JP2006310635A - Thin-film forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve a thin-film forming method based on laser transfer while avoiding the contamination, decomposition, or modification of a transfer film. <P>SOLUTION: In the thin-film forming method based on laser transfer, a transfer substrate 5 is prepared which includes a glass base plate 1 for transmitting a laser beam 9 therethrough, an ablation layer (first organic film) 2 ablated with the irradiated laser beam 9, an organic film (second organic film) 3 mixed with carbon black to provide an effect of shielding the laser beam 9, and a transfer film 4 as a thin film (enzyme film) containing glucose oxidase sequentially laminated on the glass plate 1. The transfer film 4 of the transfer substrate 5 and a p-type silicon substrate (circuit board) 6 as a board to be transferred are provided to be opposed to each other with a spacer 7 on the circuit board 6 disposed therebetween. Thereafter, the ablation layer 2 is irradiated with the laser beam 9 from the side of the glass plate 1 to transfer a transfer film 4a onto the side of the circuit board 6. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for forming a thin film, and more particularly to a method for forming a thin film on a circuit board including circuit elements and the like.

  In recent years, circuit devices included in electronic devices and the like have become biosensors (semiconductors) that use enzyme membranes as well as circuit elements such as IC chips, capacitors, and resistors in order to reduce size, increase density, and increase functionality. Sensor) and the like are strongly required to be integrated on one circuit board. However, in the conventional method combining lithography and etching, it is necessary to perform lithography and etching a plurality of times, particularly when a plurality of different types of semiconductor sensors (enzyme films constituting the semiconductor sensor) are provided on a circuit board. For this reason, it has been difficult to produce a semiconductor sensor (an enzyme film constituting the semiconductor sensor) on a circuit board at a low cost.

  As a method for forming a thin film such as an enzyme film without using a conventional method combining lithography and etching, there is a thin film transfer method using laser light as disclosed in Patent Document 1.

FIG. 10 is an explanatory diagram of transfer of a transfer member to a transfer target member by the conventional laser transfer method disclosed in Patent Document 1. In FIG. 10, in the conventional transfer method using a laser, an ablation layer 111 ablated by the irradiated laser beam 113 and a transfer material layer 112 are sequentially laminated on a support layer 110 that transmits the laser beam 113. By irradiating the ablation layer 111 with the laser beam 113 from the support layer 110 side, the transfer material 112a is scattered and transferred to the transfer member 103 side. According to this method, it is possible to form a thin film such as an enzyme film in an extremely short time and at a low cost as compared with a method combining conventional lithography and etching.
JP-A-9-150582

  In the conventional laser transfer method, the transfer material 112a is transferred onto the transfer target member 103 by utilizing the ablation of the ablation layer 111 and rapid volume expansion. However, at this time, not only the transfer material 112a but also the material constituting the ablation layer 111 is transferred at the same time. Therefore, the transferred transfer material 112a is contaminated by the material constituting the ablation layer 111. It was difficult to prevent a decrease in the reliability of the material 112a.

  As the laser beam 113 used for laser transfer, a short-wavelength laser such as a harmonic YAG laser or an excimer laser is used because the energy threshold (processing threshold) for occurrence of ablation is small and the transfer pattern can be miniaturized. desirable. However, it is difficult to completely absorb the laser beam 113 only by the ablation layer 111, and a part of the irradiated laser beam 113 is also absorbed by the transfer material layer 112. Therefore, the material constituting the transfer material layer 112 is not suitable for transferring biomaterials and some polymer materials that are decomposed or altered by light in the ultraviolet region.

  The present invention has been made in view of such a situation, and an object thereof is to realize a thin film forming method by laser transfer that does not cause contamination, decomposition, or alteration of a transfer material.

  In order to achieve the above object, a thin film forming method according to the present invention includes a transfer substrate in which a first organic film, a second organic film, and a transfer film are sequentially stacked on one surface of a first substrate. The transfer film surface of the transfer substrate is disposed so as to face the second substrate, and the first organic film is expanded by irradiating laser light from the other surface of the first substrate. The transfer film is transferred onto the second substrate.

