JPS63148627A - Method of lithographing by electron beam lithography equipment - Google Patents

Abstract

PURPOSE:To reduce the time for detecting marks and improve the lithography speed by a method wherein a mark provided on the boundary between adjacent regions is utilized in common for the adjacent regions. CONSTITUTION:An electron beam 2 is shaped so as to have a required form and a current density and applied to the surface of a solid object 8 to lithograph on the surface of the solid object 8. At that time, the surface of the solid object 8 is divided into a plurality of regions and alignment marks 16 for position detection are provided corresponding to the divided regions and one alignment mark 16 is utilized in common for the adjacent regions for lithography. When the lithography of one region is finished, the alignment mark 16 on the boundary between the finished region and an adjacent region is detected and the coordinates of the alignment mark 16 are stored and again utilized for the region on which lithography is to be performed next. With this constitution, the number of the alignment marks 16 to be detected corresponding to the respective regions can be reduced so that the lithography speed can be improved.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a drawing method using an electron beam drawing apparatus.

In particular, the present invention relates to a method for detecting alignment marks in region division for direct drawing.

[Conventional technology]

When performing direct drawing with an electron beam, 1, for example, JP-A-57
As described in Japanese Patent No. 204127, alignment marks provided at the corners of a predetermined area are detected, the position to be drawn is corrected, and drawing is performed.

[Problem that the invention seeks to solve]

In the above-mentioned conventional technology, alignment marks are provided for each drawing area, alignment marks are detected for each area, and correction is performed at five positions. For this reason.

The time required for mark detection occupies a large proportion of the time, which is one factor that hinders improvement in drawing speed.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for drawing an electron beam drawing bag, which eliminates the drawbacks of the prior art described above, reduces the time required for mark detection, and improves drawing speed.

[Means for solving problems]

The above object is achieved by commonly using marks provided at the boundaries of regions in adjacent regions.

[Effect]

The alignment mark at the boundary with the adjacent area where drawing has been completed has been detected, and the coordinates of the alignment mark are memorized and used again in the area to be drawn next.
The number of alignment marks to be detected for each area can be reduced, and the drawing speed can be improved.

〔Example〕

Figure 2 shows an overview of the electron beam lithography system.

The electron beam 2 is controlled to have a desired shape and current density by an electromagnetic lens 4, and is irradiated onto a wafer 8 whose surface is coated with an electron beam sensitizer. The position of the stage 9 is controlled by a laser interferometer 15 and a stage control system 13, and the position of the stage 9 is 0.01 μm.1. It is measured with high precision at The alignment mark on the wafer 8 directs the electron beam 2 to the deflector 6.
The mark position on the wafer 8 is scanned by the mark detection circuit 11 and recognized by the computer 12.

The third example of marks and semiconductor chips placed on a wafer
As shown in the figure. In FIG. 3, the rough alignment mark 17 is detected to determine the approximate position and rotation of the wafer.

The shaded part is the block 18, and each block 18
Alignment marks 16 are placed at each of the four corners.

Several semiconductor chips 19 are included in each block 18,
This chip corresponds to a so-called LSI.

FIG. 1 shows an embodiment of the present invention, in which zero alignment marks 16 are not provided for each block 18, but are provided only at the boundaries of each block 18. When recognizing a block with diagonal lines, two of the four alignment marks use alignment marks on the adjacent block.

The method of recognizing the combined blocks will be specifically explained using No. 4-.

・°shi'fjS4□. Hey a1. , □9. ) □, the alignment mark 16 is placed in the scribe area. -Generally, silicon wafers go through various processes, so the position of the pattern shifts due to thermal deformation, etc.

Therefore, the above mark detection is extremely important in order to achieve accurate overlay.

The area surrounded by the four matching marks (xlrys) to (X4?y4) is called a block. The shape of this block is defined by equations (1) and (2).

X=ax+by+cxy+d ・(1
)Y=ex+fy+gxy+h=(
2) Here, X, Y: Actual coordinates a"h: Correction coefficient represents.

In the case of the first region, the electron beam lithography device detects the deviation amount (Δx1.Δy1) to (ΔX4.Δya) from the ideal position of the four points, and calculates the simultaneous equations (3) to (10). By finding the solution, the correction coefficient a − h is found.

Δxx=a xs+b yt+c X1yl+d
−(3) Δ yl=e xt+byt+g x
tyx+h −(4)Δxz=a xz+by
z+c xzyz+d 0°1(5)Δyz=e
X2+fyz+gxzyz+h=(6)Δxs=
a xa+by3+ CX8y3+d −(7)Δ
ya=s xs+fya+ gxaya+h −(
8) Δxa==a xa+b y4+ Cxay4+d
”°19)Δy4=s x4+f y4+gxa
ya+h.-(10) When drawing the next area, overlapping drawing is executed with high accuracy by giving the drawing position using equations (1) and (2).

Next, FIG. 5 shows a drawing sequence, FIG. 5a is a flowchart of the conventional method, and FIG. 5A is a flowchart of the present invention. In this case, mark detection is not necessary, so the drawing time can be shortened. In the comparison between FIG. 1 and FIG. 3, the number of blocks is 21 and the alignment mark detection time for each block is about 6 seconds, so the time can be reduced by about 60 seconds.

〔Effect of the invention〕

As described above, according to the present invention, by sharing the alignment mark between adjacent areas, the time for detecting the alignment mark can be shortened.
This can improve drawing speed.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the registration mark detection method according to the present invention, FIG. 2 is a configuration diagram showing an outline of an electron beam lithography apparatus, FIG. 3 is a diagram showing the relationship between conventional registration marks and blocks, and FIG. The figure is a diagram for explaining the position correction of the area to be drawn, and FIG. 5 is a diagram showing the drawing procedure of the present invention and the conventional drawing procedure. 1...Electronic score, 2...Electron beam, 3...Aperture,
4... Electromagnetic lens, 5... Plunker, 6... Deflector, 7... Backscattered electron detector, 8... Wafer, 9...
... Stage, 1° ... Deflection control system, 11 ... Mark detection circuit, 12 ... Computer, 13 ... Motor control system, 14 ... Laser interferometric length meter, 15 ... Laser light source , 16... alignment mark, 17... rough alignment mark, 18... block, 19... chip.

Claims (1)

[Claims] 1. In an electron beam lithography apparatus that forms an electron beam into a desired shape and current density and irradiates it onto a solid surface coated with an electron beam photosensitizer to draw the solid surface, the solid surface is divided into a plurality of regions. A drawing method for an electron beam drawing apparatus, characterized in that alignment marks for position detection are provided in the divided areas, and the alignment marks are commonly used in adjacent areas for drawing.