JP2002231603A - Method of forming resist pattern and method of manufacturing active matrix substrate using the same - Google Patents

Abstract

(57) Abstract: As a method of controlling the tapered shape of a side surface of a resist used when forming a lower layer wiring of a device having a multilayer wiring structure, a resist having different sensitivities is applied in multiple layers, and a developing step is performed. Has been proposed to change the post-bake temperature of the resist.
If the required baking temperature is high, the peelability of the resist deteriorates. If the baking temperature is low, the adhesion of the resist to the film to be etched decreases. In applying a two-layer resist film,
The amount of drying after application of the lower resist film 3 is made larger than the amount of drying of the upper resist film 4 so that the amount of drying of the upper and lower resist films is made different, and the amount of retreat of the upper resist film 14 during development is increased. By doing so, a resist pattern exhibiting a gentler forward taper angle θ can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device having a configuration in which an upper layer wiring is formed with an insulating film interposed therebetween on a lower layer wiring. The present invention relates to a method of attaching and forming.

[0002]

2. Description of the Related Art The etching shape of a lower wiring on a device having a multi-layer wiring structure is such that a side surface thereof has a forward taper so that an upper wiring formed crossing the upper wiring is not disconnected by a step of a lower wiring. It needs to be controlled to assume a shape. For this reason, the following method has been considered as a method of controlling the tapered shape of the side surface of the resist used when forming the lower layer wiring. (1) Multi-layer coating of resists having different sensitivities (Japanese Patent Application No. 60-131145, Japanese Patent Application No. 09-097167)
And JP-A-02-134819). (2) Apply resists having different wavelength bands to be exposed in multiple layers. (3) Change the post-bake temperature in the development process. (4) Changing the etching conditions to change the etching amount for the resist.

Next, a conventional method of forming a forward taper of a resist pattern using the above (1) to (3) will be described with reference to a sectional view of FIG.

First, a film to be etched 102 is deposited on a base substrate 101, and first resists having different sensitivities or different photosensitive wavelength bands (absorption wavelengths) for controlling the taper angle of the film 102 to be etched. The film 103 and the second resist film 104 are applied (FIG. 4A).

Next, the first resist film 103 and the second resist film 104 are irradiated with ultraviolet rays through a mask 107.
It is exposed to light (FIG. 4B).

Next, the exposed first resist film 103 and second resist film 104 are treated with a developing solution and post-baked (heated). The first resist film 10 is developed by a developing process.
To control the taper angle θ of the third and second resist films 104, the post-bake temperature is changed, and to decrease the taper angle θ, the temperature is increased (FIG. 4C).

[0007]

However, with respect to the above methods (1) to (3), the methods (1) and (2) require two types of resists and their supply systems, and the apparatus becomes complicated. In (3), when the post-baking temperature is increased, the peelability of the resist deteriorates, and when the post-baking temperature is lowered, the adhesion of the resist to the film to be etched decreases.

[0008] Regarding (4), since the etching process conditions themselves greatly change from the conventionally used etching conditions, it is necessary to set the etching conditions for simultaneously optimizing the etching rate of the film to be etched and the etching rate of the resist. There was a drawback that it was difficult.

An object of the present invention is to provide a method of forming a resist pattern which can realize a forward tapered wiring pattern by a simple method without complicating a resist pattern forming apparatus or changing an etching process. is there.

[0010]

According to a method of forming a resist pattern according to the present invention, a first resist film and a second resist film are sequentially formed on a film to be etched, and the first resist film and the second resist film are formed. Exposing and developing a resist pattern to form a resist pattern comprising the first resist film and the second resist film, wherein the first resist film and the second resist film are sequentially formed. The step of applying the first resist film on the film to be etched, applying a first drying process to the first resist film, and subsequently applying the second resist film on the first resist film Then, a second resist film is formed on the second resist film.
The drying time of the first drying process is longer than the drying time of the second drying process, or the first drying process is longer than the second drying process. This is performed at a high temperature, and after the step of forming the resist pattern, the film to be etched is removed by etching using the resist pattern as a mask to form a wiring pattern in which the side surface of the film to be etched exhibits a forward tapered shape. The process of performing is continued.

