JP2007019192A - Charged particle beam lens and charged particle beam aligner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a charged particle beam lens exhibiting higher uniformity. <P>SOLUTION: A charged particle beam lens installed in a charged particle beam aligner for exposing an object using a charged particle beam comprises substrates 110a, 110b and 110c having a plurality of openings 130a, 130b and 130c. The plurality of the openings include an opening which passes a charged particle beam used for exposure, and an opening which does not pass a charged particle beam used for exposure. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a charged beam lens and a charged beam exposure apparatus mainly used for exposure of a semiconductor integrated circuit or the like.

In the production of semiconductor devices, a multi-charged beam exposure system that simultaneously draws a pattern with a plurality of charged beams without using a mask has been proposed.
In a multi-charged beam exposure apparatus using this system, the low uniformity of the multiple charged beams used for exposure hinders the formation of a highly accurate exposure pattern over the entire exposure area, and the drawing performance and reliability of the exposure apparatus are reduced. Leading to a decline. Therefore, how to increase the uniformity of the charged beam lens used in the exposure apparatus is indispensable for improving the apparatus performance.

The main literature on electrostatic electron lenses (electrostatic lenses) is shown below.
A. D. Feinerman et al. (J. Vac. Sci. Technol. A 10 (4), p611, 1992) anodic-bonds V-grooves made of micromechanical technology and V-grooves made by crystal anisotropic etching of Si to fibers. Thus, it is disclosed to form a three-dimensional structure composed of three electrodes that are electrostatic single lenses. Si has a membrane frame, a membrane, and an opening through which the electron beam passes. K.K. Y. Lee et al. (J. Vac. Sci. Technol. B12 (6), p3425, 1994), an aligned microcolumn for a structure in which multiple layers of Si and Pyrex glass are bonded using the anodic bonding method. Disclosed is a technique for manufacturing an electronic lens. Sasaki (J. Vac. Sci. Technol. 19, 963 (1981)) discloses a configuration in which an Einzel lens array is formed by three electrodes having a lens aperture array. In the electrostatic lens configured as described above, generally, a lens action can be obtained by applying a voltage to the center electrode of the three electrodes and grounding the other two.
J. Vac. Sci. Technol. A 10 (4), p611, 1992 J. Vac. Sci. Technol. B12 (6), p3425, 1994 J. Vac. Sci. Technol. 19, 963 (1981)

For example, in a charged beam lens configured by forming a plurality of apertures in an array, a charged beam lens configured by an aperture near the center of the area where the aperture is formed has the same charged beam in four directions. Surrounded by a lens. However, the charged beam lens constituted by the opening at the extreme end in the opening area has similar charged beam lenses only in two or three directions. Thus, the electric field state of the charged beam lens may change depending on the position in the area.As a result, for example, the charged beam that has passed through the charged beam lens around the area has an optical axis that did not occur near the center of the area. May occur.
Such a decrease in the uniformity of the charged beam lens in the area may lead to a decrease in the drawing performance and reliability of the exposure apparatus.

  The present invention has been made in view of the above background, and an object thereof is to provide a charged beam lens with higher uniformity.

In order to solve the above-described problems, the present invention has a charged beam lens and a charged beam exposure apparatus configured as follows.
(1) A charged beam lens installed in a charged beam exposure apparatus that exposes an exposure target using a charged beam, comprising a substrate on which a plurality of openings are formed, wherein the plurality of openings include the exposure A charged beam lens, comprising: an aperture through which a charged beam used for the light passes; and an aperture through which the charged beam used for the exposure does not pass.

  (2) A charged beam lens installed in a charged beam exposure apparatus that exposes an exposure target using a charged beam, comprising at least three substrates each having a plurality of apertures, the at least three The plurality of openings formed in at least one of the substrates includes an opening through which a charged beam used for the exposure passes and an opening through which the charged beam used for the exposure does not pass. Characteristic charged beam lens.

