WO2007015306A1

WO2007015306A1 - Charged particle beam plotting device and method

Info

Publication number: WO2007015306A1
Application number: PCT/JP2005/014345
Authority: WO
Inventors: Satoru Mabuchi
Original assignee: Fujitsu Limited
Priority date: 2005-08-04
Filing date: 2005-08-04
Publication date: 2007-02-08

Abstract

An integral control unit (46) relatively moves a transmitting image of a first aperture (21) in the first aperture and an evaluation block (1) of a block mask (22) so as to change relative positional relationship of a transmission hole (2) in the transmitting image of the first aperture and positions the transmission hole (2) at measurement points in the transmitting image so as to measure a current value of electron beams which have successively pass through the transmission hole (2) by a Faraday cup (33). According to this, electron beam current value distribution uniformity is evaluated. An electron beam plotting is actually performed by using only the region where the current value in the transmitting image of the first aperture (21) is uniform. With this configuration, it is possible to integrally plot a patter of a predetermined design value.

Description

Specification

Charged particle beam drawing apparatus and method

Technical field

The present invention relates to a charged particle beam drawing apparatus and method for drawing a desired pattern on a substrate using a charged particle beam, particularly an electron beam.

Background art

Conventionally, as a device for drawing a desired pattern on a sample such as a semiconductor substrate, an electron beam drawing apparatus using a variable shaped beam such as a rectangle or a triangle has been used. In this electron beam drawing apparatus, when a fine pattern is drawn, the number of figures per unit area increases, so the drawing time increases in proportion to this and the throughput is significantly reduced.

Therefore, recently, a so-called block drawing apparatus has been proposed that uses a plurality of types of blocks having apertures corresponding to complex patterns that are repeatedly used to form a semiconductor chip or the like. This block drawing apparatus uses a block mask which is a second aperture mask in which a plurality of types of blocks are arranged in a matrix, and a transmission image of the first aperture mask is formed on the aperture formed in a desired block. And the pattern of the block is drawn at once.

By the way, in the electron beam drawing apparatus, the focus of the lens for projecting the transmission image of the first aperture on the second aperture mask, for example, slightly in the electron beam irradiation source, An ideal lens cannot be constructed due to an optical system manufacturing error or the like. In such a case, the transmission image of the first aperture mask becomes non-uniform due to the electron beam irradiation source, and the current density of the electron beam in the transmission image of the second aperture mask changes. As a result, each aperture cannot be accurately projected, and the pattern cannot be drawn in a desired state. This problem is recognized as inevitable even in block drawing devices, and measures to deal with it are being considered.

FIG. 12 is a perspective view schematically showing a method for evaluating the uniformity of the transmitted image of the first aperture mask resulting from the electron beam irradiation source in the conventional block drawing apparatus.

In the conventional block drawing apparatus, the second mask mask 102 is used as the second aperture mask. In this case, an evaluation pattern 11 la˜: L 1 Id is formed on four sides of the block (the leftmost block 111 in the illustrated example)! Using this block mask 102, adjustment is made so that the sample current value measured at the current value measurement point on the sample such as a semiconductor substrate is maximized, and the first aperture mask 101 is transmitted through the block 111 of the block mask 102. The images are superimposed, and the rectangular pattern apertures 11 la to 11 Id of the block 111 are drawn on the sample in a lump. Then, by measuring the line width dimensions of the actually drawn rectangular patterns 112a to 112d and comparing the measured values to estimate pattern forming defects, the first aperture caused by the electron beam irradiation source is estimated. The uniformity of the transmission image of the mask 101 is evaluated.

Patent Document 1: Japanese Patent Laid-Open No. 6-120126

Disclosure of the invention

However, in the above-described conventional evaluation method, an evaluation pattern is drawn on the sample surface, and the line width dimension is measured. The same process as when forming a pattern must be followed, and there is a problem that requires extra work by detour.

[0008] Further, when the line width dimensions of the rectangular patterns 112a to 112d for evaluation are measured to estimate pattern formation defects, and it is evaluated that a non-uniform portion exists in the transmission image of the first aperture mask 101, Since the pattern forming defect is caused by the electron beam irradiation source and is inherent to the apparatus, the pattern forming defect always occurs in the same portion in the transmission image of the first aperture mask 101. Therefore, there is a problem that when a pattern such as a wiring of a semiconductor element is actually formed, a portion having a narrow line width always occurs in the same portion, and the dimensional variation is remarkably deteriorated.

[0009] In this regard, Patent Document 1 discloses an electron beam transmission larger than the transmission image of the first aperture mask at the four corners of the second aperture mask in which a plurality of types of apertures corresponding to the repetitive pattern are formed. A technique is disclosed in which holes are provided and correction is performed using a shaping deflection sensitivity coefficient obtained from dimensional calibration of an electron beam. This technique corrects the specimen surface so that a uniform electron beam is irradiated on any part of the second aperture mask, regardless of which part of the second aperture mask is deflected. In this case, the forming deflection as described above The sensitivity coefficient is calculated, the transmission image of the first aperture mask is positioned, the collapsed transmission image is scanned in the vicinity, and the electron beam current that has passed through the second aperture mask is constant. It is necessary to go through a complicated process of obtaining the center coordinates, obtaining the shaping deflection coordinates for the design arrangement coordinates of each aperture on the second aperture mask, and obtaining the shaping deflection correction coefficient. In return for such a large increase in process, it is possible to irradiate a uniform electron beam on the surface of the sample.

