JP2005142101A - Manufacturing method for electrode substrate, deflector using the electrode substrate and charged particle beam exposure device using the deflector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the cost and to improve the reliability of a charged particle beam deflector. <P>SOLUTION: A metal other than gold is filled in an opening of the substrate corresponding at least to configuration and arrangement of a pair of electrodes of the deflector to form at least a pair of metal bodies used as the electrodes. The substrate part between the pair of metal bodies is removed to exposure opposed surfaces of the pair of metal bodies, and oxidation-protective films comprising several layers of gold or the like are formed on the opposed surfaces. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electrode substrate suitable for use in a deflector for a charged beam such as an electron beam or an ion beam, and a manufacturing method thereof.

  2. Description of the Related Art Conventionally, a multi-charged particle beam exposure apparatus that directly draws a resist on a semiconductor wafer using a plurality of charged particle beams such as an electron beam and an ion beam is known. In such an apparatus, a deflector array is used for a blanker array for individually turning on / off a plurality of charged particle beams, an electron lens array for individually forming images of a plurality of charged particle beams at desired positions, and the like. Used.

  Patent Document 1 discloses a method of manufacturing a blanking aperture array by forming a plurality of openings two-dimensionally at a predetermined interval on a semiconductor crystal substrate such as silicon and forming a deflection electrode pair around each opening. Has been. As the electrode main material, gold or a metal corresponding to the resistivity of gold is used.

In Patent Document 2, as a manufacturing method of an electron beam deflection apparatus, a laminated body having a plurality of wiring circuit layers is formed using an X-ray resist as an insulator, and the X-ray resist of the laminated body is exposed and developed to obtain a deflection electrode. An opening is formed in the portion to be the same, a metal material such as gold is filled in each opening by electrolytic plating, the X-ray resist in the portion between the pair of deflection electrodes is removed by exposure and development, and the aperture is formed. A method of forming is disclosed.
JP 7-297107 A JP 2002-217089 A

  In the above-described conventional example, an electrode is formed by directly plating gold in a hole formed by a resist and opening only at one end. However, in this case, since the current efficiency of the gold plating is poor, voids or the like are generated in the deposited metal body due to the generation of hydrogen gas, and it is difficult to obtain a voidless metal body.

Further, the deflection electrode pair of Patent Document 1 is (1) supported on a substrate around each opening, that is, supported in a direction perpendicular to the traveling direction of the charged particle beam (hereinafter referred to as the optical axis direction). Since there is no means to perform the deformation, it is easy to deform. (2) Since the insulator (insulating film on the substrate surface) is exposed near the charged beam, the charged beam is caused to charge up on the surface of the insulator and passes through the opening. There is a possibility that proper deflection and position control of the charged beam may not be performed.
In addition, the substrate of Patent Document 2 has insufficient heat resistance because an unexposed portion of the X-ray resist becomes a substrate, and there is a possibility of deterioration due to aging, charged particle beam irradiation, and dimensional changes. .

In a multilayer printed wiring board or the like, a through hole is formed by screen printing or a dispensing nozzle using a metal paste. That is, a metal paste is embedded in a circular hole with a diameter of φ0.1 mm to φ0.2 mm. However, when a method such as evacuation is used to embed in a shape in which the ratio of embedment height / aperture (aspect ratio) is 4.0 or more as in a deflector array of a multi-charged particle beam exposure apparatus, In the case of a silicon substrate having a thickness of 0.4 mm or less, the mechanical strength is low, and there is a problem that the silicon substrate is damaged during embedding.
In addition, as a method of attaching a metal protective film which is difficult to oxidize to a metal whose desired shape is exposed in the thickness direction, there is an example of a printed circuit board (aspect ratio of 1.0 or less). There is no previous example with a ratio of 4.0 or more.

  An object of the present invention is to solve the above-described problems in the conventional example, and to provide a method of manufacturing an inexpensive and highly reliable electrode substrate.

