KR20060011165A - Method for manufacturing organic thin film transistor - Google Patents

Abstract

The present invention discloses a method for manufacturing an organic thin film transistor which can be manufactured by integrating high performance organic thin film transistors by forming an electrode on a organic semiconductor or a dielectric by contact printing. The disclosed invention comprises the steps of etching the etching material to form a stamper having an uneven structure; Performing a surface treatment for adjusting adhesion to the metal film on the stamper having the uneven structure; Depositing and etching a metal film on the surface-treated uneven stamper to form a plurality of electrodes; Aligning the stamper on which the electrodes are formed on the substrate on which the organic film is formed, and then forming an electrode on the organic film; Separating the electrodes and the stamper.

Here, the etching material is silicon or PDMS, and the surface treatment process of the stamper having the concave-convex structure reduces the adhesion between the metal film and the stamper by plasma treatment.

Organic, silicon, etched, printing, electrode, adhesive

Description

Organic thin film transistor manufacturing method {METHOD FOR MANUFACTURING ORGANIC THIN FILM TRANSISTOR}

1A illustrates the structure of a TFT having a bottom contact structure in an organic thin film transistor according to the prior art.

1B illustrates the structure of a TFT having a top contact structure in an organic thin film transistor according to the prior art.

2A to 2E illustrate a process of manufacturing a source / drain electrode of an organic thin film transistor according to the present invention.

* Description of the symbols for the main parts of the drawings *

100: support 101: stamper

105: electrode 200: substrate

206: organic film

The present invention relates to an organic thin film transistor, and more particularly, to an organic thin film transistor manufacturing method which can be formed by integrating organic thin film transistors by forming an electrode on a organic semiconductor or a dielectric by contact printing. It is about.

At present, as the information age progresses, devices for mass information processing and display devices for displaying the same are being rapidly developed. Display devices are rapidly changing from conventional CRTs to flat display devices such as OLED (Organic Light Emitting Diode) and P (Plasma Display Panel).

Among them, OLED is gaining importance as next generation display with advantages such as self-luminous and low power. Such OLEDs require transistors, which are switching elements for each pixel, in an active spherical method having high resolution and low power.

When the transistors are fabricated with organic devices, OLEDs have more advantages with lower cost and flexibility.

In the organic light emitting device as described above, when electrons and holes are injected into the organic light emitting layer formed between the first electrode, which is an electron injection electrode, and the second electrode, which is a hole injection electrode, the electrons and holes are combined to form a pair. Exciton generated by this is an element that disappears and emits light while falling from the excited state to the ground state.

Such organic thin film transistors have an advantage that they can be driven at a lower voltage (5 to 10V) than plasma display panels (PDPs) or inorganic thin film transistor displays.

In addition, organic thin film transistors have excellent characteristics such as wide viewing angle, high-speed response, and high contrast, so that they can be used as pixels of graphic displays, pixels of television image displays, or surface light sources. The device can be formed on a flexible transparent substrate such as plastic, can be made very thin and light, and has good color, making it suitable for the next generation flat panel display (FPD).

In addition, compared to the well-known liquid crystal display (LCD), it does not need a backlight (backlight) has the advantage of low power consumption and excellent color.

In general, organic thin film transistors can be roughly divided into a simple matrix and an active matrix in their structure and driving method.

The simple matrix organic thin film transistor has advantages in that it is easier to fabricate and has a simpler driving method than an active matrix organic thin film transistor. However, as the power consumption increases and the number of scan lines increases, driving becomes difficult.

The active matrix organic thin film transistor uses a thin film transistor (TFT) or a single crystal silicon transistor made of low temperature polysilicon (LTPS).

The TFT structure of the active matrix organic thin film transistor is largely divided into a bottom gate structure and a top gate structure.

In the bottom gate structure, the first and second electrodes, the source electrode and the drain electrode, are formed on the bottom contact structure and the organic layer formed on the bottom of the channel layer. It is divided into a top contact structure.

1A is a diagram illustrating a structure of a TFT having a bottom contact structure in an organic thin film transistor according to the prior art.

As shown in FIG. 1A, a metal film is deposited on the substrate 10 and etched using a photolithography process to form the gate electrode 1.

Then, the gate insulating film 5 is applied on the entire region of the substrate 10 on the substrate 10 on which the gate electrode 1 is formed.

