JP2006295033A - Thin film device and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology for controlling occurrence of a trouble such as cracking of a thin film element layer in a thin film device where a substrate and the thin film element layer are bonded through adhesive. <P>SOLUTION: The thin film device comprises a substrate (22), an adhesive layer (24) provided on one surface of the substrate, a thin film element layer (14) including a thin film element and bonded to one surface side of the substrate by the adhesive layer, and a protective layer (16) composed of a material having a thermal expansion coefficient substantially equal to that of the constitutional material of the substrate and covering the upper side of the thin film element layer substantially entirely. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a thin film device such as a thin film element or a thin film circuit, and an electronic apparatus including the same.

  A technique using a transfer technique is known as a method for manufacturing a thin film device. For example, in Japanese Patent Application Laid-Open No. 10-125929 (Patent Document 1) and Japanese Patent Application Laid-Open No. 10-125930 (Patent Document 2), a transfer body such as a thin film transistor is previously formed on a transfer source substrate via a release layer. A method is disclosed in which the transfer target is transferred to the transfer destination substrate by bonding the transfer target to the transfer destination substrate and then irradiating the release layer with light or the like to cause peeling. In addition, in the process of moving the transfer object from the transfer source substrate to the transfer destination substrate, the transfer object is once transferred from the transfer source substrate to the temporary transfer substrate, and then transferred from the temporary transfer substrate to the transfer destination substrate. Two-time transfer processes that transfer the body are also known. According to these methods, a desired electronic device can be manufactured by forming multiple types of thin film elements and thin film circuits with different manufacturing conditions on the transfer source substrate under optimum conditions and then moving them to the transfer destination substrate. can do. In particular, when a two-time transfer process is employed, the up-down direction does not have to be reversed between the transfer target formed on the transfer source substrate and the transfer target finally transferred to the transfer destination substrate. There are advantages.

Japanese Patent Laid-Open No. 10-125929 JP-A-10-125930

  In the thin film device manufactured by using the transfer technique described above, an adhesive is interposed between the thin film element layer as a transfer target and the transfer destination substrate, and both are bonded. As this adhesive, a thermosetting or photocurable adhesive is usually used. However, this type of adhesive may cause a relatively large shrinkage or expansion during manufacture or subsequent use, and this may cause cracks in the thin film element layer disposed on the upper side of the adhesive. In some cases, this could cause problems.

  Then, this invention aims at providing the technique which can suppress that malfunctions, such as a crack, arise in a thin film element layer in the thin film device by which a board | substrate and a thin film element layer are joined via an adhesive material. .

  The first aspect of the present invention includes a substrate, an adhesive layer provided on one surface of the substrate, a thin film element, and a thin film element layer bonded to the one surface side of the substrate by the adhesive layer; A thin film device including a protective layer made of a material having a thermal expansion coefficient substantially equal to that of the constituent material of the substrate and provided to cover substantially the entire upper side of the thin film element layer.

  The present invention of the second aspect includes a substrate, an adhesive layer provided on one surface of the substrate, a thin film element, the thin film element layer bonded to the one surface side of the substrate by the adhesive layer, A protective layer that is made of a material having a thermal expansion coefficient substantially equal to the thermal expansion coefficient of the constituent material of the substrate and is provided so as to cover substantially the entire thin film element layer in the thin film element layer. Thin film device.

  Here, the “thin film element” in the present invention means a thin film transistor, a thin film diode, other thin film semiconductor elements, a thin film circuit including the semiconductor element, a photoelectric conversion element used for a solar cell or an image sensor, switching, and the like. Element, memory, actuator such as piezoelectric element, micromirror (piezo thin film ceramics), magnetic recording medium, magneto-optical recording medium, recording medium such as optical recording medium, magnetic recording head, coil, inductor, thin film high permeability material Micro magnetic devices, filters, reflective films, dichroic mirrors, polarizing elements and other optical thin films, semiconductor thin films, superconducting thin films (eg, YBCO thin films), magnetic thin films, metal multilayer thin films, metal ceramic multilayer thin films, metal semiconductor multilayers Thin film, ceramic semiconductor multilayer thin film, organic thin film and multilayer thin film of other materials Etc. are included.

  According to the configuration of the first or second aspect of the present invention, since the structure in which the upper and lower sides of the adhesive layer are sandwiched between the material layers having substantially the same thermal expansion coefficient is realized, the shrinkage and expansion of the adhesive layer are suppressed, It is possible to suppress the occurrence of defects such as cracks in the thin film element layer.

