JP3241007B2 - Electron beam exposure apparatus and electron beam exposure method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electron beam exposure apparatus and an electron beam exposure method, and more particularly to an electron beam exposure apparatus and an electron beam exposure method for performing exposure using a partial collective mask.

[0002]

2. Description of the Related Art Conventionally, a direct-writing type electron beam exposure apparatus in which a pattern is drawn by directly irradiating a resist on a wafer with an electron beam (electron beam) does not use a glass mask, but uses an electron lens. To generate a rectangular electron beam using an aperture, and to irradiate a desired position by adjusting the voltage applied to the deflecting plate. , The pattern was drawn on the wafer , but the exposure time was long, and the throughput, which is a measure of substantial working efficiency, was considerably low.

In order to solve this problem, there is a method using a partial batch mask which enables high throughput.
Electron beam exposure method using the cell projection mask has a first aperture and second aperture, it is proposed that the exposure time is shortened by the use of a pre-second aperture in which a plurality of mask patterns are produced. That is, the repetition pattern of the mask pattern extracted from the design data is
It is prepared on an aperture and is sequentially exposed.

As described above, in the exposure method using an electron beam using a partial batch mask, the repetition of the mask pattern is formed on the second aperture, so that the exposure throughput is remarkably improved.

For example, as shown in FIG. 6, when connecting respective patterns of a mask A, a mask B, and a mask C having different mask patterns, the origin positions of the masks are determined based on the rectangular opening for variable shaping. Good adjustment accuracy was obtained between the masks directly adjusted by the adjustment.

[0006]

However, in the electron beam exposure apparatus using the partial batch mask shown in the above conventional example, a good connection accuracy can be obtained between directly adjusted masks. It is difficult to obtain good connection accuracy between a plurality of masks other than the masks described above, and FIG. 7 shows this state.

As shown in FIG. 7, when connecting a plurality of mask patterns, a mask A, a mask B, and a mask C, respectively, a mask A and a mask B and a mask A and a mask C
, A good connection accuracy can be obtained. However, in the connection between the mask B and the mask C, the connection state between the mask A and the mask B and between the mask A and the mask C is adjusted. A shift occurs between B and the mask C.

Accordingly, there is a problem that a connection error occurs in the connection between partial collective masks as the pattern of the partial collective mask to be used is increased (increased).

An object of the present invention is to provide an electron beam exposure apparatus and an electron beam exposure method that improve the connection accuracy in connecting different mask patterns.

[0010]

According to an aspect of the present invention, there is provided an electron beam exposure apparatus for performing an exposure process using an electron beam using a partial batch mask having different mask patterns. An offset value storage unit for storing an offset value group corresponding to a connection error between different mask patterns, and selecting an offset value between desired mask patterns from the offset value group stored by the offset value storage unit; The selected offset value is added to the position data of the mask pattern to be exposed next time, and the exposure is performed by controlling the deflection of the electron beam based on the added result.

[0011] The invention according to claim 2 is the invention according to claim 1.
In the following, the electron beam lithography system
The mask pattern to be exposed and the next exposure
Offset value with the expected mask pattern offset value
Select from the set of offset values stored in the storage means and select
Offset value of the mask pattern to be exposed next time.
Adds to the position data, and based on the added result, the electron beam
And exposure is performed by controlling the deflection.

According to a third aspect of the present invention, a different mask pattern is provided.
Exposure with electron beam using partial batch mask with mask
In the electron beam exposure method for performing the processing, a different mask is used in advance.
Stores a group of offset values according to the connection error between patterns
Offset value storage process and mask pattern to be exposed
And the position data of the mask pattern to be exposed next time.
And the position data extraction process
Mask pattern to be exposed and extracted next time
Offset based on position data with mask pattern
The offset is stored in the offset value storage process.
Offset value selection process to select from the
The offset value selected in the
Mask pattern to be exposed next time extracted by the
Offset value adding process to be added to the
It has, based on the result of the addition Ri by the offset value adding step
And exposure processing by controlling the deflection of the electron beam.
I do.

[0013] The invention according to claim 4 is the invention according to claim 3.
, The electron beam exposure method is based on the mask pattern
To be exposed by the offset value selection process
Between the mask pattern of
Offset stored in the offset value storage process
It is characterized by selecting from a set value group.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an electron beam exposure apparatus and an electron beam exposure method according to embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram showing an electron beam exposure apparatus according to an embodiment of the present invention. In FIG. 1, an electron beam exposure apparatus 100 includes a used mask recognition apparatus 1, an inter-field mask adjustment table 2, and a connection adjustment table 3.
The deflection position control device 4, the electron gun 5, the blanking electrode 6, the first aperture 7, the forming lens 8, the forming deflector 9, the second aperture 10, and the reduction lens 11.
, A deflector 12 and a projection lens 13.

