JP3055415B2 - Backside exposure apparatus and method for manufacturing nonlinear element substrate - 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 of irradiating a photosensitive film formed on a surface of a substrate having a specific pattern with light to selectively cause a photochemical reaction on the photosensitive film. The present invention relates to a backside exposure apparatus for causing a photochemical reaction to occur in a self-aligned manner on a photosensitive film using a specific pattern formed as a light-shielding film.

[0002]

2. Description of the Related Art Conventionally, when a predetermined pattern is formed on a photosensitive film such as a photoresist using a specific mask, a metal wiring or the like formed in advance on the surface of a substrate is used as a light-shielding film, and from the back surface of the substrate. A method of irradiating light to form a photosensitive film formed on a substrate surface in a specific pattern in a self-aligned manner with respect to a light-shielding film such as an electrode wiring has been proposed (for example, Japanese Patent Application Laid-Open No. Sho 61-61). 223781). Conventionally, the backside exposure apparatus used in such a process uses an exposure apparatus having a configuration in which light including a specific wavelength component is irradiated onto the entire surface of a substrate mainly using a high-pressure mercury lamp as shown in FIG. As an example, FIGS. 3 and 4 show a thin film transistor (hereinafter referred to as T) of an active matrix type liquid crystal display device.
An abbreviated as FT) will be described with reference to a process using the above exposure apparatus in an array manufacturing process. First, a positive electrode is formed on the outermost surface of a light-transmitting substrate 31 having a gate electrode 32 selectively formed from a lower layer and a gate insulating film 33, a semiconductor layer 34, and an etching stopper film 35 continuously formed on the entire surface. A photoresist 36 is uniformly applied (FIG. 3A).

The translucent substrates 31 are placed one by one on the stage 22 of the exposure apparatus shown in FIG.
After the positioning is performed so that almost the entire surface is within the irradiation region where the ultraviolet intensity is uniform, the shutter 23 is opened, and light from the light source 25 is irradiated from the back surface (FIG. 3B). In the present exposure apparatus, the light of the point light source 25 is made parallel by using the lens system 24, and a predetermined region excluding the outer peripheral portion of the translucent substrate 31 is evenly irradiated with ultraviolet rays. After irradiating ultraviolet rays for a predetermined time, the shutter 23 is closed, and the translucent substrate 31 is taken out from the stage 22. Subsequently, when the light-transmitting substrate 31 on which the exposure processing has been completed is subjected to development processing, the gate electrode 32 is formed.
A photoresist pattern 36 'is formed only on the gate electrode 32 in a self-aligned manner using the photomask as a photomask.
(C)).

After removing the etching stopper film 35 in a region other than the predetermined region on the gate electrode 32, an ohmic contact layer 37 is formed on the entire surface, and then the ohmic contact layer 37 of the TFT portion and the amorphous Si semiconductor layer 34 are formed.
Are converted into islands (FIG. 4A). Thereafter, a transparent conductive film 38 is formed on the entire surface to form a pixel electrode having a predetermined pattern on the pixel portion, and then a metal film 39 for source / drain wiring is formed on the entire surface of the substrate.
Is formed, and the ohmic contact layer 37 and the metal film 39 for source / drain wiring remaining on the etching stopper film 35 are collectively etched to form source / drain wirings 39a and 39b, thereby completing the TFT array. (FIG. 4 (b)).

In the TFT array manufactured by the above method, when forming a pattern of an etching stopper film,
By using a metal gate electrode as a light-shielding film and exposing from the back surface of the substrate, a pattern of an etching stopper film almost equal to the width of the gate electrode can be formed. Therefore, the parasitic capacitance formed between the gate electrode and the source electrode is extremely small, and good display characteristics can be obtained.

[0006]

However, in the above-mentioned conventional backside exposure apparatus, since the light source is a point light source, only a circumferential irradiation area can be secured, and a uniform illuminance distribution over a wide area cannot be obtained. In addition, only one substrate can be processed at a time due to the problem of uniformity of the irradiated ultraviolet light. To process a substrate having as large an area as possible in the irradiation area, a certain degree of positioning is required. For this reason, there has been a problem that productivity is poor, and it is not possible to cope with a large-sized substrate such as a liquid crystal display device which will become larger and larger in the future.
In addition, the high-pressure mercury lamp, which is the light source, is expensive, which increases the production cost and shortens the life of the light source.
A relatively long time, such as preliminary lighting for stabilizing the light intensity after the replacement, also has a problem that the operation rate is poor.

