND (ground), and the other comb-tooth electrode has a DC voltage called dispersion voltage (CV) and a dispersion voltage (DF) An asymmetric electric field waveform signal in which a voltage pulse called V is superimposed is applied.

  That is, an asymmetric electric field waveform signal (voltage signal) is applied to the ion filter unit 200 via a drive circuit (a part of the control unit 900). The drive circuit has an output impedance. Further, when an asymmetric electric field waveform signal is applied, a capacitance that is a load capacitance is generated in the ion filter unit 200. Hereinafter, for the sake of convenience, the capacitance generated in the ion filter unit 200 is also referred to as “the capacitance of the ion filter”.

Therefore, the shape of the asymmetric electric field waveform signal applied to the ion filter unit 200 is mainly determined by the time constant τ depending on the output impedance of the drive circuit and the capacitance of the ion filter. The time constant τ is a time required to reach about 63% of the final ultimate voltage, and is expressed by the following equation (15).
τ (seconds) = output impedance (Ω) × ion filter capacitance (F) (15)

  Therefore, even if it is attempted to apply an ideal rectangular waveform asymmetric electric field waveform signal having sharp rising and falling as shown in FIG. 7A, the rising and falling are shown as an example in FIG. 7B. In some cases, an asymmetric electric field waveform signal with a blunt falling shape may be applied.

  It is difficult to make the magnitude of the output impedance of the drive circuit completely zero, and it always has a certain finite value.

  Here, it is considered that the capacitance of the ion filter is divided into a capacitance generated in a portion to be an ion channel between the opposing comb electrode 211 and the comb electrode 212 and a capacitance generated otherwise.

When the asymmetric electric field waveform signal is applied, a portion that becomes an ion channel between the comb-shaped electrode 211 and the comb-shaped electrode 212 facing each other is electrically a capacitor (see FIG. 8). The dielectric in this capacitor is the ionized gas to be analyzed. Hereinafter, for convenience, the capacitance of the capacitor is also referred to as “ion channel capacitance”. The capacitance of the ion channel has a certain value determined by the number of comb teeth, the interval between the two comb electrodes, and the like. For example, when the distance between the two comb electrodes is reduced (narrow), the capacitance of the ion channel increases.
For this reason, it is difficult to make the time constant τ completely zero, and the rise and fall of dullness as shown in FIG.

  Incidentally, in FIG. 5 described above, yup and ydown need to have a relationship of yup << W and ydown << W with respect to the interval W between the electrode A and the electrode B. If yup and ydown are equal to or longer than the interval W, ions to reach the detection unit 600 also contact the electrode A or B along the way, and charge is released before reaching the detection unit 600. The function of the ion filter is lost.

  In order to lower the voltage of the asymmetric electric field waveform signal applied between the electrode A and the electrode B, it is necessary to shorten the distance W. In this case, in order to maintain the relationship of yup << W and ydown << W, it is necessary to shorten the pulse period T in the asymmetric electric field waveform signal. In other words, it is necessary to increase the frequency of the asymmetric electric field waveform signal.

  Then, as the frequency of the asymmetric electric field waveform signal increases, the influence of the ion channel capacitance on the blunting of the signal waveform increases. If it is extreme, the amplitude of the asymmetric electric field waveform signal may not be amplified to a desired voltage. As described with reference to FIG. 7B, there is a possibility that the electric field may fall before reaching Emax.

  That is, in order to reduce the voltage of the ion detector 10, it is necessary to shorten the interval between the two comb electrodes in the ion filter unit 200, but this inevitably increases the frequency of the asymmetric electric field waveform signal. And increase the capacitance of the ion channel. Both of these act to increase the dullness of rising and falling with respect to the asymmetric electric field waveform signal applied to the ion filter unit 200.

  Next, the capacitance between the comb electrode and the support layer will be described as the capacitance generated in a portion other than the ion channel.

  FIG. 9 (A) is a plan view of the ion filter portion 200, and FIG. 9 (B) is a cross-sectional view taken along the line C-C in FIG. 9 (A). The comb electrode 211 has a capacitance C <b> 1 with respect to the support layer 203, and the comb electrode 212 has a capacitance C <b> 2 with respect to the support layer 203. The support layer 203 has a resistance value R1 and is connected to the capacitance C1 and the capacitance C2, and generates a capacitance component between the comb electrode 211 and the comb electrode 212.

This is added to the capacitance of the ion channel and causes a further rise and fall in the asymmetric electric field waveform signal applied to the ion filter unit 200. In the capacitance of the ion channel, the dielectric constant is approximately 1 because the dielectric is a gas, but in the capacitances C1 and C2, the BOX layer 202 to be a dielectric is a silicon oxide film (SiO ₂ ), and the relative dielectric constant Is about 4. In addition, since the BOX layer 202 is a thin film usually having a thickness of 0.5 μm or less, the capacitance generated in a portion other than the ion channel is large.

The capacitance C (F) between two electrodes is expressed by the following equation (16). Here, ε ₀ is a dielectric constant of vacuum, that is, 8.8542 × 10 ⁻¹² (m ⁻³ kg ⁻¹ s ⁴ A ² ), and ε is a relative dielectric constant (air: about 1, SiO ₂ : about 4). ), S is the area (m ² ) of the electrodes, and d is the distance (m) between the electrodes.
C = ε ₀ × ε × S / d (16)

  In the ion filter unit 200, one of the comb-tooth electrode 211 and the comb-tooth electrode 212 is connected to GND, and an asymmetric electric field waveform signal is input to the other. FIG. 10 shows an example in which the comb electrode 211 is connected to GND.

  Further, if the support layer 203 is not electrically connected anywhere and is in a so-called floating state, charges due to ions may accumulate and become a high voltage. Therefore, as shown in FIG. 10, the support layer 203 is normally connected to GND.