  Preferably, the substrate is a resin substrate, and the protective layer is formed using a resin material.

  Thereby, the board | substrate and protective layer which consist of a material with a substantially equal coefficient of thermal expansion can be implement | achieved easily.

  The third aspect of the present invention is an electronic apparatus including the thin film device manufactured by the manufacturing method described above. Here, the “electronic device” refers to a general device having a circuit board and other elements and having a certain function, and the configuration thereof is not particularly limited. Such electronic devices include, for example, IC cards, mobile phones, video cameras, personal computers, head mounted displays, rear or front projectors, televisions, roll-up televisions, fax machines with display functions, and digital cameras. Finder, portable TV, DSP device, PDA, electronic notebook, electric bulletin board, display for advertisement announcement, and the like.

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

  FIG. 1 is a schematic cross-sectional view illustrating the structure of a thin film device according to an embodiment. FIG. 2 is a cross-sectional view showing a specific example of a thin film element included in a thin film element layer (details will be described later). The thin film device of this embodiment shown in FIG. 1 includes a substrate 22, an adhesive layer 24, a thin film element layer 14, and a protective layer 16.

  The substrate 22 supports each element, and various types such as a glass substrate and a resin substrate can be adopted. In the present embodiment, a resin substrate (plastic substrate) made of an acrylic resin or the like is employed as the substrate 22.

  The adhesive layer 24 is made of a thermosetting or photo-curable adhesive, and is provided on one surface of the substrate 22 and has a function of bonding the thin film element layer 14 and the substrate 22.

  The thin film element layer 14 includes a thin film element such as the thin film transistor T illustrated in FIG. 2, and is bonded to one surface side of the substrate 22 by the adhesive layer 24.

  The protective layer 16 is made of a material having a thermal expansion coefficient substantially equal to the thermal expansion coefficient of the constituent material of the substrate 22 and is provided so as to cover substantially the entire upper side of the thin film element layer 14. In the present embodiment, the protective layer 16 is formed using, for example, an acrylic resin or a polyimide resin.

  The thin film device of the present embodiment has such a configuration. Next, a preferred example of a method for manufacturing the thin film device will be described.

  3 and 4 are diagrams for explaining a method of manufacturing a thin film device according to an embodiment. 3 and 4 exemplify a two-time transfer process in which a transfer target formed in advance on a transfer source substrate is temporarily held by a temporary transfer substrate and then moved to a transfer destination substrate.

  First, as shown in FIG. 3A, a release layer 12 is formed on one side of the transfer source substrate 10, and a thin film device 14 is formed on the release layer 12. Here, the transfer source substrate 10 in this step has an appropriate thickness and can withstand a heat-resistant material such as quartz glass or soda glass, for example, about 350 ° C. to 1000 ° C. which is a process temperature of a semiconductor device. Is used. The transfer source substrate 10 is desirably transparent to the wavelength of the light so that energy can be applied to the release layer 12 by light irradiation in a later step. Moreover, as the peeling layer 12, what has the characteristic which produces peeling by receiving energy provision, such as light irradiation, is used. Such a release layer 12 can be formed of, for example, a semiconductor film such as an amorphous silicon film, a metal film, a conductive oxide film, a conductive polymer film, or a conductive ceramic.

  Next, as shown in FIG. 3B, a protective film 16 made of acrylic resin, polyimide resin, or the like is formed so as to cover substantially the entire upper side of the thin film device 14. The protective film 16 can be formed by, for example, a spin coating method.

  Next, as shown in FIG. 3C, the water-soluble adhesive 18 is interposed between one surface of the temporary transfer substrate 20 and one surface of the transfer source substrate 10 to transfer the temporary transfer substrate 20 and the transfer surface. The original substrate 10 is bonded. Since the temporary transfer substrate 20 does not need to have special heat resistance, various substrates such as a glass substrate plastic substrate can be used.

  Next, as shown in FIG. 3D, energy is applied to the release layer 12 of the transfer source substrate 10 to cause peeling at the interface between the release layer 12 and the transfer source substrate 10. Specifically, as shown in the figure, the release layer 12 is irradiated with laser light through the transfer source substrate 10 to cause laser ablation in the release layer 12. Ablation is a state in which a solid material that absorbs irradiated light (a constituent material of the release layer 12) is photochemically or thermally excited, and its surface and internal atomic or molecular bonds are cut and released. In general, all or part of the constituent material of the release layer 12 appears as a phenomenon that causes a phase change such as melting and transpiration (vaporization). In addition, a phase change may result in a fine foamed state, which may reduce the bonding force. As a result, the thin film device 14 is transferred from the transfer source substrate 10 to the temporary transfer substrate 20 as shown in FIG.