[0010] The present invention has been made in view of the above problems, and it is possible to reliably transmit a transmission image of the first aperture mask caused by the charged particle irradiation source with a simple configuration without actually drawing on the sample surface. Evaluate uniformity, and based on the evaluation, improve pattern dimensional accuracy by suppressing pattern size variation in actual drawing without increasing the number of processes. It is an object of the present invention to provide a charged particle beam drawing apparatus and method capable of drawing.

[0011] The charged particle irradiation apparatus of the present invention includes a first aperture formed with a charged particle beam irradiation means and a first aperture for shaping the charged particle beam irradiated from the charged particle beam irradiation means. The relative positional relationship between the mask, the second aperture mask formed with a plurality of second apertures corresponding to the repetitive pattern, and the transmission image of the first aperture and the second aperture is variable. And a current value measuring means for measuring a charged particle beam current value of a transmission image of the second aperture, wherein the second aperture mask includes at least one of the second apertures. One is a transmission hole smaller than the transmission image of the first aperture, and the positional variable means changes the relative positional relationship of the transmission holes in the transmission image of the first aperture, The serial current value measurement means for measuring a charged particle beam current value of the transmission image from the transmission hole at multiple sites in the transmission image of the first aperture, respectively.

[0012] One aspect of the charged particle irradiation apparatus of the present invention is that the charged particle beam current value in the transmission image of the first aperture is based on the charged particle beam current value measured by the current value measuring unit. Control means for evaluating the distribution uniformity is further included.

In one aspect of the charged particle irradiation apparatus of the present invention, the control means Based on the evaluation result, a portion satisfying the distribution uniformity criterion in the transmission image of the first aperture is selected and used for charged particle beam drawing.

[0014] The charged particle irradiation method of the present invention includes a first aperture mask in which a first aperture for forming an irradiated charged particle beam is formed, and a plurality of second apertures corresponding to a repetitive pattern. A charged particle beam is drawn by using a second aperture mask in which at least one of the second apertures is a transmission hole smaller than the transmission image of the first aperture. When performing, a step of irradiating the first aperture mask with charged particle beams and projecting a transmission image of the first aperture onto the second aperture mask; and in a transmission image of the first aperture Steps for measuring the charged particle beam current values of the transmission images from the transmission holes at a plurality of locations in the transmission image of the first aperture by changing the relative positional relationship of the transmission holes in the first aperture. Including

In one aspect of the charged particle irradiation method of the present invention, the charged particle beam current value in the transmission image of the first aperture based on the charged particle beam current value measured by the current value measuring means. The method further includes the step of evaluating the distribution uniformity.

In one aspect of the charged particle irradiation method of the present invention, based on the evaluation result of the distribution uniformity, the step of selecting a portion satisfying the distribution uniformity criterion in the transmission image of the first aperture Is further included.

Brief Description of Drawings

FIG. 1 is a schematic diagram showing a schematic configuration of an electron beam lithography apparatus according to a first embodiment.

FIG. 2 is a schematic perspective view for explaining main operations in the electron beam lithography apparatus according to the first embodiment.

[FIG. 3] FIG. 3 is a flowchart illustrating a method of evaluating the uniformity of a transmitted image of a first aperture in a first aperture mask in order of steps.

FIG. 4A is a schematic plan view showing a state where a transmission image of the first aperture is projected onto an evaluation block of the block mask.

FIG. 4B is a schematic plan view showing a state in which the transmission image of the first aperture is projected onto the evaluation block of the block mask. FIG. 4C is a schematic plan view showing a state in which a transmission image of the first aperture is projected onto the evaluation block of the block mask.

[FIG. 4D] FIG. 4D is a schematic plan view showing a state in which a transmission image of the first aperture is projected onto the evaluation block of the block mask.

FIG. 4E is a schematic plan view showing a state where a transmission image of the first aperture is projected onto the evaluation block of the block mask.

FIG. 5 is a flowchart showing a correction method for correcting electron beam irradiation using the evaluation results in FIG. 3 in order of steps.

[6A] FIG. 6A is a schematic diagram showing a variable rectangle as a wiring pattern.

FIG. 6B is a schematic diagram showing the aperture of the connection hole.

FIG. 7A is a schematic plan view showing an example of a transmission image of the first aperture mask.

FIG. 7B is a schematic plan view showing electron beam drawing when electron beam irradiation correction is not performed.

[FIG. 7C] FIG. 7C is a schematic plan view showing a drawn contact pattern when electron beam irradiation is not corrected.

FIG. 7D is a schematic plan view showing electron beam drawing when correction of electron beam irradiation is performed.

FIG. 7E is a schematic plan view showing a drawn contact pattern when electron beam irradiation is corrected.

FIG. 8A is a schematic cross-sectional view showing an n-type MOS transistor manufacturing method using the electron beam lithography apparatus according to the first embodiment in the order of steps.

FIG. 8B is a schematic cross-sectional view showing, in the order of steps, a method for manufacturing the n-type MOS transistor using the electron beam lithography apparatus according to the first embodiment, following FIG. 8A.

FIG. 8C is a schematic cross-sectional view showing, in the order of steps, a method for manufacturing the n-type MOS transistor using the electron beam lithography apparatus according to the first embodiment, following FIG. 8B.

FIG. 8D is a schematic cross-sectional view showing, in the order of steps, a method for manufacturing the n-type MOS transistor using the electron beam lithography apparatus according to the first embodiment, following FIG. 8C.