  In the example of FIG. 10, a capacitance C <b> 3 is generated between the comb electrode 212 and the support layer 203. The capacitance C3 can be reduced by reducing the area of the surface where the comb electrode 212 and the support layer 203 face each other. That is, the capacitance generated in a portion other than the ion channel can be reduced. Since the comb electrode 211 is connected to the same GND as the support layer 203, the capacitance generated between the comb electrode 211 and the support layer 203 is not a problem.

  Therefore, when the bluntness of the asymmetric electric field waveform signal applied to the ion filter unit 200 is large and can not be ignored, it is preferable to reduce the capacitance generated in the portion other than the ion channel. Hereinafter, an embodiment of the ion filter unit 200 having a configuration in which the capacitance generated in a portion serving as an ion channel and the capacitance generated in a portion other than the ion channel are reduced will be described.

Example 1
The ion filter part 200 of Example 1 is shown by FIG. 11 (A)-FIG.12 (C). FIG. 11A is a plan view of the ion filter unit 200 according to the first embodiment, FIG. 11B is a cross-sectional view taken along the line AA in FIG. 11A, and FIG. It is BB sectional drawing in 11 (A). 12A is a cross-sectional view taken along the line CC in FIG. 11A, FIG. 12B is a cross-sectional view taken along the line DD in FIG. 11A, and FIG. It is EE sectional drawing in 11 (A).

  In the ion filter unit 200 of the first embodiment, the electrode layer 201 is etched while leaving the wiring to the comb electrode 211 and the comb electrode 212 as a minimum. That is, the comb-tooth electrode 211 and the comb-tooth electrode 212 are electrically separated from the peripheral portion of the electrode layer 201, and the areas of the comb-tooth electrode 211 and the comb-tooth electrode 212 are minimized. Note that reference numeral 301 in FIG. 11A denotes an electrode pad for the comb electrode 211, and reference numeral 302 denotes an electrode pad for the comb electrode 212. Each electrode pad is provided for contact with wire bonding or probe pins, but it is preferable that the area of this portion is also kept to a minimum necessary area.

  In the ion filter unit 200, one of the comb-tooth electrode 211 and the comb-tooth electrode 212 is connected to GND, and an asymmetric electric field waveform signal is input to the other. FIG. 13 shows the case where the comb electrode 211 is connected to GND and the asymmetric electric field waveform signal is input to the comb electrode 212 in the ion filter unit 200 of the first embodiment. Conversely, the comb electrode 212 may be connected to the GND, and the asymmetric electric field waveform signal may be input to the comb electrode 211.

  In the ion filter unit 200 of the first embodiment, the electrode layer 201 has a ring-like frame-like part (hereinafter, referred to as a ring-shaped frame) that is electrically separated from the comb electrode 211 and the comb electrode 212. (Also referred to as “electrode 213”). If this electrode 213 is put in a floating state without being connected anywhere, charges may be charged at the time of ion detection, resulting in high voltage and damaging the function of the ion filter. Therefore, the electrode 213 is connected to GND (see FIG. 13).

In FIG. 11A, a region P surrounded by a broken line is a BOX layer 202 and a support layer 203 corresponding to a portion to be an ion channel (a BOX layer 202 corresponding to a gap between adjacent comb teeth 310 and comb teeth 320 and A region from which the support layer 203) and the BOX layer 202 and the support layer 203 corresponding to the intermediate portions (portions excluding both the tip end portion and the base end portion) of the three comb teeth of each comb electrode are removed It is.
That is, in the ion filter unit 200 according to the first embodiment, an ion channel that is a passage through which ions can pass is formed in the region P, and no capacitance is generated in the region P.
In addition, you may leave at least one part of the BOX layer 202 and the support layer 203 corresponding to the intermediate part of each of the three comb teeth of each said comb-tooth electrode. In this case, capacitance occurs in the region P, but the intermediate portion of each of the three comb teeth of each comb electrode can be supported by the support layer 203, and bending or vibration of the comb teeth described later can be suppressed.

Here, each comb-tooth electrode is a comb-shaped electrode including a plurality of comb teeth and a connecting portion for connecting the plurality of comb teeth.
Therefore, hereinafter, each comb electrode is also referred to as a “comb electrode”. That is, hereinafter, the comb-tooth electrode 211 is also referred to as a “comb-shaped electrode 211”, and the comb-tooth electrode 212 is also referred to as a “comb-shaped electrode 212”.

  As shown in FIG. 11A, the comb-shaped electrode 211 includes a plurality of (here, three) comb teeth 310 and a connecting portion 303 that connects the plurality of comb teeth 310 (on the −b side in FIG. 11A). Wide vertical stripe portion). The electrode pad 301 (the narrow vertical stripe portion on the −b side in FIG. 11A) is adjacent to the −b side of the connecting portion 303 and is electrically connected (conductive) to the connecting portion 303. ).

  The comb-shaped electrode 212 includes a plurality of (here, three) comb teeth 320 and a connecting portion 304 (a wide vertical stripe portion on the + b side in FIG. 11A) that connects the plurality of comb teeth 320. The electrode pad 302 (narrow narrow stripe portion on the + b side in FIG. 11A) is adjacent to the + b side of the connecting portion 304 and is electrically connected (conductive) to the connecting portion 304.

The number, shape, and size of the comb teeth of each comb electrode can be changed as appropriate.
Further, the shape and size of the connecting portion of each comb electrode can be changed as appropriate.
A configuration in which at least one of the two connecting portions 303 and 304 also functions as an electrode pad may be employed. In this case, at least one of the two electrode pads 301 and 302 may not be provided.