  Next, as shown in FIG. 4B, the temporary transfer substrate 16 and the substrate 22 are joined by interposing an adhesive 24 between the one surface of the temporary transfer substrate 20 and the one surface of the substrate 22. To do. Examples of the adhesive 24 used in this step include an epoxy resin adhesive.

  Next, the soluble adhesive 18 is dissolved and removed, whereby the thin film device 14 is transferred from the temporary transfer substrate 20 to the substrate 22 as shown in FIG.

  Thus, the thin film device of the present embodiment realizes a structure in which the upper and lower sides of the adhesive layer 24 are sandwiched between the material layers (substrate 22 and protective layer 16) having substantially the same thermal expansion coefficient. And the occurrence of defects such as cracks in the thin film element layer 14 can be suppressed.

  Next, an example of an electronic apparatus including a thin film device manufactured by the manufacturing method described above will be described. The thin film device according to the present embodiment can be applied to the manufacture of a liquid crystal display panel, an electroluminescence display panel, and the like that constitute a display unit, a circuit unit, and the like in various electronic devices.

  FIG. 5 is a schematic perspective view illustrating an example of an electronic apparatus. FIG. 5A shows an application example to a mobile phone, and the mobile phone 530 includes an antenna portion 531, an audio output portion 532, an audio input portion 533, an operation portion 534, and a display portion 535. FIG. 5B shows an application example to a video camera. The video camera 540 includes an image receiving unit 541, an operation unit 542, an audio input unit 543, and a display unit 544. FIG. 5C illustrates an example of application to a television device, and the television device 550 includes a display portion 551. FIG. 5D illustrates an application example to a roll-up television device, and the roll-up television device 560 includes a display portion 561. Further, the thin film device according to the present invention is not limited to the above-described example, and can be applied to various electronic devices. For example, in addition to these, it can also be used for a fax machine with a display function, a finder for a digital camera, a portable TV, an electronic notebook, an electric bulletin board, a display for advertisements, and the like.

  The present invention is not limited to the contents of the above-described embodiments, and various modifications can be made within the scope of the gist of the present invention. For example, although the protective layer 16 is provided on the upper side of the thin film element layer 14 in the thin film device of the above-described embodiment, the protective layer may be included in the thin film element layer, or has a plurality of layers. May be.

  FIG. 6 is a schematic cross-sectional view illustrating another structural example of the thin film device. The thin film device shown in FIG. 6 basically has the same configuration as that of the thin film device shown in FIG. 1 described above, and the protective layer 16a is substantially entirely within the thin film element layer 14a. The difference is that it is provided so that Such a protective layer 16a is formed together with the thin film element layer 14a. Also with this configuration, the shrinkage of the adhesive layer 24 is suppressed, and it is possible to suppress the occurrence of defects such as cracks in the thin film element layer 14.

It is a schematic cross section explaining the structure of the thin film device of one Embodiment. It is sectional drawing which shows the specific example of a thin film element. It is process drawing explaining the specific example of the manufacturing method of a thin film device. It is process drawing explaining the specific example of the manufacturing method of a thin film device. It is a schematic perspective view which shows the example of an electronic device. It is a schematic cross section explaining the other structural example of a thin film device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Transfer source substrate, 12 ... Release layer, 14 ... Thin film element layer, 16 ... Protective layer, 18 ... Water-soluble adhesive, 20 ... Temporary transfer substrate, 22 ... Substrate, 24 ... Adhesive

Claims (4)

A substrate,
An adhesive layer provided on one side of the substrate;
A thin film element layer including a thin film element and bonded to one side of the substrate by the adhesive layer;
A protective layer made of a material having a thermal expansion coefficient substantially equal to the thermal expansion coefficient of the constituent material of the substrate, and provided to cover substantially the entire upper side of the thin film element layer;
A thin film device comprising: A substrate,
An adhesive layer provided on one side of the substrate;
A thin film element layer including a thin film element and bonded to one side of the substrate by the adhesive layer;
A protective layer made of a material having a thermal expansion coefficient substantially equal to the thermal expansion coefficient of the constituent material of the substrate, and provided in the thin film element layer so as to cover substantially the entire thin film element layer;
A thin film device comprising:   The thin film device according to claim 1, wherein the substrate is a resin substrate, and the protective layer is formed using a resin material. An electronic apparatus comprising the thin film device according to claim 1.

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