JP2005300693A - Pattern-forming method by photolithography - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form a desired polygonal pattern by photolithographic techniques, while reducing the man-hours and cost. <P>SOLUTION: In the method for forming a pattern of a square contact hole 17 in a photosensitive organic insulating film 11 by photolithographic techniques, the hole 16 in a patterning mask 10 is formed to have a notch 15, by cutting a corner farther outward than the pattern figure 14. A contact hole 17 of a desired figure is formed in the photosensitive organic insulating film 11, by exposing the film through this patterning mask 10. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a pattern formation method by photolithography, and more particularly, to a method for forming a pattern of contact holes for interlayer connection by a photolithography technique in the manufacture of a liquid crystal display panel.

  In the manufacturing process of a liquid crystal display panel, an insulating layer is stacked on the source and drain of a TFT (thin film transistor) formed on a glass substrate, and a transparent electrode for liquid crystal alignment is stacked on the insulating layer. In order to connect the source / drain and the transparent electrode separated via the insulating layer, generally, a contact hole is formed in the insulating layer by a photolithography technique, and the source exposed in the contact hole A transparent electrode of a different layer is connected to the drain. Specifically, a photosensitive organic insulating film is applied to the upper surface of the insulating layer by spin coating or the like, and exposed through a patterning mask provided with a predetermined hole shape, thereby patterning the contact hole in the photosensitive organic insulating film.

Here, a case where a 10 μm × 10 μm square interlayer contact hole is opened using photolithography technology is considered.
As shown in FIG. 6, an organic insulating film 3 including a photosensitive material having a certain thickness is applied to the upper surface of the source / drain 4 stacked on the glass substrate 5, and the contact hole pattern is organically formed by exposure from the lamp 1. In order to project on the insulating film 3, a mask 2 in which a square hole 6 of 10 μm × 10 μm is formed is interposed.

  When a certain amount of lamp 1 is turned on in this state, the light beam passes through the non-light-shielded hole 6 of the mask 2 to expose the photosensitive organic insulating film 3. Then, the sufficiently exposed organic insulating film 3 is immersed in a developing solution to remove unnecessary portions, whereby the organic insulating film 3 in which the contact hole pattern 7 is formed is formed.

  However, as shown in FIG. 7, the contact hole pattern 7 formed at this time does not have the desired 10 μm × 10 μm square shape due to light scattering at the square corner of the hole 6 of the mask 2. Becomes round, and as a result, a pattern close to a circular shape is formed. As described above, the pattern formation is not as designed, which is an important problem in the manufacture of a liquid crystal display panel, and a fundamental solution is required. Further, since this phenomenon appears more conspicuously as the exposure amount is smaller, there is a problem that the exposure amount, that is, the exposure time cannot be reduced, and the manufacturing throughput is not improved.

  Japanese Patent Laid-Open No. 9-213609 discloses a method of obtaining a desired rectangular pattern by performing a plurality of exposures using a plurality of masks. However, a plurality of masks are required and the number of exposures is also increased. Therefore, there is a problem that the cost increases and the number of work steps increases.

JP-A-9-213609

  The present invention has been made in view of the above problems, and an object of the present invention is to enable a desired polygon pattern to be formed by a photolithography technique while reducing work man-hours and costs.

In order to solve the above problems, the present invention provides a method of performing exposure through a pattern-shaped hole formed in a patterning mask by a photolithography technique and transferring the pattern shape to a photosensitive organic insulating film.
The pattern shape is a shape having corners,
The holes of the patterning mask are notched so as to widen the corners of the pattern shape outward, and the pattern shape is transferred to the photosensitive organic insulating film by exposing through the patterning mask. There is provided a pattern forming method using photolithography.

  With this configuration, the holes of the patterning mask are formed with notches in the corners of the pattern shape, and the photosensitive regions exposed through the patterning mask are placed by placing the light scattering corner area outside the required pattern shape. The shape patterned on the conductive organic insulating film can be changed to the designed pattern shape. Further, as disclosed in the prior art publication, since a polygonal shape can be formed with a single patterning mask without using a plurality of masks, costs and man-hours can be reduced.

  The exposure amount is adjusted so that the size of the pattern shape formed in the photosensitive organic insulating film is smaller than the size of the hole of the patterning mask.

  That is, in the past, the phenomenon that pattern transfer becomes inaccurate due to light scattering at the corners of a polygon appeared more conspicuously as the exposure amount is smaller, but with the above configuration, projection through the holes produces a desired pattern shape. Therefore, the exposure amount, that is, the exposure time is reduced, and as a result, the manufacturing throughput is improved.

  A contact hole for interlayer connection between the TFT electrode on the glass substrate of the liquid crystal display panel and the electrode layer for controlling the liquid crystal through the photosensitive organic insulating film has the pattern shape.

  With the above-described configuration, in the formation of the contact hole of the liquid crystal display panel, the defect that the interlayer between the TFT electrode and the electrode layer is insulated without opening the contact hole by placing the light scattering region of the patterning mask outside the pattern. Can be prevented.