 Among the organic thin film transistors having the bottom gate structure, the bottom contact structure exists under the channel layer 6 made of the organic material of the source / drain electrodes 5a and 5b of the thin film transistor, so that the substrate having the gate insulating film 5 coated thereon ( A metal film is deposited and etched on 20) to form the source / drain electrodes 5a and 5b.

When the source / drain electrodes 5a and 5b are formed, an organic layer is deposited on the entire region of the substrate 10, wherein the organic material is pentacene.

When using an organic material such as pentacene, it is possible to secure low cost and flexibility.

There are various methods of depositing the organic material on the substrate 10, but generally, the organic channel layer 6 is formed by etching after deposition according to a semiconductor process.

 Although not shown in the drawing, when the channel layer 6 is formed on the substrate 10, a protective film is applied, then a contact hole is formed, and a pixel electrode electrically contacted with the drain electrode 5b is formed. An array substrate of a thin film transistor and an organic electroluminescent device (OLED) is completed.

The OLED having the bottom contact structure as described above has an advantage in that integration is excellent because the channel layer 6 made of organic material is formed on the source / drain electrodes 5a and 5b, but device characteristics are inferior.

FIG. 1B illustrates a structure of a TFT having a top contact structure in an organic thin film transistor according to the prior art.

As shown in FIG. 1B, a metal film is deposited and etched on the substrate 20 to form the gate electrode 21, and then the gate insulating layer 22 is applied on the entire region of the substrate 20.

Then, an organic channel layer 26 is formed on the substrate 20 to which the gate insulating layer 22 is applied. The channel layer 26 is generally formed using a shadow mask vacuum deposition method. do.

By depositing a shadow mask on the substrate 20 by vacuum deposition, an organic material made of pentacene is deposited on the gate electrode 21 to form the channel layer 26.

When the channel layer 26 is formed on the substrate 20, source / drain electrodes 25a and 25b are formed. The method of forming the source / drain electrodes 25a and 25b may be formed by applying a semiconductor process. It may be formed by applying a shadow mask vacuum deposition process.

In the case of forming the source / drain electrodes 25a and 25b according to the photolithography process, which is the semiconductor process, the pentacene channel layer made of an organic material may be damaged by an etching solution, or the characteristics may be degraded.

Therefore, in the top contact method, the source / drain electrodes 25a and 25b are formed by applying a shadow mask vacuum deposition method such as forming an organic channel layer. In the case of using the shadow mask vacuum deposition process, it is difficult to integrate in the process. have.

According to the present invention, a thin film transistor, which is a switching element of an organic thin film transistor, is formed in a top contact structure, and a source / drain electrode is formed by a contact printing method, thereby increasing the degree of integration while manufacturing a high performance organic light emitting device. An object of the present invention is to provide a method for manufacturing an organic thin film transistor.

In order to achieve the above object, the organic thin film transistor manufacturing method according to the present invention,

Forming a gate electrode and a gate wiring on the substrate;

Applying a gate insulating film on the substrate on which the gate electrode is formed;

Forming an organic film channel layer using an organic material on the substrate coated with the gate insulating film;

Aligning a stamper having electrodes formed on the substrate on which the organic film channel layer is formed, and then attaching an electrode formed on the stamper on the organic film channel layer formed on the substrate to form a source / drain electrode; It is characterized by.

Forming a contact hole after forming the source / drain electrode to form an organic thin film transistor, and then forming a contact hole;

The method may further include forming a pixel electrode by depositing and etching a transparent metal layer on the passivation layer on which the contact hole is formed.

The organic layer may be a pentacene-based organic material, and the source / drain electrodes may be formed by directly attaching the electrodes formed on the stamper to the organic layer channel layer by a contact printing process.

The organic thin film transistor manufacturing method of the present invention,

Etching the etching material to form a stamper having an uneven structure;

Performing a surface treatment for adjusting adhesion to the metal film on the stamper having the uneven structure;

Depositing and etching a metal film on the surface-treated uneven stamper to form a plurality of electrodes;

Aligning the stamper on which the electrodes are formed on the substrate on which the organic film is formed, and then forming an electrode on the organic film;

Separating the electrodes and the stamper.

Here, the etching material is silicon or PDMS, and the surface treatment process of the stamper having the concave-convex structure reduces the adhesion between the metal film and the stamper by plasma treatment.

In the surface treatment process of the stamper having the concave-convex structure, the adhesion between the metal film and the stamper may be reduced by treating the carboxyl compound, and the adhesion between the electrode and the organic film is greater than the adhesion between the electrode and the stamper. The forming of the electrode on the organic layer may include forming an electrode on the organic layer by a contact printing process of directly contacting the electrode formed on the stamper with the organic layer.

According to the present invention, the thin film transistor, which is a switching element of the organic thin film transistor, is formed in the top contact structure, and the source / drain electrodes are formed by the contact printing method, thereby increasing the degree of integration while manufacturing a high performance organic light emitting device.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Although the display device of the organic thin film transistor is mainly described, the same technical concept may be applied to various organic devices.

In the case of an organic thin film transistor in which pixels are arranged in a matrix form in an active region in which an image is displayed, gate lines and data lines are vertically intersected on a substrate.

The gate wiring and the data wiring are vertically intersected to define a unit pixel region, and a thin film transistor as a switching element is formed on each unit pixel region.

A metal film is deposited on a substrate made of a transparent insulator such as glass, and a gate wiring and a gate electrode are formed by a photolithography process.

When the gate electrode is formed, the gate insulating film is coated on the entire area of the substrate, and then a channel layer of an organic material is formed on the gate electrode by a shadow mask vacuum deposition method.

When the channel layer is formed on a substrate, a process of forming a source and a drain electrode is performed. The present invention provides a method of forming a source / drain electrode of an organic thin film transistor including a switching element such as a thin film transistor. .

2A to 2E are views illustrating a source / drain electrode manufacturing process of the organic thin film transistor according to the present invention.

As described above, when a channel layer made of a gate electrode, a gate insulating film, and an organic material is formed on a substrate to manufacture an organic thin film transistor, a process of forming a source / drain electrode on the channel layer is performed.

As shown in FIG. 2A, in order to form the electrode by contact printing the source / drain electrode on the substrate on which the organic film is formed, a stamper 101 is formed on the support part 100, and the stamper 101 is formed. Electrodes 105 were formed.

The stamper 101 is formed by depositing a material such as silicon or PDMS on the support part 100, and then etching the silicon or PDMS material according to the inter-electrode spacing and electrode size by a photo process. 101).

Therefore, the structure of the stamper 101 has a concave-convex structure, the concave-convex structure may be variously manufactured according to the size of the electrode, the spacing between the electrodes.

When the stamper 101 is manufactured as described above, as shown in FIG. 2B, a metal film is deposited and etched on the stamper 101 to form the electrode 105 in the uneven region of the stamper 101.

The electrode 105 may be a source / drain electrode of a thin film transistor which is a switching element when the organic thin film transistor is an active display element, and an electrode for applying a signal when the organic thin film transistor is another light emitting element.

In this case, when the electrode 105 and the stamper 101 have too strong adhesive strength in contact with each other, there is a problem in that the separation of the stamper 101 and the electrode 105 becomes difficult.

That is, in the contact printing process of forming electrodes by directly stamping electrodes on the organic thin film transistor by the stamper 101, when the electrode 105 is not separated from the stamper 101, the electrode 105 is disposed on the organic film. ) Cannot be formed.

Therefore, in the present invention, when manufacturing the stamper 101, the surface treatment using a compound containing a plasma or carboxyl that can minimize the adhesion with the electrode 105 deposited in the uneven region.

Therefore, when the plasma treatment or the chemical treatment is performed on the uneven region of the stamper 101, the adhesion force with the electrode 105 to be deposited may be reduced.

In the present invention, when the size of the adhesive force between the electrode 105 and the stamper 101 faces the stamper 101 downward, the adhesive force between the electrode 105 and the organic layer is maximum from the adhesive force that does not fall by gravity. Try to have a smaller size.

In the drawing, a plurality of metal electrodes are formed on the concave-convex structure for convenience of description. However, when forming the source / drain electrodes of the thin film transistor which is the switching element, a stamper of a region corresponding to each unit pixel region is formed. The electrode 105 is formed on the 101.

As shown in FIG. 2C, when the electrode 105 is formed on the stamper 101 of the support part 100, the substrate 200 on which the organic layer 206 is formed and the electrode 105 of the stamper 101 are formed. Align to face.

Therefore, the electrode 105 formed on the stamper 101 is aligned with the source / drain electrode forming region of the organic film 206 formed on the substrate 200.

