JPS61111532A - X-ray mask - Google Patents

Abstract

PURPOSE:To contrive to improve the positional accuracy and the pattern size accuracy by eliminating the positional shift of transcription patterns by a method wherein X-ray absorber pattern is arranged on its supporting substrate by being previously corrected with the reference of the center of an X-ray mask. CONSTITUTION:The X-ray mask 2A is formed on an X-ray absorber pattern supporting substrate 3 by being corrected so that the X-ray absorber pattern 4 and the position H of the pattern transcribed on a X-ray-sensitive resist film 6 on a wafer substrate 7 may come to a desired position. Using this X-ray mask 2A, exposure is carried out by making the center C of the mask 2A coincident with the center B of an X-ray source 1 with high accuracy. Next, the wafer substrate 7 is aligned with the X-ray mask 2A by alignment using a Fresnel zone target, thus keeping the mask 2A and the wafer substrate 7 at a required interval (d) from each other. Finally, the X-ray-sensitive resist film 6 is exposed by irradiation with an X-ray a from the X-ray source 1 to the X-ray mask 2A.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an X-ray mask used to transfer an X-ray mask pattern onto a wafer using X-rays during the manufacture of semiconductor integrated circuits. be.

[Conventional technology]

FIG. 2 is an explanatory diagram showing an X-ray mask in conventional X-ray transfer, and FIG. 3 is an explanatory diagram showing the drawbacks of the transfer using the conventional X-ray mask shown in FIG.

In Figures 2 and 3, 1 is an X-ray source such as Pd or AI, 2 is an X-ray mask, 3 is an X-ray absorber pattern support substrate such as SiN or BN, and 4 is an X-ray absorber such as Au. body pattern, 5 is a square part where an integrated circuit is formed on the surface of 7;
6 is an X-ray sensitive resist film, and T is a Ueno 1 substrate made of Si or the like. Also, A is X*.

B is the aforementioned X41! +11 center, E is the position of the X-ray absorber pattern 4, F is the position of the X-ray absorber pattern 4 to be transferred, 1 is the distance between the X-ray source 1 and the XNa mask 2, d is the X-ray The distance r between the mask 2 and the surface of the cross section 50 is the distance r from the central axis of the X-ray source 1 to the X-ray absorber pattern 4.
and Δ represents the positional deviation between the X-ray absorber pattern 4 and the pattern transferred onto the sea urchin/S portion 5. The Xi mask 2 in conventional X-ray transfer is configured as described above, The X-ray transfer method using this X-ray mask 2 is as follows.

First, as shown in Figure 3, X-ray absorption with Au.

The transferred pattern formed with high precision in body pattern 4 is
iN, BN, etc.) Ill absorber pattern support substrate 3
The X-ray mask 2 provided above and the wafer portion 5 to be transferred are placed with an interval d of several lOμm, and the X4M source 1 such as Pd or AI located above the X-ray mask 2 is
A is irradiated onto the X-ray mask 2 to selectively expose the X-ray sensitive resist film 6 formed on the wafer substrate T, such as Si, to transfer a desired pattern onto the wafer substrate T. If the X-ray sensitive resist film 6 is a negative type, the XiA that has passed through the X-ray absorber pattern support substrate 3 in the portion where the X-ray absorber pattern 4 is not present is absorbed by the wafer portion 5, and the X-ray absorber pattern in that portion is absorbed.
The glue-sensitive resist film 6 is hardened and remains on the wafer substrate 7 as a resist pattern after development.

In this case, it is clear from FIG. 3 that the XM mask 2 and the wafer part 5 are exposed with a distance d of about a10 μm, so that a positional shift Δ of the pattern occurs due to transfer. That is, in a part that is away from the axis of the center B of the X-ray source 1 by a distance r, the XIA is incident obliquely as shown in FIG. The pattern is transferred to position F on the substrate 7. This amount of deviation Δ becomes Δ=rd/i.

[Problem that the invention seeks to solve]

In the X-ray mask 2 used in conventional X-ray transfer, since the X-ray mask 2 and the wafer part 5 are exposed with an interval of several 10 μm, the X-rays are incident obliquely in areas other than the central axis of the XMA source 1. Therefore, there was a problem in that the position of the pattern transferred onto the Uchihachi substrate 7 was shifted, which deteriorated the accuracy of the pattern arrangement f# degree and the pattern size.

This invention was made to solve this problem, and it is necessary to align the center of the X-ray mask and the center of the X-ray source with high precision so that there is no misalignment of the transferred pattern on the sea urchin. The object of the present invention is to obtain an X-ray mask for X-ray transcription that can transfer the position of a pattern to be transferred with high precision by exposure.

[Means for solving problems]

The XML mask according to the present invention is constructed by forming an X-ray absorber pattern on an X-ray absorber pattern support substrate by shifting the position in advance with necessary corrections.

[Effect]

In this invention, in order to prevent misalignment of the transfer pattern, an XMA mask with a structure in which the X-ray absorber pattern is shifted on the X-ray absorber pattern support substrate is used, so during exposure, By aligning the center of the X-ray mask and the center of the X-ray source, a transferred pattern can be created without positional deviation.

