JP6942588B2 - Organic semiconductor manufacturing method and light irradiation equipment - Google Patents

Description

The present invention relates to a technique for manufacturing an organic semiconductor, and more particularly to a technique for improving the crystallinity of an organic semiconductor used as a semiconductor element.

For example, for the purpose of manufacturing display devices, touch panel devices, flexible sensors, etc., technologies for forming thin film semiconductor elements such as thin film transistors on the surface of substrates such as glass substrates and resin substrates including flexible sheets and films have been studied. ing. Particularly in recent years, organic semiconductors have been attracting attention as materials for such thin film semiconductor devices from the viewpoint that their performance and production technology have been remarkably improved and that it is possible to create devices using printing technology depending on the material. .. Further, miniaturization for improving performance (for example, the line width of an organic semiconductor pattern is 20 μm or less) is progressing.

It is known that the crystallinity of an organic semiconductor material affects the device performance as well as the inorganic semiconductor material. For example, the carrier mobility shows a high value in a single crystal organic semiconductor material, and the carrier mobility decreases as the crystallinity deteriorates. Therefore, in order to manufacture a semiconductor device having good performance, it is necessary to improve the crystallinity of the organic semiconductor material. Ideally, one semiconductor device is preferably composed of a single crystal organic semiconductor.

For example, the technique described in Patent Document 1 is a technique for producing a large-area organic semiconductor single crystal. In this technique, a concave pattern having a narrow seed crystal portion and a crystal growth portion having a continuously widening width is formed on a substrate, and a liquid containing an organic semiconductor material is supplied from the seed crystal portion to the crystal growth portion. By sequentially proceeding with and drying, a single crystal having a large area is to be obtained.

Further, the technique of Patent Document 2 is to irradiate a liquid film containing an organic semiconductor material formed on a substrate with laser light to crystallize it, and in order to improve the crystallinity of the thin film, the liquid film is subjected to. The laser beam is scanned along one scanning direction. In the technique of Patent Document 2, laser light irradiation is performed for the purpose of giving an appropriate amount of heat to the liquid film to dry and crystallize it, and single crystallization of an organic semiconductor is an indispensable purpose. No.

Japanese Unexamined Patent Publication No. 2014-216568 Japanese Unexamined Patent Publication No. 2014-179371

The above-mentioned conventional technique manufactures an organic semiconductor thin film having a relatively large area. On the other hand, for example, in the manufacture of display devices and the like, a large number of fine semiconductor elements are manufactured on one substrate. The above-mentioned prior art is not suitable for the purpose of obtaining good crystallinity in each of such semiconductor elements. Patent Document 2 mentions selectively forming a liquid film only in a necessary region, irradiating light, and the like, but does not describe a specific manufacturing method. As described above, when a large number of semiconductor elements are embedded in a substrate, a technique capable of producing individual organic semiconductors with excellent crystallinity has not been established so far. In addition, the organic semiconductor element formed on the flexible film causes expansion and contraction of the film during transportation and manufacturing processes, and the organic semiconductor pattern shifts from the design data, making accurate laser irradiation difficult. It has become.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a technique capable of forming an organic semiconductor constituting a semiconductor element on a substrate as a crystal having good crystallinity.

One aspect of the method for producing an organic semiconductor according to the present invention is a step of forming a pattern of a liquid containing an organic semiconductor material on a substrate and applying a light beam to the coated liquid in order to achieve the above object. It includes a step of irradiating and crystallizing the organic semiconductor. Here, the irradiation of the light beam corresponds to the pattern of the substrate by executing intermittent emission of the light beam and control of the incident position of the emitted light beam on the substrate. This is executed by an irradiation device capable of selectively irradiating the irradiation target area specified by the irradiation data with the light beam.

Then, the irradiation device executes the first step of irradiating the light beam with respect to the continuous pattern, with the primary irradiation region, which is a partial region including the peripheral portion of the pattern, as the irradiation target region. Later, in the pattern, the light beam is irradiated with the secondary irradiation area including the boundary between the irradiated area irradiated with the light beam and the unirradiated area or adjacent to the boundary as the irradiation target area. The entire pattern is crystallized by performing the step at least once.