Next, in the method for manufacturing an active matrix substrate according to the present invention, a step of forming a gate wiring on a transparent substrate, the step of forming the gate wiring on the gate insulating film by covering the gate wiring with a gate insulating film. Forming a drain wiring that intersects with the active matrix substrate, wherein the step of forming the gate wiring comprises:
After depositing a metal film for gate wiring on the transparent substrate,
A step of applying a first resist film on the metal film for gate wiring, a step of performing a first drying process on the first resist film, and a step of applying a second resist film on the first resist film Performing a second drying process on the second resist film, exposing and developing the first resist film and the second resist film, and forming a resist pattern including the first resist film and the second resist film. Forming a;
Etching the metal film for gate wiring by using the resist pattern as a mask to form a gate wiring having a forward tapered side surface, the drying time of the first drying process being the second drying time. Longer than the drying time of the treatment, or the first drying treatment is performed at a higher temperature than the second drying treatment, and the step of forming the gate wiring is performed using the resist pattern as a mask. This is performed by dry-etching the metal film for use.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A resist pattern forming method of the present invention is to control the taper angle of a developed resist in a photolithography process by changing drying conditions of a resist applied to two layers. Specifically, in forming the first resist film and the second resist film, the taper angle is reduced by increasing the amount of drying of the first resist film than that of the second resist film.

As an advantage of the present invention, in an etching method for controlling a taper angle and an etching shape of a pattern by utilizing receding resist, the taper angle can be controlled without changing conditions other than coating.

Next, a first embodiment of the present invention will be described with reference to the sectional view of FIG.

First, a novolak resin and a naphthoquinonediazo-based photosensitive agent dissolved in an organic solvent (eg, propylene glycol monomethyl ether acetate, ethyl lactate) on a film 2 to be etched deposited on a base substrate 1. (Viscosity: 8 to 15 cP), the first resist film 3 is applied. Subsequently, in order to volatilize the organic solvent in the first resist film 3, drying under reduced pressure (several tens Pa, 1
0-30 seconds) or heat drying (pre-bake conditions: 1)
The first resist film 3 is dried at a temperature of 10 to 130 ° C. for 60 to 200 seconds (FIG. 1A).

Next, a second resist film 4 is applied on the first resist film 3 using the same material as the first resist film 3. Subsequently, the second resist film 4 is dried mainly in order to volatilize the organic solvent in the second resist film 4. At this time, the first resist film 3 is dried more than the second resist film 4 is dried.

Specifically, after the first resist film 3 is applied,
When the first resist film 3 is dried under reduced pressure (several tens of Pa) for 30 seconds, the drying under reduced pressure (several tens Pa) after the application of the second resist film 4 is performed for 5 to 10 seconds. Or 110-13
When heating and drying at a certain temperature in the range of 0 ° C. is used, after the first resist film 3 is applied, the first resist film 3 is
20 seconds, and heat drying after application of the second resist film 4
Perform for 0 to 90 seconds.

Further, in the heating and drying, the heating time for each of the first resist film 3 and the second resist film 4 is set to one.
When fixed to 20 seconds, after the first resist film 3 is applied, the first resist film 3 is heated and dried at 110 to 130 ° C., and after the second resist film 4 is applied, the second resist film 4
Heat and dry at 100 ° C.

Each of the first resist film 3 and the second resist film 4 is applied so that the total film thickness becomes 1 to 3 μm. Subsequently, the first resist film 3 and the second resist film 4 are irradiated with ultraviolet rays (300 to 500 nm ultraviolet rays obtained from a Hg lamp or the like) through the mask 7,
It is exposed to light (FIG. 1 (b)). Next, the exposed first resist film 3 and second resist film 4 are developed with a developing solution (TMAH: 2 to 2).
5%, 60-120 seconds), and further post-baking (heating: 140-150 ° C., 60-200 seconds) (FIG. 1 (c)). At this time, the cross sections of the resist pattern 13 and the resist pattern 14 formed respectively corresponding to the first resist film 3 and the second resist film 4 are such that the first drying amount in the coating process is larger than the second drying amount. As shown in the figure, the larger the difference between the first and second drying amounts, the smaller the taper angle θ that the resist pattern 13 and the resist pattern 14 exhibit as a whole.

The resist patterns 13 and 14 thus obtained have the following characteristics.

First, in the drying under reduced pressure and the heating and drying after the application of the resist, if the first drying amount is increased from the second drying time,
The lower layer resist has a large amount of drying and the residual solvent in the resist is small, so that the speed at which the resist dissolves in the developer becomes slow.