According to the present invention, the electrode 105 formed on the stamper 101 is formed as a source / drain electrode or a signal electrode in the case of a switching thin film transistor.

Then, as shown in FIG. 2D, the electrode 105 is formed on the stamper 101 and attached to contact the organic layer 206 formed on the substrate 200.

Then, as shown in FIG. 2E, the electrode 105 formed on the stamper 101 is attached to the organic layer 206 due to the contact between the organic layer 206 and the electrode 105.

This is because the adhesive force of the stamper 101 and the electrode 105 is much larger than that of the electrode 105 and the organic film 206, as described in FIG. 2B. Are easily separated to form electrodes 105 on the organic layer 206.

Although not shown in detail in the drawings, as described above, the electrodes are formed by a contact printing process, and then a protective film is applied over the entire area of the substrate.

When the passivation layer is coated on the substrate, a contact hole process is performed to form a pixel electrode which may be in contact with the drain electrode among the electrodes.

When the contact hole is formed on the drain electrode as described above, a transparent ITO metal film is deposited and etched to form a pixel electrode in electrical contact with the drain electrode in the unit pixel region, thereby completing an array substrate of the organic thin film transistor and the organic electroluminescent device. do.

As described above, in the present invention, since the electrodes may be formed on the organic layer without performing the shadow mask vacuum deposition process in the top contact structure, the integrated organic thin film transistor may be manufactured while preventing the degradation of the organic layer.

 In particular, the microelectrodes prepared by the etching process may be formed by contact printing on the organic layer without applying the photolithography process directly to the substrate.

As described in detail above, the present invention forms a thin film transistor, which is a switching element of an organic thin film transistor, in a top contact structure, and forms a source / drain electrode by a contact printing method, thereby fabricating a high performance organic light emitting device. There is an effect to increase.

In addition, an organic electroluminescent device, an electronic paper, and an organic electronic device such as RFID may be applied to a thin film transistor manufactured by using a contact printing method, thereby implementing a high performance and high integration device.

The present invention is not limited to the above-described embodiments, and various changes can be made by those skilled in the art without departing from the gist of the present invention as claimed in the following claims.

Claims (10)

Forming a gate electrode and a gate wiring on the substrate; Applying a gate insulating film on the substrate on which the gate electrode is formed; Forming an organic film channel layer using an organic material on the substrate coated with the gate insulating film; Aligning a stamper having electrodes formed on the substrate on which the organic film channel layer is formed, and then attaching an electrode formed on the stamper on the organic film channel layer formed on the substrate to form a source / drain electrode; Organic thin film transistor manufacturing method characterized in that. The method of claim 1, Forming a contact hole after forming the source / drain electrodes to form an organic thin film transistor and then forming a contact hole; And forming a pixel electrode by depositing and etching a transparent metal layer on the passivation layer on which the contact hole is formed. The method of claim 1, The organic film is a method for manufacturing an organic thin film transistor, characterized in that the pentacene-based organic material. The method of claim 1, The source / drain electrode is formed by attaching the electrodes formed on the stamper on the organic film channel layer directly by a contact printing process. Etching the etching material to form a stamper having an uneven structure; Performing a surface treatment for adjusting adhesion to the metal film on the stamper having the uneven structure; Depositing and etching a metal film on the surface-treated uneven stamper to form a plurality of electrodes; Aligning the stamper on which the electrodes are formed on the substrate on which the organic film is formed, and then forming an electrode on the organic film; And separating the electrodes from the stamper. The method of claim 5, The etching material is an organic thin film transistor manufacturing method characterized in that the silicon or PDMS. The method of claim 5, The surface treatment step of the stamper having the concave-convex structure is a method of manufacturing an organic thin film transistor, characterized in that the adhesion between the metal film and the stamper is reduced by the plasma treatment. The method of claim 5, The surface treatment step of the stamper having the concave-convex structure is a method of manufacturing an organic thin film transistor, characterized in that the adhesion between the metal film and the stamper is reduced by a carboxyl compound treatment. The method of claim 5, The adhesive force between the electrode and the organic layer is greater than the adhesive force between the electrode and the stamper. The method of claim 5, The process of forming an electrode on the organic film is a method of forming an electrode on the organic film by a contact printing process of directly contacting the electrode formed on the stamper to the organic film.

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