  In order to achieve the above object, a manufacturing method of the present invention is a manufacturing method of an electrode substrate having a through hole and a set of electrodes arranged on the inner wall of the through hole, and the shape of the set of electrodes and A first step of forming a plurality of first openings corresponding to the arrangement in the substrate material, and a first step of forming a metal body to be the electrode by filling each of the plurality of first openings with a metal other than gold. A second opening corresponding to the shape of the step 2 and the shape in which the one set of electrodes is arranged in the through hole is formed in a portion including between and in the vicinity of the plurality of first openings. The method includes a third step of exposing the surface of the metal body, and a fourth step of forming one or more layers of an anti-oxidation metal protective film on the surface of the metal body.

  According to the present invention, a highly reliable electrode substrate can be manufactured at low cost.

The embodiments of the present invention are listed below.
[Embodiment 1] A method for producing an electrode substrate having a through hole and a set of electrodes arranged on the inner wall of the through hole,
A first step of forming a plurality of first apertures in the substrate material corresponding to the shape and arrangement of the set of electrodes;
A second step of forming a metal body serving as the electrode by filling each of the plurality of first openings with a metal other than gold;
A second opening corresponding to a shape in which the one set of electrodes is arranged in the through hole is formed in a portion including between and in the vicinity of the plurality of first openings, and a side surface of the metal body is formed in the through hole. A third step of exposing
And a fourth step of forming one or more metal protective films for preventing oxidation on the surface of the metal body.

[Embodiment 2] The substrate material is a silicon substrate, and further includes a fifth step of forming an insulating layer on at least an inner wall of the first hole after the first step. Item 2. The manufacturing method according to Item 1.
[Embodiment 3] The manufacturing method according to any one of Embodiments 1 to 3, wherein the second step is a step of forming the metal body by plating.
[Embodiment 4] Any one of Embodiments 1 to 3, wherein the second step is a step of forming the metal body by embedding a metal paste in the first opening, drying and firing the paste. The manufacturing method as described in.
[Embodiment 5] The one set of electrodes includes at least one pair of electrodes facing each other, and the openings corresponding to the one pair of electrodes among the first openings are each of the pair of electrodes. The manufacturing method according to any one of Embodiments 1 to 4, wherein the side corresponding to the side surface facing is an upper base, and the upper base is trapezoidal shorter than the lower base.

In the above description, the pair of electrodes is at least one pair of deflecting electrodes facing each other if the electrode substrate is an electrode substrate applied to a deflector, and a shield formed on the inner wall of the through hole as necessary. An auxiliary electrode such as an electrode is included.
In a preferred embodiment of the present invention, a metal shape (metal body) to be an electrode is formed by filling the first opening with a metal other than gold by a plating method or a filling method. More specifically, the plating method employs copper having a good current efficiency (near 100%), and in the case of the embedding method, fine silver powder (2 μm or less) is kneaded into a resin binder, resulting in small volume shrinkage. (2% or less after dry firing) Adopt paste. As a result, the generation of voids is reduced during the formation of the metal body, and a highly reliable metal body having predetermined metal properties is formed.
Furthermore, by removing the silicon and silicon oxide film between the metal bodies, plating a gold multilayer protective film on the exposed copper metal surface, or using the surface energy difference between the copper metal body and the silicon oxide insulator Or a gold nanoparticle dispersion.

The manufacturing method of this embodiment will be described more specifically.
As the substrate material, for example, a normal silicon substrate is used. First holes having a desired shape are formed in the substrate material (first step). The desired shape is a shape corresponding to the shape and arrangement of one set (at least one pair) of electrodes constituting the finished electrode substrate. For the formation of the first hole, any of chemical treatment by wet etching, physical treatment by laser or plasma or D-RIE, mechanical treatment by a drill or the like can be used. Thereafter, an insulating film of SiO ₂ is formed on the surface of the silicon substrate including the inner wall of the first hole by a heat treatment or a method such as CVD (fifth step). The film thickness is preferably in the range of 0.1 to 2.0 μm.
If a silicon substrate in which a desired shape such as the first opening is previously formed and the wall surface and surface of the shape are insulated is available, the first and fifth steps are omitted. Can do.

