JP5013167B2 - Insulating film surface modification method and semiconductor device manufacturing method - Google Patents

Description

  The present invention relates to an insulating film surface modification method and a semiconductor device manufacturing method, and more particularly, to an insulating film surface modification method made of a water-repellent material and a semiconductor device manufacturing using the insulating film as a gate insulating film. Regarding the method.

  In recent years, research and development of transistor structures (organic FETs) using organic semiconductor materials have attracted attention (see, for example, Non-Patent Document 1). One of the great advantages of an organic FET is that it can be manufactured by a coating process, compared to an inorganic FET using a silicon-based semiconductor material. In addition, since the coating film can be formed at a low temperature, it can be formed on a flexible substrate having no heat resistance such as plastic, and there is an advantage that the weight can be reduced.

  An organic insulating film is often used as the insulating film material of the organic FET as described above. For example, an organic insulating film made of an amorphous perfluoro resin (for example, Cytop manufactured by Asahi Glass Co., Ltd.) is used as a gate insulating film material. This amorphous perfluoro resin has high water repellency, and even when an electrode material or the like is applied to the upper layer, it repels the solvent. For this reason, after forming an amorphous perfluoro resin film, an ashing treatment is performed to remove fluorine on the surface and to expose hydrophilic groups such as hydroxyl groups contained in a trace amount on the surface, thereby making the surface water-repellent. The film was formed on the upper layer at a low value.

"Advanced Materials" (USA) 2002, Vol.14, No 2, p.99-117

  However, in the method as described above, a process of introducing an amorphous perfluoro resin into an ashing apparatus after the film formation and processing is necessary, which complicates the process. In particular, in the manufacturing process of the organic FET, it has been studied to perform all by the coating process, and there is a strong demand for process simplification.

  Accordingly, in order to solve the above-described problems, the present invention provides an insulating film surface modification method and a semiconductor device manufacturing method that modify the surface of an insulating film made of a water-repellent material without performing an ashing process. The purpose is to provide.

In order to achieve the above-described object, the surface modification method for an insulating film of the present invention is characterized by sequentially performing the following steps. First, on a substrate, Ri Do a water repellent material, a step of forming an insulating film hydroxyl groups present on the surface. Next, a step of applying a surface treatment agent for modifying the surface of the insulating film so as to reduce water repellency is performed on the surface of the insulating film.
Here, the surface treatment agent has a substituent that changes to a hydroxyl group, and a silyl group-containing compound having four silyl groups bonded to the substituent at three positions of the bond or four positions of the bond bonded to the substituent. A silicon compound composed of a silane compound is used. By applying this surface treatment agent, the silicon compound is bonded to the surface of the insulating film by the reaction between the hydroxyl group changed from the substituent and the hydroxyl group on the surface of the insulating film, and at the same time, silicon by the reaction between the hydroxyl groups of the surface treatment agent. Connect compounds together.

  According to such a method for modifying the surface of an insulating film, the surface of the insulating film is modified so that the water repellency is lowered by applying the surface treatment agent to the surface of the insulating film made of a water-repellent material. Therefore, even if an ashing process is not performed, it is possible to form a film on this insulating film only by adding a coating process.

The semiconductor device manufacturing method of the present invention includes a semiconductor device manufacturing method in which an organic semiconductor layer, a gate insulating film, and a gate electrode are stacked on a substrate in this order or in the reverse order. It is characterized by performing sequentially. First, a step of forming a gate insulating film including an insulating film existing hydroxyl group to Do Ri surface water-repellent material. Next, a step of applying a surface treatment agent for modifying the surface of the insulating film so as to reduce water repellency is performed on the surface of the insulating film.
Here, the surface treatment agent has a substituent that changes to a hydroxyl group, and a silyl group-containing compound having four silyl groups bonded to the substituent at three positions of the bond or four positions of the bond bonded to the substituent. A silicon compound composed of a silane compound is used. By applying this surface treatment agent, the silicon compound is bonded to the surface of the insulating film by the reaction between the hydroxyl group changed from the substituent and the hydroxyl group on the surface of the insulating film, and at the same time, silicon by the reaction between the hydroxyl groups of the surface treatment agent. Connect compounds together.

  According to such a method of manufacturing a semiconductor device, the surface of the insulating film is modified so that the water repellency is lowered by applying the surface treatment agent to the surface of the insulating film made of a water repellent material. Therefore, it is possible to form the insulating film on the upper layer only by adding the coating process without performing the ashing process. Thereby, the manufacturing process of the semiconductor device is simplified.