In addition, in the heating and drying after the application, as the amount of heat applied increases, the reactivity of the photosensitive agent decreases, and the sensitivity of the resist apparently decreases. As a result, the lower resist is less soluble in the developing solution than the upper resist, and a dimensional difference occurs between the upper resist pattern and the lower resist pattern. The taper angle θ becomes smaller in the entire cross section.

Further, in a dry etching technique in which a pattern is tapered by utilizing the receding resist to control the etching shape, the etching shape of the pattern can be controlled only by changing the conditions of the resist coating process (dry etching conditions, No need to change development conditions and materials).

Further, the taper angle θ of the resist pattern
The smaller the value, the thinner the edge portion of the resist pattern and the faster the resist is ashed and retreated at the time of etching, making it possible to form a forward taper on the side surface of the film to be etched.

Next, a case where the method of the first embodiment is applied to a method of manufacturing an active matrix substrate constituting a liquid crystal display device is shown in a sectional view of FIG. 2 as a second embodiment. In the present embodiment, attention is paid to the wiring state of the drain wiring formed on the gate wiring so as to intersect with the gate wiring. Therefore, the semiconductor layer, the pixel electrode, the passivation film, and the contact hole of the TFT constituting the active matrix substrate are provided. Description and illustration of the alignment film and the like are omitted.

First, on a metal film 22 made of chromium or molybdenum deposited on a transparent substrate 21 such as glass, an organic solvent (eg, propylene glycol monomethyl ether acetate, ethyl lactate, etc.) is mixed with a novolak resin and naphthoquinone diazo. The first resist film 23 is applied using a solution in which a photosensitive agent is dissolved (viscosity: 8 to 15 cP). Subsequently, in order to volatilize the organic solvent in the first resist film 23, drying under reduced pressure (several tens Pa, for 10 to 30 seconds) or drying under heating (prebaking conditions: 110 to 13)
The first resist film 23 is dried (0 ° C., 60 to 200 seconds) (FIG. 2A).

Next, a second resist film 24 is applied on the first resist film 23 using the same material as the first resist film 23. Subsequently, the second resist film 24 is dried mainly in order to volatilize the organic solvent in the second resist film 24. At this time, the drying amount of the first resist film 3 is set to be larger than the drying amount of the second resist film 24 (the drying temperature at the time of drying the first resist film 23 is set to the second resist film 24).
Or the drying temperature of the resist film is kept constant, and the drying time of the first resist film 23 is set longer than the drying temperature of the second resist film 24). Further, each of the first resist film 23 and the second resist film 24 is applied so that the total film thickness becomes 1 to 3 μm. Subsequently, the first resist film 23 and the second resist film 24 are irradiated with ultraviolet rays (300 to 500 n obtained from a Hg lamp or the like) through a mask 27 for gate wiring.
m (ultraviolet light) to expose (FIG. 2B).

Next, the exposed first and second resist films 23 and 24 are developed with a developing solution (TMAH: 2 to 5%, 60%).
~ 120 seconds) and post-baking (heating: 1)
(40-150 ° C, 60-200 seconds). At this time, the cross sections of the resist pattern 33 and the resist pattern 34 formed corresponding to the first resist film 23 and the second resist film 24 respectively have the first drying amount in the coating step of 2 times.
As shown in the figure, as the drying amount is larger than the first drying amount and the difference between the first and second drying amounts is larger, the taper angle θ that the resist pattern 33 and the resist pattern 34 exhibit as a whole becomes smaller (FIG. 2). (C)).

When the metal film 22 is dry-etched using the resist patterns 33 and 34 thus formed as a mask, the resist pattern 33 and the resist pattern 34 are also etched at the same time. When the resist pattern 33 and the resist pattern 34 become the resist pattern 53 and the resist pattern 54, respectively, the etching is completed, and the gate wiring 32 is formed (FIG. 3A).

Next, the resist patterns 53 and 54 are removed, and a gate insulating film 25 made of a silicon nitride film is formed so as to cover the gate wiring 32 (FIG. 3B).
At this time, since the side surface of the gate wiring 32 has a gentle slope, the side surface of the gate insulating film 25 also exhibits a gentle slope.

Next, a metal film made of chromium is deposited on the gate insulating film 25 and is patterned to form a drain wiring 36. The figure shows a cross-sectional view of a place where the gate wiring 32 and the drain wiring 36 intersect, and the drain wiring 3 is formed by a gentle inclination of the side surface of the gate insulating film 25.
FIG. 3 shows a state in which the wiring 6 is wired without any problem above the gate wiring 32 without disconnection (FIG. 3).
(C)).

