JP2792342B2 - Exposure method for thick film wiring pattern - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for exposing a thick wiring pattern.

[0002]

2. Description of the Related Art Conventionally, this type of thick-film wiring pattern exposure method uses a photomask in which a predetermined wiring pattern is drawn for each type and formation layer between a light source and a projection lens of an exposure machine.
Replacement / equipment with photomask carriers one by one according to the desired type and formation layer, and g-rays (43
6 nm) or h-line (405 nm) through a photomask to convert the wiring pattern drawn on the photomask into binary information of transmission / blocking, and the binarized wiring pattern information Was projected by a projection lens at a predetermined projection magnification onto a photosensitive material applied onto the substrate for a predetermined time, and the XY stage was moved stepwise to expose the entire substrate. Here, the photosensitive material applied on the substrate is a g-line or h-line, such as a photosensitive polyimide or a photosensitive register, which is widely used in the manufacture of an integrated circuit or a multi-layer substrate.
It is a negative or positive photosensitive material that is efficiently exposed to lines.

[0003]

In the above-described conventional exposure method for a thick film wiring pattern, the photosensitive material generally has a thickness of 2 mm.
When the pattern width is equal to or larger than 0 μm and the pattern width is equal to or larger than the thickness, there is a defect as shown in FIGS. That is, in the normal exposure time, the film can be cured only halfway through the thick film as shown in FIG. In the figure, 10 is a photomask, 1
1 is a light shielding portion of a photomask, 6 is a hardened portion of a thick film,
7 is an uncured portion. When FIG. 4A is developed, as shown in FIG. 4B, the cross-sectional shape of the removed portion becomes an inverted tapered shape. Therefore, if the exposure time is lengthened, the lower part of the uncured part 7 is also hardened by irregular reflection of light as shown in FIG. 4C, and the lower part cannot be removed even by developing as shown in FIG. 4D. .

[0004] Therefore, generally, a thick film of a photosensitive material is thinly coated, and exposure and development are divided into a plurality of times.
There is a problem that it is difficult to reduce the manufacturing time and the manufacturing cost.

[0005]

According to a first aspect of the present invention, there is provided a method of exposing a thick film wiring pattern for irradiating a photosensitive material with light through a photomask to form a wiring pattern and a contact hole. In the exposure method, the transmittance of the projection-type liquid crystal display is set so as to gradually increase the light transmission amount toward the inside of the wiring pattern near the boundary of the wiring pattern in the light transmitting portion provided in the light blocking portion. The projection type liquid crystal display having the voltage control device is used as a photomask under the control of a control device, and light is applied to the positive photosensitive material via the photomask.

According to a second aspect of the present invention, there is provided a method of exposing a thick film wiring pattern, wherein the light transmitting amount is increased toward the inside of the wiring pattern in the vicinity of the boundary of the wiring pattern in the light transmitting portion provided in the light blocking portion. A plurality of films are superposed so as to be gradually increased, and the superimposed films are pasted on a glass substrate to form a photomask, and the positive photosensitive material is irradiated with light through the photomask.

[0007]

Next, the present invention will be described with reference to the drawings.

FIGS. 1A to 1C are schematic diagrams showing a first embodiment of the present invention. FIG. 1A shows a relationship between the projection type liquid crystal display 1 and the voltage control device 2, and FIG.
1B shows a transmittance distribution of each liquid crystal cell 3 of the projection type liquid crystal display 1, and FIG. 1C shows a transmittance distribution of each liquid crystal cell 3 of the projection type liquid crystal display 1 having the distribution of FIG. Fig. 3 schematically shows a transmission state.

A wiring pattern having a transmittance of 100% is provided in a portion where the transmittance of light is 0%, and a voltage is set so that the transmittance gradually increases from the periphery of the wiring pattern toward the inside near the boundary of the wiring pattern. The voltage applied to each liquid crystal cell 3 of the control device 2 is changed to change the orientation 4 of the liquid crystal. Projection type liquid crystal display 1 controlled in this way
When the positive photosensitive material 5 is exposed by using FIG.
A portion which is not irradiated with light becomes a cured portion 6 and a portion which is irradiated becomes an uncured portion 7. When this is removed by a method such as wet etching, a wiring pattern having a cross-sectional shape close to a positive taper shape as shown in FIG. 2B is formed.