  As described above, according to the surface modification method for an insulating film and the method for manufacturing a semiconductor device of the present invention, it is possible to apply the coating process to the upper layer of the insulating film without adding the ashing process. Since the film can be formed, the manufacturing process is simplified. Thereby, the productivity of the semiconductor device can be improved.

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

  An example of an embodiment relating to a surface modification method for an insulating film and a method for manufacturing a semiconductor device using the same according to the present invention will be described by taking a method for manufacturing a semiconductor device including a top gate / bottom contact type thin film transistor as an example.

  First, as shown in FIG. 1A, silver ink is applied on a plastic substrate 11 made of polyethersulfone (PES) by, for example, spin coating, and heat-treated at 150 ° C. A source / drain electrode film 12 is formed.

  In addition to the above PES, the substrate 11 may be made of glass, polyethylene naphthalate (PEN), polyimide (PI), polycarbonate (PC), polyacrylate (PAR), or other highly heat-resistant plastic. As the source / drain electrode film 12, in addition to silver, metals such as gold, platinum and palladium, poly (3,4-ethylenedioxythiophene) / poly (4-styrenesulfonate) [PEDOT / PSS] A conductive organic material made of polyaniline (PANI) can also be used.

  Next, as shown in FIG. 1B, a resist pattern 13 provided with a source / drain electrode pattern is formed on the source / drain electrode film 12.

  Subsequently, as shown in FIG. 1C, the resist pattern 13 (see FIG. 1B) is used as a mask so as to be immersed in a silver etching solution, whereby the source / drain electrode film 12 (see FIG. b)) is patterned to form source / drain electrodes 12 '. Thereafter, the resist pattern 13 is removed by a remover.

  Next, as shown in FIG. 1 (d), a 1 wt% toluene solution of a pentacene derivative is applied onto the substrate 11 in a state of covering the source / drain electrodes 12 ′ by, for example, spin coating, and then a solvent at 100 ° C. Then, the organic semiconductor layer 14 is formed.

  Here, as the organic semiconductor layer 14, in addition to the pentacene derivative, a polymer material such as polythiophene, fluorene-thiophene copolymer, polyallylamine, or a low molecular material such as rubrene, thiophene oligomer, or naphthacene derivative may be used. Good.

  In addition to the spin coating method, the organic semiconductor layer 14 may be formed by a printing method such as an inkjet method, a dispenser method, a flexographic printing method, a gravure printing method, or an offset printing method. Here, an example in which the organic semiconductor layer 14 is formed in a solid film shape will be described, but the organic semiconductor layer 14 may be patterned for each element by various printing methods.

  Next, as shown in FIG. 2E, a gate insulating film is formed by depositing a water-repellent material made of amorphous perfluoro resin on the organic semiconductor layer 14a by, eg, spin coating. A first insulating film 15a is formed. As a result, the organic semiconductor layer 14 is in contact with the water repellent surface, so that the interface characteristics are good and good device characteristics are exhibited.

  Here, as the water repellent material, an organic material made of a fluororesin or a resin containing a water repellent surface treatment agent such as a perfluoroalkyl group or an alkylsilyl group can be used. Here, for example, an amorphous perfluoro resin (for example, Cytop 809M or 107M manufactured by Asahi Glass Co., Ltd.), which is a fluorine-based resin, is applied onto the organic semiconductor layer 14 by, for example, spin coating, and then the solvent is volatilized at 100 ° C. Thus, the first insulating film 15a is formed. On the surface of the first insulating film 15a, there are hydrophilic groups composed of a trace amount of hydroxyl groups (OH groups) to the extent that the water repellency of the first insulating film 15a is maintained. Here, the trace amount of hydrophilic groups is present to such an extent that the water repellency is maintained such that the contact angle of the surface of the first insulating film 15a with water is 70 degrees or more.

  In addition, although OH group exists as a hydrophilic group here, other hydrophilic groups, such as a carboxyl group (COOH group), may exist, for example.

  Subsequently, as shown in FIG. 2F, a surface treatment agent for modifying the surface of the insulating film is applied to the surface of the first insulating film 15a made of the above-described water-repellent material so that the water repellency is lowered. As a result, the modified layer A is formed. As a result, by reducing the water repellency of the first insulating film 15a, it is possible to form an upper layer.