[FIG. 9A] FIG. 9A is a schematic diagram of n using the electron beam lithography apparatus according to the first embodiment, following FIG. It is a schematic sectional drawing which shows the manufacturing method of a type MOS transistor in process order.

FIG. 9B is a schematic cross-sectional view showing, in the order of steps, a method for manufacturing the n-type MOS transistor using the electron beam lithography apparatus according to the first embodiment, following FIG. 9A.

FIG. 9C is a schematic cross-sectional view showing, in the order of steps, a method for manufacturing the n-type MOS transistor using the electron beam lithography apparatus according to the first embodiment, following FIG. 9B.

FIG. 10 is a schematic diagram showing a schematic configuration of an electron beam lithography apparatus according to a second embodiment.

FIG. 11 is a schematic diagram showing an internal configuration of a personal user terminal device.

FIG. 12 is a perspective view schematically showing a method for evaluating the uniformity of a transmitted image of a first aperture mask caused by an electron beam irradiation source in a conventional block drawing apparatus.

BEST MODE FOR CARRYING OUT THE INVENTION

[0018] Basic outline of the present invention

The present inventor has intensively studied to evaluate the uniformity of the transmission image of the first aperture mask caused by the charged particle irradiation source without actually drawing a pattern for evaluation on a sample surface such as a semiconductor substrate. By utilizing the fact that the uniformity of the transmission image corresponds to the uniformity of the charged particle beam current value, a pattern in which the local decrease of the charged particle beam current value in the transmission image is actually drawn It was conceived that the size of the pattern (for example, a line width in the case of a rectangular pattern such as a wiring; a hole diameter in the case of an opening pattern such as a connection hole) was evaluated as a variation part.

Specifically, among each block constituting the block mask, a transmission hole that is smaller than the transmission image of the first aperture is provided as a second aperture in a predetermined block. The transmission image of the first aperture and the second aperture are relatively moved to superimpose transmission holes at a plurality of locations in the transmission image, for example, at the four corners and the central portion, and from the transmission holes at these plurality of locations. Each of the charged particle beam current values of the transmission image of is measured. Then, the control means evaluates the distribution uniformity of the charged particle beam current value in the transmission image of the first aperture based on these measurement results. In the transmission image, the non-uniform part where the charged particle beam current value is lower than the other part corresponds to the size variation part of the actually drawn image.

[0020] Further, in the evaluation result of the distribution uniformity of the charged particle beam current value evaluated as described above. Based on this, the control means selects a portion satisfying the distribution uniformity criterion in the transmission image of the first aperture. The control means supplies only the selected portion, that is, the uniform portion of distribution excluding the nonuniform distribution portion of the charged particle beam current value corresponding to the line width variation portion of the actually drawn pattern, to the actual pattern drawing. . With this configuration, it is possible to easily and reliably draw an expected pattern with extremely small size variation without incurring an additional process.

[0021] A specific embodiment to which the present invention is applied

Hereinafter, embodiments of the present invention applied to an electron beam drawing apparatus and method using an electron beam as a charged particle beam will be described in detail with reference to the drawings.

[0022] (First embodiment)

FIG. 1 is a schematic diagram showing a schematic configuration of the electron beam lithography apparatus according to the first embodiment, and FIG. 2 is a schematic perspective view for explaining main operations in the electron beam lithography apparatus according to the first embodiment. It is.

As shown in FIG. 1, the electron beam drawing apparatus includes an electron beam optical system 10 for performing electron beam irradiation, an aperture mask group 20 for performing desired pattern drawing, and a sample chamber 30 in which a sample is installed. And a control system 40 for performing various controls.

The electron beam optical system 10 includes an electron gun 11 that is an electron beam irradiation source, various lenses 12a to 12e, a beam dimension control deflector 13 that controls a beam dimension of the electron beam, and an electron beam. A beam position control deflector 14 for electron beam scanning for positioning in a predetermined block of the block mask 22 to be described later, and a deflector 15 for controlling the deflection of the electron beam irradiated on the sample 31. Configured.

The aperture mask group 20 includes a first aperture mask 21 in which a first aperture for forming a charged particle beam irradiated from the electron gun 11 is formed, and a plurality of second apertures corresponding to a repetitive pattern. Are formed in each block, and these blocks are arranged side by side in the form of a matrix, the block mask 22 being a second aperture mask, and a beam limiting aperture mask for limiting the electron beam transmitted through the second aperture And is composed of 23. The first aperture mask 21 and the block mask 22 will be described later.

[0025] The sample chamber 30 is a table 3 on which a sample 31 such as a semiconductor substrate or a glass mask is placed and fixed. 2, a sample 31, and a Faraday cup 33 that is selectively installed on a table 32 and is a current value measuring unit that measures an electron beam current value of a transmission image of the second aperture, for example.

The control system 40 includes a beam size control circuit 41 that drives and controls the deflector 13 for controlling the beam size, a beam position control circuit 42 that drives and controls the deflector 14 for beam position control, and a sample 31. A deflection control circuit 43 that drives and controls the deflector 15 for controlling the deflection of the electron beam irradiated on the table, and a table drive circuit that drives and controls the table 32 in the X direction (left and right direction on the page) and the Y direction (front and back direction on the page) 44, a mask stage 45 for driving the block mask 22 in the X direction and the Y direction so as to align the desired block with the electron beam! And a beam dimension control circuit. 41, beam position control circuit 42, deflection control circuit 43, table drive circuit 44, mask stage 45, and Faraday cup 33 are connected to each other. It is composed of a part 46.