Further, in FIG. 1, a semiconductor wafer 14 placed on a sample table (not shown), a partial batch mask A16 and a partial batch mask B on the semiconductor wafer 14 are shown.
Are shown. Note that the partial collective mask is a portion where a plurality of different mask patterns prepared in advance on the second aperture 10 are opened.

The used mask recognition apparatus 1 extracts the patterns of the partial collective masks A15 and B16 as the design position data.
The inter-field mask adjustment table 2 stores mask information used at exposure field boundaries. The connection adjustment table 3 stores an offset value corresponding to a connection error between partial collective masks in advance, and based on the position data of the partial collective mask A15 and the partial collective mask B16 recognized by the used mask recognition device 1. Select an offset value. The deflection position control device 4 determines whether or not the mask pattern to be exposed is to be exposed at a field boundary.

When the deflection position control device 4 determines that the pattern is exposed on the field boundary, the deflection position control device 4 adds the selected offset value to the mask information of the partial batch mask B16 stored in the inter-field mask adjustment table 2. Then, a control signal for controlling the deflector 12 is transmitted. If it is determined that the pattern is not a pattern to be exposed at the field boundary, a control signal for controlling the deflector 12 by adding the selected offset value to the design position data of the partial batch mask B16 extracted by the used mask recognition device 1 is output. Send out.

The electron gun 5 emits an electron and emits an electron beam by focusing it on the beam. The blanking electrode 6 is an electrostatic deflector for switching between irradiation and non-irradiation of an electron beam emitted from the electron gun 5.
The first aperture 7 shapes an electron beam into a desired shape according to the formed pattern. The forming lens 8 is an electron lens for forming an image of the electron beam formed by the first aperture 7 on a second aperture 10 described later. The shaping deflector 9 determines the beam size of the electron beam transmitted through the shaping lens 8. The second aperture 10 is formed into a desired shape by simultaneously irradiating the plurality of mask patterns formed on the second aperture 10 with an electron beam. The reduction lens 11 is an electron optical lens for reducing the electron beam formed by the second aperture 10 . The deflector 12 deflects the electron beam reduced by the reduction lens 11 based on a control signal from the deflection position control device 4 . The projection lens 13 irradiates the electron beam deflected by the deflector 12 to a semiconductor wafer 14 mounted on a sample stage (not shown) to perform an exposure process.

FIG. 2 shows an example of an offset value between partial batch masks stored in the connection adjustment table 3. FIG. 3 shows an example of exposure when exposure processing is performed using an offset value.

In FIG. 2, for example, when different mask patterns of mask A and mask B are connected, (x
By controlling the deflector 12 based on the result obtained by adding the offset value of (ab, yab) to the mask information at the field boundary portion stored in the inter-field mask adjustment table 2 by the deflection position control device 4, FIG. As shown in the first exposure example, an exposure process with a small connection error at the boundary portion can be performed. Similarly, the result of adding the (xan, yan) offset value stored in the connection adjustment table 3 to the mask information at the field boundary portion of the mask N when the mask patterns of the mask A and the mask N are exposed. Since the deflector 12 is controlled based on the above, the connection state between the partial collective masks can be subjected to an exposure process with a small connection error as shown in the exposure example 2 in FIG.

FIG. 4 is a flowchart showing an operation example of the electron beam exposure apparatus according to the embodiment of the present invention. FIG.
An operation example of the electron beam exposure apparatus according to the embodiment of the present invention will be described with reference to the block diagram of FIG.

The patterns of the partial batch masks A15 and B16 are extracted as design position data, and the mask information at the field boundary between the partial batch masks is stored in the inter-field mask adjustment table 2 ( Step S1). Step S1
It is determined whether or not the pattern of the partial batch mask extracted in step 2 is to be exposed at a field boundary (step S2).

If it is determined in step S2 that the pattern is exposed on the field boundary (step S2 / Yes), the mask at the field boundary of the partial batch mask B16 stored in the inter-field mask adjustment table 2 The information is taken in (step S4).
Based on the mask information taken in step S4, an offset value between the partial collective mask A and the partial collective mask B is selected from the offset value group stored in the connection adjustment table 3 (step S5). The selected offset value is determined by the deflection position controller 4 in the partial batch mask B16.
, And the exposure process is performed by controlling the deflection of the electron beam based on the added data.

If it is determined in step S2 that the pattern is not a pattern exposed on the field boundary (step S2 / No), the design position data of the partial batch mask B16 is fetched from the used mask recognition device 1 (step S3). . Taken at scan Te' flop S3, based on the design position data to select the offset value stored in the connection adjustment table 3 (step S5), and then adds the selected offset value to the design position data of the partial batch mask B16 Then, the exposure process is performed by controlling the deflection of the electron beam based on the added data.