  (3) In the above (1) or (2), the shape of the opening through which the charged beam used for the exposure does not pass is substantially the same shape as the opening through which the charged beam used for the exposure passes. The charged beam lens described.

  (4) In the above (1) to (3), the opening through which the charged beam used for the exposure does not pass is substantially the same as the opening through which the charged beam used for the exposure passes. The charged beam lens in any one.

  (5) The openings (1) to (1), wherein an opening through which the charged beam used for exposure does not pass is formed around an area where an opening through which the charged beam used for exposure passes is formed. The charged beam lens according to (4).

  (6) In any one of the above (1) to (5), the opening through which the charged beam used for exposure does not pass is formed at the same position on all the substrates constituting the charged beam lens. The charged beam lens described.

  (7) A charged beam lens installed in a charged beam exposure apparatus that exposes an exposure target using a charged beam, comprising at least three substrates each having a plurality of openings, the at least three The substrate has an insulating film formed on the substrate surface and a conductive film formed on the insulating film, and the conductive film formed on at least one of the at least three substrates. The charged beam lens, wherein the region where the plurality of openings are not formed and the region where the plurality of openings are formed are removed so as to have the same shape.

  (8) The charged beam according to (7), wherein the conductive film formed on at least one of the base substrates is removed in an arrangement substantially similar to the arrangement of the openings. lens.

  (9) The charged beam lens according to (7) or (8), wherein the conductive film formed on at least one of the base substrates is removed around the opening. .

  (10) A charged beam exposure apparatus that exposes an exposure target using a charged beam, wherein the charged particle source emits the charged beam and a first electron optical system that forms a plurality of intermediate images of the charged particle source And a second electron optical system that projects a plurality of intermediate images formed by the first electron optical system onto the exposure target, and a stage that holds the exposure target and moves to a predetermined position, A charged beam exposure apparatus, wherein the first electron optical system includes the charged beam lens according to any one of (1) to (9).

  (11) A device manufacturing method comprising the steps of: exposing the exposure object using the exposure apparatus according to (10); and developing the exposed exposure object.

  According to the above (1) to (9), the electric field uniformity of the area through which the charged beam used for exposure passes can be improved, and a highly uniform charged beam lens can be obtained.

  The charged beam exposure apparatus according to the above (10) has high drawing performance and reliability because the charged beam lens has high uniformity.

  ADVANTAGE OF THE INVENTION According to this invention, the charged beam lens with the high uniformity with respect to the charged beam irradiated on exposure object can be provided. Further, by using this charged beam lens in a charged beam exposure apparatus, an exposure apparatus with high drawing performance and high reliability can be provided.

  Hereinafter, as a preferred embodiment of the present invention, a multi-charged beam lens and an embodiment in which an exposure object of an exposure apparatus using the same is a wafer will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a cross-sectional view schematically showing the structure of a multi-charged beam lens according to Example 1 of the present invention. The multi-charged beam lens 100 has a structure in which three substrates 110a, 110b, and 110c are arranged via an insulator 160. The three substrates 110a, 110b, and 110c have openings 130a, 130b, and 130c, conductive films 140a, 140b, and 140c, and assembly grooves 120a, 120b, and 120c, respectively. These grooves 120a, 120b, and 120c are formed. By disposing the insulator 160 therebetween, the three substrates 110a, 110b, 110c are positioned relative to each other. In this embodiment, the same potential is applied to the upper substrate conductive film 140a and the lower substrate conductive film 140c among the upper substrate conductive film 140a, the intermediate substrate conductive film 140b, and the lower substrate conductive film 140c.

As shown in FIG. 1, the conductive film 140b of the intermediate substrate is typically given a negative potential with respect to the potential of the conductive film 140a of the upper substrate and the conductive film 140c of the lower substrate.
In this embodiment, the multi-charged beam lens 100 is composed of three substrates, but the number of substrates is not limited to three and may be other numbers.