[0027] The positional relationship of the first aperture mask 21, the block mask 22, and the Faraday cup 33 that constitute the main part of the electron beam lithography apparatus in the present embodiment is as shown in FIG. Here, the block mask 22 may be arranged in a matrix form with a force provided with four blocks for convenience of illustration and a larger number of blocks (each having a different aperture).

[0028] At least one block, here the leftmost block, is the electron beam current value inspection block 1 in the block mask 22, and the first aperture projected onto the inspection block 22a is the second aperture. A transmission hole 2 having a size smaller than the transmission image of the aperture is formed. In the blocks other than the inspection block 1, various apertures are formed for batch drawing in actual electron beam drawing. In this case, if a block constituting the block mask 22 has a transmission hole for forming a contact pattern corresponding to the transmission hole 2 as the second aperture, this block is used as an inspection block. It may be used as (used for actual electron beam drawing).

Here, a method for evaluating the uniformity of the transmitted image of the first aperture in the first aperture mask by the electron beam lithography apparatus of the present embodiment will be described with reference to FIGS. The Here, FIG. 3 is a flowchart for explaining the method of evaluating the uniformity of the transmitted image of the first aperture in the first aperture mask in the order of steps. 4A to 4E are schematic plan views showing a state in which the transmission image of the first aperture is projected onto the evaluation block of the block mask.

First, the Faraday cup 33 is set on the table 32, and an electron beam is emitted from the electron gun 11 (step Sl). The overall control unit 46 drives the deflector 14 by the deflection control circuit 42 to deflect the electron beam, and projects the transmission image of the first aperture onto the evaluation block 1 of the block mask 22.

[0031] Subsequently, the overall control unit 46 relatively moves the transmission image of the first aperture in the first aperture 21 and the evaluation block 1 of the block mask 22 so that the inside of the transmission image of the first aperture The relative positional relationship of the transmission hole 2 is changed with, the transmission hole 2 is aligned with a plurality of measurement points in the transmission image, and the electron beam sequentially transmitted through the transmission hole 2 by the Faraday cup 33 is obtained. Measure the current value (step S2). Here, the four points in the transmission image (lower left part, lower right part, upper left part, upper right part) and five points in the central part are taken as measurement points.

Specifically, in the present embodiment, the position variable means for changing the relative positions of the transmission image of the first aperture and the evaluation block 1 of the block mask 22 is the mask stage 45. The overall control unit 46 drives the mask stage 45 with the first aperture 21 fixed to change the relative positional relationship of the transmission holes 2 in the transmission image of the first aperture in the first aperture 21. Let Here, as shown in FIG. 4A, the transmission hole 2 is positioned at the lower left position in a predetermined position in the transmission image of the first aperture, here in the transmission image 21a of the first aperture. The electron beam transmitted through the transmission hole 2 is incident on the Faraday cup 33 installed on the table 32.

Next, the overall control unit 46 measures the current value I of the electron beam transmitted through the transmission hole 2 by the Faraday cup 33 and records the measurement result on a predetermined recording medium (not shown). This recording medium may be incorporated in the overall control unit 46 or installed outside the overall control unit 46.

Subsequently, the overall control unit 46 drives the mask stage 45 to the first aperture 21. The relative positional relationship of the transmission holes 2 is changed in the transmission image of the first aperture. Here, as shown in FIG. 4B, the transmission hole 2 is positioned at the lower right part in the predetermined position in the transmission image of the first aperture, here in the transmission image 21a of the first aperture. The electron beam that has passed through the transmission hole 2 is incident on the Faraday cup 33 installed on the table 32.

[0035] Next, the overall control unit 46 determines the current value I of the electron beam transmitted through the transmission hole 2 by the Faraday cup 33.

Measure 2 and record the measurement results on the above recording medium.

Subsequently, the overall control unit 46 drives the mask stage 45 to change the relative positional relationship of the transmission holes 2 in the transmission image of the first aperture in the first aperture 21. Here, the transmission hole 2 is positioned at a predetermined position in the transmission image of the first aperture, here in the transmission image 21a of the first aperture, as shown in FIG. 4C. The electron beam that has passed through the transmission hole 2 is incident on the Faraday cup 33 installed on the table 32.

[0037] Next, the overall control unit 46 determines the current value I of the electron beam transmitted through the transmission hole 2 by the Faraday cup 33.

Measure 3 and record the measurement results on the above recording medium.

Subsequently, the overall control unit 46 drives the mask stage 45 to change the relative positional relationship of the transmission holes 2 in the transmission image of the first aperture in the first aperture 21. Here, the transmission hole 2 is positioned at a predetermined position in the transmission image of the first aperture, here in the transmission image 21a of the first aperture, as shown in FIG. 4D. The electron beam that has passed through the transmission hole 2 is incident on the Faraday cup 33 installed on the table 32.

[0039] Next, the overall control unit 46 determines the current value I of the electron beam transmitted through the transmission hole 2 by the Faraday cup 33.

Measure 4 and record the measurement results on the above recording medium.

Subsequently, the overall control unit 46 drives the mask stage 45 to change the relative positional relationship of the transmission holes 2 in the transmission image of the first aperture 21 in the first aperture 21. Here, as shown in FIG. 4E, the transmission hole 2 is positioned at the central position in the predetermined position in the transmission image of the first aperture, here in the transmission image 21a of the first aperture. The electron beam that has passed through the transmission hole 2 is incident on the Faraday cup 33 installed on the table 32.