In the invention configured as described above, the light beam is first irradiated to the primary irradiation region, which is a partial region including the peripheral portion of the pattern formed of the liquid containing the organic semiconductor material. As a result, minute crystals of the organic semiconductor are formed in a part of the pattern (first step). Next, the light beam is applied to the secondary irradiation area including the boundary between the irradiated area that has already been irradiated with the light beam and the unirradiated area that has not been irradiated with the light beam, or the secondary irradiation area adjacent to the boundary. (Second step).

At this time, large crystal grains can be obtained by proceeding with crystallization around the crystal of the organic semiconductor that has already been irradiated with the light beam and crystallized. By sequentially irradiating the entire pattern with a light beam to promote crystallization, large crystals can be grown on the substrate over the entire pattern. That is, according to the present invention, an organic semiconductor can be produced as a crystal having good crystallinity on a substrate.

Further, in one aspect of the light irradiation device according to the present invention, in order to achieve the above object, a substrate holding portion for holding a substrate on which a pattern formed by a liquid containing an organic semiconductor material is formed, and an intermittent light beam. The irradiation data of the substrate is controlled by controlling the light irradiation unit that executes the adjustment of the incident position of the emitted and emitted light beams on the substrate and the light irradiation unit based on the irradiation data according to the pattern. It is provided with a control unit that selectively irradiates the light beam to the irradiation target region specified by. Then, for one continuous pattern, after irradiating the light beam with the primary irradiation region, which is a partial region including the peripheral portion of the pattern, as the irradiation target region, the irradiation of the light beam of the pattern is performed. By executing the irradiation of the light beam including the boundary between the irradiated area and the unirradiated area or having the secondary irradiation area adjacent to the boundary as the irradiation target area at least once, the entire pattern is covered. Crystallize.

The invention configured in this way has a configuration suitable for carrying out the above-mentioned method for producing an organic semiconductor. That is, by performing the crystallization process of the organic semiconductor using the light irradiation apparatus according to the present invention, the organic semiconductor can be produced as crystals having good crystallinity on the substrate.

As described above, according to the present invention, a part of the pattern formed by the liquid containing the organic semiconductor material, including the peripheral portion, is first irradiated with light to start crystallization, and the irradiated region and the non-irradiated region are not. Since the region including the boundary with the irradiation region or the region adjacent to the irradiation region is sequentially irradiated with light to proceed with crystallization, an organic semiconductor having good crystallinity can be produced on the substrate.

It is a figure which shows the structural example of the semiconductor element which can apply the manufacturing method of the organic semiconductor which concerns on this invention. It is a flowchart which illustrates the manufacturing process of this semiconductor element. It is a flowchart which shows the manufacturing method of an organic semiconductor layer. It is a schematic diagram which shows the example which a plurality of semiconductor elements are provided on a substrate. It is a figure which shows the main structure of one Embodiment of the light irradiation apparatus which concerns on this invention. It is a figure which shows the mode of the light irradiation control in this light irradiation apparatus. It is a figure which illustrates the relationship between the pattern of an organic semiconductor and a pixel on a substrate. It is a flowchart which shows the light irradiation process. It is the first figure which shows the irradiation pattern of the light which irradiates a substrate, and its transition. It is a 2nd figure which shows the irradiation pattern of the light which irradiates a substrate, and its transition. It is a 3rd figure which shows the irradiation pattern of the light which irradiates a substrate, and its transition. It is a 4th figure which shows the irradiation pattern of the light which irradiates a substrate, and its transition.

FIG. 1 is a diagram showing a configuration example of a semiconductor element to which the method for producing an organic semiconductor according to the present invention can be applied. Further, FIG. 2 is a flowchart illustrating the manufacturing process of this semiconductor element. As will be described in detail later, the method for manufacturing an organic semiconductor of the present invention can be carried out, for example, as part of a manufacturing process for manufacturing an organic thin film transistor illustrated in FIG.

The organic thin film transistor TR can be manufactured, for example, as follows. As shown in FIG. 1A, the source electrode Es and the drain electrode Ed are formed on the surface of the pre-cleaned (step S101) substrate SB so as to be separated from each other (step S102). As the substrate SB, for example, an inorganic semiconductor substrate such as silicon, a glass substrate, a resin substrate containing a flexible sheet or film, a sheet-shaped substrate containing transitions such as paper, or the like can be used. Further, the substrate may be a substrate in which an insulating layer is formed on the surface of a conductive flat plate such as a metal plate.

The method of forming the source electrode Es and the drain electrode Ed is arbitrary. For example, a method of laminating a metal as an electrode material on a substrate SB by vacuum vapor deposition, sputtering film formation, plating, or the like can be used. Further, a method of partially removing the metal film previously formed on the entire surface of the substrate SB by etching may be used. Further, for example, a method may be used in which a liquid layer containing an electrode material is formed on the substrate SB by coating or printing, and the liquid layer is dried and cured.

Next, as shown in FIG. 1B, a layer OS of an organic semiconductor is formed so as to cover the surfaces of these electrodes Es and Ed (step S103). Various methods can be applied as a method for forming the organic semiconductor layer OS, but in the present invention, the liquid containing the organic semiconductor material is partially coated on the region of the substrate SB on which the organic semiconductor layer should be formed. Then, a method of crystallizing this by light irradiation is used. The specific processing content will be described later.

Next, as shown in FIG. 1C, a gate insulating film IS covering the surface of the organic semiconductor layer OS is formed (step S104). The gate insulating film IS can be formed, for example, by applying a liquid containing an insulator material to the surface of the organic semiconductor layer OS and drying and curing the liquid. Further, for example, a method of forming an insulating film such as a metal oxide by CVD (Chemical Vapor Deposition) may be used.

Next, as shown in FIG. 1D, a gate electrode Eg is formed on the surface of the gate insulating film IS (step S105). The gate electrode Eg can be formed by the same method as the source electrode Es and the like, but the manufacturing method may be different between step S102 and step S105.

In this way, a channel Ch made of an organic semiconductor is formed between the source electrode Es and the drain electrode Ed, and an organic thin film transistor TR provided with a gate electrode Eg facing the channel Ch via the gate insulating film IS is formed. NS. The organic thin film transistor TR formed in this way is subjected to appropriate post-processing such as further wiring connection and sealing processing (step S106) to complete the organic thin film transistor TR as a semiconductor element.

The organic semiconductor material used is not particularly limited, and various materials that have been put into practical use can be applied. In particular, those having the property of crystallizing and curing by heating by light irradiation or a photochemical reaction are preferable.

Here, the semiconductor element formed on the substrate SB is a single organic thin film transistor TR, but in reality, a large number of semiconductor elements are formed on one substrate SB. For example, in an organic EL display device, a liquid crystal display device, or the like, millions of thin film transistors are formed on one substrate as a switching element. In this case, for example, the gate insulating film IS may be continuous between a plurality of elements.

FIG. 3 is a flowchart showing a method for manufacturing an organic semiconductor layer. More specifically, FIG. 3A is a flowchart describing the processing contents of step S103 of FIG. 2 in more detail, and FIG. 3B is a diagram schematically showing the state of the element in the processing process. be. When the organic semiconductor layer OS is formed on the substrate SB on which the source electrode Es and the drain electrode Ed are formed, a wet treatment for forming a self-assembled monolayer (SAM) is executed on the electrode surface. (Step S201). This is a process for modifying the electrode surface to reduce the electrical resistance at the interface with the organic semiconductor layer OS. There are various known techniques for such SAM processing, and they can be appropriately selected and used, and thus the description thereof will be omitted here.

Next, a pattern of the organic semiconductor material is formed by partially adhering the liquid containing the organic semiconductor material to the surface of the substrate SB so as to cover the electrodes Es and Ed (step S202). This pattern corresponds to the shape of the semiconductor element to be formed. Various methods can be adopted as the pattern forming method. For example, as shown in the upper and middle stages of FIG. 3B, the pattern PT can be transferred from the blanket BL to the substrate SB by pressing the blanket BL supporting the pattern PT of the organic semiconductor material against the substrate SB.

As a method of supporting the pattern PT on the blanket BL, it is possible to use a printing technique using a letterpress, intaglio or lithographic plate. Further, the pattern PT may be transferred directly from the letterpress or lithographic plate to the substrate SB. In addition, the pattern PT can be formed on the substrate SB by using various methods such as silk screen printing and inkjet printing.

When the pattern PT is formed on the substrate SB, the pattern PT is in a liquid state. By irradiating this with light having an appropriate wavelength according to the material, the organic semiconductor material in the liquid is crystallized and the solvent is volatilized to form the organic semiconductor layer OS (step S203). At this time, in order to improve the crystallinity of the organic semiconductor layer OS and ideally make the entire organic semiconductor layer OS a single crystal, as shown in the lower part of FIG. 3B, the light beam L has a pattern PT. Is scanned from one end to the other end of the. As a result, crystal growth proceeds from one end to the other end of the pattern PT. That is, by scanning the light beam L, the crystallized crystallized region Rc of the pattern PT grows toward the liquid region Rl that remains liquid, and finally the entire pattern PT crystallizes.

If a single semiconductor element is formed on the substrate SB, as shown in the lower part of FIG. 3B, the light beam L is scanned against the pattern PT at a speed corresponding to the crystal growth rate to form a single crystal. It is possible to plan. However, as described above, in an actual device, a large number of semiconductor elements are provided on one substrate. Therefore, such a process that requires a long time is not realistic.

FIG. 4 is a schematic view showing an example in which a plurality of semiconductor elements are provided on the substrate. More specifically, FIG. 4A is a diagram showing an example in which a plurality of transistors are arranged on a substrate, and FIG. 4B is a perspective view showing the shape of each transistor. In FIG. 4, in order to explain the manufacturing process of the organic semiconductor layer OS, the outer shape of the transistor TR at the time when the organic semiconductor layer OS is laminated on the electrodes Es and Ed is shown instead of the finished product of the organic thin film transistor TR. Shown. Therefore, the cross-sectional views taken along the line AA in FIGS. 4 (a) and 4 (b) correspond to FIG. 1 (b).

For example, in a display device such as an organic EL display or a liquid crystal display, as shown in FIG. 4A, a large number of transistors TR are arranged in a matrix on one substrate SB. Here, transistors TR having the same shape and facing the same direction are arranged at equal pitches, but the actual device is not limited to this, and elements having different sizes, shapes, arrangement directions, and the like may coexist. The method for manufacturing an organic semiconductor using the light irradiation device shown below can be easily modified according to various element shapes, and can cope with such a case where elements that are not the same are mixed.

FIG. 5 is a diagram showing a main configuration of an embodiment of the light irradiation device according to the present invention. The light irradiation device 1 is a device that crystallizes an organic semiconductor by irradiating a substrate SB on which a pattern PT is formed with a liquid containing an organic semiconductor material as described above with a light beam. The light irradiation device 1 includes a light source unit 11, a light modulation unit 13, a projection optical system 15, a stage 17, and a control unit 20 that controls their operations. In FIG. 5, the horizontal plane is the XY plane, and the vertically upward direction is the Z direction. Further, the rotation direction around the Z axis is the θ direction.

The light source unit 11 has a laser light source such as a semiconductor laser or a gas laser, and emits the laser light L1 to the light modulation unit 13. When the organic semiconductor material is crystallized by heat, the wavelength of the laser beam L1 is in the infrared band. When the organic semiconductor material is crystallized by ultraviolet rays, the wavelength of the laser beam L1 is in the ultraviolet band. The light source is not limited to the laser light source, and may be, for example, a lamp light source. The light source unit 11 is controlled by the light source control unit 21 of the control unit 20, and intermittently emits the laser beam L1 in response to a control command from the light source control unit 21.