  FIG. 2 is a diagram schematically showing a state where the multi-charged beam lens according to this embodiment is viewed from above. Two rows of openings having the same shape as the area 170 formed with openings through which the charged beam irradiated on the wafer passes are arranged around the area 170 in the same arrangement as the openings in the area.

  In this embodiment, 16 4 × 4 apertures through which the charged beam irradiated on the wafer passes and apertures (dummy apertures) formed around the apertures are described in two rows. Is not limited to this number and may be any other number.

FIG. 3 is a diagram showing the result of calculating the influence on the charged beam by forming an aperture row around the aperture through which the charged beam used for exposure passes.
The horizontal axis of FIG. 3 shows how many aperture rows are formed around the aperture through which the charged beam used for exposure passes. The vertical axis in FIG. 3 indicates how much the optical axis tilts after the charged beam used for exposure passes through the multi-charged beam lens. A plurality of graphs are plotted as a result of calculation with respect to a plurality of apertures such as an aperture located at the end and an aperture located inside the aperture region through which the charged beam passes. .
As shown in FIG. 3, it can be seen that the inclination of the beam optical axis decreases as the aperture row is formed around the aperture through which the beam passes.

  Next, an electron beam exposure apparatus (drawing apparatus) using a multi-charged beam lens according to the present invention will be described. Although the following example is an exposure apparatus that employs an electron beam as a charged beam, the present invention can be similarly applied to an exposure apparatus that uses other types of charged beams such as an ion beam.

  FIG. 4 is a schematic view of the main part of an electron beam exposure apparatus using a multi-charged beam lens according to the present invention. In FIG. 4, reference numeral 1 denotes a multi-source module that forms a plurality of electron source images and emits an electron beam from the electron source images. The multi-source modules 1 are arranged in 3 × 3, and details thereof will be described later.

  21, 22, 23, and 24 are magnetic lens arrays, and magnetic disks MD having apertures of the same shape arranged in 3 × 3 are arranged above and below at intervals and excited by a common coil CC. Is. As a result, each aperture becomes a magnetic pole of each magnetic lens ML, and a lens magnetic field is generated by design.

  A plurality of electron source images of each multi-source module 1 are projected onto the wafer 4 by the corresponding four magnetic field lenses (ML1, ML2, ML3, ML4) of the magnetic lens arrays 21, 22, 23, 24. An optical system that acts on an electron beam before the wafer is irradiated with an electron beam from one multi-source module is defined as a column. That is, a present Example is a structure of 9 columns (col.1-col.9).

  At this time, an image is formed once by two magnetic lenses corresponding to the magnetic lens array 21 and the magnetic lens array 22, and then the image is formed by two corresponding magnetic lenses of the magnetic lens array 23 and the magnetic lens array 24. Projecting onto the wafer 4. Then, by individually controlling the excitation conditions of the magnetic lens arrays 21, 22, 23, and 24 with a common coil, the optical characteristics (focal position, image rotation, and magnification) of each column are substantially equal to each other. In other words, in other words, the same amount can be adjusted.

  A main deflector 3 deflects a plurality of electron beams from the multi-source module 1 to displace a plurality of electron source images in the X and Y directions on the wafer 4. Reference numeral 5 denotes a stage on which the wafer 4 is mounted and is movable in the XY direction orthogonal to the optical axis AX (Z axis) and the rotation direction around the Z axis, and a stage reference plate 6 is fixedly provided. Reference numeral 7 denotes a reflected electron detector that detects reflected electrons generated when a mark on the stage reference plate 6 is irradiated by an electron beam.

  Next, FIG. 5 is a detailed view of one column. The function for adjusting the optical characteristics of the electron beam irradiated from the multi-source module 1 and the multi-source module 1 onto the wafer 4 will be described with reference to FIG.

  Reference numeral 101 denotes an electron source (crossover image) formed by the electron gun. The electron beam emitted from the electron source 101 becomes a substantially parallel electron beam by the condenser lens 102. The condenser lens 102 of this embodiment is an electrostatic lens composed of three aperture electrodes.

