JPH1070063A - Exposure method and pattern-forming method of semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent thinning of pattern size caused by the proximity effect, by exposing repeatedly a semiconductor substrate to respective projection patterns generated through application of electron beams on respective mask patterns formed on a stencil mask, and by increasing/decreasing the exposure quantities at every exposure of the projection pattern. SOLUTION: By projecting on a mask pattern 14 formed on a stencil mask 13 a rectangular beam 12 formed by a first molding aperture 11, a projection pattern is generated to expose a semiconductor substrate 15 to it. In this case, the inside of the repeatedly exposed region by a partially batch-exposing method is exposed to the beam 12 with an enough exposure quantity (defined as 100) to obtain its desired pattern dimension. On the other hand, the outer edges (B) and (C) of the repeatedly exposed region by the partially batch-exposing method are exposed respectively to the beam 12 with the corresponding exposure quantities to 120 and 110, by changing their beam unblank times. By such a procedure, the foregoing exposed region is exposed repeatedly to the same kind of patterns with the different exposure quantities to complete the exposure of the whole of the semiconductor substrate 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron beam direct exposure method and a method for forming a pattern of a semiconductor device using the same.

[0002]

2. Description of the Related Art Conventionally, techniques in such a field include:
For example, (1) '92 Proceedings 36th I
international Symposium on
Electron, Ion, and Photon
Beams. (2) '93 Breakthrough seminar proceedings.

FIG. 5 is an explanatory view of such a conventional partial batch type electron beam exposure method. As shown in this figure, the conventional partial batch electron beam exposure method uses the stencil mask 3 to convert the rectangular beam 2 formed by the first shaping aperture 1 into a stencil mask 3.
Irradiation is performed on the mask pattern 4 formed thereon, and the resulting projection pattern is repeatedly exposed on the semiconductor substrate 5.

[0004]

However, in the above-mentioned conventional partial batch electron beam exposure method, there is a problem that the pattern size becomes narrow due to the proximity effect in the outer peripheral area A of the exposure area shown in FIG. Was. As a solution to this problem, there is a means in which the thinning due to the proximity effect is corrected in advance in the mask pattern on the stencil mask 3 to make it thicker, but the thinning amount of the pattern size depends on the exposure position on the semiconductor substrate. Therefore, it is necessary to form a corresponding number of mask patterns in advance.

Further, in order to obtain a desired pattern size, it is necessary to further set a level in the pattern size, which requires an enormous number of mask patterns and also requires a large number of man-hours even for exposure conditions. And it was not a viable solution. SUMMARY OF THE INVENTION It is an object of the present invention to provide an exposure method and a method for forming a pattern of a semiconductor device, which can eliminate the above-mentioned problems and can prevent the pattern size from being reduced due to the proximity effect by a simple method.

[0006]

In order to achieve the above object, the present invention provides: [1] In a partial batch type electron beam exposure method, an electron beam is generated by irradiating an electron beam onto a mask pattern formed on a stencil mask. When a semiconductor substrate is repeatedly exposed to a projection pattern to be exposed, the exposure amount is increased or decreased for each exposure.

[2] In the exposure method according to the above [1], the projection pattern is formed such that a desired region in a mask pattern formed on the stencil mask is partially extracted by a mask pattern selection / deflection system. It was done. [3] In the exposure method according to [1], the stencil mask is located at a position further away from a boundary of the mask pattern by an electron beam region formed by a first shaping aperture in at least two directions of diagonals of the mask pattern. , A mask pattern selection / deflection system calibration pattern is provided.

[4] In the partial batch type electron beam exposure method, when a semiconductor substrate is repeatedly exposed to a projection pattern generated by irradiating a mask pattern formed on a stencil mask with an electron beam, the projection pattern is masked. A desired area in the mask pattern formed on the stencil mask is partially and partially extracted by the pattern selection / deflection system a plurality of times, and the exposure amount is set for each of the projection patterns. The same position is exposed multiple times while increasing or decreasing.

[5] In a method of forming a pattern of a semiconductor device by exposure, when a semiconductor substrate is repeatedly exposed to a projection pattern generated by irradiating a mask pattern formed on a stencil mask with an electron beam,
The exposure amount is increased / decreased for each exposure, and the exposure suppresses the pattern size reduction due to the proximity effect, thereby forming a pattern of the semiconductor device.

[6] In a method of forming a pattern of a semiconductor device by exposure, when a semiconductor substrate is repeatedly exposed to a projection pattern generated by irradiating an electron beam onto a mask pattern formed on a stencil mask,
The projection pattern is obtained by partially extracting a desired region in the mask pattern formed on the stencil mask and changing the region a plurality of times by using a mask pattern selection / deflection system. When the semiconductor substrate is repeatedly exposed to a projection pattern generated by irradiating a mask pattern formed on the stencil mask with an electron beam by performing multiple exposures to the same position while increasing or decreasing the exposure amount for each exposure. The exposure amount is increased or decreased each time, and the exposure suppresses the pattern size reduction due to the proximity effect, thereby forming a pattern of a semiconductor device.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is an explanatory view of a partial batch electron beam exposure method according to a first embodiment of the present invention. As shown in this figure, the first forming aperture 1
The rectangular beam 12 formed by the stencil mask 1
Irradiation is performed on the mask pattern 14 formed on the substrate 3, and the resulting projection pattern is exposed on the semiconductor substrate 15.

