CN100573959C - A method for preparing an organic thin film transistor with patterned active layer - Google Patents

Abstract

The invention relates to the technical field of organic semiconductor devices and microfabrication, and discloses a method for preparing an organic thin film transistor with a patterned active layer. Prepare an organic semiconductor thin film layer by evaporation method, and then prepare a protective layer on the organic semiconductor thin film layer by room temperature PECVD, and make the sum of the thickness of the organic semiconductor thin film layer and the protective layer less than the thickness of the metal source and drain electrodes To ensure that the glue remover does not come into contact with the organic semiconductor thin film layer when removing the photoresist mask, causing damage to the properties of the organic semiconductor thin film layer. The invention is fully compatible with traditional IC technology, and the prepared organic thin film transistor with patterned active layer has the properties of small off-state current and high current-on-off ratio.

Description

A method for preparing an organic thin film transistor with patterned active layer

technical field

The invention relates to the technical field of organic semiconductor devices and microfabrication, in particular to a method for preparing an organic thin film transistor with a patterned active layer.

Background technique

With the development of the organic electronics industry, organic thin film transistors have shown great application potential in flexible active matrix displays and flexible integrated circuits. Patterning the active layer is an essential step to realize organic semiconductor applications.

In traditional microelectronics processing, photolithography is generally used to pattern the semiconductor layer of silicon thin film transistors, but this method cannot be directly applied to the patterning of organic semiconductor thin films, because various Both the solution and the photoresist itself will damage the properties of the organic film.

Jackson's research group has developed a method (Appl.Phys.Lett., 74, 3302, 1999) for patterning the active layer by using polyvinyl alcohol (PVA) as a negative adhesive and a protective layer, but the yield is low. Ali Afzali et al. (IBM, Adv. Mater., 15, 2066, 2003) used a solution processing method to pattern the active layer, but after the device passed through the solvent, the performance decreased significantly. Jin Jiang et al proposed to pattern the active layer by self-organization method, but the repeatability is not good. Stijn De Vusser et al. (Appl. Phys. Lett., 88, 103501, 2006) thought of using photoresist as a mask (integrated shadow mask) to pattern the active layer, but the photoresist in this method It cannot be removed, so that the subsequent manufacturing process is subject to certain restrictions.

Therefore, patterning organic semiconductor thin films is a key technical problem that currently limits the further practical application of organic thin film transistors. It is necessary to develop a technology that can pattern organic thin films without damaging the properties of organic thin films as soon as possible.

Contents of the invention

(1) Technical problems to be solved

In view of this, the main purpose of the present invention is to provide a method for preparing an organic semiconductor thin film transistor with a patterned active layer that is fully compatible with traditional microelectronic processing technology, so as to realize the organic thin film without damaging the performance of the organic film. The film is patterned.

(2) Technical solutions

In order to achieve the above object, the present invention provides a method for preparing an organic thin film transistor with a patterned active layer. The method uses a photoresist as a mask after the metal source and drain electrodes are prepared, and the mask covers the source and drain electrodes. The upper surface of the upper surface and the upper surface of the insulating gate layer except between the source and drain electrodes, then first prepare an organic semiconductor thin film layer by vacuum evaporation, and then prepare a protective layer on the organic semiconductor thin film layer by room temperature PECVD, And make the sum of the thickness of the organic semiconductor thin film layer and the protective layer less than the thickness of the metal source drain electrode, to ensure that the glue remover does not contact the organic semiconductor thin film layer when removing the photoresist mask to cause the organic semiconductor thin film Destruction of layer properties.

The preparation method of the organic thin film transistor with patterned active layer provided by the present invention specifically includes the following steps:

forming an insulating gate layer 2 on the conductive substrate 1;

forming a source electrode 3 and a drain electrode 4 on the insulating gate layer 2;

Forming a photoresist mask 5 on the source electrode 3, the drain electrode 4 and the insulating gate layer 2;

Form organic semiconductor thin film layer, this organic semiconductor thin film layer is formed on the insulating gate layer 2 between source, drain electrode and photoresist mask plate 5 respectively the first organic semiconductor thin film layer 6 and the second organic semiconductor thin film layer 7 constitute;

Form a protective layer, which is composed of a first protective layer 8 and a second protective layer 9 respectively formed on the first organic semiconductor thin film layer 6 and the second organic semiconductor thin film layer 7;

In the photoresist solvent, the photoresist mask plate 5, the second organic semiconductor thin film layer 7 and the second protective layer 9 thereon are stripped to form a patterned first organic semiconductor thin film layer 6 with the first protective layer 8, The photoresist solvent is the stripping solution.