Next, a metal such as copper, silver, tin, or aluminum is deposited in the first opening by electrolytic treatment (plating) from an aqueous solution or non-aqueous solution system to form an electrode in the silicon substrate (metal body) ) Is formed (second step). Alternatively, the metal body may be formed by embedding a metal paste having a small volume shrinkage, such as silver, in the first opening without gaps by repeatedly performing screen printing or a dispensing method. In the latter case, the substrate can be prevented from being damaged by embedding a material having a small thermal shrinkage (2 to 3%) at the normal pressure when the paste is heated and fired.
Thereafter, the surface of the silicon substrate on which the metal body is formed is polished and smoothed by a technique such as CMP as necessary. Next, the silicon oxide film (SiO ₂ ) and silicon between the paired metal bodies (between the electrodes) and silicon are removed by chemical etching or physical etching such as plasma or D-RIE so that the paired electrodes face each other. A surface parallel to the thickness direction of the silicon substrate of the metal body is exposed (third step).

Next, an activation treatment is performed on the exposed metal body surface, and then a plurality of electrode protection films are formed by repeatedly performing gold plating (electrolysis or electroless) or coating by immersion in a gold nanodispersion ( Fourth step). The activation treatment can be performed by irradiating UV light to remove organic substances or oxides attached to the metal surface by O ₃ , or by light etching using plasma or chemical etching using an acidic aqueous solution.
In the case where the gold protective film covering the surface is a single layer, it is considered that the gold protective film diffuses between the underlying electrode metals by heat treatment or the like. The protective film of the layer can form an alloy layer of electrode metal and gold of the protective film, and this layer can function as a barrier film for preventing diffusion, and there is no change in use environment under high vacuum. A highly reliable electrode structure can be obtained. The film thickness per layer of the oxidation protection film on the surface of the metal body is 0.1 μm to 3 μm.

[Embodiment 6] An electrode substrate having at least one pair of electrodes manufactured by the method according to any one of Embodiments 1 to 5, and at least one of the pair of electrodes independently of other electrodes And a potential applying means for applying a potential.
[Embodiment 7] An electrode substrate having a through-hole through which a charged particle beam passes and at least one pair of electrodes facing each other arranged on the inner wall of the through-hole, and at least one of the pair of electrodes has another A deflector comprising a potential applying means for applying a potential independently of an electrode,
Each of the pair of electrodes has a trapezoidal cross-sectional shape.

[Embodiment 8] A charged particle beam exposure apparatus for exposing a substrate to be exposed using a charged particle beam,
A charged particle source emitting a charged particle beam;
A first electron optical system for forming a plurality of intermediate images of the charged particle source;
A second electron optical system that projects a plurality of intermediate images formed by the first electron optical system onto a substrate to be exposed;
A positioning device for holding and positioning the substrate to be exposed and driving to a predetermined position;
The charged particle beam exposure apparatus, wherein the first electron optical system includes the deflector according to the sixth or seventh embodiment.
[Embodiment 9] A device manufacturing method, wherein a device is manufactured using the charged particle beam exposure apparatus according to Embodiment 8.

Embodiments of the present invention will be described below with reference to the drawings.
[Example 1]
1A and 1B are schematic views of a charged particle beam deflector 100 according to a first embodiment of the present invention, in which FIG. 1A is a top view, FIG. 1B is a cross-sectional view taken along line AA ′ in FIG. It is a dimension figure of the deflection electrode 1 in (a).

  First, the structure of the deflector 100 will be described. The deflector 100 includes a silicon substrate 4, a through-hole 5 for passing a charged particle beam provided in the thickness direction of the silicon substrate 4, a pair of deflection electrodes 1, 1 disposed on the inner wall of the through-hole 5, and Drive wirings 3 and 3 for applying an arbitrary potential to the deflection electrodes 1 and 1 from a power source (not shown) are provided. Further, an insulating film 2 is provided between the silicon substrate 4 and the deflection electrodes 1 and 1 and the drive wirings 3 and 3 so that a potential can be stably applied to the deflection electrodes 1 and 1 when operating as a deflector. It is made to be able to.

