JPH10170960A - Pattern formation method - Google Patents

Abstract

(57) [Problem] To form a gate line or the like in an active matrix type liquid crystal display device, even if an etching solution deteriorates with time, the slope of both ends in the width direction of the gate line or the like is made gentle. Be able to do it. SOLUTION: A film for forming a gate line or the like is provided on a glass substrate 21, a resist pattern 23 is provided on the film for forming a gate line or the like, and wet etching, washing and drying are repeated three times using the resist pattern 23 as a mask. As a result, the gate line 25 and the like gradually narrowing from the lower surface to the upper surface are formed. Therefore, even if the etchant deteriorates with time, the inclination of both ends 25a in the width direction such as the gate line 25 can be made gentle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a pattern forming method.

[0002]

2. Description of the Related Art For example, an active matrix type liquid crystal display device generally includes an active matrix panel on which patterns such as gate lines (scan lines) and drain lines (signal lines) are formed. Examples of such an active matrix panel include those shown in FIGS. 11 and 12. In this active matrix panel, a gate line 2 and a drain line 3 are provided in a matrix on a glass substrate 1, an inverted staggered thin film transistor 4 and a pixel electrode 5 are provided in the vicinity of each intersection thereof, and And a storage capacitor line 6 is provided.

That is, a gate line 2 including a gate electrode 7 is formed at a predetermined location on the upper surface of a glass substrate 1,
An auxiliary capacitance line 6 is formed at another predetermined location, and a gate insulating film 8 is formed over the entire upper surface thereof. A semiconductor thin film 9 made of amorphous silicon is formed at a predetermined location on the upper surface of the gate insulating film 8, and a channel protective film 10 is formed at the center of the upper surface of the semiconductor thin film 9. On both sides of the upper surfaces of the semiconductor thin film 9 and the channel protection film 10, a drain electrode 12 is provided via an ohmic contact layer 11.
And a source electrode 13 are formed.
The drain line 3 is formed at the same time when the source electrode 2 and the source electrode 13 are formed. The pixel electrode 5 is formed at a predetermined position on the upper surface of the gate insulating film 8 so as to be connected to the source electrode 13.

Next, an example of a pattern forming method of the gate line 2 including the gate electrode 7 and the auxiliary capacitance line 6 in such a conventional liquid crystal display device will be described with reference to FIGS.
This will be described with reference to FIG. First, as shown in FIG. 13, a film 14 for forming a gate line or the like made of aluminum or the like is formed on the upper surface of the glass substrate 1, and a resist pattern 15 is formed at a predetermined position on the upper surface. Next, when the film 14 for forming a gate line or the like is wet-etched using the resist pattern 15 as a mask, the gate line 2 including the gate electrode 7 and the auxiliary capacitance line 6 are formed under the resist pattern 15 as shown in FIG. . In this case, a mixed acid composed of phosphoric acid, nitric acid and acetic acid is used for the etching solution.

When the film 14 for forming a gate line or the like is wet-etched using the resist pattern 15 as a mask, as shown in FIG. 14, both ends 7a of the gate electrode 7, the gate line 2 and the auxiliary capacitance line 6 in the width direction are formed.
2a and 6a are isotropically etched. As shown in FIG. 12, the isotropic etching is performed by making the inclinations of both ends 7a in the width direction of the gate electrode 7 gentle as shown in FIG.
This is to prevent the withstand voltage of the gate insulating film 8 formed on the both ends 7a in the width direction of the gate electrode 7 from decreasing, and also to make both ends 2a in the width direction of the gate line 2 and both ends in the width direction of the auxiliary capacitance line 6. By making the slope of the part 6a gentle,
This is to prevent the drain line 3 formed on the both ends 2a in the width direction of the gate line 2 and both ends 6a in the width direction of the auxiliary capacitance line 6 via the gate insulating film 8 from being disconnected due to a step.

[0006]

However, when the gate line 2 including the gate electrode 7 and the auxiliary capacitance line 6 are formed, the etching solution is not isotropically etched when the concentration of the nitric acid component is lowered due to the deterioration over time. There is. In such a case, the inclination of the both ends 7a in the width direction of the gate electrode 7 becomes steep, and the thickness of the gate insulating film 8 formed on both ends 7a in the width direction of the gate electrode 7 becomes thin, so that the withstand voltage is reduced. In some cases, the inclination of the both ends 2a of the gate line 2 in the width direction and the both ends 6a of the storage capacitor line 6 in the width direction becomes steep, so that the two ends 2a of the gate line 2 in the width direction and the storage capacitor line 6 are formed. There is a problem that the thickness of the drain line 3 formed on the both end portions 6a in the width direction via the gate insulating film 8 becomes thin and disconnection may occur. An object of the present invention is to make it possible to make the inclination of both ends in the width direction of a pattern gentle even if the etchant deteriorates with time.