The light modulator 13 modulates the laser light L1 incident from the light source unit 11 and outputs the modulated light L3. More specifically, by modulating the laser light L1 with an appropriate light modulation device, the light output from the light modulator 13 is turned on and off and the emission direction thereof is changed. As the optical modulation device, various known technologies, that is, those using a galvanometer mirror, for example, and a MEMS (Micro) such as a digital micromirror device (Digital Micromirror Device).
Mechanical Electro Systems device, grating light valve (Grating)
In addition to a light valve (registered trademark) device that controls the light emission direction, for example, a device that generates a plurality of beams from one beam using a nonlinear optical crystal can be applied. These may be combined appropriately. The on / off of the optical output from the light modulator 13 and the emission direction thereof are controlled by the modulation control unit 23 of the control unit 20. The modulated light L3 output from the light modulator 13 is incident on the projection optical system 15.

The projection optical system 15 includes several optical elements such as a lens, converges the modulated light L3 incident from the light modulator 13, and directs an optical beam toward a substrate SB mounted on a lower stage 17. Fire as L5. The projection optical system 15 has a focus adjustment mechanism (not shown), and the light beam L5 converges on the surface (upper surface) of the substrate SB when the focus adjustment unit 25 provided in the control unit 20 drives the focus adjustment mechanism. do.

The upper surface of the stage 17 is a plane larger than the plane size of the substrate SB, and holds the substrate SB placed on the plane. A heater 171 is built in the stage 17, and the heater 171 is controlled by the heater control unit 271 of the control unit 20. The upper surface of the stage 17 is raised to a predetermined temperature by the control from the heater control unit 271. As a result, the substrate SB placed on the stage 17 is heated.

The stage 17 is supported by the stage moving mechanism 172. The stage moving mechanism 172 is controlled by the stage control unit 272 of the control unit 20, and moves the stage 17 in the XYθ direction in response to a control command from the stage control unit 272.

By combining the position adjustment of the light beam in the XY direction by the optical modulation unit 13 and the movement of the stage 17 in the XYθ direction by the stage moving mechanism 172, the light beam L5 is placed at an arbitrary position on the substrate SB on the stage 17. It can be incident.

In the control unit 20, each functional block such as the light source control unit 21, the modulation control unit 23, the focus adjustment unit 25, the heater control unit 271 and the stage control unit 272 may be realized by dedicated hardware. , A general-purpose central processing unit (CPU) including an arithmetic processor may be realized by software by executing a program prepared in advance.

The control unit 20 is further provided with a memory 28 for storing irradiation data referred to by the light source control unit 21, the modulation control unit 23, and the stage control unit 272. As will be described later, the light irradiation device 1 selectively irradiates the pattern PT formed on the substrate SB and its surroundings with a light beam. The irradiation data describes information indicating when the light beam is incident on the substrate SB at what position, and each part of the device adjusts the on / off of the light beam emission and the incident position based on the irradiation data. Selective light irradiation to the pattern PT and its surroundings is realized.

To make this possible, the irradiation data is determined based on the information representing the position and shape of the pattern PT of the organic semiconductor formed on the substrate SB. Since this information is specified at the time of designing the semiconductor element, it can be grasped from the design data. Hereinafter, the mode of light irradiation of the pattern PT in the light irradiation device 1 will be described. In other words, irradiation data may be created so that light irradiation can be realized in such a mode. In order to associate the irradiation data with the position of the pattern PT of the organic semiconductor on the substrate SB and appropriately irradiate the pattern PT with light, an alignment mark is formed on the substrate SB, and the alignment mark is read by a camera or the like. The relative position between the reference position of light irradiation and the reference position of the substrate may be adjusted.

FIG. 6 is a diagram showing an aspect of light irradiation control in this light irradiation device. As shown in FIG. 6, a large number of minute pixels arranged in a two-dimensional matrix in the X direction and the Y direction are assigned to each position of the substrate SB mounted on the stage 17. The light irradiation device 1 can turn on / off the light beam L5 and adjust its incident position on a pixel-by-pixel basis. For example, when the light incident position determined by the light modulator 13 and the projection optical system 15 is sequentially moved on the substrate SB in the X direction and the Y direction in pixel units, and the pixel is the position to be irradiated with light. Only the light beam L1 is emitted from the light source unit 11.