In the above solution, the conductive substrate 1 is used as a gate of an organic thin film transistor.

In the above solutions, the formation of the insulating gate layer 2 is performed by thermal oxidation growth, chemical vapor deposition or spin coating.

In the above solution, the formation of the source electrode 3 and the drain electrode 4 is performed by metal evaporation or magnetron sputtering technology.

In the above solution, the formation of the first organic semiconductor thin film layer 6 and the second organic semiconductor thin film layer 7 is carried out by vacuum thermal evaporation technology, so as to form an ordered, continuous and uniform organic semiconductor thin film with large crystal grains.

In the above solution, the formation of the first protective layer 8 and the second protective layer 9 is carried out by PECVD at room temperature, so as to obtain a protective film layer with good compactness and avoid damage to the organic semiconductor film caused by the high temperature process.

In the above scheme, when the photoresist mask 5, the second organic semiconductor thin film layer 7 and the second protective layer 9 thereon are peeled off, the photoresist mask 5 is peeled off using a stripping technique to obtain a patterned first Organic semiconductor thin film layer 6.

In the above scheme, the sum of the thicknesses of the organic semiconductor thin film layer and the protective layer is less than the thickness of the metal source and drain electrodes, so as to ensure that the properties of the first organic semiconductor thin film layer will not be removed by the photoresist and the photoresist stripping method. Destroyed by glue solution.

(3) Beneficial effects

As can be seen from the foregoing technical solutions, the present invention has the following technical effects:

1. The method for preparing organic thin film transistors with patterned active layers provided by the present invention is a method for preparing organic semiconductor thin film transistors with patterned active layers that is fully compatible with traditional microelectronic processing technology, and realizes Under the condition of the performance of the organic thin film, the organic thin film is patterned.

2. The preparation method of this active layer patterned organic thin film transistor provided by the present invention adopts photoresist as a mask plate after the metal source and drain electrodes are prepared, and first prepares an organic semiconductor thin film layer by vacuum evaporation, and then Adopt room temperature PECVD method to prepare a layer of protective layer on it, and make the sum of organic layer and protective layer thickness be less than the thickness of metal electrode, have guaranteed that glue removing liquid can not be contacted with organic layer when removing photoresist mask and cause The destruction of the nature of the organic semiconductor thin layer finally completes the method of the active layer patterned organic thin film transistor.

3. The method for preparing an organic thin film transistor with a patterned active layer provided by the present invention is a method for preparing an organic thin film transistor with a patterned active layer with a simple process, and this method is fully compatible with traditional microelectronic processing techniques , without any additional, special process.

4. The preparation method of the active layer patterned organic thin film transistor provided by the present invention can obtain a fine patterned active layer under the process conditions compatible with the traditional microelectronic processing technology, and complete the preparation of the organic thin film transistor device. In the integrated circuit composed of the patterned active layer organic thin film transistor obtained by the method, the organic thin film transistor has the properties of small off-state current and high current-on-off ratio.

Description of drawings

Fig. 1 is a flow chart of the method for preparing an organic thin film transistor with patterned active layer provided by the present invention;

Fig. 2 is a process flow diagram corresponding to steps in Fig. 1;

3 is a flowchart of a method for preparing an organic thin film transistor with a patterned active layer according to an embodiment of the present invention;

FIG. 4 is a schematic structural view of an organic thin film transistor with a patterned active layer prepared according to an embodiment of the present invention.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be described in further detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

The core content of the present invention is: after the preparation of the metal source and drain electrodes, the photoresist is used as a mask, and the organic semiconductor thin film layer is prepared by vacuum evaporation method, and then a layer of organic semiconductor thin film layer is prepared by room temperature PECVD method on the organic semiconductor thin film layer. protective layer, and make the sum of the organic semiconductor thin film layer and the protective layer thickness less than the thickness of the metal source drain electrode, to ensure that the glue remover does not contact the organic semiconductor thin film layer when removing the photoresist mask, causing the Destruction of the properties of organic semiconductor thin film layers.