  In the ion filter portion 200 of the first embodiment, as shown in FIGS. 14A to 14D, the connection portion 303 and the base end portions of the three comb teeth 310 (−b side of FIG. 11A) A capacitance C4 is generated between the portion on the −b side of the large lattice portion of a) and the support layer 203, and the tip portions of the three comb teeth 320 (the small lattice portion on the −b side of FIG. Capacitance C5 is generated between the + b side portion of the base end portion of the three comb teeth 310 and the support layer 203, and the tip portions of the three comb teeth 310 (small lattice portion on the + b side in FIG. 11A) and A capacitance C6 is generated between the base layer of the three comb teeth 320 (the large lattice portion on the + b side in FIG. 11A) on the −b side and the support layer 203, and the coupling portion 304 and the three combs are formed. Capacitance C7 is generated between the base layer portion of the tooth 320 on the + b side and the support layer 203. That.

  In the ion filter unit 200 according to the first embodiment, as shown in FIG. 14B, a capacitance C8 is generated between the electrode pad 301 and the support layer 203, and the electrode pad 301 and the connecting portion 303 in the comb electrode 211 are formed. Between the electrode pad 302 and the coupling portion 304 in the comb-shaped electrode 212 (see FIG. 11A). A capacitance C10 is generated between the horizontal stripe portion 11 (A) on the + b side and the support layer 203, and a capacitance C11 is generated between the electrode pad 302 and the support layer 203.

  Further, in the ion filter unit 200 of the first embodiment, as shown in FIG. 14C, a part of the comb teeth 320 closest to the −a side (excluding both the tip and the base of the comb teeth 320) A capacitance C12 is generated between the support layer 203 and the portion on the −a side of the portion (the oblique lattice portion on the −a side of FIG. 11A).

  Further, in the ion filter unit 200 of the first embodiment, as shown in FIG. 14D, a part of the comb teeth 310 on the + a side (a part excluding both the tip and the base end of the comb teeth 310) A capacitance C13 is generated between the support layer 203 and the portion on the + a side of (the oblique lattice portion on the + a side in FIG. 11A).

  That is, the capacitances C4, C5, C6, C7, C8, C9, C10, C11, C12, and C13 are all capacitances generated in portions other than the ion channel.

Example 2
An ion filter unit 200 of Example 2 is shown in FIGS. 15A to 15C and FIGS. 16A to 16C. FIG. 15A is a plan view of the ion filter unit 200 according to the first embodiment, FIG. 15B is a cross-sectional view taken along the line AA in FIG. 15A, and FIG. 15A is a sectional view taken along line BB in FIG. 15A, FIG. 16A is a sectional view taken along line CC in FIG. 15A, and FIG. 16B is a sectional view taken along line DD in FIG. FIG. 16C is a cross-sectional view taken along line E-E in FIG. 15A.

In FIG. 15A, a region P surrounded by a broken line includes a BOX layer 202 corresponding to a portion serving as an ion channel and a support layer 203 (a BOX layer 202 corresponding to a gap between adjacent comb teeth 310 and comb teeth 320 and In the region where the support layer 203) and the BOX layer 202 and the support layer 203 corresponding to the middle part of each of the three comb teeth of each comb electrode (the part excluding both the front end part and the base end part) are removed. is there.
That is, in the ion filter unit 200 according to the second embodiment, an ion channel that is a passage through which ions can pass is formed in the region P, and no capacitance is generated in the region P.
Note that at least a part of the BOX layer 202 and the support layer 203 corresponding to the intermediate portions of the three comb teeth of each of the comb electrodes may be left. In this case, although capacitance occurs in the region P, the intermediate portion of each of the three comb teeth of each comb electrode can be supported by the support layer 203, and bending or vibration of the comb teeth described later can be suppressed.

  In FIG. 15A, regions Q1, Q2, Q3, and Q4 surrounded by a broken line are regions where only the support layer 203 corresponding to the portion other than the ion channel is removed.

  More specifically, the region Q1 is a region where the support layer 203 corresponding to the electrode pad 301 (the support layer 203 on the −c side of the electrode pad 301) is removed. That is, the capacitance C8 does not occur in the region Q1 (see FIGS. 14B and 16A).

  The area Q2 is an area where the support layer 203 (the support layer 203 on the -c side of the electrode pad 302) corresponding to the electrode pad 302 is removed. That is, the capacitance C11 does not occur in the region Q2 (see FIGS. 14B and 16A).

  In the region Q3, the support layer 203 (the connection part 303 and the support layer 203 on the −c side of the part) corresponding to the part on the −b side of the base end part of the connection part 303 and the three comb teeth 310 is removed. It is an area. That is, the capacitance C4 does not occur in the region Q3 (see FIGS. 14B, 14D, 16A, and 16C).

  The region Q4 is a region where the support layer 203 (the connection portion 304 and the support layer 203 on the −c side of the part) corresponding to the part on the + b side of the base end part of the connection part 304 and the three comb teeth 320 is removed. It is. That is, the capacitance C7 does not occur in the region Q4 (see FIGS. 14A to 14C, 15C, 16A, and 16B).

  In the ion filter unit 200 according to the second embodiment, as illustrated in FIGS. 15C to 16C, the + b side portions of the distal ends of the three comb teeth 320 and the proximal ends of the three comb teeth 310 are used. And the support layer 203, a capacitance C <b> 5 is generated, and the tip portion of the three comb teeth 310 of the comb electrode 211 and the base end portion of the three comb teeth 320 on the −b side, and the support layer 203. Capacitance C6 is generated.

  Further, in the ion filter portion 200 of the second embodiment, as shown in FIG. 16A, a capacitance C9 is present between the region between the electrode pad 301 and the connection portion 303 in the comb electrode 211 and the support layer 203. As a result, a capacitance C10 is generated between the region between the electrode pad 302 and the connection portion 304 in the comb electrode 212 and the support layer 203.

  Further, in the ion filter unit 200 of the second embodiment, as shown in FIG. 16B, a part of the comb teeth 320 closest to the −a side (excluding both the tip and the base end of the comb teeth 320) A capacitance C12 is generated between the support layer 203 and the portion on the -a side of the portion (see FIG. 15A).