  Reference numeral 103 denotes an aperture array in which apertures are two-dimensionally arranged, and reference numeral 104 denotes a lens array in which electrostatic lenses having the same optical power are two-dimensionally arranged. Reference numerals 105 and 106 denote deflector arrays formed by two-dimensionally arraying electrostatic eight-pole deflectors that can be driven individually. Reference numeral 107 denotes a two-dimensional array of individually driven electrostatic blankers. It is the formed blanker array. The multi-charged beam lens according to the present invention forms a lens array 104. FIG. 5 shows an example in which openings are formed one by one around the opening through which the charged beam applied to the wafer passes.

  Each function will be described with reference to FIG. The substantially parallel electron beam from the condenser lens 102 is divided into a plurality of electron beams by the aperture array 103. The divided electron beam forms an intermediate image of the electron source on the corresponding blanker of the blanker array 107 via the electrostatic lens of the corresponding lens array 104.

  At this time, the deflector arrays 105 and 106 individually adjust the position of the intermediate image of the electron source formed on the blanker array 107 (position in the plane orthogonal to the optical axis). Further, since the electron beam deflected by the blanker array 107 is blocked by the blanking aperture AP in FIG. 4, the wafer 4 is not irradiated. On the other hand, the electron beam not deflected by the blanker array 107 is not blocked by the blanking aperture AP in FIG.

  Returning to FIG. 5, a plurality of intermediate images of the electron source formed by the multi-source module 1 are projected onto the wafer 4 through two magnetic field lenses corresponding to the magnetic field lens array 21 and the magnetic field lens array 22.

  At this time, among the optical characteristics when a plurality of intermediate images are projected onto the wafer 4, the rotation and magnification of the image are adjusted by the deflector arrays 105 and 106 that can adjust the position of each intermediate image on the blanker array. The focal position can be adjusted by dynamic focus lenses (electrostatic or magnetic lens) 108 and 109 provided for each column.

  Next, FIG. 7 shows a system configuration diagram of this embodiment. The blanker array control circuit 41 is a circuit that individually controls a plurality of blankers that constitute the blanker array 107, and the deflector array control circuit 42 is a circuit that individually controls the deflectors that constitute the deflector arrays 105 and 106. It is. The D_FOCUS control circuit 43 is a circuit that individually controls the dynamic focus lenses 108 and 109, and the main deflector control circuit 44 is a circuit that controls the main deflector 3. The backscattered electron detection circuit 45 is a circuit that processes a signal from the backscattered electron detector 7. These blanker array control circuit 41, deflector array control circuit 42, D_FOCUS control circuit 43, main deflector control circuit 44, and backscattered electron detection circuit 45 are as many as the number of columns (col. 1 to col. 9). Equipped.

  The magnetic lens array control circuit 46 is a circuit that controls the common coils of the magnetic lens arrays 21, 22, 23, and 24, and the stage drive control circuit 47 is a laser interferometer (not shown) that detects the position of the stage 5. This is a control circuit for driving and controlling the stage 5 in cooperation with the above. The main control system 48 controls the plurality of control circuits and manages the entire electron beam exposure apparatus.

  FIG. 8 is a cross-sectional view schematically showing the structure of the multi-charged beam lens according to the second embodiment of the present invention. This embodiment provides a specific example in which a conductive film formed on a base substrate is patterned.

  The multi-charged beam lens 700 has a structure in which three base substrates 710a, 710b, and 710c are arranged via an insulator 760. The three base substrates 710a, 710b, and 710c have openings 730a, 730b, and 730c, conductive films 740a, 740b, and 740c, insulating films 750a, 750b, and 750c, and assembly grooves 720a, 720b, and 720c, respectively. By disposing the insulator 760 between the grooves 720a, 720b, and 720c, the three base substrates 710a, 710b, and 710c are positioned with respect to each other. The conductive films 740a, 740b, and 740c are patterned to remove the portions 770a, 770b, and 770c. In this embodiment, among the conductive films 740a, 740b, and 740c, the same potential is applied to the conductive films 740a and 740c.