  In the deflector 100, the thickness of the silicon substrate 4 is mainly determined by the necessary deflection sensitivity. Here, a silicon substrate having a thickness of 200 μm was used. As shown in FIGS. 1B and 1C, the deflection electrodes 1, 1 have an upper base of about 50 μm, a lower base of about 70 μm, and a high height in a cross section perpendicular to the axis (optical axis) 8 of the through-hole 5. Is formed in a trapezoidal shape of about 15 μm. Further, the deflection electrodes 1 and 1 are formed such that the electrode metal 11 portion is made of a low resistance metal such as Cu, Sn, Ag, Al and the like in the trapezoidal shape, and its exposed surface (on the opposite side of the surface in contact with the inner wall of the through hole). Two protective films 12 made of a metal that is difficult to oxidize, such as gold, are formed in a thickness of 0.1 to 3 μm. That is, the deflection electrodes 1 and 1 on the inner wall of the through hole have a thickness of about 15 μm and a height of about 200 μm, which is the same as the through hole 5. The distance between the pair of deflection electrodes 1 and 1 is 30 μm. The drive wirings 3 and 3 are made of a low resistance metal such as Au, Cu or Al, and the insulating film 2 is made of a silicon nitride film or a silicon oxide film.

  In this deflector 100, when a charged particle beam (not shown) is irradiated so as to pass in the direction of its optical axis (axis of the through hole 5) 8, it is charged when each of the deflection electrodes 1 and 1 is electrically grounded. The particle beam passes through the through hole 5 without changing its trajectory. However, when different potentials are applied to the deflection electrodes 1 and 1, an electric field is generated in the through hole 5, and the charged particle beam can be deflected in a desired direction.

Next, a manufacturing method of the deflector 100 of FIG. 1 will be described with reference to FIG.
As shown in FIG. 2A, a first opening (aspect ratio of 13.3) having a width of 15 μm corresponding to the cross-sectional shape and arrangement of the electrode metal 11 of FIG. 1 is formed in the insulating silicon substrate 4 having a thickness of 200 μm. ) 15 was formed by D-RIE (first step), and a thermal oxide film (insulating film) 2 was formed to 2 μm on the surface of the silicon substrate 4 and the wall surface of the first opening 15 (fifth step).

Next, as shown in FIG. 2B, 1.5 A / dm ^{2 in a} copper sulfate plating bath of 95 g / L of copper sulfate pentahydrate and 180 g / L of sulfuric acid in the first opening 15 of the silicon substrate 4. The copper was deposited for 15 hours under the electrolytic conditions (second step), and as shown in FIG. 2C, the portion of the deposited metal body 16 protruding from the surface of the silicon substrate 4 was subjected to CMP polishing. Flattened.
Next, as shown in FIG. 2D, the metal bodies 16 and 16 are etched again by D-RIE to expose the surface of the opposing electrode metal 11 (metal body 16) (third step). . That is, the second opening 17 was formed. In the mask for forming the second opening, the distance between the metal bodies 16 and 16 was 30 μm. When changing the opening interval, the dimensions of the mask, the etching conditions, and the thickness of the Au protective film described later may be adjusted as necessary.

The outermost surface of the electrode metal 11 (metal body 16) whose surface is exposed is activated by O ₂ plasma, and an electroless plating solution having a gold concentration of 2 g / l, PH = 5.0, and a plating solution temperature of 75 ° C. ± 5 ° C. As shown in FIG. 2 (e), a 0.2 μm protective film is formed by treatment, and further, a second protective film is formed by immersion in a gold nanodispersion (fourth step). The deflection electrode 1 having the protective film 12 on the surface of the electrode metal 11 was formed. The thickness of the Au protective film was set to ˜1.5 μm.

   In addition, when the electrode whose surface is exposed is copper, the surface is washed with a degreasing agent, and then with an electroless gold plating solution having a gold concentration of 1.2 g / l, PH = 7.0, and a plating temperature of 85 ° C. , A 0.05 μm-base (copper-substituted) gold plating film was formed, followed by reduction gold plating with a gold concentration of 3.0 g / l, PH = 7.0, plating temperature of 50 ° C. using sodium gold sulfite, Similarly to the above, a 1.5 μm Au protective film can be formed.