As shown in Figure 1, Figure 1 is a flow chart of a method for preparing an organic thin film transistor with a patterned active layer provided by the present invention, the method includes the following steps:

Step 101: forming an insulating gate layer 2 on the conductive substrate 1;

The process flow corresponding to this step is shown in Figure 2-1. In this step, the conductive substrate 1 is a conductive material with low resistivity, which is used as a gate of an organic thin film transistor; the formation of an insulating gate layer 2 by thermal oxidation growth, chemical vapor deposition or spin coating.

Step 102: forming a source electrode 3 and a drain electrode 4 on the insulating gate layer 2;

The process flow corresponding to this step is shown in FIG. 2-2. The formation of the source electrode 3 and the drain electrode 4 is performed by metal evaporation or magnetron sputtering technology.

Step 103: forming a photoresist mask 5 on the source electrode 3, the drain electrode 4 and the insulating gate layer 2;

The process flow corresponding to this step is shown in Figure 2-3. In this step, the photoresist is spin-coated, and after exposure and development, a photoresist mask pattern is formed.

Step 104: forming a first organic semiconductor thin film layer 6 and a second organic semiconductor thin film layer 7 on the insulating gate layer 2 and the photoresist mask plate 5;

The process flow corresponding to this step is shown in Figure 2-4. In this step, the formation of the first organic semiconductor thin film layer 6 and the second organic semiconductor thin film layer 7 is carried out by vacuum thermal evaporation technology to form large crystals. Ordered continuous uniform organic semiconductor thin film.

Step 105: forming a first protective layer 8 and a second protective layer 9 on the first organic semiconductor thin film layer 6 and the second organic semiconductor thin film layer 7;

The process flow corresponding to this step is shown in Figure 2-5. In this step, the formation of the first protective layer 8 and the second protective layer 9 is carried out by PECVD at room temperature to obtain a protective film layer with good compactness. And avoid the damage caused by the high temperature process to the organic semiconductor thin film.

Step 106: peel off the photoresist mask plate 5, the organic semiconductor 7 in the non-active area, and the second protective layer 9 on the organic semiconductor 7 in a photoresist solvent to form a patterned first organic semiconductor film with a protective layer Layer 6;

The process flow corresponding to this step is shown in Figures 2-6. In this step, when stripping the photoresist mask 5, the organic semiconductor 7 in the non-active region and the second protective layer 9 on the organic semiconductor 7 , the photoresist mask plate 5 is peeled off using a lift-off technique to obtain a patterned organic semiconductor thin film layer 6; the sum of the thickness of the organic semiconductor thin film layer and the protective layer is less than the thickness of the metal source and drain electrodes, so as to ensure the active area The properties of the organic semiconductor thin film will not be damaged by the photoresist and the stripping solution used when stripping the photoresist.

The specific implementation method and steps of the present invention are further described below, as shown in FIG. 3 , which is a flowchart of a method for preparing an organic thin film transistor with a patterned active layer according to an embodiment of the present invention.

1. As shown in Figure 3-1, a 500nm-thick polyimide gate dielectric insulating film layer is prepared on a heavily doped p-type silicon conductive substrate by spin-coating technology.

2. As shown in Figure 3-2, electron beam metal evaporation technology is used to deposit 80nm thick gold as the source and drain electrodes.

3. As shown in Figure 3-3, spin-coat 9918 positive photoresist with a thickness of 1400nm, and form a photoresist mask pattern after exposure and development.

4. As shown in Figure 3-4, a 40nm copper phthalocyanine organic semiconductor film was evaporated using vacuum thermal evaporation technology.

5. As shown in Figure 3-5, use room temperature PECVD to grow a 20nm silicon oxide thin layer as a protective layer. Meet the requirements: 40nm+20nm<80nm.