As shown in FIG. 8, the conductive film 740b is typically given a negative potential with respect to the potentials of the conductive films 740a and 740c.
In this embodiment, the multi-charged beam lens 700 is composed of three base substrates, but the number of base substrates is not limited to three and may be other numbers.

  FIG. 9 is a diagram schematically showing a state where the multi-charged beam lens according to this embodiment is viewed from above. The conductive film is removed in two rows around the area 780 so as to have the same shape as the area 780 in which the opening through which the charged beam irradiated on the wafer passes is formed. is there.

  In this embodiment, a figure is shown in which 16 4 × 4 apertures through which a charged beam irradiated on a wafer passes and two rows of conductive films around the apertures are removed. The number of conductive films formed is not limited to this number, but may be other numbers.

  Further, in this embodiment, it is possible to improve the uniformity of the multi-charged beam lens without increasing the number of openings formed in the substrate, without causing a decrease in the strength of the substrate due to an increase in the numerical aperture, A highly charged multi-charged beam lens can be obtained.

    The multi-charged beam lens exemplarily described here can also be applied to a charged beam exposure apparatus such as the electron beam exposure apparatus exemplarily shown in FIG. 4 similarly to the first embodiment. The exposure apparatus is suitable for manufacturing a device such as a semiconductor device.

  Next, as a third embodiment of the present invention, a semiconductor device manufacturing process using the charged beam exposure apparatus according to the above embodiment will be described. FIG. 10 is a diagram showing a flow of an entire manufacturing process of a semiconductor device. In step 1 (circuit design), a semiconductor device circuit is designed. 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 using lithography using the exposure apparatus and wafer to which the exposure control data has been input. The next step 5 (assembly) is called a post-process, and is a process for forming a semiconductor chip using the wafer produced in step 4, and is an assembly process (dicing, bonding), packaging process (chip encapsulation), etc. Process. In step 6 (inspection), the semiconductor device manufactured in step 5 undergoes inspections such as an operation confirmation test and a durability test. A semiconductor device is completed through these processes, and is shipped in Step 7.

  The wafer process in step 4 includes the following steps. An oxidation step for oxidizing the surface of the wafer, a CVD step for forming an insulating film on the wafer surface, an electrode formation step for forming electrodes on the wafer by vapor deposition, an ion implantation step for implanting ions on the wafer, and applying a photosensitive agent to the wafer The resist processing step, the exposure step for printing and exposing the circuit pattern onto the wafer after the resist processing step by the above-described exposure apparatus, the development step for developing the wafer exposed in the exposure step, and the etching for removing portions other than the resist image developed in the development step Step, resist stripping step to remove resist that is no longer needed after etching. By repeating these steps, multiple circuit patterns are formed on the wafer.

It is a figure for demonstrating the structure of the multi-charged beam lens which concerns on Example 1 of this invention. It is the figure which looked at the multi-charged beam lens concerning Example 1 of the present invention from the upper surface. It is a figure which shows the change of the uniformity of the multi-charged beam lens which concerns on the Example of this invention. It is a figure which shows the principal part outline of the electron beam exposure apparatus which concerns on the Example of this invention. It is a figure for demonstrating the electron optical system for every column which concerns on the Example of this invention. It is a figure for demonstrating the function of the multi source module which concerns on the Example of this invention. It is a figure for demonstrating the structure of the system of the electron beam exposure apparatus shown in FIG. It is a figure for demonstrating the structure of the multi-charged beam lens which concerns on Example 2 of this invention. It is the figure which looked at the multi-charged beam lens concerning Example 2 of the present invention from the upper surface. It is a figure which shows the flow of the whole manufacturing process of a semiconductor device.

