JPS60208832A - Photomask and manufacture of semiconductor device using the same - Google Patents

Abstract

PURPOSE:To eliminate the necessity of preparing a different photomask for each pattern, by using a photomask in which a pattern can be changed arbitrarily by an external driving system while the photomask remains placed in an exposure unit. CONSTITUTION:Liquid crystal of melted dichromatic dye having anisotropy in absorption of visible light in the macroaxis and the brachyaxis directions such as azo-methine dye, for example, nematic liquid crystal 9 having negative dielectric anisotropy whose molecules are configurated vertically by the electric field is provided with transparent substrates 1 and 2 on both sides thereof and a photomask 10 is provided. The substrates 1 and 2 have stripe transparent electrodes 3, 4, 5 and 6. The scanning electrode 14 and the display electrode 15 are driven by an external driving system 13 such that a voltage is applied to a predetermined region of the liquid crystal whereby a pattern 16 on the photomask 10 is rendered light-transmissive.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a photomask used in manufacturing a semiconductor device and a method of manufacturing a semiconductor device using the photomask.

Structure of the conventional example and its problems As shown in FIG. 1, the conventional photomask used in the manufacture of semiconductor devices consists of forming a light blocking material 2 such as chrome having a uniform pattern on a glass substrate 1. I was using something. With such a foot mask, only one type of predetermined pattern can be formed on one glass substrate, and when patterns of different types of songs are required, it is necessary to form them on different glass substrates.

The manufacture of normal semiconductor devices requires from several to more than ten photomasks. Also, using the same exposure device,
When transferring different types of patterns onto a semiconductor substrate, it was necessary to replace the photomask and align each type of pattern.

OBJECTS OF THE INVENTION The present invention provides a photomask in which any pattern can be rewritten and a method for manufacturing a semiconductor device using the photomask.

Structure of the Invention The present invention involves dissolving a dichroic dye, which has anisotropy in light absorption in the long and short axis directions of the molecule, into a liquid crystal whose molecular arrangement changes with an electric field. A light transmitting material having a scanning electrode made of a transparent 4% layer formed in a stripe shape and a display electrode made of a transparent conductive layer formed in a stripe shape in a direction different from the above. For sequential scanning, between the scanning electrode and the display electrode 1
A voltage is applied to change the light absorption rate of the liquid crystal in a predetermined region to form a photomask having a predetermined pattern. Then, light is irradiated from one side of the photomask on which a predetermined pattern has been formed, and a semiconductor substrate placed on the other side is irradiated with light that has passed through a region of the photomask with a low light absorption rate, and the semiconductor substrate is irradiated with the photomask. The present invention provides a method for forming a pattern corresponding to a pattern.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be explained based on FIG. 2 A dichroic dye, such as an azomethine dye, which has anisotropy in absorption of visible light in the long axis direction and short axis direction of seven molecules is dissolved. Striped transparent electrodes 3 are placed on both sides of a nematic liquid crystal 9 with negative dielectric anisotropy in which molecules are vertically aligned by an electric field.
, 4 and 6°6 are formed to form a photomask.

The striped transparent electrodes 3, 4 and 5, 6 are
As shown in Figure (A), 41. Even if it is formed in multiple layers through insulating layers 7 and 8 made of magnesium oxide and magnesium oxide, it is possible to form single layers 3 and 6 on transparent substrates 1 and 2 at a predetermined interval as shown in FIG. 2(B). However, in order to form a high-resolution pattern, it is better to form it in multiple layers as shown in FIG. 2(A). Further, the transparent electrodes have one side as a scanning electrode 16 and the other side as a display electrode 16. In order to apply a voltage to the liquid crystal in a predetermined area by line sequential scanning, the stripe electrodes 3, 4 and 6, 6 on both sides of the liquid crystal 9 are connected to each other. Install them orthogonally.