In the above embodiment, the case where the resist film is applied twice has been described as an example. However, in the application step, the resist film is repeatedly applied and dried three or more times, dried, exposed, developed, and becomes more complicated. It is also possible to obtain a more gentle etching shape of the wiring by obtaining the resist cross-sectional shape.

[0033]

According to the method of forming a resist pattern of the present invention, the amount of drying after the application of the lower resist film is made larger than that of the upper resist film in applying the two resist films. The drying after the application of the lower resist film is performed at a higher temperature than the drying after the application of the upper resist film, and the drying amount of the upper and lower resist films is made different to increase the retreat amount of the upper resist film during development. As a result, a resist pattern having a more gentle forward tapered shape can be obtained, and a gentle taper can be formed on the side surface of the film to be etched using the resist pattern as a mask. Therefore, the pattern formed on the film to be etched thus obtained does not have a fear of disconnection due to a step of the film to be etched.

[Brief description of the drawings]

FIG. 1 is a sectional view illustrating a method of forming a resist pattern according to a first embodiment of the present invention in the order of steps.

FIG. 2 is a sectional view illustrating a method for manufacturing an active matrix substrate according to a second embodiment of the present invention in the order of steps.

FIG. 3 is a cross-sectional view showing a manufacturing method following FIG. 2 in the order of steps;

FIG. 4 is a cross-sectional view showing a conventional resist pattern forming method in the order of steps.

[Explanation of symbols]

1, 101 Undersubstrate 2, 102 Etched film 3, 23, 103 First resist film 4, 24, 104 Second resist film 7, 27, 107 Mask 13, 14, 33, 34, 53, 54, 113, 114
Resist pattern 21 Transparent substrate 22 Metal film 25 Gate insulating film 32 Gate wiring 36 Drain wiring

 ──────────────────────────────────────────────────続 き Continuing on the front page F term (reference) 2H025 AA03 AA09 AA18 AB15 AB16 AD03 BJ10 DA11 DA12 DA40 EA10 FA39 2H096 AA25 AA26 BA09 CA20 KA10 5F046 NA09 NA12 5F110 AA30 BB01 CC07 DD02 EE04 EE23 EE50 Q0304

Claims (8)

[Claims] A step of sequentially forming a first resist film and a second resist film on a film to be etched; exposing and developing the first resist film and the second resist film to form the first resist film and the second resist film; Forming a resist pattern made of the second resist film, wherein the step of forming the first resist film and the second resist film in order comprises forming the first resist film into a film to be etched. After applying the first resist film, the first resist film is subjected to a first drying process. Subsequently, the second resist film is applied on the first resist film, and then the second resist film is applied to the second resist film.
A method of forming a resist pattern, wherein the method is performed by performing a drying process. 2. The method according to claim 1, wherein a drying time of the first drying process is longer than a drying time of the second drying process. 3. The method according to claim 1, wherein the first drying process is performed at a higher temperature than the second drying process. 4. A step of forming a wiring pattern having a tapered side surface by etching the film to be etched using the resist pattern as a mask after the step of forming the resist pattern. The method for forming a resist pattern according to claim 1, 2 or 3. 5. A method comprising: forming a gate wiring on a transparent substrate; and forming a drain wiring on the gate insulating film, the drain wiring intersecting the gate wiring, by covering the gate wiring with a gate insulating film. A method for manufacturing an active matrix substrate, wherein the step of forming the gate wiring comprises:
After depositing a metal film for gate wiring on the transparent substrate,
A step of applying a first resist film on the metal film for gate wiring, a step of performing a first drying process on the first resist film, and a step of applying a second resist film on the first resist film Performing a second drying process on the second resist film, exposing and developing the first resist film and the second resist film, and forming a resist pattern including the first resist film and the second resist film. Forming a;
Etching the metal film for the gate wiring by using the resist pattern as a mask to form a gate wiring having a forward tapered side surface. 6. The method for manufacturing an active matrix substrate according to claim 5, wherein a drying time of the first drying processing is longer than a drying time of the second drying processing. 7. The method of manufacturing an active matrix substrate according to claim 5, wherein the first drying process is performed at a higher temperature than the second drying process. 8. The method of manufacturing an active matrix substrate according to claim 5, wherein the step of forming the gate wiring is performed by dry-etching the gate wiring metal film using the resist pattern as a mask.