[0007]

According to the first aspect of the present invention,
A pattern forming film is provided on a substrate, a resist pattern is provided on the pattern forming film, and wet etching, washing, and drying are repeated a plurality of times using the resist pattern as a mask. This is to form a narrow pattern.

According to the first aspect of the present invention, wet etching, washing, and drying are repeated a plurality of times using the resist pattern as a mask, thereby forming a pattern whose width gradually decreases from the lower surface to the upper surface. ,
Even if the etchant deteriorates with time, the inclination of both ends in the width direction of the pattern can be made gentle.

[0009]

1 to 5 show respective steps of manufacturing a liquid crystal display device to which a first embodiment of the present invention is applied. Therefore, a pattern forming method in this embodiment will be described with reference to these drawings in order.

First, as shown in FIG.
A gate line etc. forming film (pattern forming film) 22 made of aluminum or the like is formed on the upper surface of the substrate, and a resist pattern 23 is formed at a predetermined position on the upper surface. Next, wet etching is performed using the resist pattern 23 as a mask,
When washing and drying are repeated three times, a gate line (scanning line) 25 including a gate electrode 24 and an auxiliary capacitance line 26 are formed below the resist pattern 23 as shown in FIGS. In this case, each time the wet etching is performed, a step is generated at both ends 24a, 25a, 26a in the width direction of the gate electrode 24, the gate line 25, and the auxiliary capacitance line 26. Here, FIG. 3 shows a process of three times of wet etching, and a dashed line shows a state after the first wet etching and a two-dot chain line shows a state after the second wet etching. That is, first, wet etching is performed to such an extent that the glass substrate 21 is not exposed, and thereafter, the etching solution is removed, washed and dried, and then wet etching, removal of the etching solution, washing and drying are performed again. Two steps are generated at both ends 24a, 25a, 26a in the width direction of the line 25 and the auxiliary capacitance line 26. Furthermore, wet etching, removal of etchant, cleaning,
When drying is performed, three steps having a gentler inclination than when two steps are formed at both ends 24a, 25a, 26a in the width direction are formed. As described above, even if the etching solution is deteriorated due to a change with time, the etching is gradually performed, so that the influence of the degree of the deterioration is small, and the etching solution can be formed in a tapered shape. Next, when the resist pattern 23 is peeled off, it becomes as shown in FIG.

Next, as shown in FIG.
4. A gate insulating film 27 is formed on the entire upper surface of the glass substrate 21 including the gate lines 25 and the auxiliary capacitance lines 26. Next, a semiconductor thin film 28 made of amorphous silicon is formed at a predetermined location on the upper surface of the gate insulating film 27.
Next, a channel protective film 29 is formed at the center of the upper surface of the semiconductor thin film 28. Next, ohmic contact layers 30 made of n ⁺ silicon are formed on both sides of the upper surfaces of the semiconductor thin film 27 and the channel protection film 29. Next, a drain electrode 31 and a source electrode 32 are formed on each upper surface of the ohmic contact layer 30, and a drain line (signal line) 33 is formed simultaneously with the formation of the drain electrode 31 and the source electrode 32. Before forming the source electrode 32 and the like, a predetermined portion of the upper surface of the gate insulating film 27 is made of ITO.
Is formed so as to be connected to the source electrode 32.

As described above, in this pattern forming method,
By repeating wet etching, washing and drying three times using the resist pattern 23 as a mask, the gate electrode 2 gradually narrows in width from the lower surface to the upper surface.
Since the gate line 25 and the auxiliary capacitance line 26 including the gate electrode 24 are formed, even if the etching solution deteriorates with time, both ends 24a, 25a, 26a in the width direction of the gate line 25 including the gate electrode 24 and the auxiliary capacitance line 26 are formed. Can be made gentle.

In the first embodiment, wet etching, washing and drying are repeated three times. However, the present invention is not limited to this, and may be repeated a plurality of times.

FIGS. 6 to 10 show respective manufacturing steps of a liquid crystal display device to which the second embodiment of the present invention is applied. Therefore, a pattern forming method in this embodiment will be described with reference to these drawings in order.