  Further, in the ion filter unit 200 of the second embodiment, as shown in FIG. 16C, a part of the comb teeth 310 on the + a side (a part excluding both the tip and the base end of the comb teeth 310) A capacitance C13 is generated between the support layer 203 and the portion on the + a side of (see FIG. 15A).

  That is, capacitances C5, C6, C9, C10, C12, and C13 generated in the ion filter unit 200 of the second embodiment are capacitances generated in portions other than the ion channel.

  As can be seen from the above description, in the ion filter unit 200 of the second embodiment, the capacitance between the two comb electrodes 211 and 212 and the support layer 203 is smaller than that of the ion filter unit 200 of the first embodiment. , C7, C8, and C11.

  By the way, in the ion filter unit 200, when the tips of the comb teeth in the comb electrode 211 and the comb electrode 212 are free to move, stress due to convection of the chemical solution during manufacturing, gravity, physical vibration or asymmetric electric field waveform signal An electrostatic force or the like causes deformation of the comb teeth, vibration, contact with the adjacent comb teeth, and so-called sticking phenomenon in which the adjacent comb teeth are adhered while being in contact with each other. In the worst case, the comb electrode may be broken.

  In the ion filter unit 200 of the second embodiment, the portions where the capacitances C5 and C6 of the BOX layer 202 and the support layer 203 are generated on the −c side of the tip portion of the comb teeth are left in a rib shape (FIG. 15C) See FIG. 16 (A)). In this case, since the tip of the comb teeth is fixed to the rib portion and cannot move freely, the comb teeth can be prevented from being bent or vibrated, and the above-described disadvantages can be suppressed. Hereinafter, for the sake of convenience, the portion formed of the BOX layer 202 and the support layer 203 remaining in a rib shape is also referred to as a “rib portion”.

  Moreover, in the ion filter part 200 of Example 2, the part in which the capacitances C9 and C10 are generated is also left in a rib shape (see FIG. 16A). Thus, if the BOX layer 202 and the support layer 203 are left on the −c side of the portion between the connecting portion of each comb-shaped electrode and the electrode pad, the electrode pad and the connecting portion can be prevented from being bent or vibrated.

Example 3
The ion filter part 200 of Example 3 is shown by FIG. 17 (A)-FIG. 17 (C), FIG. 18 (A)-FIG. 18 (C). FIG. 17A is a plan view of the ion filter unit 200 according to the first embodiment, FIG. 17B is a cross-sectional view taken along the line AA in FIG. 17A, and FIG. 17A is a sectional view taken along line BB in FIG. 17A, FIG. 18A is a sectional view taken along line CC in FIG. 17A, and FIG. 18B is a sectional view taken along line DD in FIG. FIG. 18C is a cross-sectional view taken along the line E-E in FIG. 17A.

In FIG. 17A, a region P surrounded by a broken line includes a BOX layer 202 corresponding to a portion to be an ion channel and a support layer 203 (a BOX layer 202 corresponding to a gap between adjacent comb teeth 310 and comb teeth 320 and In the region where the support layer 203) and the BOX layer 202 and the support layer 203 corresponding to the intermediate portions (portions excluding both the tip end portion and the base end portion) of each of the three comb teeth of each comb electrode are removed is there.
That is, in the ion filter unit 200 according to the third embodiment, an ion channel that is a passage through which ions can pass is formed in the region P, and no capacitance is generated in the region P.
Note that at least a part of the BOX layer 202 and the support layer 203 corresponding to the intermediate portions of the three comb teeth of each of the comb electrodes may be left. In this case, although capacitance occurs in the region P, the intermediate portion of each of the three comb teeth of each comb electrode can be supported by the support layer 203, and bending or vibration of the comb teeth described later can be suppressed.

  Further, in FIG. 17A, regions Q1, Q2, Q3, Q4, Q5, and Q6 enclosed by broken lines are regions from which only the support layer 203 corresponding to the portion other than the ion channel is removed. .

  More specifically, the region Q1 is a region where the support layer 203 corresponding to the electrode pad 301 (the support layer 203 on the −c side of the electrode pad 301) is removed. That is, the capacitance C8 does not occur in the region Q1 (see FIGS. 14B and 18A).

  The area Q2 is an area where the support layer 203 (the support layer 203 on the -c side of the electrode pad 302) corresponding to the electrode pad 302 is removed. That is, the capacitance C11 does not occur in the region Q2 (see FIGS. 14B and 18A).

  In the region Q3, the support layer 203 (the connection part 303 and the support layer 203 on the −c side of the part) corresponding to the part on the −b side of the base end part of the connection part 303 and the three comb teeth 310 is removed. It is an area. That is, the capacitance C4 does not occur in the region Q3 (see FIGS. 14B, 14D, 18A, and 18C).

  The region Q4 is a region where the support layer 203 (the connection portion 304 and the support layer 203 on the −c side of the part) corresponding to the part on the + b side of the base end part of the connection part 304 and the three comb teeth 320 is removed. It is. That is, the capacitance C7 does not occur in the region Q4 (see FIGS. 14A to 14C, 17C, and 18A and 18B).

  Region Q5 is a support corresponding to a part of the comb teeth 320 closest to the -a side (a part on the -a side of the part excluding both the tip end and the base end of the comb teeth 320, see FIG. 17A) This is a region where the layer 203 (the support layer 203 on the −c side of the part) has been removed. That is, the capacitance C12 does not occur in the region Q5 (see FIGS. 14C, 16B, and 18B).

  A region Q6 corresponds to a part of the comb teeth 310 on the + a side closest to the part (a part on the + a side of a portion excluding both the tip end and the base end of the comb teeth 310, see FIG. 17A). (The support layer 203 on the -c side of the site) is an area where it is removed. That is, the capacitance C13 does not occur in the region Q6 (see FIGS. 14D, 16C, and 18C).