FIG. 5 is a diagram showing an example of the field boundaries and the order of exposure when exposing the pattern of the partial batch mask.

In FIG. 5, for example, a partial batch mask A
1 to F, the mask information in the exposure field of the partial batch mask A in the exposure order 1 is based on the design position data stored in the used mask recognition device 1 shown in FIG. Things.
The mask information at the field boundary of the partial batch mask A is based on the mask information stored in the inter-field mask adjustment table 2. By repeating the above-described operations from the exposure order 1 to 2, 3,..., 6 in the order of exposure, the accuracy in pattern connection can be improved.

[0028]

As is apparent from the above description, according to the electron beam exposure apparatus and the electron beam exposure method of the present invention, an offset value corresponding to a connection error between each partial mask is previously stored in a connection adjustment table. An offset value is selected based on the extracted design position data, and the selected offset value is added to the design position data at the time of actual exposure to control the deflection of the electron beam for exposure. The connection accuracy between them can be suppressed to 0.02 μm or less, and it is possible to easily correct a plurality of different mask patterns.

According to the first and third aspects of the present invention, different
Offset value according to the connection error for each mask pattern
It can be stored, so the mask at the time of partial batch mask exposure
Connection accuracy can be improved.

According to the second and fourth aspects of the present invention, the exposure
The part to be exposed next time immediately before exposure
Extracts the design position data of the batch mask pattern and exposes it
Select the offset value when exposing the scheduled partial batch mask
Exposure processing without reducing throughput.
It can be performed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an electron beam exposure apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing an offset value group stored in a connection adjustment table.

FIG. 3 is a diagram showing a connection state between partial collective masks exposed by an electron beam exposure apparatus according to an embodiment of the present invention.

FIG. 4 is a flowchart illustrating an operation example of the electron beam exposure apparatus according to the embodiment of the present invention.

FIG. 5 is a diagram showing a field boundary and an exposure order in the embodiment of the present invention.

FIG. 6 is a first diagram showing a processing example of a conventional electron beam exposure apparatus using a partial batch mask.

FIG. 7 is a second diagram illustrating a processing example of a conventional electron beam exposure apparatus using a partial batch mask.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 mask recognition device used 2 inter-field mask adjustment table 3 connection adjustment table 4 deflection position control device 5 electron gun 6 blanking electrode 7 first aperture 8 shaped lens 9 shaped deflector 10 second aperture 11 reduced lens 12 deflector 13 Projection lens 14 Semiconductor wafer 15 Partial batch mask A 16 Partial batch mask B

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 21/027 G03F 7/20 504

Claims (4)

(57) [Claims] 1. An electron beam exposure apparatus for performing an exposure process using an electron beam using a partial batch mask having different mask patterns, wherein an offset value group storing an offset value group corresponding to a connection error between the different mask patterns in advance. Means for selecting an offset value between desired mask patterns from an offset value group stored by the offset value storage means, and adding the selected offset value to position data of a mask pattern to be exposed next time. An electron beam exposure apparatus, wherein the exposure is performed by controlling the deflection of the electron beam based on the added result. 2. The method according to claim 1, wherein the electron beam exposure apparatus stores an offset value between the mask pattern to be exposed and the mask pattern to be exposed next time in the offset value storing means when exposing the mask pattern to be exposed. Selecting from a group of offset values, adding the selected offset value to the position data of the mask pattern to be exposed next time, and performing exposure control by deflecting the electron beam based on the added result. The electron beam exposure apparatus according to claim 1 . 3. An electron beam exposure method for performing an exposure process using an electron beam using a partial batch mask having different mask patterns, wherein an offset value group is stored in advance in accordance with a connection error between the different mask patterns. A position data extracting step of extracting position data of a mask pattern to be exposed and a mask pattern to be exposed next time; and the mask pattern to be exposed extracted by the position data extracting step and the mask to be exposed next time. An offset value selecting step of selecting an offset value based on position data with a pattern from the offset value group stored in the offset value storing step; and extracting the offset value selected in the offset value selecting step into the position data. The mask pattern to be exposed next time extracted by And an offset value adding step for adding the position data over emissions, electron beam exposure method, characterized by deflection control shite exposure the electron beam based on a result of the addition by the offset value adding step. 4. The method according to claim 1, wherein, when exposing the mask pattern to be exposed, the offset value selecting step sets an offset value between the mask pattern to be exposed and the mask pattern to be exposed next time by the offset value. 4. The electron beam exposure method according to claim 3, wherein the offset value is selected from the group of offset values stored in the storing step.