JP2007321217A - Method for forming protective film on device and device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve adhesiveness of a protective film having a specific pattern. <P>SOLUTION: The protective film 3 has portions 3B and 3A showing relatively strong and weak adhesion forces, respectively, at a boundary between the protective film 3 and a substrate 1 to enable patterning of the protective film 3. The portion 3A showing a relatively weak adhesion force in the protective film is removed, and the protective film having the specific pattern is formed on the substrate 1. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for forming a protective film for a device, and more particularly to a method for forming a patterned protective film.

  2. Description of the Related Art Conventionally, in facsimiles, copying machines, radiation imaging apparatuses, and the like, image information is once recorded as a latent image on an image recording unit, and then image information is read from the image recording unit.

  For example, in the recording and reproduction of medical radiation images, a photoelectric conversion element such as a selenium plate made of a-Se that is sensitive to radiation such as X-rays is used as a photoreceptor (radiation image recording medium), and radiation is applied to the photoreceptor. The latent image charge corresponding to the radiation image information is accumulated by irradiating the radiation carrying the image information, and then the photosensitive member is scanned with a laser beam. There is known a system that reads an electrostatic latent image carried by a latent image charge, that is, radiation image information by detecting through an electrode. In recent years, the use of an organic EL light-emitting element as a light source constituting the image reading unit has been studied.

  In general, a protective film is provided on these elements for physical and chemical protection of the elements. Polyparaxylylene can be easily formed into a film by a CVD method, and as a film (parylene film). It has been studied as a protective film for electrical components, electrical circuit boards, and many other components because of its excellent moisture resistance and voltage resistance, chemical inactivity, and high chemical resistance. However, on the other hand, it is known that the property of the adhesion of the parylene coating to the base material varies greatly depending on the type of the base material.

Patent Document 1 uses a parylene coating for the separation layer as part of this adhesive property to the substrate, and partially adheres to the separation layer at the interface with the substrate by surface modification of the substrate. A technique is described in which the separation layer can be easily peeled off by providing a good portion and a poor portion. On the other hand, Patent Document 2 describes a technique of irradiating ultraviolet rays after forming a parylene film as a method for improving the adhesion to a substrate.
JP 2005-183615 A Japanese Patent Laid-Open No. 1-168859

  When coating precision parts, particularly when forming a protective film for a device, there is a case where a protective film is formed on a certain part on the substrate from the viewpoint of wiring or the like and a protective film is not desired to be formed on a certain part. In such a case, conventionally, a protective film with a predetermined patterning is attached, or after forming the protective film, a part of the protective film where the protective film is not to be formed is subjected to physical and chemical treatment. The technique of removing was taken.

  However, the method of pasting a protective film patterned like the former has a problem that it cannot cope with precision coating, and the method of removing the protective film partially after forming the latter protective film is a work to remove If the emphasis is placed on the property, it is necessary to weaken the adhesion between the entire protective film and the substrate to some extent, but if so, the adhesion between the protective film after patterning and the substrate is not sufficient, while the patterned film is patterned. If importance is attached to the adhesion of the protective film, the adhesion between the protective film after patterning and the substrate is ensured, but the protective film of the portion where the protective film is not desired cannot be sufficiently removed or removed. In this case, there is a problem that the substrate is eroded. In particular, in the case of precision parts such as devices, there is a demand for an easy patterning method of a protective film because there are limitations on temperature and chemicals in physical and chemical treatments when partially removing the protective film.

  The present invention has been made in view of the above circumstances, and provides a protective film forming method for a device in which patterning of the protective film is easy and the adhesion of the patterned protective film is good, and a device having the patterned protective film. It is for the purpose.

  The method for forming a protective film for a device of the present invention is a method for forming a protective film for a device, wherein a predetermined patterned protective film is formed on a substrate, and the protective film and the protective film can be patterned with respect to the protective film. A protective film having a predetermined patterning is formed on the substrate by forming a relatively strong portion and a weak portion at the interface with the substrate and removing a relatively weak portion of the protective film. It is characterized by forming.

  The protective film is preferably an organic film made of a polyparaxylylene material. In this case, it is preferable that the protective film is selectively irradiated with ultraviolet rays to form a relatively strong part and a weak part.

  It is preferable to provide a film holding member at the end of the protective film of the relatively strong adhesion remaining on the substrate.