[Comparative example]
As a comparative example, a deflector was manufactured by a process that does not require a protective film. That is, gold is directly plated as the deflection electrode 1 (= metal body 16) in the opening 15 of the silicon substrate obtained in the first and fifth steps of the first embodiment in the second step of the first embodiment. After embedding in a thickness of 200 μm, a deflector was produced in the same manner as in Example 1 except that the fourth step was not performed.
Hydrogen gas was generated during plating, and voids were observed in the obtained gold electrode film metal body 16, and the desired deflection electrode 1 could not be obtained.

[Example 2]
A silicon substrate having a thickness of 2 μm formed on the surface of the substrate and the hole wall surface by punching a hole of 15 μm by D-RIE (aspect ratio 13.3) on an insulating silicon substrate having a thickness of 200 μm (see FIG. 2 (a)), copper was precipitated for 15 hours under an electrolytic condition of 1.5 A / dm ^{2 in} a copper sulfate plating bath of 95 g / L of copper sulfate pentahydrate and 180 g / L of sulfuric acid (FIG. 2B). )). Next, the protrusion (metal body 16) on the substrate surface is flattened by CMP polishing (FIG. 2C), and then the opposing surface of the opposing electrode metal 11 (metal body 16) is exposed. The space between the electrode metals 11 was etched by RIE (FIG. 2D).

  The exposed electrode metal 11 extending in the optical axis direction is soft-etched with a 10% aqueous solution of sulfuric acid-hydrogen peroxide to activate the outermost surface of the copper, and is immersed in a gold nano-dispersion to form a first protective film After forming and drying and baking, a second protective film was formed with the same solution (FIG. 2 (e)). In this case, the thickness of the protective film was 0.2 μm for the first layer and 0.2 μm for the second layer. As a result, a deflection electrode 1 similar to that in Example 1 was obtained.

[Example 3]
As in Example 2, a 15 μm hole (aspect ratio of 13.3) was formed in a silicon substrate having an insulating property of 200 μm thickness by D-RIE, and a thermal oxide film was formed on the substrate surface and the hole wall surface by 2 μm. Copper was deposited on a silicon substrate (FIG. 2 (a)) for 15 hours under an electrolytic condition of 1.5 A / dm ^{2 in} a copper sulfate plating bath of 95 g / L copper sulfate pentahydrate and 180 g / L sulfuric acid (FIG. 2). 2 (b)). Next, the protrusion on the substrate surface by the deposited copper (metal body 16) is flattened by CMP polishing (FIG. 2C), and then the opposing surface of the opposing electrode metal 11 (metal body 16) is exposed. Therefore, the space between the electrodes was again etched by D-RIE (FIG. 2D).
The outermost surface of the electrode metal 11 exposed in the thickness direction was activated by O ₂ plasma, and in the same manner as in Example 2, immersion in a gold nanodispersion and drying and firing were performed two or more times (FIG. 2). (E)). As a result, the same protective film 12 as in Example 2 was obtained.

  As described above, it is possible to form a metal body in a desired shape on a silicon substrate body having insulation properties at low cost and with high reliability, and to achieve three-dimensional integration of Si wafers such as semiconductors and LSIs. It became possible to apply.

[Example 4]
Next, an embodiment of a device production method using an electron beam exposure apparatus using the electrode substrate described above as a blanker will be described.
FIG. 3 shows a flow of manufacturing a microdevice (a semiconductor chip such as an IC or LSI, a liquid crystal panel, a CCD, a thin film magnetic head, a micromachine, etc.). In step 1 (circuit design), circuit design of a micro device, for example, a semiconductor device is performed. In step 2 (EB data conversion), exposure control data for the exposure apparatus is created based on the designed circuit pattern. On the other hand, in step 3 (wafer manufacture), a wafer is manufactured using a material such as silicon. Step 4 (wafer process) is called a pre-process, and an actual circuit is formed on the wafer by lithography using the wafer and the exposure apparatus to which the prepared exposure control data is input. The next step 5 (assembly) is referred to as a post-process, and is a process for forming a semiconductor chip using the wafer produced in step 4, such as an assembly process (dicing, bonding), a packaging process (chip encapsulation), and the like. including. In step 6 (inspection), the semiconductor device manufactured in step 5 undergoes inspections such as an operation confirmation test and a durability test. Through these steps, the semiconductor device is completed and shipped (step 7).

