KR100492729B1 - A method of forming pattern using printing process - Google Patents

Abstract

The present invention relates to a method for forming a pattern of a liquid crystal display device through a printing method, by applying a release agent, a release accelerator, to the inside of the grooves of the cell filled with ink so that the ink is easily transferred to the layer to be processed. The surface of the layer to be processed is subjected to chemical or physical surface treatment to improve adhesion with the ink.

Description

Pattern Forming Method by Printing Method {A METHOD OF FORMING PATTERN USING PRINTING PROCESS}

The present invention relates to a pattern forming method by a printing method, in particular, by adding a releasable additive for facilitating the peeling of ink in the grooves of the cell filled with ink during circuit patterns such as thin film transistors to facilitate the transfer of ink to the transfer roll It relates to a pattern forming method by a printing method that can be made.

In display devices, particularly flat panel displays such as liquid crystal display devices, each pixel includes an active device such as a thin film transistor to drive the display device. The driving method is often called an active matrix driving method. In the active matrix method, the active elements are arranged in each pixel arranged in a matrix to drive the pixel.

1 is a view showing an active matrix liquid crystal display device. The liquid crystal display of the structure shown in the figure is a TFT LCD using a thin film transistor as an active element. As shown in the figure, each pixel of the TFT LCD in which N × M pixels are arranged vertically and horizontally has a gate line 4 to which a scan signal is applied from an external driving circuit and a data line 6 to which an image signal is applied. It includes a TFT formed in the intersection area. The TFT includes a gate electrode 3 connected to the gate line 4, a semiconductor layer 8 formed on the gate electrode 3, and activated when a scan signal is applied to the gate electrode 3, and the semiconductor layer. (8) and a source / drain electrode 5 formed thereon. In the display area of the pixel 1, an image signal is applied through the source / drain electrode 5 as the semiconductor layer 8 is connected to the source / drain electrode 5 to activate the liquid crystal (not shown). Is formed on the pixel electrode 10.

2 is a diagram showing the structure of a TFT disposed in each pixel. As shown in the figure, the TFT includes a substrate 20 made of a transparent insulating material such as glass, a gate electrode 3 formed on the substrate 20, and an entire substrate 20 on which the gate electrode 3 is formed. A gate insulating layer 22 stacked over the semiconductor insulating layer 22, a semiconductor layer 6 formed on the gate insulating layer 22 and activated when a signal is applied to the gate electrode 3, and formed on the semiconductor layer 6. A source / drain electrode 5 and a passivation layer 25 formed on the source / drain electrode 5 to protect the device.

The source / drain electrode 5 of the TFT is electrically connected to a pixel electrode formed in the pixel, so that a signal is applied to the pixel electrode through the source / drain electrode 5 to drive the liquid crystal to display an image. do.

In an active matrix display device such as a liquid crystal display device as described above, each pixel has a size of several tens of micrometers, and therefore, an active device such as a TFT disposed in the pixel must be formed with a fine size of several micrometers. Furthermore, as the desire for high-definition display devices such as high-definition television (HDTV) has increased in recent years, more pixels must be disposed on the screen of the same area, and thus, active element patterns (gate line and data line patterns) included in the pixels are included. ) Should also be more finely formed.

On the other hand, in order to fabricate an active device such as a TFT, a pattern, a line, and the like of the active device are formed by a photolithography method using an exposure apparatus. However, in such a photolithography method, since a photoresist is laminated on a patterned layer and then an etching method using a photo process is used, there is a limit in forming a fine pattern. In addition, since the exposure area of the exposure apparatus is limited during the photo process of the display element, the photo process must be performed by dividing the screen in order to produce a large area display element. Therefore, there is a problem in that productivity is lowered because the exact position is difficult to match during the processing of the divided region and the photo process must be repeated many times.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a pattern forming method capable of forming a pattern on a large-area display element by one step by a printing method.

Another object of the present invention is to provide a pattern forming method which can form a fine pattern by applying a release agent to the inside of the groove of the cliché filled with ink during printing to smoothly peel the ink from the cliché.

Still another object of the present invention is to provide a pattern forming method capable of preventing the ink transferred to the layer to be peeled off through chemical or physical surface treatment of the layer to be formed and processed on the substrate.

In order to achieve the above object, the pattern formation method of the present invention comprises the steps of applying a release agent in the groove of the cliché (offset plate) corresponding to the position of the pattern to be formed, and the release agent is applied And filling the ink into the groove of the cliché, and transferring the ink filled into the groove of the cliché to the layer to be processed.

As a method of transferring ink to the layer to be processed, a transfer roll may be used, or a method in which an ink-filled cell is directly contacted with the layer to be processed may be used.

The cliché is formed of a silicon-based material such as SiOx, and the release agent, which is a release accelerator, is applied to the inside of the groove so that the ink in the groove is easily peeled from the cliché and easily transferred to the processing layer. The to-be-processed layer is composed of a metal layer, an insulating layer made of SiOx or SiNx, and a semiconductor layer, the surface of which is subjected to physical or chemical treatment.

In the present invention, a printing method is used to form an active element pattern of a display element such as a liquid crystal display element. In particular, gravure offset printing is a printing method in which ink is applied to a concave plate to scrape off excess ink, and printing is known as a printing method in various fields such as publishing, packaging, cellophane, vinyl, polyethylene, and the like. In the present invention, such an printing method is used to produce an active element or a circuit pattern applied to the display element.

Since gravure offset printing transfers ink onto a substrate using a transfer roll, it is possible to form a pattern by one transfer even in the case of a large display element by using a transfer roll corresponding to the area of a desired display element. do. Such gravure offset printing can be used to pattern various patterns of display devices, for example, TFTs as well as gate patterns and data lines, pixel electrodes, and capacitor metal patterns connected to the TFTs.

Hereinafter, a pattern forming method according to the present invention will be described in detail with reference to the accompanying drawings.

3 is a view showing a method of forming an ink pattern on a substrate using a printing method according to the present invention. As shown in the figure, in the printing method, first, the groove 102 is formed at a specific position of the concave plate or the cliché 100 corresponding to the pattern to be formed on the substrate, and then the ink 104 inside the groove 102. To fill. The grooves 102 formed in the cliché 100 are formed by a general photolithography method, and the filling of the ink 104 into the grooves 102 is pattern forming ink 104 on the upper part of the cliché 100. ) And then push the doctor blade 108 in contact with the substrate 120. Therefore, the ink 104 is filled in the groove 102 by the progress of the doctor blade 108 and the ink 104 remaining on the surface of the cliché 100 is removed.

As shown in FIG. 3 (b), the ink 104 filled in the groove 102 of the cliché 100 is in contact with the surface of the cliché 100 to rotate the transfer roll 110. Transferred to the surface. The transfer roll 110 is formed to have the same width as the width of the panel of the display device to be manufactured, and has a circumference of the same length as the length of the panel. Therefore, the ink 104 filled in the groove 102 of the cliché 100 is transferred to the circumferential surface of the transfer roll 110 by one rotation.

Thereafter, as shown in FIG. 3 (c), the transfer roll 110 is rotated in contact with the surface of the layer 120 to be formed on the substrate 120. The transferred ink 104 is transferred to the processing layer 121, and the ink pattern 122 is formed by applying UV irradiation or heat to the transferred ink 104 to dry it. In this case, the desired pattern 122 may be formed over the entire substrate 120 of the display device by one rotation of the transfer roll 110.

As described above, in the printing method, the cliché 100 and the transfer roll 110 may be manufactured according to the size of the desired display element, and a pattern may be formed on the substrate 120 by one transfer, thus providing a large area. The pattern of the display element can also be formed by one process.

The to-be-processed layer 121 may be a metal layer for forming a metal pattern of an electrode such as a gate electrode, a source / drain electrode, a gate line, a data line, or a pixel electrode of the TFT, or may be an insulating layer such as SiOx or SiNx.

When forming a pattern of an actual display element, the ink pattern 122 serves as a resist in a conventional photo process. Therefore, after forming the ink pattern 122 as described above on the metal layer or the insulating layer, the metal layer or the insulating layer is etched by a general etching process, so that the metal layer (ie, the electrode structure) or the insulating layer (for example, contact) of the desired pattern Holes, etc.) can be formed.

As described above, the printing method has many advantages. In particular, it is a representative advantage of the printing method that an ink pattern can be formed on a large display device by one step or a more precise pattern can be formed than a conventional photolithography process.

However, the above-described gravure offset printing method has a problem in that the ink pattern 122 is easily separated from the layer to be processed when the ink pattern 122 is formed by retransfer of ink. This problem is caused by the following causes.

The first reason is that the adhesion between the processing layer 121 and the ink 104 itself is weak, and this weakening of the adhesion, in particular, the processing layer 121 composed of a material such as an insulating layer such as SiOx or SiNx or a semiconductor layer made of Si. ) And the ink 104. The second cause is that the ink 104 does not peel smoothly from the grooves 102 of the cliché 100 upon ink transfer from the cliché 100 to the transfer roll 110. Therefore, some ink remains in the groove 102, and as a result, the surface of the ink peeled off and transferred to the transfer roll 110 becomes uneven, so that when the ink is retransmitted onto the substrate 120, the substrate ( The adhesion between the ink 120 and the ink becomes weak, and the ink pattern 122 is easily separated from the substrate 120.

When a part of the ink pattern 122 is separated from the layer to be processed or a gap occurs at the interface due to the above-described causes, the layer to be processed is etched by a subsequent etching process to form a pattern of the display element. At this time, the etching liquid flows into the peeled portion or the gap, and the processing layer 121 of the unwanted portion is etched. Therefore, in the display element which requires a high precision pattern, it becomes the cause of the fatal defect of a product defect.

In order to solve such a problem, the present invention provides a method of improving adhesion with the ink 104 through chemical or physical surface treatment of the layer 121 to be processed.

The surface treatment method of the layer to be processed according to the present invention for improving adhesion with ink is largely divided into a chemical treatment method and a physical treatment method.

First of all, chemical treatment methods include an adhesion enhancing agent, that is, a primer coating method, a plasma treatment method, a UV treatment method, and the like, on a surface of a layer to be processed.

As the material of the primer, HMDS (Hexa Methyl Disilazane) having excellent binding strength with ink or a resin having excellent adhesive properties, such as polyethyleneimine, isocyanate compound, polyester resin, and vinyl acetate resin, is used. HMDS is applied to an insulating layer, such as SiOx or SiNx, or a to-be-processed layer 121, such as a semiconductor layer, to solve the weakening of adhesion due to physical properties of the to-be-processed layer 121 and the ink on the surface of the to-be-processed layer 121. When the gas is applied in the gas phase and the surface is treated, the silicon groups in the HMDS are chemically bonded to the processing layer 121 and the methyl groups are combined with the ink as the HMDS is applied to the processing layer 121. The bonding force between the layer and the layer to be processed 121 is improved. Likewise, the above-mentioned resins serve as an adhesive between the ink and the layer to be processed 121, thereby further strengthening the bonding force between the layer 121 and the ink.

In the plasma treatment method, when a gas such as N 2, O 2, He, H, or the like is plasma-treated to the target layer 121, a COOH, CO or OH group that improves the binding force with ink on the surface thereof is formed. Is generated. In addition, after the plasma treatment, the surface of the layer 121 to be processed is finely sharpened, thereby increasing the surface area of the layer to be contacted with the ink, thereby increasing the bonding force with the ink.

The UV treatment method is a method of increasing the bonding force between the ink and the layer to be processed by irradiating the UV to the layer 121 to be processed, and after the UV treatment, as described above, COOH or OH groups are generated on the surface to better bond with the ink.

As a physical treatment method, the surface of the processing layer 121 is roughened to increase the surface area of the processing layer 121 in contact with the ink, thereby improving their bonding strength. There is a corona discharge using a voltage, or a sandblast method of spraying fine sand particles (CaCo ₃ ) together with compressed air from a nozzle onto the surface of the layer 121 to be processed.

FIG. 4 is an enlarged view of region A in FIG. 3C, and illustrates the interface between the layer 121 and the ink 122 when the above physical processing method is performed. As shown in the figure, the surface of the processing layer 121 is in contact with the ink 122 as the surface becomes finely bumpy due to physical treatment such as corona discharge or sand blast. The surface area becomes wider. As described above, as the contact area of the layer 121 to be in contact with the ink 122 is increased, the ink 122 and the layer 121 to be processed are larger than before, that is, when the layer 121 is flat. Cohesion between them can be improved.

On the other hand, without using a transfer roll as a method of transferring ink to the layer to be processed, as shown in FIG. 5, the cliché 200 filled with ink is formed on the substrate 220 on which the layer 221 is to be formed. After direct contact with, the printed pattern 222 may be formed on the layer 221 by removing it again.

In addition, in order to solve the problem caused by poor peeling of the cliché and the ink as described above, in the present invention, a release agent for smoothly peeling the ink 104 from the groove 102 formed in the cliché 100 is used. Used. This release agent is a kind of peeling accelerator, which is formed between the groove 102 and the ink 104 of the cliché 100 so that the ink 104 can be smoothly peeled from the cliché 100 even by a weak force. To this end, the release agent 103 is applied to the inside of the groove 102 before the ink 104 is applied to the cliché 100 in FIG. 3 (in the drawing, it is only applied to the bottom of the groove, but also to the sidewall of the groove. ).

In addition, in the present invention, the cliché 100 is formed of a silicon-based material such as SiOx for smooth peeling of the ink 104. In general, since the ink 104 has a hydrophobic property and the silicon-based material has a hydrophilic property, the affinity between the ink 104 and the silicon-based material is weak. Therefore, as described above, when the cliché 100 is formed of a silicon-based material, the ink 104 may be smoothly peeled from the cliché 100 by low affinity. The low affinity between the silicon-based material and the ink causes a weakening of the adhesion between the processing insulating layer such as SiOx or SiNx and the processing semiconductor layer, which is the reason for the HMDS treatment of the processing layer.

As described above, in the present invention, the ink 104 is smoothly peeled from the cliché 100 by applying the release agent 103 to the groove of the cliché 100 or by forming the cliché 100 from an SiOx-based material. As a result, an accurate ink pattern can be always formed on the substrate 120. In addition, the HMDS treatment of the layer 120 of the substrate 120 may prevent the ink pattern 122 retransferred from the transfer roll 110 from falling off from the layer 121. By the process of the present invention, it is possible to form a fine ink pattern 122 on the substrate 120, as a result it is possible to manufacture a display device having a large area with a fine pattern.

6 is a view showing a case in which the printing method is applied to the actual manufacturing line. In the drawing, reference numeral 130 denotes a belt, which proceeds in a direction indicated by an arrow, on which a liquid crystal panel is disposed in the manufacturing line of the substrate 120, for example, a liquid crystal display, and proceeds along the advancing direction of the belt.

As shown in the figure, in the actual manufacturing line, the cliché 100 is formed in a roll shape and is in contact with the transfer roll 110. As the belt 130 proceeds, the substrate 120 proceeds to be input to the transfer roll 110, and as the belt 130 continues to progress, the substrate 120 at a speed corresponding to the traveling speed of the belt 130. The transfer roll 110 in contact with the) is rotated. Meanwhile, in addition to the rotation of the transfer roll 110, the cliché 100 is also rotated so that the ink 104 filled in the grooves (not shown) of the cliché 100 is transferred to the transfer roll 110. The ink 104 transferred to the transfer roll 110 is retransferred onto the substrate 120 to form an ink pattern 122.

As described above, when the printing of one substrate is finished, the next substrate 120 disposed on the belt 130 is inputted to the transfer roll 110 again, and the same process is repeated as described above. It is possible to print on the substrate.

As described above, the substrate on which the ink pattern 122 is formed is transported to a subsequent line so that a subsequent photo process is performed to form a fine pattern such as a display device.

The pattern forming method by the printing method may be used not only for the active element or circuit of a display element such as a liquid crystal display element but also for element formation on a semiconductor wafer. In addition, the releasable additive used in the present invention is not limited to a specific material, and will include all materials that serve as separation promoters capable of separating the ink and the processed layer smoothly. Such other examples or modifications of the present invention will be readily conceived by anyone skilled in the art to which the present invention pertains using the basic concepts of the present invention.

