JP3157934B2 - Thin film processing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insulating substrate used for a liquid crystal display device or the like and having a thin film such as a transparent electrode formed on the surface thereof. The present invention relates to a method of processing a thin film with high accuracy.

[0002]

2. Description of the Related Art FIG. 3 is a sectional view of a liquid crystal display device 1 on which the present invention is based. In general, the liquid crystal display device 1 has insulating substrates 2 and 3 such as, for example, a glass substrate having a light transmitting property, which are arranged to face each other. A gate electrode 4 made of a metal thin film such as chromium or tantalum is formed on the surface of the insulating substrate 2 on the liquid crystal 15 layer side, and a nitride such as silicon nitride is formed so as to cover the surface and the entire surface of the insulating substrate 2. The insulating films 5a and 5b made of a material are formed.

Further, a semiconductor film 8a such as polycrystalline silicon is formed on the gate electrode 4 on which the insulating film 5b is formed.
Further, an insulating film 5c is formed thereon, and semiconductor films 8b and 8c are formed on both sides thereof. Semiconductor films 8 on both sides
Source electrodes 6a and 6b made of titanium, molybdenum, aluminum or the like are formed on the surfaces of the electrodes b and 8c, and ITO (indium tin oxide) or the like is formed on a portion of the insulating film 5b where the source electrodes 6a and 6b are not formed. A pixel electrode 7 made of a transparent conductive film is formed. Further, an insulating film 5d is formed so as to cover the entire source electrodes 6a and 6b.
An alignment film 9 made of polyimide is formed on the entire surface of the insulating film 5d and the pixel electrode 7, thereby forming a pixel electrode substrate 10.

A black mask 11 made of a metal thin film or the like is formed on the surface of the insulating substrate 3 on the liquid crystal 15 layer side, and a transparent conductive film such as ITO is formed on the surface and the surface of the insulating substrate 3. Is formed.
An alignment film 13 is formed so as to cover the surface of the counter electrode 12 to form a black mask substrate 14. The pixel electrode substrate 10 and the black mask substrate 14 are bonded together, and the liquid crystal 15 is injected and sealed, so that the liquid crystal display device 1 is formed.

The above-described pixel electrode substrate 10 and black mask substrate 14 are manufactured by repeatedly patterning the insulating substrates 2 and 3 by photoetching. Note that photolithography is included in the photoetching. The photolithography method uses the substrate 2,
A step of applying a photoresist to the surfaces 2a and 3a of the substrate 3, a step of irradiating the surface of the formed photoresist layer with ultraviolet light through a mask, and partially dissolving the photoresist altered by the exposure with a developer. Process and
The remaining photoresist is roughly baked by heat and fixed. Processing apparatuses are individually prepared corresponding to these steps, and the substrates 2 and 3 are sequentially transported between the respective processing apparatuses. At this time, the substrates 2 and 3
In general, a single-wafer method in which a sheet is transported and processed one by one is adopted.

FIG. 4 shows the substrate 2 in the patterning process.
FIG. 4 is a cross-sectional view of a plate 21 on which a plate 2 is placed. Among the processes of the photolithography method, a plate 21 as shown in FIG. 4 is used particularly in an exposure step or a printing step in which accurate positioning of the substrate 22 is required. The plate 21 is formed with a plurality of insertion holes 23 penetrating from the mounting surface 21a of the substrate 22 to the opposite surface 21b. The substrate 22 is adsorbed to the plate 21 by discharging air from a surface 21b opposite to the mounting surface 21a as indicated by an arrow A.
The substrate 22 is separated from the plate 21 by injecting air toward the substrate 22 as indicated by an arrow B. In this way, when the substrate 22 is conveyed to the next processing step after the processing or when the substrate 22 is roughly positioned on the plate 21, the substrate 22 is separated from the plate 21, and when the processing is actually performed or the positioning is performed. In the case of performing the adjustment, the plate 21 and the substrate 22 are attracted to each other to perform exposure and printing processes.

[0007]

In manufacturing a liquid crystal display device, it is strongly desired to improve patterning manufacturing accuracy.
To date, technical progress has been seen in improving the flatness and smoothness of the substrate itself, and reducing damage to the substrate during film formation.
Significant progress has also been made in improving the flatness and smoothness of the plate on which the substrate is placed.

With these advances, when the flatness of the substrate and the plate is the same when the substrate is placed on the plate, the friction coefficient between the two increases, and the substrate does not slide on the plate. Occurs. In addition, at the stage of performing various processes on the substrate, the residue after drying in the chemical solution process, and the component precipitated from the substrate when performing the baking process,
It becomes a sticky substance. Even if this substance adheres to the surface of the substrate opposite to the surface to be patterned, the phenomenon that the substrate does not slip occurs as described above.

For this reason, in the printing process, there is a possibility that the substrate may be transported poorly and the substrate may be damaged.
Also, in the exposure process, as a method of roughly positioning the substrate on the plate, for example, pre-alignment such as pin alignment for mechanically pressing the substrate against immovable reference pins provided on the plate cannot be performed. Even if the apparatus is temporarily stopped, or even if exposure can be performed, the patterning position is shifted, so that the processing is not performed as designed and the productivity is significantly reduced.

An object of the present invention is that it is possible to smoothly carry out the positioning or transport of the substrate in the step of forming a thin film pattern predetermined to provide a thin-film processing how to improve productivity.

[0011]

[0012]

According to the present invention, there is provided a thin film processing method for forming a thin film having a predetermined pattern on one surface of an insulating substrate, wherein at least one of the steps of forming the thin film is performed. And forming unevenness on the other surface of the insulating substrate to improve slippage on a plate on which the insulating substrate is mounted.

[0013]

According to the present invention, on the other surface of the insulating substrate,
When forming the thin film, irregularities are formed to improve the slip on a plate on which the insulating substrate is placed. When the thin film formed on one surface of the insulating substrate is processed into a predetermined pattern by photoetching, components included in the insulating substrate itself in each step of photoetching, for example, by heat treatment, are processed on the other surface side. There is a case where the chemical solution is deposited and adheres or the chemical solution remains after the chemical solution treatment and adheres as a sticky substance, so that it does not easily slip on the plate on which the insulating substrate is placed when performing the processing. Therefore, unevenness is formed on the other surface of the insulating substrate to improve the sliding of the insulating substrate.

According to the invention, prior to the execution of at least one of the steps of forming a thin film having a predetermined pattern on one surface of the insulating substrate, irregularities are formed on the other surface of the insulating substrate. Form.

In the case where the other surface of the insulating substrate is smoothed by a polishing process or the like in order to improve the processing accuracy of the formed thin film, the other surface of the insulating substrate is formed on a plate of an apparatus for performing the above-described steps. When the insulating substrate is placed with its smoothed surface in contact with the insulating substrate, the substrate may not slip easily. In addition, the components contained in the substrate itself are deposited and adhered by the heat treatment in each step, or the chemical solution remains as a sticky substance after the chemical solution treatment and adheres, and there is also a case where it is difficult to slip on the plate. is there. Therefore, the erosion treatment is performed on the other surface prior to the execution of at least one step to form irregularities, so that air is interposed between the substrate and the plate, so that the substrate becomes slippery.

[0016]

FIG. 1 is an enlarged sectional view of an insulating substrate 32 according to one embodiment of the present invention. As shown in FIG. 1, a surface 32 of the insulating substrate 32 on which electrodes and the like are laminated before the processing is performed.
“a” is polished to form a base coat layer to maintain a high degree of smoothness, and a film is formed on the surface 32a using various substances. On the other hand, the opposite surface 32
As for b, irregularities are formed by a chemical solution treatment described later.

On the opposite surface 32b, in the process of forming a thin film on the substrate 32, a residue after chemical treatment or a component precipitated from the insulating substrate 32 itself due to heat treatment is formed of an adhesive substance. Adheres. Therefore, when the process is performed, the plate on which the substrate 32 is placed and the substrate 32 adhere to each other, and the substrate 32 may not easily slide on the plate. Further, even when the adhesive substance is not attached to the opposite surface 32b of the insulating substrate 32, if the flatness between the opposite surface 32b of the insulating substrate 32 and the surface of the plate is the same, the friction coefficient between the two is reduced. As a result, the insulating substrate 32 becomes less slippery.

In order to solve the above problems, for example, the opposite surface 3 of the insulating substrate 32 is made of a mixed chemical solution of hydrogen fluoride having a concentration of 0.13% and nitric acid having a concentration of 59.9%.
2b is subjected to an erosion process. By immersing in the mixed chemical solution, the opposite surface 32b of the insulating substrate 32 made of glass itself is eroded to form irregularities on the surface, and the adhesive substance attached to the opposite side 32b of the insulating substrate 32 is removed. Can be. Therefore, the opposite surface 32b of the insulative substrate 32 and the plate adhere to the plate due to the adhesive substance, and the plate becomes less slippery, or the opposite surface 32b of the insulative substrate 32 and the plate become less slippery because they have the same flatness. Is eliminated.

FIG. 2 shows an insulating substrate 3 according to an embodiment of the present invention.
FIG. 4 is a process chart showing a process step 2; In the processing step for the insulating substrate 32, first, in step a1, the processing step for the insulating substrate 32 is received, and in step a2, the insulating substrate 32 is cleaned to remove dust and the like. In order to improve the smoothness on the surface 32a of the insulating substrate 32 and to enhance the adhesion between the formation layer and the insulating substrate 32,
Further, a base coat film is formed to protect the surface 32a from a chemical solution or the like. Next, in step a4, the process of immersing the insulating substrate 32 in the above-mentioned mixed chemical solution is performed, and then, in step a5, patterning is performed on the surface 32a of the insulating substrate 32 by photolithography.

The process of forming the liquid crystal display device 1 using the insulating substrates 2 and 3 of the present invention will be described with reference to FIG. Opposing surfaces 2a of a pair of insulating substrates 2 and 3 facing each other
A smoothness is maintained by applying a base coat film to 3a. In addition, the surface 2 on the opposite side to the surfaces 2a and 3a on the opposite side
The surfaces 2b and 3b are immersed in a mixed chemical solution to erode the surfaces 2b and 3b of the insulating substrates 2 and 3, thereby forming irregularities and removing the adhesive substance.

Next, the opposing surface 2 of the opposing insulating substrate 2
On a, a gate electrode 4 is formed, and a patterning process is performed. In the patterning process, first, an insulating film 5a is applied so as to cover the gate electrode 4, and an insulating film 5b is formed thereon so as to cover the insulating film 5a and the surface 2a of the insulating substrate 2. Further, a semiconductor film 8a is formed on the surface of the insulating film 5b on the gate electrode 4, and an insulating film 5c is further formed thereon. Semiconductor films 8b and 8c are formed so as to cover a part of insulating film 5c and semiconductor film 8a, and source electrodes 6a and 6b are formed so as to cover these semiconductor films 8b and 8c and the ends of semiconductor film 8a thereunder. Is formed. On one source electrode 6a side, a picture element electrode 7 is formed so as to cover the insulating film 5a, an insulating film 5d is applied so as to cover the source electrodes 6a, 6b and the insulating film 5a, and finally, the insulating substrate 2 is formed. The orientation film 9 is applied so as to cover all the films laminated by patterning on the surface 2a of the pixel electrode 2 to form the pixel electrode substrate 10.

Further, the opposite side surface 3a of another insulating substrate 3
First, a black mask 11 is formed, and a counter electrode 12 is formed on the surface of the black mask 11 and the surface 3 a of the insulating substrate 3.
Is formed, and an alignment film 13 is applied so as to cover the entire surface, whereby a black mask substrate 14 is formed.

Each time a film for forming the pixel electrode substrate 10 or the black mask substrate 14 is formed, a step of applying a photoresist to the insulating substrates 2 and 3 and a step of applying a mask to the formed photoresist The step of irradiating the photoresist with ultraviolet light, the step of dissolving the photoresist with a developer, and the step of heating and fixing the remaining photoresist are repeatedly performed. The picture element electrode substrate 10 and the black mask substrate 14 thus manufactured are bonded together, and a liquid crystal 15 is injected between the substrates and sealed, whereby the liquid crystal display device 1 is manufactured.

As described above, before patterning the opposing surfaces 2a, 3a of the insulating substrates 2, 3, the other surface 2a
By immersing b and 3b in the mixed chemical solution, the adhesive substance adhering to surfaces 2b and 3b of insulating substrates 2 and 3 is removed, and the problem that insulating substrates 2 and 3 do not slip on the plate is solved. You. Furthermore, even if the adhesive substance is not attached, the plate and the surfaces 2b, 3 of the insulating substrates 2, 3
In the case where the flatness of the insulating substrates 2 and 3 is high and the insulating substrates 2 and 3 are difficult to slip due to the same flatness with the surface b, the surfaces 2b and 3b of the insulating substrates 2 and 3 are eroded by the above-mentioned mixed chemical solution, so that Are formed, and the coefficient of friction is lowered to make it slippery.

Therefore, when performing each process of substrate formation, particularly when performing fine positioning, the insulating substrates 2 and 3 do not slip on the plate, so that no positional displacement occurs. Thus, more precise processing can be performed, and the productivity of the liquid crystal display device 1 is significantly improved.

In this embodiment, the step of dipping the surfaces 2b and 3b of the insulating substrates 2 and 3 in the mixed chemical solution is performed.
The patterning is performed before the patterning process is performed on the surfaces 2a and 3a of the substrate 3. However, the process may be performed during the patterning process, and the timing may be performed at any stage of the patterning process that is repeatedly performed a plurality of times. . In this embodiment, the number of times of the processing was only one. However, the processing was performed a plurality of times as long as the insulating substrates 2 and 3 were worn away due to the erosion and no inconvenience occurred in manufacturing the liquid crystal display device. May be applied.

Further, regarding the type and concentration of the mixed chemical solution, in this embodiment, 0.13% hydrogen fluoride and 59.9%
A mixture of nitric acid and nitric acid is used as a mixed chemical, but any type or concentration of chemical may be used as long as the chemical can erode the materials of the insulating substrates 2 and 3.

[0028]

As described above, according to the present invention, by forming irregularities on the other surface of an insulating substrate on which a thin film formed on one surface is processed into a predetermined pattern, various processing steps can be performed. When the insulating substrate is transported, the friction between the transport path and the other surface of the insulating substrate can be reduced to facilitate transport. Furthermore, since the substance having tackiness attached to the other surface of the insulating substrate during processing and deposited from the insulating substrate itself can be removed at the time of forming unevenness, strict alignment is required. In the processing step, misalignment due to poor slippage of the insulating substrate can be prevented.

According to the present invention, the step of forming irregularities on the other surface of the insulating substrate includes the step of forming a thin film applied to the one surface, for example, a resist coating step of a photo-etching process, and an exposing step. At least one of a developing step, a baking step, an etching step, and a resist removing step.
It may be performed before one step and may be performed a plurality of times if necessary. Therefore, work efficiency can be improved, and the accuracy of the insulating substrate itself is improved, so that productivity can be improved.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view of an insulating substrate 32 according to one embodiment of the present invention.

FIG. 2 is a process chart showing processing steps of a thin film processing method according to one embodiment of the present invention.

FIG. 3 is a cross-sectional view of the liquid crystal display device 1 on which the present invention is based.

FIG. 4 is a sectional view of a plate 21 on which a substrate 22 is placed in a patterning process.

[Explanation of symbols]

 2, 3, 32 Insulating substrate 10 Pixel electrode substrate 14 Black mask substrate

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A 62-69216 (JP, U) JP-A 63-157054 (JP, U) (58) Fields studied (Int. Cl. ⁷ , DB name) G02F 1/1333 500 G02F 1/13 101 H01L 21/84 G09F 9/00 G09F 9/30-9/46

Claims (1)

(57) [Claims] 1. A thin film processing method for forming a thin film having a predetermined pattern on one surface of an insulating substrate, wherein at least one of the steps of forming the thin film is performed prior to execution of the other of the insulating substrate. A method for processing a thin film, comprising forming irregularities on a surface of a plate on which an insulative substrate is placed so as to improve sliding on the plate.