  According to this aspect, since the second organic film is interposed between the first organic film and the transfer film, the first organic film heated by the laser beam and the transfer film are not in direct contact with each other. It is possible to prevent the transfer film transferred onto the second substrate from being contaminated by the expanded first organic film. Therefore, the transfer of the transfer film having high reliability to the second substrate, which has been difficult to realize by the conventional thin film formation method by laser transfer, can be realized. Therefore, the reliability formed by the thin film formation method by laser transfer can be improved. A circuit device having a high transfer film can be provided.

  In the above configuration, the energy density of the laser beam is preferably larger than the processing threshold value of the first organic film and smaller than the processing threshold value of the second organic film. By doing so, since the second organic film that is not subjected to processing (ablation) by the laser light is interposed between the first organic film and the transfer film, the transfer film is more effectively the first film. It is possible to prevent contamination by the organic film. Furthermore, it is preferable that the second organic film shields the irradiated laser beam. By doing so, since the second organic film shields the laser light, the material constituting the transfer film can be prevented from being decomposed and altered by the laser light transmitted through the first organic film. .

  In the above structure, the transfer film is preferably transferred with an interval between the second substrate and the transfer film surface of the transfer substrate. By doing so, the transfer film can be transferred onto the second substrate without being affected by the surface state of the second substrate (such as a step existing on the surface of the second substrate). Further, since the distance from the surface of the second substrate can be controlled to be constant, the transfer film can be transferred onto the second substrate with good reproducibility and stability.

  According to the present invention, it is possible to realize a thin film formation method by laser transfer that does not cause contamination, decomposition, or alteration of the transfer film.

  1 to 6 are explanatory views of transfer of a transfer film to a circuit board by the thin film forming method of the embodiment of the present invention. Hereinafter, as an embodiment of the present invention, an example of manufacturing a circuit device including an ISFET (Ion Sensitive Field Effect Transistor) using a titanium sapphire laser having a wavelength of 800 nm will be described.

  In FIG. 1, a transfer substrate 5 shields laser light by mixing an ablation film 2 containing a copper phthalocyanine dye having a strong absorption band at a wavelength of 800 nm and carbon black on a glass plate 1 that transmits light having a wavelength of 800 nm. The organic film 3 having the effect of the above and the transfer film 4 transferred to a circuit board to be described later are sequentially laminated. The ablation film 2 is produced by applying, for example, an epoxy resin mixed with a dye with a roll coater. At this time, the thickness of the ablation film 2 is 1 μm or less. The organic film 3 is a PET film having an effect of shielding laser light by mixing carbon black. Furthermore, the transfer film 4 is a thin film (enzyme film) containing glucose oxidase, and is formed by spin coating. The glass substrate 1 is an example of the “first substrate” in the present invention, the ablation film 2 is an example of the “first organic film” in the present invention, and the organic film 3 is an example of the “second organic film” in the present invention. .

  As shown in FIG. 2, the transfer film 4 of the transfer substrate 5 made of this laminated film and the p-type silicon substrate (circuit substrate) 6 that is a transfer target substrate are opposed to each other via a spacer 7. The spacer 7 is made of a polysilicon film on the silicon substrate 6 and has a height of 1 to 2 μm. As a result, a certain distance is provided between the silicon substrate 6 and the transfer film 4 of the transfer substrate 5. Here, a thermal oxide film (not shown) is formed on the surface of the silicon substrate 6, and further source / drain regions 8 are provided by ion implantation. Further, an integrated circuit portion (not shown) having a function of amplifying and detecting a current change between the source and drain is formed in the silicon substrate 6 and is electrically connected to the source and drain regions. ing. The p-type silicon substrate (circuit substrate) 6 is an example of the “second substrate” in the present invention.