[0041] Next, the overall control unit 46 determines the current value I of the electron beam transmitted through the transmission hole 2 by the Faraday cup 33.

Measure 5 and record the measurement results on the recording medium.

[0042] Then, in step S2, the overall control unit 46 in the transmission image 21a of the first aperture Based on the current value I ~ 1 of the electron beam transmitted through the transmission hole 2 at five locations, the transmission image 21a

1 5

The distribution of the electron beam current value is calculated, and the distribution uniformity of the electron beam current value is evaluated (step S3).

In the present embodiment, a large number of measurements are made in more detail in the force transmission image 21a exemplified for the case of measuring electron beam current values at five measurement points in the transmission image 21a of the first aperture. A point may be taken to evaluate the distribution uniformity of the electron beam current value. In general, the more measurement points, the more accurately the distribution uniformity can be evaluated.

Furthermore, in the present embodiment, based on the evaluation of the distribution uniformity of the electron beam current value, only the portion where the distribution of the electron beam current value is determined to be uniform in the transmission image 21a of the first aperture is used. This is used for subsequent actual pattern drawing.

FIG. 5 is a flowchart showing, in order of steps, a correction method for correcting electron beam irradiation using the evaluation results of FIG.

First, the overall control unit 46 has a uniform electron beam current value in the transmission image 21a of the first aperture based on the distribution uniformity of the electron beam current value evaluated in step S3. The area is determined to be a part suitable for pattern drawing, and the position information of the area is recorded on a predetermined recording medium (step S4).

[0046] Then, the overall control unit 46 sends the position information to the beam position control circuit 42 (step S5). The beam position control circuit 42 feeds back the position information from the overall control unit 46 to the deflector 14 that positions the electron beam on the block mask 22 by deflecting the electron beam, and transmits it in the transmission image 21a of the first aperture 21. In step S6, the irradiation state of the electron beam is corrected so that only the region where the electron beam current value is uniform is used. The actual electron beam drawing is executed in such a corrected state.

[0047] The electron beam irradiation was corrected by the correction method described above! A specific example in which an actual pattern was drawn was examined based on a comparison with a case where the correction was not performed. Here, electron beam drawing of the connection hole in the SRAM is illustrated.

[0048] Normally, the electron beam adjustment during drawing is performed only on the so-called variable rectangle 3 that becomes the wiring pattern in the superposition of the first aperture mask 21 and the block mask 22 as shown in FIG. 6A. The electron dose is calculated from the current density measured in the variable rectangle 3 The On the other hand, the electron dose in the block mask 22 is drawn with the electron dose determined by the variable rectangle on the assumption that the transmission image of the first aperture is uniform. When the transmission image of the first aperture is inferior in uniformity, the electron dose is determined by a variable rectangle that is formed using the right end in the transmission image of the first aperture. Therefore, the second aperture of the block mask 22 using the left end having a lower current density is drawn, for example, the aperture 4 of the connection hole as shown in FIG. 6B (exemplifying a continuous hole and a single hole). In this case, the size of the drawn hall pattern is smaller than the design value. If the hole pattern size is reduced, the contact resistance value increases, which may cause defects.

As described above, in the present embodiment, the uniform region of the electron beam current value is determined based on the distribution of the electron beam current value in the transmission image 21a of the first aperture. FIG. 7A shows the state of the transmission image 21a determined in this way. Here, a case where the lower left part of the transmission image 21a is a non-uniform region 52 (a region indicated by oblique lines in the figure), and the transmission image 21a includes a uniform region 51 and other non-uniform regions 52 is illustrated.

[0050] When correction of electron beam irradiation is not performed, the entire transmission image 21a is subjected to electron beam drawing as shown in FIG. 7B. As shown in the figure, the transmission image 21a of the first aperture and the block in which the second aperture of the block mask 22 is made into a plurality of micro holes 53 are overlapped, and the transmission image of the micro holes 53 is mounted on the table 32. Draw on the resist (not shown) on the fixed semiconductor substrate. The contact pattern drawn at this time is shown in FIG. 7C. As shown in the figure, since the entire transmission image 21a was used for drawing, in the portion corresponding to the uniform region 51, each contact pattern 54 was formed in a uniform size, whereas the non-uniform region was formed. In the portion corresponding to 52, each contact pattern 54 is formed smaller in size than the portion corresponding to the uniform region 51.

In contrast, in the present embodiment, as shown in FIG. 7D, the non-uniform region 52 is excluded and only the uniform region 51 is used for pattern drawing. As shown in the figure, the uniform area 51 in the transmission image 21a of the first aperture and the block in which the second aperture of the block mask 22 is made into a plurality of micro holes 53 are overlapped, and the transmission image of the micro holes 53 is displayed as a table. Draw on the resist (not shown) on the semiconductor substrate placed and fixed on 32. The contact pattern drawn at this time is shown in Fig. 7E. Select the uniform area 51 in the transmission image 21a as shown in the figure. Since it was used for drawing, all the contact patterns 54 are formed in a uniform size.

Thus, according to the present embodiment, the uniformity of the transmission image 21a of the first aperture caused by the electron gun 11 is reliably evaluated with a simple configuration without actually drawing on the sample 31, Furthermore, based on the evaluation, the pattern size of the pattern to be drawn can be improved and the pattern of the expected design value can be drawn at once without increasing the number of processes and suppressing the pattern size variation in actual drawing. Is possible.