Here, the surface treatment agent is composed of a silicon compound having a substituent that changes to a hydrophilic group. Examples of such a substituent include alkoxy groups such as methoxy group (OCH ₃ ) and ethoxy group (OC ₂ H ₅ ), and halogen atoms such as chlorine (Cl) and fluorine (F). These react with moisture in the air, for example, and change into OH groups. The OH group of the silicon compound reacts with the OH group on the surface of the first insulating film 15a to bond the silicon compound to the first insulating film 15a, and the reaction between the OH groups of the silicon compound causes the silicon compound to react. Are connected to form the modified layer A. In the reaction of the OH group, since water is generated as a reaction product, the water further reacts with the substituent of the surface treatment agent, and the reaction is promoted in a chain manner.

  At this time, in order to promote these reactions, it is preferable to perform heat treatment after the surface treatment agent is applied on the first insulating film 15a.

  For this reason, in order to bond with the first insulating film 15a and bond the silicon compounds together, the surface treatment agent is a silyl group in which both ends are composed of silyl groups in which two or more of the bonding hands are bonded to the substituent. It is preferable that the group-containing compound or the silane compound in which three or more bonds are bonded to the substituent. In particular, the surface treatment agent is composed of a silyl group-containing compound in which both ends are bonded with silyl groups bonded to the substituent at three positions on the bond, or a silane compound bonded to the substituent at four positions on the bond. By doing so, OH groups present on the surface of the modified layer A can be increased, which is preferable. Thereby, since the water repellency of the first insulating film 15a is remarkably lowered, it is possible to easily form the film on the upper layer.

  Examples of the silicon compounds described above include bistrichlorosilylethane (Bis (trichlorosilyl) ethane), bistriethoxysilylethane (Bis (triehoxysilyl) ethane), bistriethoxysilylmethane (Bis (triehoxysilyl) methane), bistriethoxysilyloctane ( Bis (triehoxysilyl) octhane), hexaethoxydisilane, hexamethoxydisilane, tetramethoxysilane, tetramethoxysilane, hexachlorodisilane, hexachlorodisiloxane, octachlorodisiloxane Examples thereof include trichlorosilane, tetrachlorosilane, and tetrafluorosilane. Here, for example, a surface treating agent made of hexamethoxydisilane is used.

  Here, the steps shown in FIGS. 2E to 2F will be described in detail with reference to the schematic diagram of FIG. First, FIG. 3A shows a state in which the first insulating film 15a made of the amorphous perfluoro resin described with reference to FIG. 2E is formed, and the surface of the first insulating film 15a is formed on the surface. Trace amounts of OH groups are present.

Next, FIG. 3 (2) shows a state immediately after the surface treatment agent made of hexamethoxydisilane (silicon compound) is applied. From this state, the OCH ₃ group of hexamethoxydisilane (indicated by OMe in the figure) reacts with moisture in the air to form an OH group as shown in FIG. 3 (3). The silicon compound is bonded to the first insulating film 15a by the reaction between the OH group of the silicon compound and the OH group on the surface of the first insulating film 15a. Further, the silicon compounds are linked to each other by the reaction between the OH groups of the silicon compounds.

  As a result, the surface of the modified layer A described with reference to FIG. 2F is terminated with a plurality of OH groups, and the OH groups are increased, so that the water repellency of the surface of the first insulating film 15a is increased. Decreases, and film formation on the upper layer becomes possible.

  Next, as shown in FIG. 4G, a second insulating layer made of a crosslinkable polymer material made of, for example, polyvinylphenol (PVP) is formed on the first insulating film 15a having the modified layer A formed on the surface thereof. 15b is formed. Thereby, the gate insulating film 15 formed by sequentially laminating the first insulating film 15a and the second insulating film 15b is formed. As a result, the gate electrode side, which will be described later, becomes the gate insulating film 15 covered with the crosslinkable polymer material, so that leakage current is reliably prevented. Examples of the crosslinkable polymer material as described above include polymethyl methacrylate (PMMA), polyimide, polyvinyl alcohol (PVA), polyvinylidene fluoride (PVDF), polyisobutylene (PIB), polystyrene (PS) in addition to PVP. ), Polyvinyl chloride (PVC), polyethylene terephthalate (PET), polycarbonate (PC), benzocyclobutene (BCB), and the like.

  Here, the gate insulating film 15 in which the first insulating film 15a and the second insulating film 15b are sequentially stacked is formed. However, even if the gate insulating film 15 is formed using only the first insulating film 15a. In addition, an insulating film may be further stacked on the second insulating film 15b.

  Next, as shown in FIG. 4H, a gate electrode material made of silver paste is pattern-coated on the second insulating film 15b by, for example, screen printing. Next, heat treatment is performed to dry and solidify the silver paste, thereby forming a gate electrode 16 made of silver.