  In the ion filter portion 200 of the third embodiment, as shown in FIGS. 17C to 18C, the tip end portions of the three comb teeth 320 and the portion on the + b side of the base end portions of the three comb teeth 310. And the support layer 203, a capacitance C 5 is generated, and a capacitance C 6 is formed between the support layer 203 and the −b side portions of the tip ends of the three comb teeth 310 and the base ends of the three comb teeth 320. It is happening.

  Further, in the ion filter unit 200 of Example 3, as shown in FIG. 18A, a capacitance C9 is provided between the support layer 203 and the region between the electrode pad 301 and the connecting portion 303 in the comb electrode 211. As a result, a capacitance C10 is generated between the region between the electrode pad 302 and the connection portion 304 in the comb electrode 212 and the support layer 203.

  That is, the capacitances C5, C6, C9, and C10 generated in the ion filter unit 200 of Example 3 are all capacitances generated in portions other than the ion channel.

  As can be seen from the above description, in the ion filter unit 200 of the third embodiment, the capacitance between the two comb-shaped electrodes 211 and 212 and the support layer 203 is larger than the capacitance C12 of the ion filter unit 200 of the second embodiment. , C13 is reduced.

  In the ion filter unit 200 of Example 3, the portions where the capacitances C5 and C6 of the BOX layer 202 and the support layer 203 are generated are left in a rib shape on the −c side of the tip portion of the comb teeth (see FIG. 17C). The portions in which the capacitances C9 and C10 respectively occur are also left in the form of ribs (see FIG. 18A). In this case, the same effect as that of the second embodiment can be obtained.

Example 4
The ion filter part 200 of Example 4 is shown by FIG. 19 (A)-FIG. 19 (C), FIG. 20 (A)-FIG. 20 (C). FIG. 19A is a plan view of the ion filter unit 200 according to the first embodiment, FIG. 19B is a cross-sectional view taken along line AA in FIG. 19A, and FIG. 19A is a sectional view taken along line BB in FIG. 19A, FIG. 20A is a sectional view taken along line CC in FIG. 19A, and FIG. 20B is a sectional view taken along line DD in FIG. FIG. 20 (C) is a cross-sectional view taken along the line E-E in FIG. 19 (A).

In FIG. 19A, a region P surrounded by a broken line includes a BOX layer 202 corresponding to a portion to be an ion channel and a support layer 203 (a BOX layer 202 corresponding to a gap between adjacent comb teeth 310 and comb teeth 320 and In the region where the support layer 203) and the BOX layer 202 and the support layer 203 corresponding to the intermediate portions (portions excluding both the tip end portion and the base end portion) of each of the three comb teeth of each comb electrode are removed is there.
That is, in the ion filter unit 200 of the fourth embodiment, an ion channel which is a passage through which ions can pass is formed in the region P, and no capacitance occurs in the region P.
Note that at least a part of the BOX layer 202 and the support layer 203 corresponding to the intermediate portions of the three comb teeth of each of the comb electrodes may be left. In this case, although capacitance occurs in the region P, the intermediate portion of each of the three comb teeth of each comb electrode can be supported by the support layer 203, and bending or vibration of the comb teeth described later can be suppressed.

  Further, in FIG. 19A, regions Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q8, Q9, and Q10 surrounded by broken lines are all support layers 203 corresponding to portions other than the ion channel. Is the area that has been removed.

  More specifically, the region Q1 is a region where the support layer 203 corresponding to the electrode pad 301 (the support layer 203 on the −c side of the electrode pad 301) is removed. That is, the capacitance C8 does not occur in the region Q1 (see FIGS. 14B and 20A).

  The area Q2 is an area where the support layer 203 (the support layer 203 on the -c side of the electrode pad 302) corresponding to the electrode pad 302 is removed. That is, the capacitance C11 does not occur in the region Q2 (see FIGS. 14B and 20A).

  In the region Q3, the support layer 203 (the connection part 303 and the support layer 203 on the −c side of the part) corresponding to the part on the −b side of the base end part of the connection part 303 and the three comb teeth 310 is removed. It is an area. That is, the capacitance C4 does not occur in the region Q3 (see FIGS. 14B, 14D, 20A, and 20C).

  The region Q4 is a region where the support layer 203 (the connection portion 304 and the support layer 203 on the −c side of the part) corresponding to the part on the + b side of the base end part of the connection part 304 and the three comb teeth 320 is removed. It is. That is, the capacitance C7 does not occur in the region Q4 (see FIGS. 14A to 14C, 19C, 20A, and 20B).

  The region Q5 is a portion of the support layer 203 (the portion on the -a side) which corresponds to a part of the comb teeth 320 closest to the -a side (a portion on the -a side of the portion excluding both the tip and the base end of the comb teeth 320). This is the region where the c-side support layer 203) has been removed. That is, the capacitance C12 does not occur in the region Q5 (see FIGS. 14C, 16B, and 20B).

  The region Q6 is the support layer 203 (the −c side of the part) corresponding to a part of the comb tooth 310 on the most + a side (the part on the + a side of the part excluding both the tip part and the base end part of the comb tooth 310). The support layer 203) is removed. That is, the capacitance C13 does not occur in the region Q6 (see FIGS. 14D, 16C, and 20C).

  The region Q7 is a region where the support layer 203 (the support layer 203 on the −c side of the region) corresponding to the region between the coupling portion 303 and the electrode pad 301 in the comb electrode 211 is removed. That is, the capacitance C9 does not occur in the region Q7 (see FIGS. 14B, 16A, 18A, and 20A).

  The area Q8 is an area from which the support layer 203 (the support layer 203 on the -c side of the area) corresponding to the area between the connection portion 304 and the electrode pad 302 in the comb electrode 212 is removed. That is, the capacitance C10 does not occur in the region Q8 (see FIGS. 14B, 16A, 18A, and 20A).