Next, a method for manufacturing a semiconductor device using the electron beam lithography apparatus of this embodiment will be described. Here, an n-type MOS transistor is exemplified as the semiconductor device, but the application target of the electron beam lithography apparatus according to the present embodiment is of course applied to other various semiconductor devices that are not limited to the n-type MOS transistor. Can do.

FIGS. 8A to 8D and FIGS. 9A to 9C are schematic cross-sectional views showing, in the order of steps, a method for manufacturing an n-type MOS transistor using the electron beam lithography apparatus according to the first embodiment. Here, the left side of each figure shows the device formation region, and the right side shows the mark formation region.

[0054] First, as shown in FIG. 8A, a so-called STI (Shallow

The element isolation trench 66 is formed by the Trench Isolation method, and the step mark trench 67 is formed in the mark formation region.

Specifically, first, a silicon nitride film 62 is formed on the silicon semiconductor substrate 61 by, for example, a low pressure CVD method. Thereafter, a resist 63 is applied on the silicon nitride film 62, and the resist 63 is processed by lithography to form a groove pattern 64 in the device formation region and a groove pattern 65 in the mark formation region.

Next, using the resist 63 as a mask, the silicon nitride film 62 is reinforced by reactive ion etching (RIE) using a fluorine-based gas as an etching gas. Subsequently, using the resist 63 and the silicon nitride film 62 as a mask, the etching gas is switched to a phosphorous gas, and the silicon semiconductor substrate 61 is processed to a depth of, for example, about 300 nm by RIE. At this time, an element isolation groove 66 that follows the groove pattern 64 in the element isolation region of the silicon semiconductor substrate 61 is formed in the device formation region, and a step mark groove that follows the groove pattern 65 in the silicon semiconductor substrate 61 in the mark formation region. A certain alignment mark 67 is formed.

[0056] Subsequently, as shown in FIG. 8B, an STI element isolation structure 68 is formed in the device formation region. Specifically, the resist 63 is removed by ashing or the like, the silicon nitride film 62 is removed by a hydrofluoric acid solution or the like, and then the silicon isolation film 66 and the step mark groove 67 are embedded on the entire surface by, eg, CVD method. An acid film (not shown) is deposited. Then, the silicon oxide film is polished by CMP (Chemical Mechanical Polishing) using the surface of the silicon semiconductor substrate 61 as a stopper to form an STI element isolation structure 68 in which the element isolation groove 66 is filled with silicon oxide in the device formation region. To do. At the same time, the alignment mark 67 is filled with silicon oxide in the mark formation region.

Next, as shown in FIG. 8C, a transistor structure 70 is formed in the device formation region.

Specifically, first, a p-type wall 71 is formed by ion-implanting a P-type impurity, for example, boron B, into the active region defined by the STI element isolation structure 68 of the silicon semiconductor substrate 61.

Next, after forming a gate insulating film 72 on the surface of the active region by, for example, a thermal oxidation method, a polycrystalline silicon film (not shown) is deposited by CVD as a gate material. The silicon film is processed into an electrode shape by lithography and dry etching, and the gate electrode 73 is patterned.

[0059] Next, a silicon oxide film (not shown) is deposited on the entire surface so as to cover the gate electrode 73, and the entire surface of the silicon oxide film is anisotropically etched (etched back). Sidewall spacers 74 are formed by leaving the oxide film only on both sides of the gate electrode 73.

[0060] Next, using the gate electrode 73 and the sidewall spacer 74 as a mask, an n-type impurity such as phosphorus (P) is ion-implanted into the surface layer of the active region on both sides of the structure composed of these, and the source Z drain 75 is formed.

Next, a silicon oxide film (not shown) is deposited on the entire surface, and the surface of the silicon oxide film is polished and flattened by a CMP method to form an interlayer insulating film 76. At this time, the transistor structure 70 embedded in the interlayer insulating film 76 is completed in the device formation region.

Subsequently, as shown in FIG. 8D, a resist 77 having an opening 77a for digging up the alignment mark 67 in the mark formation region is formed.

Specifically, a resist 77 is applied to the entire surface of the interlayer insulating film 76, and the resist 77 is processed by, for example, electron beam drawing, and the mark formation region is filled with silicon oxide. An opening 77a that exposes a peripheral portion centering on the mark 67 is formed. Since the alignment at the time of electron beam drawing does not require high accuracy of about 0.5 m or less, for example, the so-called optical rough alignment mechanism attached to the electron beam drawing apparatus is used to perform the electron beam drawing by light exposure. Use the alignment mark to be used relatively roughly.

Subsequently, as shown in FIG. 9A, silicon oxide in the alignment mark 67 in the mark formation region is removed.

Specifically, RIE is performed using the resist 77 as a mask and a fluorine-based gas as an etching gas, and the interlayer insulating film 76 is covered by following the opening 77a of the resist 77 to open the opening 76a in the interlayer insulating film 76. At the same time, the silicon oxide filler filling the groove pattern 65 in the mark forming region is removed, and the alignment mark 67 is exposed from the opening 76a.

Subsequently, as shown in FIG. 9B, a resist 78 having a contact pattern 78a for forming a contact hole in the transistor structure 70 is formed.