As shown in FIG. 3, the silicon substrate 6 is moved to a portion corresponding to the channel of the source and drain regions, and the titanium sapphire laser light 9 is irradiated from the glass substrate 1 side so that the transfer film 4 is transferred. Here, as shown in FIG. 4, the titanium sapphire laser light 9 to be irradiated exits from the transmitter 11 and passes through a mechanical shutter 12 that enables single pulse irradiation. The diameter is shaped. By exchanging this mask, it is possible to arbitrarily change the condensing diameter and condensing shape of the laser, and the spot diameter is adjusted to be 50 μm square. Further, the energy of the irradiated laser is adjusted in advance so as to be higher than the processing threshold of the ablation film 2 and lower than the processing threshold of the organic film 3, and is adjusted to about 1 J / cm ² in the first embodiment of the present invention. The irradiation position of the laser beam can be changed at high speed by the scanning mirror 14.

  As shown in FIG. 5, since the ablation film 2 irradiated with the laser light 9 contains copper phthalocyanine as a pigment, it strongly absorbs the laser light 9 having a wavelength of 800 nm and is ablated. That is, the ablation film 2 is explosively melted, evaporated or sublimated to become the ablation film 2a. Since a high pressure is generated simultaneously with this ablation, the organic film 3 and the transfer film 4 are deformed so as to swell toward the p-type silicon substrate 6 by the pressure. In addition, since the energy of the laser beam 9 to be irradiated is adjusted in advance to be lower than the processing threshold value of the organic film 3, the organic film 3 is not ablated.

  As a result, as shown in FIG. 6, a part of the thin film containing glucose oxidase (transfer film 4a) is pressed against the silicon substrate 6 and transferred stably and reproducibly to a predetermined channel portion. The ablated film 2 that has been ablated is then cooled and becomes solid again, and remains between the glass substrate 1 and the organic film 3.

  Further, since the organic film 3 having an effect of shielding the laser light by mixing carbon black exists between the ablation film 2 and the transfer film 4, the transfer film 4a is directly heated by the laser light 9. Or can be prevented from being decomposed or altered.

  Finally, as shown in FIG. 7, by separating the transfer substrate 5 from the circuit substrate 6, the circuit substrate 6 provided with the transfer film 4a is obtained.

  As described above, in the embodiment of the present invention, problems such as contamination of the transfer material due to the ablation material and decomposition / degeneration of the transfer material, which has been a problem in the conventional laser transfer method, do not occur. Therefore, the transfer film (glucose oxidase) 4a Since a decrease in reliability can be suppressed, a highly accurate ISFET (semiconductor sensor) using glucose oxidase as a transducer on the circuit board 6 can be realized.

  Moreover, in the said embodiment, although the case where the glass plate 1 was used as a support substrate was shown, the support substrate does not necessarily need to be plate-shaped, and it is an ablation film | membrane on the transparent film 1a which permeate | transmits the laser beam 9 to be irradiated. 2, the multilayer film 5a in which the organic film 3 and the transfer film 4 are sequentially formed may be wound around a drum and supplied. According to this method, the drum can be fed each time the transfer in the scanning area of the scanning mirror is completed and the laser beam 9 can be repeatedly irradiated, so that the cost can be reduced and the productivity can be improved.

  FIG. 8 is a diagram showing a circuit device in which a semiconductor sensor and circuit elements formed by using the embodiment of the present invention are mounted on one circuit board. In this case, two semiconductor sensors are mounted. This circuit device 20 prepares a circuit board 6a on which circuit elements (electronic components) 16 are mounted, and repeats the thin film forming method by laser transfer shown in FIGS. 1 to 7 in a predetermined region where semiconductor sensors 15a and 15b are provided. Thus, a thin film such as an enzyme film is formed, and the corresponding semiconductor sensors 15a and 15b are formed. By doing in this way, compared with the method of combining the conventional lithography and etching, it becomes possible to manufacture the circuit device 20 in a very short time and at a low cost.

  Furthermore, although the case where an enzyme film (a thin film containing glucose oxidase) is used as the transfer film 3 has been described in the above embodiment, a copper foil can be applied as the transfer film 3.

  Hereinafter, as an example of using a copper foil as the transfer film 3, a case where a spiral inductor made of a copper foil is formed on the printed wiring board 6b will be described with reference to FIG. FIG. 9 is an explanatory diagram of transfer of copper foil to a printed wiring board by the thin film forming method of the embodiment of the present invention. The difference from the previous embodiment is that the transfer film 4 is a copper foil, the circuit board 6 is a printed wiring board, and the spacer 7 is made of a resist.