As described above, in the present invention, in the gravure printing method used in forming a pattern of a display device, the cliché is formed of a silicon-based material, and a release promoting additive for promoting promotion is applied to the inside of the groove of the cliché filled with ink, thereby The ink can be peeled off smoothly to accurately form the desired pattern. Further, in the present invention, it is possible to prevent the printed ink pattern from falling off from the processed layer through the surface treatment of the processed layer such as an insulating layer or a semiconductor layer laminated on a substrate and etched by a subsequent process.

1 is a plan view showing the structure of a general liquid crystal display device.

FIG. 2 is a cross-sectional view illustrating a thin film transistor structure of the liquid crystal display shown in FIG. 1.

3 is a view showing a pattern forming method by a gravure offset printing method according to the present invention.

4 is an enlarged view of region A of FIG. 3 when physical surface treatment is performed on a layer to be processed;

5 is a view showing a pattern forming method by a direct contact printing method according to the present invention.

6 is a view showing that the gravure printing method of Figure 3 is applied to the actual manufacturing line.

Explanation of symbols on main parts of drawing

100: cliché 102: home

103: release agent additive 104: ink

108: doctor blade 110: transfer roll

120, 220: substrate 121, 221: processed layer

122, 222: ink pattern

Claims (19)

Applying a release accelerator into the groove of the cliché corresponding to the pattern position to be formed; Filling ink into the groove; Transferring the ink filled in the groove of the cliché to the layer to be processed; And And etching the to-be-processed layer using the ink pattern transferred to the to-be-processed layer as a mask. The method of claim 1, wherein the transferring of the ink to the layer to be processed comprises: contacting the ink-filled cliché on the layer to be processed; and Removing the cliché from the layer to be processed, and then transferring ink to the layer to be processed. The method of claim 1, wherein the transferring of the ink to the layer to be processed comprises: rotating the transfer roll onto the cliché to transfer the ink filled in the grooves to the surface of the transfer roll; and Rotating the transfer roll onto the layer to be processed of the substrate to retransfer ink on the surface of the transfer roll to the layer to be processed. 4. The pattern forming method according to claim 3, wherein the cliché is formed in a roll shape and contacts the transfer roll. delete The method of claim 1, wherein the cliché is made of a silicon-based material. The method of claim 1, wherein the layer to be processed comprises a metal layer. The method of claim 1, wherein the layer to be processed includes an insulating layer made of SiOx or SiNx. The pattern forming method of claim 1, wherein the layer to be processed is a semiconductor layer. The method of claim 1, wherein the layer to be processed is surface-treated with an adhesion enhancing agent. The method of claim 10, wherein the adhesion enhancer is a pattern forming method, wherein the layer to be processed is Hexa Methyl Disilazane (HMDS). The method of claim 10, wherein the layer to be processed is surface treated by Hexa Methyl Disilazane (HMDS). The method of claim 10, wherein the layer to be processed is selected from the group consisting of polyethyleneimine, an isocyanate compound, a polyester resin, and a vinyl acetate resin. The pattern forming method according to claim 1, wherein the surface of the layer to be processed is treated by a plasma method. The pattern forming method according to claim 1, wherein the surface of the layer to be processed is treated by a UV method. The pattern forming method as claimed in claim 1, wherein the surface of the layer to be processed is treated by a sandblast method. The method of claim 1, further comprising drying an ink retransferred into the layer to be formed to form an ink pattern. Applying a release accelerator into the groove of the cliché corresponding to the pattern position to be formed; Filling ink into the groove; Rotating the transfer roll onto the cliché to transfer the ink filled in the grooves to the surface of the transfer roll; Rotating the transfer roll while being in contact with the layer to be processed of the substrate to retransfer ink on the surface of the transfer roll to the layer to be processed; And And etching the to-be-processed layer using the ink pattern transferred to the to-be-processed layer as a mask. Applying a release accelerator into the groove of the cliché corresponding to the pattern position to be formed; Filling ink into the groove; Contacting the ink-filled cliché with a substrate; Transferring the ink to the layer by removing the cliché from the layer to be processed; And And etching the to-be-processed layer using the ink pattern transferred to the to-be-processed layer as a mask.