Specifically, a resist 78 is applied to the entire surface of the interlayer insulating film 76, alignment is performed with high accuracy by an electron beam using the alignment mark 67, the resist 78 is processed by electron beam drawing, and a transistor in the resist 78 is obtained. An opening 78a is formed at a position aligned with the upper part of the source / drain 75 of the structure 70. Here, the electron beam drawing apparatus disclosed in this embodiment is used. That is, as described above, a block in which only the region where the electron beam current value distribution is uniform in the transmission image 21a of the first aperture is used and the second aperture of the block mask 22 is an aperture corresponding to the contact pattern 78a. And draw an electron beam on resist 78.

Subsequently, as shown in FIG. 9C, a contact hole 79 is patterned in the transistor structure 70.

Specifically, RIE is performed using the resist 78 as a mask and a fluorine-based gas as an etching gas, and the interlayer insulating film 76 is covered according to the contact hole pattern 78a of the resist 78, and the source is supplied to the interlayer insulating film 76. A contact hole 79 exposing a part of the surface of the / drain 75 is formed.

Although not shown in the figure after the squeezing force, the conductive plug formed by filling the contact hole 79 with a conductive material and the wiring or contour connected to the conductive plug and extending on the interlayer insulating film 76 The n-type MOS transistor is completed through a process of filling wiring holes 79 and forming wirings extending on the interlayer insulating film 76.

[0067] As described above, by performing electron beam drawing for forming the contact hole 79 of the n-type MOS transistor using the electron beam drawing apparatus of the present embodiment, uniform as intended. A contact hole 79 that is fine in size is formed, and a highly reliable n-type MOS transistor can be manufactured with a high yield.

[0068] (Second Embodiment)

The electron beam drawing apparatus of the present embodiment is configured in substantially the same manner as in the first embodiment, but the transmission image of the first aperture in the first aperture 21 and the evaluation block 1 of the block mask 22 This is different in that the position variable means for relatively moving the position is different.

FIG. 10 is a schematic diagram showing a schematic configuration of the electron beam lithography apparatus according to the second embodiment.

This electron beam drawing apparatus is different from the electron beam drawing apparatus of the first embodiment in that the control system 40 does not have a mask stage 45. In the present embodiment, the deflector 14 serves as a position variable means for changing the relative positions of the transmission image of the first aperture and the evaluation block 1 of the block mask 22.

That is, in this embodiment, when projecting the transmission image of the first aperture 21 onto the evaluation block 1 of the block mask 22, the overall control unit 46 keeps the block mask 22 fixed and the beam position. The deflector 14 is driven by the control circuit 42 to deflect the electron beam, and the relative positional relationship of the transmission holes 2 is changed in the transmission image of the first aperture in the first aperture 21.

According to the present embodiment, as in the first embodiment, the transmission image 21a of the first aperture due to the electron gun 11 can be surely uniform with a simple configuration without actually drawing on the sample 31. In addition, based on the evaluation, without increasing the number of processes, the pattern size variation is improved by suppressing pattern size variation in actual drawing, and the pattern of the desired design value is batched. It becomes possible to draw.

[0072] Further, since the mask stage 45 is unnecessary, the apparatus configuration is simplified correspondingly, and the versatility of the apparatus is improved.

Note that steps S1 to S3 of the evaluation method shown in FIG. 3 and the steps of the correction method shown in FIG. Program codes for steps S4 to S6 can be realized by running programs stored in RAM or ROM of the computer. This program and a computer-readable storage medium storing the program are included in the embodiment of the present invention.

Specifically, the program is recorded on a recording medium such as a CD-ROM, or provided to a computer via various transmission media. As a recording medium for recording the program, besides a CD-ROM, a flexible disk, a hard disk, a magnetic tape, a magneto-optical disk, a nonvolatile memory card, or the like can be used. On the other hand, the transmission medium of the program is a communication medium (wired line such as an optical fiber) in a computer network (LAN, Internet or other WAN, wireless communication network, etc.) system for propagating and supplying program information as a carrier wave. Or wireless lines).

[0075] Further, the function of the above-described embodiment is realized not only by executing the program supplied by the computer, but there is an OS (operating system) in which the program is running on the computer. When the functions of the above-described embodiment are realized in cooperation with the above-mentioned embodiment, or all of the processing of the supplied program is partially performed by a function expansion board or a function expansion unit of the computer, the above-described embodiment Such a program is also included in the embodiment of the present invention when the above function is realized.

For example, FIG. 11 is a schematic diagram showing the internal configuration of a personal user terminal device. In FIG. 11, 1200 is a computer PC. PC1200 is equipped with CPU1201, and executes device control software stored in ROM1202 or hard disk (HD) 1211 or supplied from flexible disk drive (FD) 1212 to control each device connected to system node 1204 Control.

[0077] According to the program stored in the CPU 1201, the ROM 1202 or the hard disk (HD) 1211 of the PC 1200, steps S1 to S3 in FIG. 3 and steps S4 to S6 in FIG. Realized.

Reference numeral 1203 denotes a RAM, which functions as a main memory, work area, and the like for the CPU 1201. 1205 Is a keyboard controller (KBC) that controls the input of commands from the keyboard (KB) 1209 and devices not shown.

[0079] Reference numeral 1206 denotes a CRT controller (CRTC), which controls display on a CRT display (CRT) 1210. 1207 is a disk controller (DKC) that stores boot programs (startup programs: programs that start running (operating) the hardware and software of the computer), multiple applications, editing files, user files, and network management programs. Controls access to the hard disk (HD) 1211 and flexible disk (FD) 1212.