FIG. 2(C) is a plan view of the photomask, showing a state in which an electric field is applied to the liquid crystal in a predetermined region. Dichroic dyes generally have a rod-like shape and are arranged parallel to the liquid crystal molecules, so by changing the molecular arrangement of the liquid crystal with an electric field, the molecular arrangement of the dichroic dye can also be changed in conjunction. This makes it possible to electrically control the amount of light absorbed by the dye. If an azomethine dye is used as a dichroic dye, g-1ine (43
It is possible to control the amount of absorption of a wavelength of 43 nm, which is close to 61 nm), and allow light of the wavelength to pass through only the portion where an electric field is applied between the scanning electrode and the display electrode, for example, the dotted line portion in FIG. 2(C).

FIG. 3 shows a method of manufacturing a semiconductor device by a pattern transfer method using an odomask 10 according to the present invention. The photomask 1o formed by the method of the present invention is installed in an exposure device, such as a reduction projection exposure device, and the photomask 10 is irradiated with light X from one direction, and the light transmitted through the photomask 10 is reduced by the reduction lens 11. The pattern on the photomask is transferred and projected onto the semiconductor substrate 12. The pattern 16 on the photomask is connected to the scanning electrode 14 by an external drive system 13.
Then, the display electrode 15 is driven to apply a voltage to the liquid crystal in a predetermined region to make only the predetermined region 16 transparent.

It goes without saying that the dichroic dye is not limited to those having the above-mentioned wavelengths, and may be dyes that absorb other wavelengths.

Furthermore, the light X may be a laser beam other than an ultra-high pressure mercury lamp,
It can be used both for photosensitization of photosensitive resins on semi-merged substrates and for the formation of photoreaction products in reactive scum.

Effects of the Invention When the photomask according to the present invention is used, the pattern can be arbitrarily changed by an external drive system while the photomask is installed in an exposure apparatus. Therefore, unlike the conventional method, there is no need to prepare a different photomask for each pattern, and there are no defects or dust adhesion that occur when replacing the mask, and the photomask has a long lifespan. If you want to form a specific pattern on a test basis, with the conventional method,
Since the photomask produced was used only once, the cost and time of producing the photomask was wasted.

The photomask according to the present invention has the excellent feature that patterns can be formed and changed easily and in a short time by linking the drive system 13 with a pattern design system.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of the structure of a conventional photomask, and Figure 2 (A
) is a manufacturing cross-sectional view of a photomask according to one embodiment of the present invention, FIG. 2 (CB) is a structural cross-sectional view of a photomask according to another embodiment of the present invention, and FIG. FIG. 3 is a schematic diagram for explaining a pattern transfer method using a photomask according to the present invention. 3.4, 5.6... Striped transparent electrode, 9
...Liquid crystal, 10...Photomask, 1
2...Semiconductor substrate, 14.15...Scan 2 display electrode.

Claims (2)

[Claims] (1) A scanning electrode in which a dichroic dye, which has anisotropy in light absorption in the long and short axis directions of the molecule, is dissolved in a liquid crystal whose molecular arrangement changes depending on an electric field, and the liquid crystal is formed by a transparent conductive layer. and a display electrode, and the photomask is characterized in that the light absorption rate of the liquid crystal in a predetermined area is changed by line sequential scanning. (2) A dichroic dye whose light absorption is anisotropic in the long and short axis directions of the molecule is melted into a liquid crystal whose molecular arrangement changes by an electric field, and the liquid crystal is formed by a transparent conductive layer. An electric field is applied to the scanning electrode and the display electrode of a photomask which is installed between the scanning electrode and the display electrode, and the light absorption rate of the liquid crystal in a predetermined area is changed by line sequential scanning. With a pattern that changes the light absorption rate of a predetermined region of the photomask formed, 11σ light is emitted from one side of the photomask to form a pattern corresponding to the photomask on a semiconductor substrate placed on the other side. A method for manufacturing a semiconductor device, characterized in that: