JPS6224260A - Pattern forming method - Google Patents

Abstract

PURPOSE:To make the positioning accuracy of a pattern and the resolution excellent even if a desired pattern dimension is large by transferring a divided pattern on a plate to be transferred, to which a resist is applied. CONSTITUTION:The large pattern 2 is divided into four parts through the pattern data input operation of X and Y coordinates by an electron beam plotter, and divided patterns 3, 4, 5 and 6 are set on the pattern data. Alignment marks (7, 8) - (13, 14) are set on the pattern data outside a pattern area for said divided pattern. With respect to four photomask blanks, original masks 18, 19, 20 and 21 are produced, and a photomask blank 25 is prepared. The original mask 18 is closely adhered and fixed at the prescribed position of a left-hand upper part on the photomask blank 25, and an ultraviolet beam is passed upward through the original mask 18 to expose the photoresist 24 of the photomask blank 25. Through development, etching and a photolithography stage for removing a resist, the divided pattern 3 and the alignment marks (7, 8) are formed. Then a synthetic pattern 27 is formed in the same manner.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a pattern forming method used in microfabrication of various displays and semiconductor integrated circuits, and in particular, to a pattern forming method for transferring a large pattern onto a transfer target plate. This invention relates to a pattern forming method useful for.

[Conventional technology]

A method using an optical pattern generator is known as a conventional pattern forming method. This optical pattern generator focuses light emitted from a light source such as a xenon lamp using a condenser lens, forms a rectangle that is magnified (e.g. 5 to 10 times) through a barrier pull aperture, and then converts this rectangle into a reduced projection lens. Reduce through (e.g. 17
This device exposes a transfer plate (for example, a photomask blank coated with Niresist) placed on an XY stage at a magnification of 5 to 1710 times. Here, the barrier pull aperture forms a rectangle with four blades, and by adjusting the interval between the facing blades, an arbitrary rectangle can be obtained. Then, the XY stage is connected to a length measuring device such as a length measuring device that uses light wave interference or a linear encoder, and
The pattern to be exposed on the transfer plate is positioned by driving and adjusting each table. After the above-mentioned exposure, predetermined steps of development, etching, and resist peeling are performed to form a pattern on the transfer plate.

(Problem to be solved by the invention) However, when the size of the pattern to be formed on the transfer plate becomes larger, it is necessary to increase the size of the length measuring machine to match the size of the pattern to be formed on the transfer plate. , the accuracy of the length measuring machine decreases due to the limit of machining accuracy, which ultimately forces a decrease in pattern positioning accuracy.In addition, the resolution decreases due to the decrease in rectangular positioning accuracy due to the barrier pull aperture, and furthermore, the reduction projection lens The resolution also decreases.

An object of the present invention was to solve the above-mentioned problems, and to provide a pattern with high pattern positioning accuracy and resolution even when the pattern size to be formed on a transfer plate becomes large. Another object of the present invention is to provide a forming method.

[Means for solving problems]

In order to solve such problems, the present invention creates a plurality of original masks each having a desired pattern divided into a plurality of divided patterns, and applies resist to each divided pattern of the original mask one by one. This pattern forming method is characterized in that the desired pattern is formed by transferring and compositing onto a predetermined position of a plate to be coated.

[For production]

According to the present invention, even if the desired pattern size is large, the divided pattern is transferred to the transfer plate coated with resist, thereby eliminating the above-mentioned disadvantages of increasing the size and improving pattern positioning accuracy and resolution. It can be made good.

〔Example〕

Examples of the present invention will be described in detail below.

The desired large pattern of this embodiment is an F-shaped pattern 2 formed on a photomask 1 as shown in FIG. This photomask 1 is made by depositing a light-shielding film made of Cr and Cr×OY on a light-transmitting substrate with dimensions of 3201Ilffi x 0.23mmt, and then applying the light-shielding film through a photolithography process. is selectively patterned to form an F-shaped pattern 2, and this pattern area is 25
It has a 0mm opening.