  As is apparent from the above description, according to the present invention, the hole of the patterning mask has a shape in which a notch is provided at the corner of the pattern shape, and the corner region for light scattering is arranged outside the pattern. The pattern shape as designed without rounded corners can be formed on the photosensitive organic insulating film exposed through the holes, and the man-hours and costs are not increased.

Embodiments of the present invention will be described with reference to the drawings.
In the present embodiment, a process of patterning a rectangular interlayer contact hole in a positive type photosensitive organic insulating film by a photolithography technique will be described.

As shown in FIG. 1, an aluminum film 12 to be a TFT electrode film formed by a vapor deposition apparatus or the like is laminated on a glass substrate 13, and a photosensitive organic insulating film 11 is applied to the upper surface of the aluminum film 12 by spin coating or the like. doing.
As shown in FIGS. 1 and 2, the patterning mask 10 has holes 16 having notches 15 formed by notching the periphery of the four corners 14 a of the square pattern shape 14 outward of the pattern. That is, in consideration of light scattering at the four corners 14a, the notches 15 are provided in an L shape so as to surround the vicinity of the four corners 14a, and a hole 16 having a locally larger size than the pattern shape 14 of 10 μm × 10 μm is formed. Yes. In this embodiment, the width of the notch 15 is set to 0.5 μm for one width a of the L-shape shown in FIG. 2 and 1.5 μm for the other width b. It can be appropriately adjusted according to the shape of the pattern angle.

The lamp 1 is turned on with the patterning mask 10 having the above structure interposed between the lamp 1 and the photosensitive organic insulating film 11, and the photosensitive organic insulating film 11 is exposed.
At this time, the notches 15 at the four corners of the hole 16 of the patterning mask 10 have an exposure amount smaller than the original exposure amount when the organic insulating film 11 is exposed due to light scattering, and the notch shape is projected onto the organic insulating film 11. As a result, the pattern of the rectangular contact hole 17 is projected as designed.

  In other words, the patterning mask hole is conventionally exposed to a pattern shape with a large exposure amount using a patterning mask that is smaller than the transfer pattern. The desired pattern shape is obtained with a small exposure amount. The exposure amount at this time is such that the film thickness of the photosensitive organic insulating film 11 is smaller than the size of the hole 16 of the patterning mask 10 so that the size of the pattern shape formed on the photosensitive organic insulating film 11 is smaller. The exposure time is appropriately adjusted in consideration of the above conditions.

Next, when the exposed photosensitive organic insulating film 11 is immersed in a developer, the exposed portion is removed, and a desired rectangular contact hole 17 as shown in FIG. 3 is formed.
Next, as shown in FIGS. 4 and 5, an ITO film 18 serving as an electrode layer is formed on the photosensitive organic insulating film 11 having the contact hole 17 by a vapor deposition apparatus or the like. The film 18 and the aluminum film 12 are conductively connected.

As described above, if the manufacturing method according to the present invention is used, it is not affected by light scattering at the hole 16 corners of the patterning mask 10, in other words, by utilizing light scattering at the notch 15, a desired rectangular shape is obtained. It is possible to form a pattern of the contact hole 17.
Further, since the patterning mask 10 is formed to be larger than the pattern shape required by the notch 15, the exposure amount of the lamp 1 can be reduced from the exposure amount conventionally required, resulting in the exposure time. This shortens the manufacturing throughput.
Note that the pattern shape of the contact hole 17 to be formed is not limited to a quadrangular shape, and any shape may be used as long as it has a corner.

It is a perspective view explaining contact hole formation of an embodiment of the present invention. It is a top view of a patterning mask. It is a perspective view which shows a contact hole. It is a perspective view which shows the interlayer connection of an aluminum film and an ITO film. It is sectional drawing which shows the interlayer connection of an aluminum film and an ITO film. It is a perspective view explaining the conventional contact hole formation. It is a perspective view which shows the conventional contact hole.

Explanation of symbols

10 Patterning mask 11 Photosensitive organic insulating film 12 Aluminum film (TFT electrode)
13 Glass substrate 14 Pattern shape 14a Four corners 15 Notch 16 Hole 17 Contact hole 18 ITO film (electrode layer)

Claims (3)

In a method of transferring the pattern shape to the photosensitive organic insulating film by performing exposure through a pattern shape hole formed in the patterning mask by photolithography technology,
The pattern shape is a shape having corners,
The holes of the patterning mask are notched so as to widen the corners of the pattern shape outward, and the pattern shape is transferred to the photosensitive organic insulating film by exposing through the patterning mask. A pattern forming method using photolithography.   The pattern by photolithography according to claim 1, wherein an exposure amount is adjusted so that a size of the pattern shape formed in the photosensitive organic insulating film is smaller than a size of the hole of the patterning mask. Forming method.   3. The contact hole for interlayer connection between the TFT electrode on the glass substrate of the liquid crystal display panel and the electrode layer for liquid crystal control through the photosensitive organic insulating film has the pattern shape. Pattern formation method by photolithography.

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