  FIG. 4 shows a detailed flow of the wafer process. In step 11 (oxidation), the wafer surface is oxidized. In step 12 (CVD), an insulating film is formed on the wafer surface. In step 13 (electrode formation), an electrode is formed on the wafer by vapor deposition. In step 14 (ion implantation), ions are implanted into the wafer. In step 15 (resist process), a photosensitive agent is applied to the wafer. In step 16 (exposure), the circuit pattern is printed onto the wafer by exposure using the exposure apparatus described above. In step 17 (development), the exposed wafer is developed. In step 18 (etching), portions other than the developed resist image are removed. In step 19 (resist stripping), unnecessary resist after etching is removed. By repeatedly performing these steps, multiple circuit patterns are formed on the wafer. By using the manufacturing method of the present embodiment, a highly integrated microdevice that has been difficult to manufacture can be manufactured at low cost.

It is a figure explaining the structure of the deflector which concerns on Example 1 of this invention. It is a figure explaining the manufacturing method of the deflector of FIG. It is a figure explaining the flow of the manufacturing process of the device by the exposure apparatus to which this invention is applied. It is a figure explaining the wafer process in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Deflection electrode 2 Insulating film 3 Drive wiring 4 Silicon substrate 5 Through-hole 11 Electrode metal 12 Protective film 15 1st opening 16 Metal body 17 2nd opening 100 Deflector

Claims (7)

A method of manufacturing an electrode substrate having a through hole and a set of electrodes disposed on an inner wall of the through hole,
A first step of forming a plurality of first apertures in the substrate material corresponding to the shape and arrangement of the set of electrodes;
A second step of forming a metal body serving as the electrode by filling each of the plurality of first openings with a metal other than gold;
A second opening corresponding to a shape in which the one set of electrodes is arranged in the through hole is formed in a portion including between and near the plurality of first openings to face the through hole of the metal body. A third step of exposing the surface;
And a fourth step of forming one or more metal protective films for preventing oxidation on the surface of the metal body.   2. The substrate material according to claim 1, wherein the substrate material is a silicon substrate, and further includes a fifth step of forming an insulating layer on at least an inner wall of the first hole after the first step. Production method.   The pair of electrodes includes at least one pair of electrodes facing each other, and the openings corresponding to the pair of electrodes of the first openings are side surfaces facing each other of the pair of electrodes. The manufacturing method according to claim 1, wherein the side corresponding to is an upper base and the upper base is trapezoidal shorter than the lower base.   An electrode substrate having at least one pair of electrodes manufactured by the method according to any one of claims 1 to 3, and a potential for applying a potential to at least one of the pair of electrodes independently of other electrodes And a deflecting device. An electrode substrate having a through-hole through which a charged particle beam passes and at least one pair of electrodes opposed to each other in parallel planes disposed on an inner wall of the through-hole, and at least one of the pair of electrodes as another electrode A deflector comprising a potential applying means for independently applying a potential,
Each of the pair of electrodes has a trapezoidal cross section. A charged particle beam exposure apparatus that exposes a substrate to be exposed using a charged particle beam,
A charged particle source emitting a charged particle beam;
A first electron optical system for forming a plurality of intermediate images of the charged particle source;
A second electron optical system that projects a plurality of intermediate images formed by the first electron optical system onto a substrate to be exposed;
A positioning device for holding and positioning the substrate to be exposed and driving to a predetermined position;
6. A charged particle beam exposure apparatus, wherein the first electron optical system includes the deflector according to claim 4 or 5.   A device manufacturing method, wherein a device is manufactured using the charged particle beam exposure apparatus according to claim 6.

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