  A device having a patterning protective film of the present invention is manufactured by the method for forming a protective film of a device of the present invention.

  The method for forming a protective film of a device of the present invention forms a relatively strong part and a weak part at the interface between the protective film and the substrate so that the protective film can be patterned. Since the protective film having a predetermined patterning is formed on the base material by removing the relatively weak part of the protective film, the protective film of the relatively strong adhesive force remaining on the base material is in close contact with the base material. While it is possible to improve the property, it is possible to easily remove a portion having a relatively low adhesion from the substrate.

  In particular, the method for forming a protective film of a device of the present invention forms a relatively strong and weak adhesion portion at the interface between the protective film and the substrate so that the protective film can be patterned. A protective film having a predetermined patterning can be formed on the base material regardless of the type of base material for forming the film.

  Hereinafter, a method for forming a protective film of a device of the present invention will be described with reference to the drawings, taking as an example a case where a parylene film is partially formed as a protective film on a surface on which an electrode is disposed on a substrate. FIG. 1 is a process diagram in the case where a parylene film is partially formed on a surface on which an electrode is arranged on a substrate, and wiring is performed on the electrode.

  First, a parylene coating 3 is formed on the substrate 1 and the entire surface of the electrode 2 by a polymerization method on the electrode 2 disposed on the substrate 1 shown in FIG. 1A (FIG. 1B). ). After the parylene coating 3 is formed, a mask 4 is disposed on the portion of the parylene coating 3 to be removed, and the entire parylene coating 3 is irradiated with ultraviolet rays (FIG. 1 (c)). After the irradiation, the parylene coating 3A portion covered with the mask 4 remains weak in adhesion to the electrode 2, and the parylene coating 3B portion not covered with the mask 4 adheres to the substrate 1. Becomes stronger (FIG. 1 (d)). Next, the parylene coating 3A portion having a weak adhesion is removed from the electrode 2 (FIG. 1 (e)). Subsequently, the wiring 5 is connected to the electrode 2 (FIG. 1 (f)), and the wiring 5 is fixed by the film holding member 6 so as to cover the end of the parylene coating 3B (FIG. 1 (g)).

  In FIG. 1, the parylene coating 3 is formed only on the base material 1, but the separation between the parylene coating 3 </ b> B portion and the base material 1 is further suppressed by providing up to the side surface of the base material 1 or the side surface and the bottom surface. Is possible.

  In the method for forming a protective film for a device of the present invention, a relatively strong part and a weak part are provided at the interface between the protective film and the base material so that the protective film can be patterned. It is not limited, but can be selected widely from metals such as gold, silver, aluminum, iron, copper and nickel, plastics such as ABS, PBT, vinyl chloride resin and styrene. Further, the substrate may have flexibility and elasticity in addition to a certain degree of rigidity, and the thickness is not limited.

  In particular, when the base material is an extremely thin glass (for example, several tens of μm), if a protective film is formed with an emphasis on adhesion, the protective film in a portion where the protective film is not desired can be sufficiently removed. However, in the method for forming a protective film according to the present invention, the adhesive force is relatively low at the interface with the base material so that the protective film can be patterned. The strong and weak parts are formed and the relatively weak adhesion is removed, so there is no problem such as cracking. On the other hand, the remaining relatively strong adhesion is against the substrate. Since the adhesion is good, sufficient adhesion can be ensured.

  In addition, a groove or a step is formed in advance on the base material side, a relatively strong part and a weak part are formed with this as a boundary, and a blade or the like is put in the groove or the step part, thereby making the relative The part with weak adhesion can be removed cleanly.

  The most suitable means for forming the relatively strong and weak adhesion parts may be selected according to the type of protective film. UV irradiation, coupling agent, corona discharge, plasma treatment, ozone cleaning, acid treatment, surface It can be selected as appropriate from the method of performing physical and chemical treatment such as roughening, but when the protective film is an organic film made of a polyparaxylylene material, A region can be selected precisely with little influence.

  The wavelength of ultraviolet irradiation is preferably 300 to 400 nm. When the wavelength is shorter than this, the coating is liable to be deteriorated, and when the wavelength is longer, long-time irradiation is required, which is not economical. The intensity of ultraviolet rays varies slightly depending on the wavelength, the type of substrate and the protective film, and further varies depending on the combination of these. For example, a 1 kW mercury lamp is irradiated for about 10 minutes from 20 cm above the parylene coating. Thereby, the adhesiveness with respect to glass can be strengthened.