An object of the present invention is to solve the above-mentioned problems and to provide a backside exposure apparatus which can process a large number of large-area substrates at a low cost with good productivity and has a very high operation rate. .

[0008]

The back surface exposure apparatus of the present invention has a basic structure that can transport a large amount of a large area substrate and irradiate light from the back surface of the substrate. And as a light source of light to irradiate the backside of the substrate,
It has a structure in which a plurality of long straight tube fluorescent lamps that emit light containing a wavelength component that causes a photochemical reaction of a photosensitive film formed on the substrate surface are arranged along the substrate transport direction. With such a device configuration, a large amount of substrates can be transported continuously,
In addition, uniform light can be emitted over a wide area. In addition, since the intensity of the light emitted from one fluorescent lamp is not so strong, the fluorescent lamp can be replaced without stopping the device as long as multiple fluorescent lamps are not cut off at the same place, and like a high pressure mercury lamp. It has the feature that replacement work can be performed quickly because the temperature does not become high.

[0009]

As described above, the backside exposure apparatus of the present invention can expose a large area of substrate in a large amount with good uniformity, and requires much less time for maintenance of the apparatus than the conventional apparatus. As a result, the production cost can be significantly reduced.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a schematic configuration diagram of a backside exposure apparatus according to an embodiment of the present invention. The present apparatus includes a substrate transport unit that can continuously transport the translucent substrate 11 at a constant speed, and a light source unit located below the substrate transport unit. The substrate transport unit has a configuration in which a plurality of linear rollers 12 rotating via a drive unit are connected. The linear roller 12 can irradiate the light from the light source unit to the light-transmitting substrate 1 as effectively as possible, and can adjust the interval according to the size of the light-transmitting substrate 1, so that the conveyance is not hindered. Each interval is maintained.

The light source section is constituted by a straight tube type fluorescent lamp 13 and a reflecting plate 14 arranged substantially in parallel with the linear roller 12. The straight tube type fluorescent lamp 13 contains a commercially available ultraviolet light component, and a germicidal lamp, a fluorescent lamp for copying, a fluorescent lamp for insects, a black light blue fluorescent lamp, an ion lamp, and the like can be used. It can be appropriately selected according to the type of the photosensitive film formed on the surface of the substrate 1. A reflection plate 14 is provided below the straight tube fluorescent lamp 13,
The light emitted from the straight tube type fluorescent lamp 3 can be effectively used as the translucent substrate 1
It has a structure that can irradiate one back surface.

In the configuration of the apparatus shown in FIG. 1, since the light source is a straight tube type fluorescent lamp, uniformity can be basically secured at a depth of about the length of the fluorescent lamp. In addition, since a plurality of fluorescent lamps are arranged in a direction perpendicular to the substrate traveling direction and irradiate ultraviolet light from the back side while transporting the substrate, the intensity of the ultraviolet light between the fluorescent lamps is increased. In principle, even if there is a variation, a substrate having an infinite length or a large number of substrates can be simultaneously irradiated with ultraviolet light with high uniformity. For example, in the case of using a 40-tube straight tube fluorescent lamp currently on the market, the length of the tube is 1198 mm, and the uniformity in the depth direction within a range of about 1000 mm excluding the base and the filament portion. Can be secured. When a fluorescent lamp is used, the intensity of ultraviolet light per lamp is lower than that of a high-pressure mercury lamp, but high productivity can be maintained by arranging a plurality of lamps and adjusting the transport speed or the length of the transport path. In addition, since the intensity of ultraviolet light per line is low, even if one of the lines is cut, the total energy applied to the substrate can be kept within the process margin, so that the fluorescent lamp can be used without stopping the apparatus. Exchanges can be made and very high availability can be achieved.