〔Example〕

Figure WL1 is an explanatory diagram showing one embodiment of an X-ray mask for X-ray transfer according to the present invention. In Figure 1, 1.3
, 4.5, 6, 7. B, z and d are the same as in FIGS. 2 and 3.

In addition, two people are X-ray masks according to the present invention, C is the center of the X-ray mask 2, G is the center of the X-ray absorber pattern 4, and H is the center of the X-ray sensitive resist film 6 to be transferred. The center of the pattern, Ra, is the distance between the center C of the two X-ray masks and the center G of the X-ray absorber pattern 4, and R is the distance between the X &
t represents the distance between the center C of the mask 2A and the center H of the pattern on the X-ray sensitive resist film 6 to be transferred.

The two X-ray masks according to the present invention corrected the X-ray absorber pattern 4 and the position H of the pattern to be transferred to the X-ray sensitive resist film 6 on the substrate T to the desired position. It is formed on the absorber pattern support base 3. Using these two X-ray masks, align the center C of the two X-ray masks with the center B of the X-ray source 1 with high precision, and
'j't.

Regarding the formation position of the XM absorber pattern 4, the positional deviation Δ of the pattern transferred onto the Unihachi substrate 7 is 51CΔ=rd/J− as described in the conventional example of FIG. Therefore, as shown in FIG. 1, if the center C of the two X-ray masks and the center B of the X-ray source 1 match, the X-ray absorber pattern 4 is located at a distance from the center C of the X-ray mask 2A. When a desired pattern is to be transferred to the position H of the mask, the center G of the X-ray absorber pattern 4 is formed at a distance Ra from the center C of the X-ray mask 2A. At this time, the relationship between ELa and ordinary is ! Ra =□几j+d. The XM absorber pattern 4 formed at the position G from the center C of the X-ray mask 2A to the substrate 7
The position of the pattern transferred onto the Ueno 1 substrate T is the sum of Ra and the positional deviation Δ, so the position of the pattern transferred onto the Ueno 1 substrate T becomes the desired position H. In this way, by correcting the position of the X-ray absorber pattern 4 to form the ''C X-ray absorber pattern 4, the pattern can be transferred to a desired position on the sea urchin substrate 7.

Next, a transfer procedure using two X&I masks produced by pressing as described above will be described.

Seven alignment marks that can determine the center C of the X-ray mask 2 are formed in advance on the two φX41 masks. Therefore, alignment is performed using an alignment method formed on the two X-ray masks and an optical alignment device so that the center C of the two X-ray masks coincides with the center B of the X-ray source 1. The 1-line accuracy at this time is
It should be within ±100μm. If the center C of the X-ray mask 2A does not coincide with the center B of the The Uni/S substrate T is aligned with respect to the mask 2AK using an alignment method using a 7-layer zone tag, and a predetermined distance d is left between the two XN masks and the Uni8 substrate 7.

Finally, from X-ray source 1 to X-ray mask 2) l! A is irradiated to make the cyst film 6 sensitive to X-rays, and the cyst film 6 is exposed to light.

In addition, in the above embodiment, the center of the X-ray source 1 and the X-ray mask 2
After performing 7 alignments with the center of the person, X-ray mask 2
Seven alignments between the person and the wafer part 5 are performed, but after seven alignments are performed between the X-ray mask 2A and the wafer part 5, each center of the X-ray mask 2A, sea urchin/part 5 and X41! 7 alignments with the center of source 1 may be performed.

Further, in the above embodiment, seven alignment methods are limited, but any alignment method having such +fR ability may be used.

[Effects of the Invention] As explained above, the present invention provides an X-ray absorber with respect to the center of the X-ray mask in the Xi mask used when transferring a pattern onto a semiconductor surface by X-ray irradiation. Since the pattern is placed on the Xi absorber pattern support substrate after being corrected in advance, there is no misalignment of the transferred pattern, and the accuracy of the position and pattern size of the X absorber pattern transferred onto the substrate is improved. It has the effect of improving

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing an embodiment of the present invention, Fig. 2 is an explanatory diagram showing transfer using a conventional X-ray mask, and Fig. 3 is an explanatory diagram showing drawbacks in conventional X-ray transfer. be. In the figure, 1 is an X-ray source, 2 is an X-ray mask, 3 is an X-ray absorber pattern support substrate, 4 is an X-ray absorber pattern, and 5 is an X-ray absorber pattern.
1 is the Ueno 1 part, 6 is the X#1 sensitive resist film, and 7 is the Ueno\substrate. In addition, the same reference numerals in each figure indicate the same or corresponding parts @ Agent: Masuo Oiwa (2 others) Figure 2 ■ 1/1

Claims (1)

[Claims] In an X-ray mask equipped with an X-ray absorber pattern used when transferring a pattern onto a semiconductor wafer by X-ray irradiation, the X-ray absorber pattern is arranged as an X-ray absorber with the center of the X-ray mask as a reference. An X-ray mask characterized in that it is formed on a pattern support substrate with prior correction.