  First, a transfer substrate 5b using a copper foil is formed by forming an ablation film 2 and an organic film 3 on a glass substrate 1, and then sputtering, electrolytic plating, or copper foil film 4b on the organic film 3. It is formed by thermocompression bonding or the like. The thickness of the copper foil 4b as a transfer film is 5 μm.

  Next, the copper foil 4b of the transfer substrate 5b and the printed wiring board 6b are opposed to each other through a spacer 7b made of resist. The height of the spacer is several μm.

  Thereafter, the printed wiring board 6b is moved to a desired position where the spiral inductor is formed, and the titanium sapphire laser light 9 is irradiated from the glass substrate 1 side so that the copper foil 4b is transferred. As a result, the copper foil 4b is transferred onto the printed wiring board 6b based on the same principle as described in the previous embodiment.

  Since the wiring pattern 4c constituting the spiral inductor to be transferred is determined by the scanning of the scanning mirror 14 shown in FIG. 4, it is not necessary to create a mask each time as in the conventional photolithography method. Any shape can be produced on 6b. For this reason, the manufacturing cost of the printed wiring board which has a spiral inductor can be reduced.

  Further, since the transferred copper foil 4c is not contaminated by the ablated material as in the conventional laser transfer method, it is formed with a reproducible and stable film quality, so that variation in inductance value can be reduced. Is possible.

  As described above, when a copper foil is applied as the transfer film 3, a printed wiring board in which a spiral inductor made of copper foil is formed on a printed wiring board with high accuracy and extremely small characteristic variation is provided. Can do.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

It is explanatory drawing of transcription | transfer to the circuit board of the transfer film by the thin film formation method of embodiment of this invention. It is explanatory drawing of transcription | transfer to the circuit board of the transfer film by the thin film formation method of embodiment of this invention. It is explanatory drawing of transcription | transfer to the circuit board of the transfer film by the thin film formation method of embodiment of this invention. It is the schematic of the laser irradiation apparatus used for the laser transfer by embodiment of this invention. It is explanatory drawing of transcription | transfer to the circuit board of the transfer film by the thin film formation method of embodiment of this invention. It is explanatory drawing of transcription | transfer to the circuit board of the transfer film by the thin film formation method of embodiment of this invention. It is explanatory drawing of transcription | transfer to the circuit board of the transfer film by the thin film formation method of embodiment of this invention. It is a figure which shows the circuit apparatus which mounted the semiconductor sensor and circuit element which were formed using embodiment of this invention on one circuit board. It is explanatory drawing of transcription | transfer to the printed wiring board of the copper foil by the thin film formation method of embodiment of this invention. It is explanatory drawing of transfer to the to-be-transferred member of the transfer member by the conventional laser transfer method.

Explanation of symbols

1 Glass substrate 2 Epoxy resin mixed with pigment (ablation film)
3 PET film mixed with carbon black (organic film)
4 Thin film containing glucose oxidase (transfer film)
4a Transferred transfer film 5 Transfer substrate 6 p-type silicon substrate (circuit board)
7 Spacer (Polysilicon film)
8 Source / drain region 9 Titanium sapphire laser light 15, 15a, 15b Semiconductor sensor 16 Electronic component (circuit element)
20 Circuit equipment

Claims (4)

A transfer substrate in which a first organic film, a second organic film, and a transfer film are sequentially laminated on one surface of the first substrate, and the transfer film surface of the transfer substrate is opposed to the second substrate. Place and
Irradiating a laser beam from the other surface of the first substrate to expand the first organic film, and transferring the transfer film onto the second substrate through the second organic film; Thin film forming method.   2. The thin film forming method according to claim 1, wherein an energy density of the laser light is larger than a processing threshold of the first organic film and smaller than a processing threshold of the second organic film.   The thin film forming method according to claim 1, wherein the second organic film shields the irradiated laser beam.   The thin film formation according to any one of claims 1 to 3, wherein the transfer film is transferred with an interval between the second substrate and the transfer film surface of the transfer substrate. Method.

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