Explanation of symbols

  1: multi-source module, 3: main deflector, 4: wafer, 5: stage, 6: stage reference plate, 7: backscattered electron detector, 21, 22, 23, 24: magnetic lens array, 41: blanker array control Circuit: 42: Deflector array control circuit, 43: D_FOCUS control circuit, 44: Main deflection control circuit, 45: Reflected electron detection circuit, 46: Magnetic lens array control circuit, 47: Stage drive control circuit, 48: Main control system , 100: Multi-charged beam lens, 101: Electron source, 102: Condenser lens, 103: Aperture array, 104: Lens array, 105, 106: Deflector array, 107: Blanker array, 108, 109: Dynamic focus lens, 110a , 110b, 110c: substrate, 120a, 120b, 120c: groove for assembly 130a, 130b, 130c: opening, 140a, 140b, 140c: conductive film, 160: insulator, 170: area where an opening through which a charged beam irradiated on the wafer passes is formed, 700: multi-charged beam lens, 710a, 710b, 710c: base substrate, 720a, 720b, 720c: assembly groove, 730a, 730b, 730c: opening, 740a, 740b, 740c: conductive film, 750a, 750b, 750c: insulating film, 770a, 770b, 770c : Part from which conductive film has been removed, 760: insulator, 780: area where an aperture through which a charged beam applied to the wafer passes is formed, MLA: magnetic lens array, ML: magnetic lens, MD: magnetic disk , CC: common coil.

Claims (11)

A charged beam lens installed in a charged beam exposure apparatus that exposes an exposure target using a charged beam,
A substrate having a plurality of openings formed therein;
The charged beam lens, wherein the plurality of openings include an opening through which a charged beam used for the exposure passes and an opening through which the charged beam used for the exposure does not pass. A charged beam lens installed in a charged beam exposure apparatus that exposes an exposure target using a charged beam,
Comprising at least three substrates each having a plurality of openings formed therein;
The plurality of openings formed in at least one of the at least three substrates include an opening through which a charged beam used for the exposure passes and an opening through which the charged beam used for the exposure does not pass. A charged beam lens, comprising: 3. The charged beam lens according to claim 1, wherein the shape of the aperture through which the charged beam used for exposure does not pass is substantially the same as the shape of the aperture through which the charged beam used for exposure passes. 4. The charge according to any one of claims 1 to 3, wherein the opening through which the charged beam used for the exposure does not pass is substantially the same as the opening through which the charged beam used for the exposure passes. Beam lens. The opening through which the charged beam used for the exposure does not pass is formed around an area where the opening through which the charged beam used for the exposure passes is formed. The charged beam lens described in 1. 6. The charged beam lens according to claim 1, wherein an opening through which a charged beam used for exposure does not pass is formed at the same position on all the substrates constituting the charged beam lens. A charged beam lens installed in a charged beam exposure apparatus that exposes an exposure target using a charged beam,
Comprising at least three substrates each having a plurality of openings formed therein;
The at least three substrates include an insulating film formed on the substrate surface;
A conductive film formed on the insulating film;
The conductive film formed on at least one of the at least three substrates has the same shape in a region where the plurality of openings are not formed and a region where the plurality of openings are formed. A charged beam lens that has been removed. The charged beam lens according to claim 7, wherein the conductive film formed on at least one of the base substrates is removed in an arrangement substantially the same as the arrangement of the openings. 9. The charged beam lens according to claim 7, wherein the conductive film formed on at least one of the base substrates is removed around the opening. A charged beam exposure apparatus that exposes an exposure target using a charged beam,
A charged particle source that emits the charged 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 the exposure target;
A stage that holds the exposure target and moves to a predetermined position;
A charged beam exposure apparatus, wherein the first electron optical system includes the charged beam lens according to claim 1.   11. A device manufacturing method comprising the steps of: exposing the exposure object using the exposure apparatus according to claim 10; and developing the exposed exposure object.

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