  Here, the gate electrode 16 is made of silver. However, in addition to silver, metals such as gold, platinum, and palladium, and poly (3,4-ethylenedioxythiophene) / poly (4-styrene) are used. Sulfonate) [PEDOT / PSS], a conductive organic material made of polyaniline (PANI) can also be used.

  In addition, although an example in which the gate electrode material is applied in a pattern using the screen printing method has been described here, for example, an inkjet method, a flexographic printing method, an offset printing method, or a pad printing method may be used.

  According to such a surface modification method for an insulating film and a method for manufacturing a semiconductor device using this method, the surface of the first insulating film 15a is modified so that the water repellency is lowered by applying a surface treatment agent. Therefore, it is possible to form a film on the upper layer of the first insulating film 15a only by adding a coating process without performing an ashing process. Thereby, the manufacturing process of the semiconductor device is simplified, so that the productivity of the semiconductor device can be improved.

  Furthermore, according to the manufacturing method of the semiconductor device of the present embodiment, since all the film forming steps can be performed by the coating process, the manufacturing steps can be further simplified.

  In the above embodiment, the method for manufacturing the top gate / bottom contact type transistor has been described as an example. However, the present invention is not limited to this, and the top gate / top contact type and the bottom gate / top contact type are described. Even a top gate / bottom contact type transistor manufacturing method can be applied.

It is manufacturing process sectional drawing for demonstrating embodiment which concerns on the manufacturing method of the semiconductor device of this invention (the 1). It is manufacturing process sectional drawing for demonstrating embodiment which concerns on the manufacturing method of the semiconductor device of this invention (the 2). It is a schematic process diagram for explaining a surface modification method of an insulating film of the present invention. It is manufacturing process sectional drawing for demonstrating embodiment which concerns on the manufacturing method of the semiconductor device of this invention (the 3).

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Board | substrate, 14 ... Organic-semiconductor layer, 15 ... Gate insulating film, 15a ... 1st insulating film, 16 ... Gate electrode

Claims (6)

On a substrate, forming Ri Do a water repellent material, the insulating film existing hydroxyl groups on the surface,
Applying to the surface of the insulating film a surface treatment agent that modifies the surface of the insulating film so that water repellency is low ;
A step of performing a heat treatment after the step of applying the surface treatment agent; and
Including
As the surface treatment agent, a silyl group-containing compound having a silyl group bonded to the substituent and having three substituents that change to a hydroxyl group at both ends, or four bonds of the bond are bonded to the substituent. Using a silicon compound comprising
By applying the surface treatment agent, the silicon compound is bonded to the surface of the insulating film by a reaction between a hydroxyl group changed from the substituent and a hydroxyl group on the surface of the insulating film. A method for modifying the surface of an insulating film, wherein the silicon compounds are linked together by a reaction between them . Examples of the silicon compound include bistrichlorosilylethane, bistriethoxysilylethane, bistriethoxysilylmethane, bistriethoxysilyloctane, hexaethoxydisilane, hexamethoxydisilane, tetraethoxysilane, tetramethoxysilane, hexachlorodisilane, hexachlorodisiloxane, octachloro Use at least one of trisiloxane, tetrachlorosilane, and tetrafluorosilane
The method for modifying the surface of an insulating film according to claim 1. The hydroxyl group of the insulating film is present to such an extent that the water repellency at which the contact angle with water on the surface of the insulating film is 70 degrees or more is maintained.
The method for modifying the surface of an insulating film according to claim 1. The insulating layer Ru Der organic material
請 Motomeko 1 surface modification method of the insulating film according. The insulating layer, Ru perfluororesin der amorphous
請 Motomeko 1 surface modification method of the insulating film according. In a method for manufacturing a semiconductor device in which an organic semiconductor layer, a gate insulating film, and a gate electrode are stacked on a substrate in this order or in the reverse order,
Forming the gate insulating film on the Do Ri surface water-repellent material includes an insulating film which hydroxyl is present,
Applying to the surface of the insulating film a surface treatment agent that modifies the surface of the insulating film so that water repellency is low ;
A step of performing a heat treatment after the step of applying the surface treatment agent; and
Including
As the surface treatment agent, a silyl group-containing compound having a silyl group bonded to the substituent and having three substituents that change to a hydroxyl group at both ends, or four bonds of the bond are bonded to the substituent. Using a silicon compound comprising
By applying the surface treatment agent, the silicon compound is bonded to the surface of the insulating film by a reaction between a hydroxyl group changed from the substituent and a hydroxyl group on the surface of the insulating film. A method of manufacturing a semiconductor device, wherein the silicon compounds are connected to each other by a reaction between them .

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