JPS6242527A - Mask structure for x-ray lithography - Google Patents

Abstract

PURPOSE:To prevent the blurring of the end section of a resist pattern by laminating and forming mask patterns having the same shape consisting of an X-ray absorbent. CONSTITUTION:A layer 3 composed of a compound such as boron nitride and a film 4 consisting of polyimide, etc. are shaped onto a mask base material 2 such as an silicon wafer. First mask patterns 7 consisting of thin-layers in gold, etc. and a coating layer 8 composed of an X0ray transmitting material such as polyimide coating the patterns 7 are formed onto the film 4. Second mask patterns 9 consisting of thin-layers in gold, etc. formed to the same shape as the patterns 7 and a coating layer 10 composed of the same material as the layer 8 are formed onto the layer 8. According to the constitution, the end sections of the patterns 7, 9 are shaped vertically because of the thin patterns 7, 9, thus resulting in no blurring of the end sections of the resist patterns.

Description

[Detailed description of the invention] b) Industrial application field The present invention relates to a mask structure for X-ray phosphorography.

口) Conventional technologyCurrently, the transfer technology used is the optical method.Furthermore, in order to increase the C2 resolution, the development of a reduction projection type exposure device is required. has been done.

However, a pattern with a full-fledged COI μ or less is required (
If it becomes C2, it will become necessary to use X-rays as a transfer technology. Koushi runner-up is Tevmicron, Ring 2
Publication date: June 20, 1985, published by Fisso Techniques Takikashu Publishing House, Science Forum, Date of publication: June 20, 1985. .

a) X-ray C: In contrast, the transmittance of the mask substrate is high and the transmittance of the absorber (pattern constituent material) is low. Not only X-rays but also detection light (visible light is preferable)
C) High mechanical strength and good dimensional stability d) Good flatness of the substrate e) Good chemical resistance The mask for use is as shown in Figure 2. I: The upper part of the birec ring (1) 6; The center part is opened and the silicon wafer (2) with a thickness of ft 0.5 tm is used.
On this substrate (2), a 4 tone thick boron oxide layer (3) and a 2.5μ thick first polyimide layer m (4
1k & no, on this polyimide (two mask patterns (5) [6) made of gold, which is an X-ray absorbing material, are formed with a thickness of t-1μ, and on this pattern (5J (5) (4) Top (2) 2μ thick second polyimide layer (
6) was provided and 7'C was the serial number O c) Problems to be solved by the invention By the way, in the mask pattern (51(5)) for lithography using the nine After cleaning, etching C: Etching the predetermined shape, or etching the etching pattern C1, etc. from the lit-off method. Deformation of the resist pattern (: ↓It is difficult to form the edges of the remask pattern vertically, resulting in a shape with a stubborn*1 shape. When transferring the C pattern onto the resist, there is a problem that blurring occurs at the edges.

2) Means for Solving the Problems The present invention was developed in view of these points (-), and therefore, thin mask patterns of the same shape are provided in multiple layers.

E) Action Since the edge of the mask pattern with a thin film thickness is formed, the edge of the pattern is formed vertically.Also, since this mask pattern is formed with multiple layers, when transferred to the resist ( There is also no risk of X-rays passing through.

f) Example FIG. 1 is a sectional view showing a mask structure for unexploded 4X-ray phosphorography, and FIGS. 3 to 6 are sectional views showing a manufacturing method for making such a mask structure. Using these figures, the mask structure of the present invention will be explained together with the manufacturing method. First, c CV D on a silicon wafer (2) with a thickness of 0.5 fl.
Is the layer made of borosulfide (3) by the method? i-4μ thickness I: Form and dry the first polyimide with a thickness of 2.5μ with a spinner cloth [;
(4)' (Figure 3). Next, a gold layer t0.5μ
A desired first mask pattern (7) (71i) is formed using a photo-etching technique.
figure). At this time, since the thickness of the gold layer is thin, the first mask pattern t7) (the edge of the sword is not inclined and is vertically
Two are formed. Missing C; From spinner coating 2, the first polyimide film containing the first mask pattern (7) (7) t-
4) A second polyimide film (8) with a thickness of 1 μm is provided on top (
FIG. 5) 0 Furthermore, 1; a second mask pattern (9) (9)"ik forming pattern having the same shape as the first mask pattern (7) (7) and the same thickness (0.5μ); FIG. , this second mask pattern V C9) (9) k including tr7J2
A sixth polyimide film having a thickness of 1 μm is formed on the polyimide film (8) by coating with a spinner (FIG. 6).

After that, the central part of the silicon wafer 1 (2) is removed by etching, and the remaining Unino (2) (: reinforcing Pyrex ring (1) is connected to complete the process (Figure 1). Using the alignment mask structure, make α: As shown in Figure 7, the upper and lower ends of 5 two grooves α3 are accurate (20).

2μ width pattern: Formed. On the other hand, if a groove (L6) is created in a 4000A thick resist (C151) made of PMMA formed on a substrate I with a width of 0.2μ using the conventional mask structure shown in Fig. 8 As shown in Figure C
The upper end of the double series αe has a width of α2μ, but the lower end has a width of (1
152 width [;, and the groove was not formed accurately.

Incidentally, in the mask structure of this embodiment, two layers are formed on the mask pattern in a straight line, and nine layers are formed, but it is also possible to form three layers, four layers, and even multiple layers.

g) Effects of the Invention As mentioned above, since the X-ray imaging mask structure of the present invention has two thin mask patterns of the same shape formed in multiple layers, the edge of the mask pattern can be vertically cut into two. , Curse during transfer; Xl at the edge of the mask pattern! Further fine processing can be performed without blurring of the resist pattern C2 formed at the time of transfer due to the transmission of A.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view showing the present invention's X-ray phosphorography mask structure, Fig. 2 is a cross-sectional view showing a conventional X-ray phosphorography mask structure, and Figs. 3 to 6 are uninvented mask structures. 7 and 8 are cross-sectional views of resist patterns transferred using the mask structure of the present invention and the conventional mask structure, respectively. (1)--Pyrex ring, (2)...Silicon Cueva, (3)...Terra boron layer, t4)(
6) (8) (1G... polyimide film, (5) (5J)
...Mask pattern, (71 (71...First mask pattern, (9)(9)...Second mask pattern.

Claims (1)

[Claims] 1) a mask substrate, a first mask pattern made of an X-ray absorbing material formed on the mask substrate, a covering layer made of an and a second mask pattern made of an X-ray absorbing material formed in the same shape as the first mask pattern.