  In the region Q9, the support layer 203 (the support portion 203 on the tip and the -c side of the portion) corresponding to the tip of the three comb teeth 320 and the portion on the + b side of the base end of the three comb 310 It is an area that has been removed. That is, the capacitance C5 does not occur in the region Q9 (see FIGS. 17C to 18C and FIGS. 19C to 20C).

  Region Q10 is the support layer 203 (the tip portion and the support layer 203 on the -c side of the portion) corresponding to the tip portion of the three comb teeth 310 and the portion on the −b side of the base end portion of the three comb teeth 320 Is the area being removed. That is, the capacitance C6 does not occur in the region Q10 (see FIGS. 17C to 18C and FIGS. 19C to 20C).

As can be seen from the above description, in the ion filter unit 200 of the fourth embodiment, the capacitance between the two comb electrodes 211 and 212 and the support layer 203 is smaller than that of the ion filter unit 200 of the third embodiment. , C6, C9, C10.
That is, in the ion filter unit 200 of the fourth embodiment, since the support layers 203 corresponding to the two comb electrodes 211 and 212 and the two electrode pads 301 and 303 are all removed, the two comb electrodes 211, 212, and 2 are removed. The capacitance between the two electrode pads 301 and 303 and the support layer 203 can be made substantially zero.

  However, in the fourth embodiment, since there are no rib portions as in the second and third embodiments, the regions Q9 (corresponding to C5), Q10 (corresponding to C6), Q7 (C9) are used to suppress the above-mentioned inconvenience to some extent. Correspondence), a rib may be left in at least one of Q8 (C10).

  In the ion filter unit 200 of the first to fourth embodiments described above, only the support layer 203 is removed in each region Qn (n is any one of 1 to 10), but the support layer is present in at least one region Qn. Both 203 and the BOX layer 202 may be removed.

  Next, the manufacturing method of the ion filter part 200 is demonstrated.

  FIG. 21 shows a cross-sectional view of a silicon-on-insulator (SOI) wafer substrate used in semiconductor manufacturing. The wafer substrate is composed of an electrode layer 201, a BOX layer 202, and a support layer 203. In practice, the support layer 203 is thicker than the BOX layer 202 and the electrode layer 201 because mechanical strength is required, but is shown smaller for convenience.

(1) An NSG (Nitride silicon glass) film 221 is deposited on the electrode layer 201 (see FIG. 22). This NSG film 221 is an insulating film.
(2) The NSG film is etched by the photolithography process to open two contact holes (see FIG. 23) so that the metal layer deposited in the later step is electrically connected to the electrode layer.
(3) A metal layer 222 such as aluminum, gold or copper is deposited.
(4) The metal layer 222 is etched away by a photolithography process, leaving a portion covering each contact hole (see FIG. 24). One of the remaining two metal layers 222 is a pad electrode to which a signal line for inputting an asymmetric electric field waveform signal is connected to the electrode layer 201, and the other is a pad electrode connected to GND. Wire bonding is performed and bumps are attached to these pad electrodes.
(5) A nitride protective film 223 is formed to protect the periphery of the opening of the pad electrode (see FIG. 25).
(6) A photoresist 224 is applied to the entire surface.
(7) Pattern the comb electrode structure (see FIG. 26). An example pattern of a comb electrode structure is shown in FIG.

  Here, the etching portion for singulating the chips and the portion for individually cutting the chips (the boundary between the chips, a so-called dicing area in the semiconductor chip) are also patterned so as to be etched. In the case of the comb electrode, the distance between the comb teeth is narrow, and if the width of the comb teeth is thin, the comb electrode is easily broken due to vibration in dicing and pressure applied from fluid. For this reason, in this embodiment, a conventional method of chipping and chipping using a diamond blade is not employed, but a method of chipping by etching from both the front and back surfaces of the wafer substrate is employed.

(8) The electrode layer 201 is etched up to the BOX layer 202 to create a gap between the comb electrodes (see FIG. 28). At this time, the etching part for individualizing the chip at the chip boundary is also removed by etching.
(9) The support wafer 226 is attached using the adhesive 225 (see FIG. 29). In the present embodiment, since the chips are individualized by etching from the front and back surfaces of the wafer substrate, the support wafer 226 is attached so as not to be separated.
(10) Photoresist 227 is applied to the support layer 203, and the portion from which the support layer 203 is removed is patterned (see FIG. 30).

  FIG. 30 shows the case of the second embodiment.

(11) The support layer 203 is etched down to the BOX layer 202 (see FIG. 31).
(12) The BOX layer 202 is etched to penetrate the ion channel portion (see FIG. 32). At this time, at the same time, the boundary of the chip is also removed, and the chip is singulated.
(13) The photoresist 227 on the support layer side is removed (see FIG. 33).
(14) Remove the support wafer 226 (see FIG. 34).
(15) The photoresist 224 on the electrode layer side is removed (see FIG. 35). Thus, the ion filter unit 200 is obtained.
In addition, the ion filter part 200 of the said Example 2 is shown by FIG.

  Moreover, the ion filter part 200 of the said Example 1, 3, 4 is patterning the part which removes the support layer 203 corresponding to each in the process (10) of the manufacturing method of the ion filter part 200 mentioned above, and the above-mentioned. The ion filter unit 200 can be manufactured in the same procedure as that of the manufacturing method.

  As apparent from the above description, in the method of manufacturing the ion filter unit 200, the method of manufacturing the ion filter of the present invention is performed.

  As described above, the ion filter unit 200 according to the present embodiment (the ion filter unit 200 of Examples 2 to 4) includes the support layer 203 and the BOX layer 202 (insulating layer) laminated on the support layer 203. And two comb-shaped electrodes 211 and 212 (first and second comb-shaped electrodes, which are stacked on the BOX layer 202 and arranged to face each other such that a plurality of comb teeth mesh with each other in a plane orthogonal to the stacking direction. And a region of the BOX layer 202 and the support layer 203 corresponding to the gap between the comb teeth 310 of the comb electrode 211 and the comb teeth 320 of the comb electrode 212 adjacent to each other. An ion filter characterized in that a passage through which ions can pass in the stacking direction is formed, and a region of the support layer 203 corresponding to at least a part of the electrode layer 201 does not exist (is not present). .