Reference numeral 1208 denotes a network interface card (NIC), which performs bidirectional data exchange with a network printer, another network device, or another PC via the LAN 1220.

Industrial applicability

[0081] According to the charged particle beam drawing apparatus and method of the present invention, the uniformity of the transmission image of the first aperture mask reliably caused by the charged particle irradiation source with a simple configuration without actually drawing on the sample surface. In addition, based on the evaluation, without increasing the number of processes, the pattern size variation can be improved by suppressing pattern size variation in actual drawing, and patterns with the desired design values can be drawn at once. It becomes possible.

Claims

The scope of the claims

[1] charged particle beam irradiation means;

A first aperture mask on which a first aperture for forming the charged particle beam irradiated with the charged particle beam irradiation means is formed; and

A second aperture mask formed with a plurality of second apertures corresponding to the repetitive pattern;

Position varying means for varying the relative positional relationship between the transmission image of the first aperture and the second aperture;

Current value measuring means for measuring a charged particle beam current value of a transmission image of the second aperture; and

Including

In the second aperture mask, at least one of the second apertures is a transmission hole smaller than the transmission image of the first aperture,

The position variable means changes the relative positional relationship of the transmission holes in the transmission image of the first aperture, and the current value measurement means changes the transmission holes in a plurality of locations in the transmission image of the first aperture. A charged particle beam drawing apparatus for measuring a charged particle beam current value of a transmission image of a mosquito.

[2] The apparatus further includes control means for evaluating the distribution uniformity of the charged particle beam current value in the transmission image of the first aperture based on the charged particle beam current value measured by the current value measuring means. The charged particle beam drawing apparatus according to claim 1, wherein:

[3] The control means may select a portion satisfying the distribution uniformity criterion in the transmission image of the first aperture based on the distribution uniformity evaluation result, and use the selected portion for charged particle beam drawing. 3. The charged particle beam drawing apparatus according to claim 2, wherein

[4] The transmission image of the first aperture is rectangular,

The charged particle beam current value of the transmission image from the transmission hole at each of the four corners and the center of the transmission image of the first aperture is measured by the current value measuring unit, respectively. The charged particle beam drawing apparatus according to 1.

[5] The position varying means is a mask for mounting and fixing the second aperture mask so as to be movable. 2. The charged particle beam drawing apparatus according to claim 1, wherein the second aperture mask is a stage, and the second aperture mask is moved relative to the transmission image of the first aperture on the mask stage.

[6] The position variable means is a magnetic field deflector for deflecting the charged particle beam irradiated from the charged particle beam irradiation means, and transmits a transmission image of the first aperture with respect to the second aperture mask. The charged particle beam drawing apparatus according to claim 1, wherein the charged particle beam drawing apparatus is moved.

[7] a first annotator mask having a first aperture for shaping the irradiated charged particle beam;

A plurality of second apertures corresponding to a repetitive pattern are formed, and at least one of the second apertures is a second aperture mask having a smaller transmission hole than the transmission image of the first aperture When

When performing charged particle beam drawing using

Irradiating a charged particle beam to the first aperture mask and projecting a transmission image of the first aperture onto the second aperture mask; and

The charged particle beam current of the transmission image of the transmission hole is changed at a plurality of locations in the transmission image of the first aperture by changing the relative positional relationship of the transmission holes in the transmission image of the first aperture. Measuring each value and

A charged particle beam drawing method comprising:

[8] The method further includes a step of evaluating distribution uniformity of the charged particle beam current value in a transmission image of the first aperture based on the charged particle beam current value measured by the current value measuring means. 8. The charged particle beam drawing method according to claim 7,

9. The method according to claim 8, further comprising a step of selecting a portion satisfying the distribution uniformity criterion in the transmission image of the first aperture based on the evaluation result of the distribution uniformity. The charged particle beam drawing method as described.

[10] The transmission image of the first aperture is rectangular,

In the step of measuring the charged particle beam current value, the charged particle beam current value of the transmission image from the transmission hole at the four corners and the central portion in the transmission image of the first aperture is calculated. The charged particle beam drawing according to claim 7, wherein each is measured. Method.

[11] In the step of measuring the charged particle beam current value, the second aperture mask is movably mounted and fixed on a mask stage, and the second aperture mask is placed on the mask stage. The charged particle beam drawing method according to claim 7, wherein the charged particle beam is moved with respect to the transmission image of the first aperture.

[12] In the step of measuring the charged particle beam current value, the transmitted image of the first aperture is moved with respect to the second aperture mask by deflecting the irradiated charged particle beam. 8. The charged particle beam drawing method according to claim 7,

[13] a first annotator mask having a first aperture for shaping the irradiated charged particle beam;

A plurality of second apertures corresponding to a repetitive pattern are formed, and at least one of the second apertures is a second aperture mask having a transmission hole smaller than a transmission image of the first aperture When

When performing charged particle beam drawing using

On the computer,

A program for running

[14] The step of further evaluating the distribution uniformity of the charged particle beam current value in the transmission image of the first aperture based on the charged particle beam current value measured by the current value measuring means in a computer The program according to claim 13 for execution.

[15] The computer program further comprising: causing the computer to select a portion satisfying the distribution uniformity criterion in the transmission image of the first aperture based on the evaluation result of the distribution uniformity. 14. The program described in 14.