Such a large pattern 2 can be created using an electron beam lithography system.
It is divided into four parts by inputting the coordinate pattern data, and on the pattern data, the lines shown in Fig. 3 (a), (b), (C
) and (d), respectively.
．． 5 and 6, and place alignment marks (7, 8) outside the pattern area of these divided patterns 3 to 6.
(9,10), (11,12) and (13
, 14) are also set on the pattern data.

Next, as a transfer plate for the pattern data, as shown in FIG. 4, on a transparent substrate 15 (this example: quartz glass),
A light-shielding/light-shielding film 16 (this example: Cr film, film thickness: 100 mm) formed by a sputtering method, and an electron beam positive resist 17 (this example: PBS) coated by a spin coater method.
(manufactured by Chisso@, film thickness: 4000 mm) are prepared. Four photomask blanks are prepared.

For these four photomask blanks, the division patterns 3, 4, 5 and 6 and alignment marks (7°8), (9,1
0), (11, 12), and (13, 14) are exposed by drawing, and through the photolithography process of development, etching, and resist removal, the original masks 18, 19, 20, and 21 shown in Figure 3 are manufactured. do.

Next, as shown in FIG. 5, a sputtering method was applied onto a light-transmitting substrate 22 (this example: soda lime glass) as a transfer target to which the desired large-scale pattern of this example shown in FIG. 2 was transferred. Light-shielding film formed by □23 (this example: total film thickness of Cr film and crx oY film 1 from the substrate □1
00 persons) and a positive photoresist 24 (this example: AZ-1350 (Hoechst 1) coated by a roll coater method).
A photomask blank 25 having a film thickness of 8,000 yen) is prepared, and is fixed on a surface plate by vacuum suction. Then, the original mask 18 shown in FIG. 3(a) is tightly fixed at a predetermined position on the upper left side of the photomask blank 25, and ultraviolet light is passed through the original mask 18 from one side to the photoresist 24 of the photomask blank 25. After the photolithography process of developing, etching, and removing the resist, □' is aligned with the divided pattern 3 as shown in Figure 1 (a). □ Next, the divided pattern 3 and the alignment mark (7, 8)
form.

A new photoresist 24 is applied onto the photomask blank 25 on which the ridges (7, 8) are formed, and the original mask 19 shown in FIG. 3(b) is applied to the photomask blank 25.
Place it on top. At this time, the alignment mark 9 of the original mask 19 is placed in alignment with the already formed alignment mark 7 through an optical microscope. Then, the original mask 19 is closely fixed on the photomask blank 25,
After going through the same photolithography process as described above, the first
Form division patterns 4 and 7 alignment marks (9° 10) as shown in Figure (b), and create a composite pattern 26 by combining the previously formed division pattern 3 and the newly formed division pattern 4.
form.

Next, the composite pattern 26 and the alignment mark (7
, 8> and (9, 10) are formed on the photomask blank 25, and a third photoresist 24 is applied.
An original mask 20 shown in Figure (C) is placed on this photomask blank 25. At this time, the 7 alignment marks 11 of the original mask 20 are placed in alignment with the already formed alignment marks 8 through an optical microscope.

Then, the original mask 20 is closely fixed onto the photomask blank 25, and the same photolithography process as described above is performed to form the dividing pattern 5 and alignment marks (11, 12) as shown in FIG. 1(C). A composite pattern 27 is formed by the previously formed divided patterns 3 and 4 and the currently formed divided pattern 5.

And finally, the above composite pattern 27 and alignment marks (7, 8), (9, 10) and (11, 12)
) is newly formed on the photomask blank 25, and a photoresist 24 is newly applied, and the original mask 21 shown in FIG. 3(C) is placed on this photomask blank 25. At that time, the original mask 21 is
The alignment marks 13 and 14 are placed in alignment with the previously formed alignment marks 12 and 10, respectively. Then, the original mask 21 is closely fixed on the photomask blank 25, and the same photolithography process as described above is performed to form the dividing pattern 6 and alignment marks (13, 14) as shown in FIG. 1(d). form,
A composite pattern 28 is formed with the previously formed divided patterns 3.4 and 6.

According to this embodiment, the pattern positioning accuracy is 51)l
) The error was within about III, and in terms of pattern resolution, a pattern line width of up to 1 μm was possible. Therefore, with high positioning accuracy for large patterns,
It was also confirmed that high-resolution patterns could be formed.