  In this case, since at least part of the support layer 203 corresponding to the electrode layer 201 does not exist, the capacitance generated between the electrode layer 201 and the support layer 203 can be reduced.

  As a result, the waveform blunting of the voltage applied between the comb electrodes 211 and 212 (between the electrodes) can be suppressed.

  It is to be noted that the passage through which ions can pass in the stacking direction is essential in a region corresponding to at least a part of the gap between the adjacent comb teeth 310 and the comb teeth 320 of the BOX layer 202 and the support layer 203. It suffices if the film is formed by removing the film.

  In the present embodiment, when the ion filter portion 200 is manufactured, after laminating the support layer 203, the BOX layer 202, and the electrode layer 201, a region corresponding to the gap between the support layer 203 and the BOX layer 202 (in the following And a region of the support layer 203 corresponding to at least a part of the electrode layer 201 (a region that forms a capacitor together with the electrode layer 201 (hereinafter also referred to as a “capacitor region”)). But it is not limited to this.

  For example, when the ion filter unit 200 is manufactured, the support layer 203 without the gap corresponding region and the capacitor region, the BOX layer 202 without the gap corresponding region, and the electrode layer 201 may be laminated.

  For example, when the ion filter unit 200 is manufactured, the gap between the BOX layer 202 is formed after laminating the support layer 203 in which the gap corresponding region and the capacitor region do not exist, the BOX layer 202 in which the gap corresponding region exists, and the electrode layer 201 The corresponding area may be removed.

  For example, when the ion filter unit 200 is manufactured, the gap between the support layer 203 is formed after laminating the support layer 203 in which the gap correspondence region and the capacitor region exist, the BOX layer 202 in which the gap correspondence region does not exist, and the electrode layer 201 The corresponding region and the capacitor region may be removed.

  For example, when the ion filter portion 200 is manufactured, after laminating the support layer 203 in which no gap corresponding region exists and the capacitor region exists, the BOX layer 202 in which no gap corresponding region exists, and the electrode layer 201, The capacitor region of the support layer 203 may be removed.

  For example, when the ion filter unit 200 is manufactured, after laminating the support layer 203 in which the gap corresponding region does not exist and the capacitor region exists, the BOX layer 202 in which the gap corresponding region exists, and the electrode layer 201, The capacitor region of the support layer 203 and the gap corresponding region of the BOX layer 202 may be removed.

  For example, when the ion filter unit 200 is manufactured, a support layer 203 in which a gap corresponding region exists and a capacitor region does not exist, a BOX layer 202 in which a gap corresponding region exists, and an electrode layer 201 are stacked. The gap corresponding region of the layer 203 and the gap corresponding region of the BOX layer 202 may be removed.

  For example, when the ion filter unit 200 is manufactured, a support layer 203 in which a gap corresponding region exists and a capacitor region does not exist, a BOX layer 202 in which a gap corresponding region does not exist, and an electrode layer 201 are stacked. The gap corresponding region in the layer 203 may be removed.

  Further, for example, when the electrode layer 201 does not have a comb electrode such as the electrode layer 213 or a layer surrounding the electrode pad, the support layer 203 corresponding to the entire region of the electrode layer 201 may not be present.

  The at least part of the electrode layer 201 includes at least part of the plurality of comb teeth 310 of the comb electrode 211 (at least part of at least one comb tooth 310) and at least of the plurality of comb teeth 320 of the comb electrode 212. A portion (at least a portion of at least one comb tooth 320), a portion conducting to a plurality of comb teeth of the comb electrode 211 (connecting portion 303 and electrode pad 301), and a plurality of comb teeth of the comb electrode 212 It is preferable to include at least one of the portions (the connecting portion 304 and the electrode pad 302). Since these are portions that cause capacitance with the corresponding support layer 203 in the electrode layer 201, it is preferable that the support layer 203 corresponding to at least one of them does not exist.

  Moreover, in the ion filter part 200 of Examples 2-4, the comb-shaped electrodes 211 and 212 have the connection parts 303 and 304 which connect a some comb tooth, respectively, and two comb-shaped electrodes 211 and 212 of the support layer 203. There is no region corresponding to the connecting portions 303 and 304. In addition, it is preferable that at least one part of the area | region corresponding to at least one of the connection parts 303 and 304 of the two comb-shaped electrodes 211 and 212 of the support layer 203 does not exist in addition to this.

  In the ion filter units 200 of Examples 2 to 4, the electrode layer 201 is electrically connected to the comb electrode 211 and is electrically connected to the electrode pad 301 (first electrode pad) and the comb electrode 212 to which the wiring is connected. Including the electrode pad 302 (second electrode pad) to be connected, there is no region corresponding to the two electrode pads 301 and 302 of the support layer 203. Note that the present invention is not limited to this. In short, the electrode layer 201 includes at least one of the electrode pad 301 and the electrode pad 302, and at least one of the regions of the support layer 203 corresponding to at least one of the two electrode pads 301 and 303. It is preferred that no part is present.

  Moreover, in the ion filter part 200 of Example 2, 3, the area | region corresponding to the front-end | tip part of the several comb tooth of the interdigital electrode 211,212 of the support layer 203 remains. In addition, the area | region corresponding to the front-end | tip part of the several comb tooth of the at least one of the comb-shaped electrodes 211 and 212 of the support layer 203 may exist in addition to this.

  In this case, in the ion filter unit 200 of the second and third embodiments, deformation and vibration of the comb teeth are suppressed, and the electrode spacing and the electrode thickness are reduced without causing deterioration in durability and reliability. It is possible to Therefore, the ion filter unit 200 can be driven by a battery.