In this embodiment, a case where a fluorescent lamp which emits ultraviolet light is used as the straight tube type fluorescent lamp has been described. However, as a wavelength component of ultraviolet light, a photoresist generally used as a photosensitive film is taken as an example. And 200nm or more 2
Less than 50 nm, 250 nm or more and less than 340 nm, 340
Any fluorescent lamp that emits light including at least one of the wavelength ranges of nm to less than 380 nm, 380 nm to less than 420 nm, 420 nm to less than 460 nm, or a plurality of wavelength ranges can be used. However, the wavelength range emitted by the fluorescent lamp is not necessarily limited to the above wavelength range, but may be applied as long as the photosensitive film formed on the translucent substrate contains a wavelength component that causes light or a chemical reaction. Needless to say.

(Embodiment 2) FIGS. 5 and 6 schematically show a TFT array process of an active matrix type liquid crystal display device partially using the backside exposure apparatus of the present invention. Cr gate electrode 42 selectively formed from the lower layer, SiNx gate insulating film 43 continuously formed on the entire surface, amorphous Si semiconductor layer 44, SiNx etching stopper film 4
5, a positive photoresist 46 is uniformly applied to the outermost surface of the light-transmitting substrate 41 having the substrate 5 (FIG. 5A). The light-transmissive substrate 41 is irradiated with light from the back surface using the back surface exposure apparatus described in the first embodiment (FIG. 5B). In the back exposure apparatus shown in this embodiment, a fluorescent lamp containing a wavelength component capable of sensitizing the photoresist 46 is used.
Further, in the backside exposure apparatus shown in this embodiment, since a 64-inch straight tube fluorescent lamp is used, uniform light can be irradiated in the depth direction within a range of about 1400 mm.
With a glass substrate of mx 500 mm size, three substrates can be simultaneously transferred in the depth direction, and high productivity can be secured.

The photoresist 46 formed on the light-transmitting substrate 41 is exposed to light irradiated from the back surface. However, since a part of the light is blocked by the gate electrode 42, the photoresist 46 is formed on the gate electrode 42. The exposed photoresist is not irradiated with light. When the substrate is developed, the gate electrode 42 is self-aligned using the gate electrode 42 as a photomask.
A photoresist pattern 46 'is formed only on the upper surface (FIG. 5C). Normal photoresist pattern 46 '
Is 0.5-1 μm with respect to the pattern of the gate electrode 42 due to the irradiation light at the time of exposure, dissolution with a developer, etc.
About thin.

A photoresist 46 'on the gate electrode 42
After removing the etching stopper film 45 other than the region where the is formed, an amorphous Si ohmic contact layer 47 containing phosphorus as an impurity is formed on the entire surface, and then the TFT is formed.
The ohmic contact layer 47, the etching stopper film 45, and the semiconductor layer 44 in the portion are converted into islands (FIG. 6A).
Subsequently, after the ITO pixel electrode 48 and the source and drain wirings 49a and 49b each formed of a laminated film of Al and Ti are formed in a predetermined shape, a passivation film 50 is formed on the entire surface of the substrate.

Next, a positive photoresist 51 is uniformly applied on the entire surface of the translucent substrate 41 (FIG. 6B). When the translucent substrate 41 is irradiated with light from the back surface again using the back surface exposure apparatus shown in Embodiment 1, and then subjected to development processing, the gate electrode 42 and the source / drain electrodes 49a and 49b are photo-etched. The gate electrode 42 and the source / drain electrodes 48a and 48b are self-aligned as masks.
A photoresist pattern 41 'is formed only on the top.
Thereafter, after the passivation film 50 is etched, the photoresist 51 is removed to complete the TFT array (FIG. 6C).

In the TFT array manufactured by the above method, when forming the pattern of the etching stopper film,
The pattern of the etching stopper film which is almost equal to the width of the gate electrode can be formed by the back surface exposure. Therefore, the parasitic capacitance formed between the gate electrode and the source electrode is small, and the back surface can be uniformly and uniformly exposed to the substrate having a large area. For example, even with a liquid crystal panel having a large area of 15 inches or more, good display characteristics with high uniformity can be obtained.

Furthermore, in the processing of the passivation film in addition to the formation of the etching stopper film, the exposure process can be performed easily without requiring very high-precision alignment of a conventional stepper or the like. A large area substrate can be processed in the process.