At this time, the inside of the area to be repeatedly exposed by the partial batch exposure method is exposed with an exposure amount (this is set to 100) that can obtain a desired pattern size. Further, at the outer edges B and C of the area to be repeatedly exposed by the partial batch exposure method, the exposure amounts are exposed at 120 and 110, respectively, by changing the beam unblank time. Exposure to the semiconductor substrate is completed by repeatedly exposing the same projection pattern in this procedure.

As described above, according to the first embodiment, the exposure is performed by changing the exposure amount according to the position of the exposure area.
The thinning of the pattern size can be corrected using the same mask pattern on the stencil mask, and the pattern dimensional accuracy can be improved. Furthermore, since the number of mask patterns on a stencil mask required for the same type of pattern exposure can be reduced, more mask patterns of different pattern types can be formed on the same stencil mask, thereby improving the exposure throughput. In addition to this, it is expected that the stencil mask will be economically produced.

Next, a second embodiment of the present invention will be described. FIG. 2 is an explanatory view of a partial batch type electron beam exposure method according to a second embodiment of the present invention. When a projection pattern is generated in the same manner as in the first embodiment, the rectangular beam 22 formed by the first shaping aperture 21 is formed in a half area of the mask pattern 24 on the stencil mask 23 by the mask pattern selection / deflection system. And projecting the resulting projection pattern onto a region D on the semiconductor substrate 25 with an exposure dose of 12
Exposure is performed at 0. At this time, 1 is provided below and on the left side of the area D.
/ 2 region is selected according to the site.

Similarly, using the projection pattern extracted from the mask pattern 24, the exposure amount 1
Exposure is performed at 15, 110. In the exposure of the remaining area, the entire mask pattern is exposed at an exposure amount of 100, and the exposure of the semiconductor substrate is completed. As described above, according to the second embodiment, by exposing the projection pattern partially extracted from the mask pattern according to the position of the exposure area while changing the exposure amount,
In addition to the effects of the first embodiment, fine grain exposure can be performed in units of the extracted area, and the pattern size can be controlled with higher accuracy.

Next, a third embodiment of the present invention will be described. FIG. 3 is a perspective view of a stencil mask for explaining a partial batch type electron beam exposure method according to a third embodiment of the present invention. In this embodiment, a description will be given of an example of position detection for performing beam positioning, which is necessary for executing the above-described second embodiment.

In FIG. 3, on the extension of the diagonal line 37 of the mask pattern 34 on the stencil mask 33, the area 38 of the rectangular beam 32 formed by the first shaping aperture (not shown) is separated from the boundary of the mask pattern 34. ,
At a position in contact with the mask pattern, a mask pattern selection system calibration pattern 36 of 20 μm square arranged in pairs at right angles is provided.

Then, the rectangular beam 32 formed by the first shaping aperture is deflected by the mask pattern selection system, and is gradually moved from above the mask pattern 34 onto the extension of the diagonal line 37 of the mask pattern 34, as shown in FIG. At the position, the current value becomes zero with the current measuring device on the exposure stage. That is, when the rectangular beam 32 is irradiated on the region 38 in FIG. 3, the rectangular beam 32 is shielded entirely in the light shielding region of the stencil mask 33, so that the current value becomes zero by the current measuring device. , This is the origin. Further, as the mask pattern selection system continues to move, the rectangular beam 32 passes through the mask pattern selection system calibration pattern 36,
The current value increases again, and the position can be detected.

By performing this operation in two diagonal directions of the mask pattern, a DAC (D / A converter) for driving the mask pattern selection system and the stencil mask 3
The correlation of the deflection positions on 3 can be obtained. As described above, according to the third embodiment, by providing the mask pattern selection system calibration pattern 36 on the stencil mask 33, a desired portion of the mask pattern 34 can be extracted with high accuracy.

Next, a fourth embodiment of the present invention will be described. FIG. 4 is an explanatory view of a partial batch type electron beam exposure method according to a fourth embodiment of the present invention. As in the second embodiment,
When a projection pattern is generated by partially extracting from the mask pattern 44, the mask pattern selection / deflection system formed the first shaping aperture 41 in a quarter of the mask pattern 44 on the stencil mask 43. The rectangular beam 42 is irradiated, and the resulting projection pattern (a) is exposed to the area D on the semiconductor substrate 45 at an exposure amount of 10.

Next, a rectangular beam 42 formed by the first shaping aperture 41 is formed in a 2/4 region of the mask pattern 44.
And the resulting projection pattern (b) is exposed at a dose of 5 to the region D on the semiconductor substrate 45. next,
A rectangular beam 42 formed by the first shaping aperture 41 is applied to a region 領域 of the mask pattern 44, and the resulting projection pattern (c) is similarly projected onto the region ４ of the mask pattern 44 by the first shaping aperture 41. The formed rectangular beam 42 is irradiated, and the projection pattern (d) generated by the irradiation is exposed to the areas D on the semiconductor substrate 45 at exposure amounts of 5 and 100, respectively.