The light used here must cure the photosensitive material efficiently, and the projection type liquid crystal display 1 must be able to transmit and block this light. Further, the projection type liquid crystal display 1 is required to have a high display capacity and a high resolution. Examples of the wavelength of light include g-line (436 nm) and h-line (405n).
m) and the like, and a positive-type photosensitive resist and a positive-type photosensitive polyimide, which are sensitive to this wavelength efficiently. Further, the projection type liquid crystal display 1 that selectively transmits / blocks this light is realized by controlling the molecular structure of liquid crystal, controlling the alignment of liquid crystal molecules, and conducting various studies on alignment material.

FIG. 3 is a sectional view showing a second embodiment of the present invention, in which a plurality of films 8 having the distribution shown in FIG.
2 shows a photomask composed of: The film 8 used here cannot completely block light with one sheet,
In order to block light, a plurality of sheets are required. A wiring pattern having a transmittance of 100% is provided in a portion where the light transmittance is 0%, and a plurality of films 8 are provided so that the transmittance gradually increases from the periphery of the wiring pattern toward the inside near the boundary of the wiring pattern. Holes are formed by changing the light transmission area of each, and are superimposed on the stairs. Then, the laminated film 8 is stuck on a glass substrate 9, and the positive type photosensitive material is exposed using this as a photomask.

As a result, as shown in FIG. 2 (a), a portion which is not irradiated with light becomes a cured portion 6, and a portion which is irradiated becomes an uncured portion 7. When this is removed by a method such as wet etching, a wiring pattern having a cross-sectional shape close to a positive taper shape as shown in FIG. 2B is formed.

[0013]

As described above, the present invention provides a photomask having a transmittance distribution so that the thickness of the positive photosensitive material is 20 μm or more and the width of the wiring pattern is equal to or greater than the thickness. Even in the case of the above, there is an effect that the sectional shape of the removed portion of the positive photosensitive material can be improved from the reverse tapered shape to the positive tapered shape without performing the exposure phenomenon in a plurality of times.

[Brief description of the drawings]

FIGS. 1A to 1C are schematic diagrams showing a first embodiment of the present invention.

FIGS. 2A and 2B are each a positive photosensitive material 5;
FIG. 3 is a vertical cross-sectional view when the image is exposed and a vertical cross-sectional view after development.

FIG. 3 is a sectional view showing a second embodiment of the present invention.

FIGS. 4A to 4D are cross-sectional views showing an example of the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Projection liquid crystal display 2 Voltage controller 3 Liquid crystal cell 4 Liquid crystal orientation 5 Positive photosensitive material 6 Cured part 7 Uncured part 8 Film 9 Glass substrate 10 Light blocking part 11 Photomask

Claims (2)

(57) [Claims] In a method of exposing a photosensitive material to light through a photomask through a photomask to expose a thick film wiring pattern for forming a wiring pattern or a contact hole, a light transmitting portion provided in a light blocking portion is provided. The transmittance of the projection type liquid crystal display is controlled by a voltage control device so as to gradually increase the amount of light transmission in the vicinity of the boundary of the wiring pattern toward the inside of the wiring pattern, and a projection type liquid crystal display having the voltage control device is provided. A method of exposing a thick film pattern, comprising irradiating a positive photosensitive material with light through the photomask as a photomask. 2. A plurality of films are stacked so as to gradually increase the amount of transmitted light near the boundary of the wiring pattern in the light transmitting portion provided in the light blocking portion and toward the inside of the wiring pattern. A method for exposing a thick film pattern, comprising: applying a superposed film on a glass substrate to form a photomask, and irradiating the positive photosensitive material with light through the photomask.