In this embodiment, the case where the present invention is applied to a method for processing an etching stopper and a passivation film of a TFT array has been described.
The present invention is also applicable to a method for processing a semiconductor film. It goes without saying that the present invention can be applied to a method of manufacturing an active matrix type liquid crystal display device using a non-linear element other than the TFT, and further to a method of manufacturing a non-linear element substrate other than the liquid crystal display device.

[0022]

By using the backside exposure apparatus of the present invention, it is possible to continuously process a large number of large-area substrates. Further, by arranging a plurality of straight tube fluorescent lamps side by side as a light source, the device can be easily replaced without stopping the apparatus unless a plurality of fluorescent lamps are cut off at the same place at the same time. With the above features, it is possible to realize extremely high productivity and operation rate which have not been achieved in the past.

Further, by manufacturing a non-linear element substrate such as an active matrix type liquid crystal display device using the backside exposure apparatus of the present invention, a non-conventional non-linear element substrate having a large area, high uniformity and high performance is realized. can do.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of a backside exposure apparatus of the present invention.

FIG. 2 is a schematic view showing an example of a conventional backside exposure apparatus.

FIG. 3A shows a state in which a positive type photoresist 36 is uniformly applied in a process using a conventional exposure apparatus in a TFT array manufacturing process, and FIG. FIG. 3C shows a state in which light from 25 is irradiated. FIG. 4C shows a state in which a photoresist pattern 36 ′ is formed.

FIG. 4A is a diagram showing a state where an ohmic contact layer 37 and an amorphous Si semiconductor layer 34 of a TFT portion are islanded in a process using a conventional exposure apparatus in a TFT array manufacturing process. Showing the state in which the TFT array is completed

FIG. 5A shows a TFT using the backside exposure apparatus of the present invention.
FIG. 4B shows a state in which the positive photoresist 46 is uniformly applied in the array forming step, and FIG. 4C shows a state in which light is irradiated from the back surface, and FIG. FIG. 9 is a view showing a state where a photoresist pattern 46 ′ is formed.

FIG. 6 (a) is an ohmic contact layer 4 in a TFT section.
7, a diagram showing a state where the etching stopper film 45 and the semiconductor layer 44 are islanded. FIG. 7 (b) shows a state where the positive photoresist 51 is uniformly applied. FIG. 7 (c) shows a state where the TFT array is completed. Diagram shown

[Explanation of symbols]

 Reference Signs List 11 translucent substrate 12 linear roller 13 straight tube fluorescent lamp 14 reflector 21 translucent substrate 22 stage 23 shutter 24 lens system 25 point light source 31 translucent substrate 32 gate electrode 33 gate insulating film 34 semiconductor layer 35 etching Stopper film 36 Photoresist 37 Ohmic contact layer 38 Pixel electrode 39 Source / drain wiring 41 Translucent substrate 42 Gate electrode 43 Gate insulating film 44 Semiconductor layer 45 Etching stopper film 46, 46 ′ Photoresist 47 Ohmic contact layer 48 Pixel electrode 49 Source / drain wiring 50 passivation film 51 photoresist

────────────────────────────────────────────────── ─── Continued from the front page (56) References JP-A-3-283529 (JP, A) JP-A-62-23755 (JP, A) JP-A-5-224395 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) G03F 7/20 G02F 1/1365 H01L 21/027

Claims (2)

(57) [Claims] 1. An exposure apparatus for selectively irradiating light to a photosensitive film from a rear surface of a light-transmitting substrate having a selectively formed opaque film and a photosensitive film formed on the entire surface. It has a structure for transporting the optical substrate at a constant speed, and has a structure in which a plurality of straight tube fluorescent lamps are arranged in parallel on the back surface side of the substrate. A backside exposure apparatus having a structure capable of irradiating light. 2. A method of manufacturing a non-linear element substrate in which one or both of a column wiring and a row wiring, a non-linear element, and a picture element electrode are formed on a light-transmitting substrate. A method of forming a pattern of a photosensitive film by irradiating light emitted from a plurality of straight tube fluorescent lamps from the back side.