These exposure positions are the same, so that multiple exposures are performed. As a result, the entire area of the mask pattern 44 is dividedly exposed at four levels of exposure amounts 120, 110, 105, and 100. Thus, according to the fourth embodiment,
By exposing the projection pattern partially extracted from the mask pattern in accordance with the position of the exposure area while changing the exposure amount, in addition to the effect of the second embodiment, the pattern can be more precisely exposed by multiple exposures. The dimensions can be controlled.

It should be noted that the present invention is not limited to the above embodiment, and various modifications are possible based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

[0024]

As described above, according to the present invention, the following effects can be obtained. (A) By performing exposure while changing the exposure amount according to the position of the exposure area, it is possible to correct the pattern size thinning using the same mask pattern on the stencil mask, and to improve the pattern dimensional accuracy. It becomes possible.

Further, since the number of mask patterns on the stencil mask required for pattern exposure of the same type can be reduced, it is possible to form more mask patterns of different pattern types on the same stencil mask.
As a result, the exposure throughput can be improved, and an economical effect in manufacturing a stencil mask can be expected. (B) By exposing the projection pattern partially extracted from the mask pattern in accordance with the position of the exposure area while changing the exposure amount, in addition to the effect in (A) above, the extracted area is further used as a unit. Fine grain exposure can be performed, and the pattern size can be controlled with higher accuracy.

(C) Mask Pattern Selection System By providing a calibration pattern on a stencil mask, a desired portion of the mask pattern can be deflected and extracted with high accuracy. (D) By exposing a projection pattern partially extracted from the mask pattern according to the position of the exposure area while changing the exposure amount, in addition to the effect of the second embodiment,
By the multiple exposure, it is possible to control the pattern size with higher accuracy.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a partial batch type electron beam exposure method according to a first embodiment of the present invention.

FIG. 2 is an explanatory view of a partial batch type electron beam exposure method according to a second embodiment of the present invention.

FIG. 3 is a perspective view of a stencil mask for explaining a partial batch type electron beam exposure method according to a third embodiment of the present invention.

FIG. 4 is an explanatory view of a partial batch type electron beam exposure method according to a fourth embodiment of the present invention.

FIG. 5 is an explanatory diagram of a conventional partial batch electron beam exposure method.

[Explanation of symbols]

 11, 21, 41 First shaping aperture 12, 22, 32, 42 Rectangular beam 13, 23, 33, 43 Stencil mask 14, 24, 34, 44 Mask pattern 15, 25, 45 Semiconductor substrate 36 Mask pattern selection system Calibration pattern 37 Diagonal line of mask pattern 38 Area of rectangular beam

Claims (6)

[Claims] In a partial batch type electron beam exposure method, when a semiconductor substrate is repeatedly exposed to a projection pattern generated by irradiating an electron beam onto a mask pattern formed on a stencil mask, an exposure is performed for each exposure. An exposure method characterized by increasing or decreasing the amount. 2. The exposure method according to claim 1, wherein the projection pattern partially extracts a desired region in a mask pattern formed on the stencil mask by a mask pattern selection / deflection system. Exposure method. 3. The exposure method according to claim 1, wherein the stencil mask is further away from a boundary of the mask pattern in at least two directions of diagonals of the mask pattern by an electron beam region formed by a first shaping aperture. An exposure method comprising providing a mask pattern selection / deflection system calibration pattern in contact with a position. 4. A partial batch type electron beam exposure method, wherein when a semiconductor substrate is repeatedly exposed to a projection pattern generated by irradiating an electron beam onto a mask pattern formed on a stencil mask, the projection pattern is a mask pattern. A desired area in a mask pattern formed on the stencil mask is partially and partially extracted by the selective deflection system, and the number of exposures is increased or decreased for each of the projection patterns. An exposure method, wherein the same position is exposed multiple times while performing the exposure. 5. A method for forming a pattern of a semiconductor device by exposure, comprising: (a) when repeatedly projecting a projection pattern generated by irradiating an electron beam onto a mask pattern formed on a stencil mask onto a semiconductor substrate, And (b) forming a pattern of a semiconductor device by suppressing a pattern size reduction due to a proximity effect by the exposure. 6. A method for forming a pattern of a semiconductor device by exposure, comprising: (a) repeatedly exposing a semiconductor substrate to a projection pattern generated by irradiating a mask pattern formed on a stencil mask with an electron beam; The projection pattern is obtained by partially extracting a desired region in the mask pattern formed on the stencil mask and changing the region several times by a mask pattern selection / deflection system. When the semiconductor substrate is repeatedly exposed to a projection pattern generated by irradiating a mask pattern formed on the stencil mask with an electron beam by performing multiple exposures to the same position while increasing or decreasing the exposure amount, each exposure is performed. (B) The exposure causes an increase or decrease in the amount of exposure. A method of forming a pattern of a semiconductor device, comprising: forming a pattern of a semiconductor device while suppressing a reduction in size.