6. As shown in Figure 3-6, adopt the stripping method, use acetone to remove the adhesive 9918, and complete the preparation of the organic semiconductor thin film transistor with the active layer patterned.

As shown in FIG. 4 , FIG. 4 is a schematic structural view of an organic thin film transistor with a patterned active layer prepared according to an embodiment of the present invention.

The specific embodiments described above have further described the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (9)

1; a kind of preparation method of OTFT of active layer graph; it is characterized in that; this method adopts photoresist as mask after the metal source and drain electrodes preparation finishes; this mask covers the source; the upper surface of drain electrode and the source of removing; insulated gate layer upper surface beyond between the drain electrode; earlier prepare the organic semiconductor thin-film layer then with vacuum vapour deposition; on this organic semiconductor thin-film layer, adopt room temperature PECVD legal system to be equipped with layer protective layer again; and making this organic semiconductor thin-film layer and the thickness of this protective layer thickness sum less than described metal source and drain electrodes, the liquid of guaranteeing to remove photoresist does not contact with this organic semiconductor thin-film layer when removing the photoresist mask and causes the destruction of this organic semiconductor thin-film layer character.

2, the preparation method of the OTFT of active layer graph according to claim 1 is characterized in that, this method may further comprise the steps:

Go up formation insulated gate layer (2) in conductive substrates (1);

Go up formation source electrode (3) and drain electrode (4) at insulated gate layer (2);

Go up formation photoresist mask (5) at source electrode (3), drain electrode (4) and insulated gate layer (2);

Form organic semiconductor film layer, this organic semiconductor thin-film layer is made of the first organic semiconductor thin-film layer (6) that forms respectively on insulated gate layer (2) between source, the drain electrode and photoresist mask (5) and the second organic semiconductor thin-film layer (7);

Form protective layer, this protective layer is made of first protective layer (8) that forms respectively on the first organic semiconductor thin-film layer (6) and the second organic semiconductor thin-film layer (7) and second protective layer (9);

Stripping photoresist mask (5), the second organic semiconductor thin-film layer (7) and second protective layer (9) on it in photoresist solvent; form the patterned first organic semiconductor thin-film layer (6) with first protective layer (8), this photoresist solvent is the described liquid that removes photoresist.

3, the preparation method of the OTFT of active layer graph according to claim 2 is characterized in that, described conductive substrates (1) is used for the grid as OTFT.

4, the preparation method of the OTFT of active layer graph according to claim 2 is characterized in that, described formation insulated gate layer (2) is undertaken by the method for thermal oxide growth, chemical vapour deposition (CVD) or spin coating.

5, the preparation method of the OTFT of active layer graph according to claim 2 is characterized in that, described formation source electrode (3) and drain electrode (4) adopt evaporation of metal or magnetron sputtering technique to carry out.

6, the preparation method of the OTFT of active layer graph according to claim 2, it is characterized in that, the described formation first organic semiconductor thin-film layer (6) and the second organic semiconductor thin-film layer (7) adopt the vacuum thermal evaporation technology to carry out, to form the orderly continuously uniform organic semiconductor thin-film of big crystal grain.

7, the preparation method of the OTFT of active layer graph according to claim 2; it is characterized in that; described formation first protective layer (8) and second protective layer (9) adopt room temperature PECVD method to carry out; with the good protective film of acquisition compactness, and the damage of avoiding high-temperature technology that organic semiconductor thin-film is caused.

8, the preparation method of the OTFT of active layer graph according to claim 2; it is characterized in that; when described stripping photoresist mask (5), the second organic semiconductor thin-film layer (7) and second protective layer (9) on it; adopt lift-off technology stripping photoresist mask (5), to obtain the patterned first organic semiconductor thin-film layer (6).

9, the preparation method of the OTFT of active layer graph according to claim 8; it is characterized in that; described organic semiconductor thin-film layer and protective layer thickness sum be less than the thickness of described metal source and drain electrodes, and the used solution that removes photoresist destroys when guaranteeing that the first organic semiconductor thin-film layer character can be by photoresist and stripping photoresist.

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