  Further, at least a part of a region (for example, at least one of the regions Q1 to Q10) corresponding to a region where the support layer 203 does not exist in the BOX layer 202 may not be present.

  In addition, the support layer 203, the BOX layer 202, and the electrode layer 201 are manufactured using an SOI (Silicon On Insulator) substrate.

  The electrode layer 201 is made of silicon into which impurities are implanted. In this case, it is possible to lower the electric resistance of the comb electrode and improve the frequency response of the asymmetric electric field waveform signal.

  Further, an ion generator 100 (ion generator) that ionizes the molecule to be measured, an ion filter unit 200 (ion filter) that selects ions from the ion generator 100, and ions selected by the ion filter unit 200 According to the ion detection apparatus 10 including the detection unit 600 (detector) for detection, downsizing and low power consumption can be achieved.

  A method for manufacturing the ion filter unit 200 according to the present embodiment is a method for manufacturing an ion filter using a substrate in which a support layer 203, a BOX layer 202 (insulating layer), and an electrode layer 201 are stacked. A step of forming, on the electrode layer 201, two comb-shaped electrodes 211, 212 (first and second comb-shaped electrodes) arranged to face each other such that a plurality of comb teeth mesh with each other in a plane orthogonal to the stacking direction. And the region of the BOX layer 202 and the support layer 203 corresponding to at least a part of the gap between the comb teeth of the adjacent comb electrodes 211 and the comb teeth of the comb electrode 212 is removed, and ions pass in the stacking direction An ion filter manufacturing method including a step of forming a passage that can be performed, and a step of removing a region of the support layer 203 corresponding to at least a part of the electrode layer 201.

  In this case, since at least a part of the support layer 203 corresponding to the electrode layer 201 is removed, capacitance generated between the electrode layer 201 and the support layer 203 can be reduced.

  As a result, the waveform blunting of the voltage applied between the comb electrodes 211 and 212 (between the electrodes) can be suppressed.

  In the above embodiment, the electrode layer 201 may be made of silicon coated with a metal. In this case, the surface of the comb electrode can be prevented from being oxidized to impair the function of the ion filter portion, or the electric resistance of the comb electrode can be lowered to improve the frequency response of the asymmetric electric field waveform signal.

  In the above embodiment, although the case where the ion filter unit 200 is manufactured from an SOI (SOI: Silicon On Insulator) wafer substrate has been described, the present invention is not limited to this.

  DESCRIPTION OF SYMBOLS 10 ... Ion detection apparatus, 100 ... Ion generation part (ion generator), 200 ... Ion filter part (ion filter), 201 ... Electrode layer, 202 ... BOX layer (insulating layer), 203 ... Support layer, 211 ... Comb electrode (First comb electrode), 212: comb electrode (second comb electrode), 213: electrode, 221: NSG film, 222: metal layer, 223: nitride protective film, 224: photoresist, 225: adhesive, 226: support wafer, 227: photoresist, 301, 302: electrode pad, 303, 304: coupling portion, 310, 320: comb tooth, 600: detection portion (detector), 900: control portion.

US Patent Application Publication No. 2015/0028196 Patent No. 4063676 gazette Patent No. 5221954

Claims (10)

A support layer;
An insulating layer laminated on the support layer;
And an electrode layer including first and second comb-shaped electrodes stacked on the insulating layer and arranged to face each other such that a plurality of comb teeth mesh with each other in a plane perpendicular to the stacking direction.
There is no region of the insulating layer and the support layer corresponding to at least a part of the gap between the comb teeth of the first comb electrode and the comb teeth of the second comb electrode adjacent to each other. A path through which ions can pass in the stacking direction is formed,
An ion filter characterized in that there is no region of the support layer corresponding to at least a part of the electrode layer.   The at least part of the electrode layer includes at least part of the first comb electrode, at least part of the second comb electrode, a part conducting to the first comb electrode, and the second part. The ion filter according to claim 1, further comprising at least one of a portion electrically connected to the comb electrode. Each of the first and second comb-shaped electrodes has a connecting portion that connects the plurality of comb teeth,
3. The ion filter according to claim 1, wherein at least a part of a region of the support layer corresponding to the connecting portion of at least one of the first and second comb electrodes does not exist. The electrode layer is electrically connected to the first comb electrode, and is electrically connected to a first electrode pad to which a wire is connected and the second comb electrode, and at least one of a second electrode pad to which a wire is connected Including
The ion filter according to any one of claims 1 to 3, wherein at least a part of a region of the support layer corresponding to the at least one of the first and second electrode pads does not exist.   The region of the support layer corresponding to the tips of the plurality of comb teeth of at least one of the first and second comb electrodes is present in any one of claims 1 to 4. Ion filter.   The ion filter according to claim 1, wherein the support layer, the insulating layer, and the electrode layer are manufactured using an SOI (SOI: Silicon On Insulator) substrate. . An ion generator for ionizing a molecule to be measured;
The ion filter according to any one of claims 1 to 6, wherein the ions from the ion generator are sorted out;
A detector for detecting ions selected by the ion filter.   The ion detection device according to claim 7, wherein the ion filter is driven by a battery. An ion filter manufacturing method using a substrate in which a support layer, an insulating layer, and an electrode layer are laminated,
Forming, on the electrode layer, first and second comb-shaped electrodes which are disposed to face each other such that a plurality of comb teeth mesh with each other in a plane orthogonal to the stacking direction;
The regions of the insulating layer and the support layer corresponding to at least a part of the gap between the comb teeth of the first comb electrode and the comb teeth of the second comb electrode adjacent to each other are removed, Forming a path through which ions can pass in the stacking direction;
Removing a region of the support layer corresponding to at least a part of the electrode layer. The method of manufacturing an ion filter according to claim 9, wherein the substrate is an SOI (SOI: Silicon On Insulator) substrate.

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