The present invention is not limited to the embodiments described above.

Of course, the desired pattern shape may be any other shape than the F-shape. Instead of the electron beam lithography device used as a means for forming the divided pattern, an optical pattern generator or a method of forming an enlarged pattern using an artwork method and reducing it with a reduction camera to obtain a pattern may be used. Further, the number of divisions is arbitrary as long as it is 2 or more. The alignment mark can be of any shape as long as it provides alignment accuracy, and its position can be anywhere outside the pattern area, and it is unnecessary if the pattern itself can be aligned. be. Regarding the photomask blank used as the transfer plate, multi-component glass such as aluminoborosilicate glass or quartz glass may be used instead of soda lime glass as the material for the light-transmitting substrate. Instead of chromium, transition metal elements such as tantalum, molybdenum, nickel, and titanium, silicon and germanium, alloys of these, oxides, nitrides, carbides, silicides, borides, and mixtures thereof ( For example, a single layer or a multilayer stack of nitride carbides) may be used, and a vacuum evaporation method, an ion blating method, etc. may be used instead of a sputtering method as a film forming method. The transfer plate may be a display electrode substrate such as an electroluminescence substrate, a semiconductor substrate, an optical recording medium, etc. instead of a photomask blank, and the resist for these transfer plates may be a positive type or negative type 7 photoresist. Alternatively, an electron beam resist may be used. In addition, as a method for transferring the original mask to these transfer plates, in addition to the contact exposure method, proximity exposure method, mirror blogie exposure method, 1x projection lens exposure method, etc. may be used.

〔Effect of the invention〕

As described above, according to the pattern forming method of the present invention, even if the size of the pattern to be formed on the transfer target plate becomes large, the positioning accuracy and resolution of the pattern can be increased, and especially on a large transfer target plate. It is of great value in pattern formation.

[Brief explanation of the drawing]

FIG. 1 is a front view showing a division pattern synthesis process in an embodiment of the present invention, FIG. 2 is a front view showing a desired pattern in an embodiment of the present invention, and FIG. 3 is a front view showing a division pattern in an embodiment of the present invention. FIG. 4 is a cross-sectional view showing the foi mask blank for manufacturing the original mask shown in FIG. 3, and FIG. 5 is a division pattern in an embodiment of the present invention. FIG. 2 is a cross-sectional view showing a photomask blank for transferring. 1... Photomask, 2... Desired pattern, 3.
4.5.6... Division pattern, 25... Photomask blank (transfer plate), 26.27.28... Composite pattern Figure 2 (cl) (b) (c) (d) Figure 4 Figure 5 Procedures Correction @ (Voluntary) 1985
February 4, 3, Relationship with the amended person case Patent applicant address 2-7-5 Nakaochiai, Shinjuku-ku, Tokyo 161
T E L 03 (952) 1151 Name H
- Ya Co., Ltd. (1) "Detailed Description of the Invention" column of the specification (2) "Brief Description of Drawings" column 5 of the specification, contents of amendment (1) Page 4 of the specification In line 12, [0,23mm' J] is corrected to r 2.3n+m' J. (2) On page 5, line 15 to line 17 of the specification, it says "Setting... (partially omitted)... and (13, 14) mark (7, 8>, division pattern 4 and alignment mark (9, 10), division pattern 5 and alignment mark (11, 12>), division pattern 6 and alignment mark (13° 14)". (3) On page 8, line 10 of the specification, "Fig. 3 (C)" is amended to "Fig. 3 (d)." (4) On page 8, line 20 of the Mei Ill. 3.4 and 6" should be corrected to "3, 4 and 5." (5) On page 11 of the specification tube, lines 11, 12, and 14, the words "front view" should be corrected to "plane view." Correct it as "Fig.".

Claims (1)

[Claims] (1) A desired pattern is divided into a plurality of parts to form a plurality of original masks each having a divided pattern, and the divided patterns of the original mask are transferred one by one to predetermined positions on a transfer plate coated with a resist. A pattern forming method, characterized in that the desired pattern is formed by synthesizing.