Examples of the polyparaxylylene material used for the protective film of the present invention include compounds having the following chemical structural formula.

(Where n is an integer greater than or equal to 5000), and may be used alone or in combination.

The parylene film is formed by vapor deposition polymerization, and the deposition mechanism is composed of three steps. That is, the first step in which the diparaxylylene (A) of the solid dimer as a raw material is vaporized, the second step in which the diradical paraxylylene (B) is generated by thermal decomposition of the dimer, and the diradical para to the substrate. This is a third step in which the adsorption and polymerization of xylylene are simultaneously performed to form a film of high molecular weight polyparaxylylene (C). The reaction formula of chemical formula (1) in these three steps is as follows.

In this process, the degree of vacuum is generally 0.1 to 100 Pa (10 ^{−3 to 1} Torr), the first process is performed at 100 to 200 ° C., the second process is performed at 450 to 700 ° C., and the third process is performed at room temperature. . These parylene coatings obtained by vapor deposition polymerization can be conformally coated on the substrate, and the coating itself can be performed at room temperature, giving a thermal history to the substrate. The coating can be done without. For this reason, it is also optimal for coating on substrates such as Se devices that cannot be processed at high temperatures.

  In addition, the parylene coating has better electrical insulation than silicone, epoxy, urethane, etc., insolubility to all organic solvents at temperatures below 150 ° C, chemical resistance not to be corroded by most acids and alkalis, vacuum Heat resistance that can withstand continuous use for 10 years at 200 ° C or higher in an inert gas atmosphere, cold resistance that does not break even at low temperatures of -150 ° C and 180 ° bending, and penetration into narrow gaps on the order of microns Therefore, it is possible to obtain a patterning protective film having a gas barrier property, which has extremely low permeability and precision, water vapor and gas permeability, and at the same time, is excellent in blocking outgas from the adherend. In addition, the parylene coating can be conformally coated with no pinholes from a thickness of 0.2 μm depending on the adherend, and furthermore, it does not leave a coating history and does not leave a coating distortion because it does not add a thermal history to the substrate. can do.

  The film holding member provided at the end of the protective film of the relatively strong adhesion remaining on the base material is an epoxy resin, and by hardening the epoxy resin, the end of the protective film is reinforced. can do. Alternatively, a method may be used in which the end portion is pressed from above with a glass member or the like, or a portion other than the end portion and its vicinity is masked and a parylene film is formed and hardened from above the end of the parylene film.

  As described above, the method for forming a protective film of the device of the present invention forms a relatively strong part and a weak part at the interface between the protective film and the substrate so that the protective film can be patterned. Since the protective film having a predetermined patterning is formed on the base material by removing the relatively weak part of the protective film, the protective film of the part having the relatively strong adhesive force left on the base material is While it is possible to improve the adhesion to the substrate, the relatively weak part of the adhesion can be easily removed from the substrate.

  Therefore, the device protective film forming method of the present invention is widely applied to highly reliable thin film device devices having organic TFT elements and organic EL elements, electro-optical devices such as liquid crystal display devices and electrophoretic display devices using these. Can be used.

Schematic which shows the process of the protective film formation method of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base material 2 Electrode 3 Parylene film 4 Mask 5 Wiring 6 Film holding member

Claims (5)

  A method for forming a protective film for a device, wherein a predetermined patterned protective film is formed on a substrate, wherein the adhesive force is relatively relative to the interface between the protective film and the substrate so that the protective film can be patterned. A protective film for a device, wherein a protective film having a predetermined patterning is formed on the base material by forming a strong part and a weak part in the protective film, and removing a relatively weak part of the protective film. Forming method.   The method for forming a protective film for a device according to claim 1, wherein the protective film is an organic film made of a polyparaxylylene material.   3. The method of forming a protective film for a device according to claim 2, wherein the protective film is selectively irradiated with ultraviolet rays to form a relatively strong part and a weak part.   4. The method of forming a protective film for a device according to claim 1, wherein a film holding member is provided at an end portion of the protective film of the relatively strong adhesion portion left on the base material. .   A device having a patterning protective film manufactured by the method for forming a protective film for a device according to claim 1.

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