First, as shown in FIG.
A film for forming a gate line or the like (pattern forming film) 42 made of aluminum or the like is formed on the upper surface of the device, and impurities such as titanium and phosphorus are ion-implanted into the film 42 for forming a gate line or the like. In this case, impurities are ion-implanted into the film 42 for forming a gate line or the like so that the concentration thereof gradually decreases from the lower surface side to the upper surface side of the film 42 for forming a gate line or the like. Next, as shown in FIG. 7, a resist pattern 43 is formed at a predetermined position on the upper surface of the film 42 for forming a gate line or the like.
To form Next, when the resist pattern 43 is used as a mask to wet-etch the film 42 for forming a gate line or the like, a gate line 45 including a gate electrode 44 and an auxiliary capacitance line 46 are formed below the resist pattern 43 as shown in FIG. You. In this case, the higher the impurity concentration, the lower the etching rate.
The slopes of both ends 44a, 45a, 46a in the width direction of the gate line 45 including the gate electrode 44 and the auxiliary capacitance line 46 become gentle. Next, when the resist pattern 43 is peeled off, it becomes as shown in FIG.

Next, as shown in FIG.
4. A gate insulating film 47 is formed on the entire upper surface of the glass substrate 41 including the gate lines 45 and the auxiliary capacitance lines 46. Next, a semiconductor thin film 48 made of amorphous silicon is formed at a predetermined location on the upper surface of the gate insulating film 47.
Next, a channel protective film 49 is formed at the center of the upper surface of the semiconductor thin film 48. Next, ohmic contact layers 50 made of n ⁺ silicon are formed on both sides of the upper surfaces of the semiconductor thin film 48 and the channel protection film 49. Next, a drain electrode 51 and a source electrode 52 are formed on each upper surface of the ohmic contact layer 50, and a drain line 53 is formed simultaneously with the formation of the drain electrode 51 and the source electrode 52. Before forming the source electrode 52 and the like, a pixel electrode 54 made of ITO is formed at a predetermined position on the upper surface of the gate insulating film 47 so as to be connected to the source electrode 52.

As described above, in this pattern forming method,
Impurities are injected into the film 42 for forming gate lines and the like so that the concentration thereof gradually decreases from the lower surface to the upper surface, a resist pattern 43 is provided on the film 42 for forming the gate lines and the like, and the resist pattern 43 is used as a mask. By performing the wet etching, the gate line 45 including the gate electrode 44 and the auxiliary capacitance line 46 gradually narrowing in width from the lower surface to the upper surface are formed. Electrode 4
4 can be made gentle at both ends 44a, 45a, 46a in the width direction of the gate line 45 and the auxiliary capacitance line 46.

In the first and second embodiments,
The case where the gate lines 25 and 45 including the gate electrodes 24 and 44 and the auxiliary capacitance lines 26 and 46 are formed has been described. However, the present invention is not limited to this, and can be applied to a case where a pattern made of an insulating film is formed. . Also,
In the first and second embodiments, the case where the present invention is applied to an inverted staggered thin film transistor has been described. However, the present invention is not limited to this, and a coplanar thin film transistor may be used, and a source electrode and a drain electrode may be formed on a glass substrate. The present invention can also be applied to a staggered thin film transistor or the like in which a drain line including the same is formed.

[0019]

As described above, according to the first aspect of the present invention, wet etching, washing and drying are repeated a plurality of times using the resist pattern as a mask.
Since the pattern gradually narrows from the lower surface side to the upper surface side, even if the etchant deteriorates with time, the inclination of both ends in the width direction of the pattern can be made gentle.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an initial step in manufacturing a liquid crystal display device to which a first embodiment of the present invention is applied.

FIG. 2 is a sectional view showing a step following FIG. 1;

FIG. 3 is a sectional view showing a part of FIG. 2;

FIG. 4 is a sectional view showing a step following FIG. 2;

FIG. 5 is a sectional view showing a step following FIG. 4;

FIG. 6 is a sectional view showing an initial step in manufacturing a liquid crystal display device to which the second embodiment of the present invention is applied.

FIG. 7 is a sectional view showing a step following FIG. 6;

FIG. 8 is a sectional view showing a step following FIG. 7;

FIG. 9 is a sectional view showing a step following FIG. 8;

FIG. 10 is a sectional view showing a step following FIG. 9;

FIG. 11 is a plan view showing a part of an active matrix panel in a conventional liquid crystal display device.

FIG. 12 is a sectional view taken along the line XX of FIG. 11;

FIG. 13 is a cross-sectional view showing an initial step in manufacturing a conventional liquid crystal display device.

FIG. 14 is a sectional view showing a step following FIG. 13;

[Explanation of symbols]

 Reference Signs List 21 glass substrate 22 film for forming gate lines, etc. 23 resist pattern 24 gate electrode 25 gate line 26 auxiliary capacitance line 33 drain line

Claims (2)

[Claims] 1. A pattern forming film is provided on a substrate, a resist pattern is provided on the pattern forming film, and wet etching, cleaning,
A pattern forming method characterized by forming a pattern whose width is gradually narrowed from a lower surface side to an upper surface side by repeating drying a plurality of times. 2. The pattern forming method according to claim 1, wherein said pattern is a gate electrode in an inverted staggered thin film transistor.