In this case, the light irradiation device 1 scans the substrate SB in the X direction and the Y direction with the light beam L5 while intermittently emitting the light beam L5 to the substrate SB according to the shape of the region to be irradiated with light. become. By repeating this operation as necessary, the substrate SB can be scanned a plurality of times with the light beam L5. That is, each pixel on the substrate SB is provided with a plurality of opportunities to be irradiated with light.

The irradiation data indicates at what timing the light beam L5 is incident on all the pixels assigned to the substrate SB. As such light irradiation control, for example, a technique practically used in an exposure apparatus used in a photolithography technique can be used.

FIG. 7 is a diagram illustrating the relationship between the organic semiconductor pattern and the pixels on the substrate. As an example, the light in the present embodiment shows the relationship between the position of the pattern PT of the organic semiconductor layer OS to be formed on the substrate SB and the position of the pixels allocated on the substrate SB as shown in FIG. The details of the irradiation process and specific examples thereof will be described.

FIG. 8 is a flowchart showing the light irradiation process. This process is executed by the control unit 20 executing a program recorded in the memory 28 in advance to cause each unit of the device to perform a predetermined operation. It is assumed that the substrate SB on which the liquid pattern PT containing the organic semiconductor material is formed is placed on the stage 17 in advance, and the focus of the projection optical system 15 is aligned with the surface of the substrate SB. Further, it is assumed that the relative position between the pattern PT of the organic semiconductor on the substrate SB and the irradiation position of the light beam specified by the irradiation data on the substrate SB is adjusted by using an alignment mark or the like.

In this light irradiation process, the light beam scans the entire substrate SB once, so that each of the plurality of pattern PTs arranged on the substrate SB has an opportunity of one light irradiation. Then, by scanning the light beam on the substrate SB a plurality of times, there is an opportunity for each pattern PT to be irradiated with light a plurality of times. Of these opportunities, when the light beam L5 is actually emitted from the projection optical system 15, the pattern PT is irradiated with light.

The irradiation pattern representing the arrangement of the pixels that irradiate the light and the pixels that do not irradiate the light in one scan is sequentially changed according to the number of scans. In FIGS. 9 to 12 described later, an irradiation pattern for one of a large number of pattern PTs formed on the substrate SB and its transition are shown, but in reality, an irradiation pattern corresponding to the entire substrate SB is prepared. .. The data representing the irradiation pattern in each scan is the above-mentioned irradiation data.

In the light irradiation process, as shown in FIG. 8, the internal parameter N in the process is set to the initial value 1 (step S301). This parameter N represents the number of scans of the light beam that is subsequently executed. Subsequently, the irradiation data representing the irradiation pattern in the Nth optical scan is read from the memory 28 (step S302). The scan performed with the parameter N set to 1 is the first optical scan.

Then, based on the read irradiation data, the light source unit 11, the optical modulation unit 13, and the stage moving mechanism 172 are operated to perform the first scanning by the light beam L5 (step S303). As a result, the light beam is selectively irradiated to the region of the substrate SB specified by the irradiation pattern.

Next, the internal parameter N and the predetermined value Nmax corresponding to the substrate SB are compared (step S304). This value Nmax corresponds to the maximum number of scans required to perform the required light irradiation on all of the pattern PTs formed on the substrate SB. If the parameter N reaches this maximum number of scans Nmax (YES in step S304), it means that the light irradiation is completed for all the pattern PTs formed on the substrate SB. Therefore, the process is terminated at this time.

On the other hand, if the parameter N does not reach the maximum number of scans Nmax (NO in step S304), it means that the pattern PT in which the light irradiation to the whole is not completed is left. Therefore, the value of the parameter N is incremented by one (step S305), and the process returns to step S102. In this way, the second, third, ..., Scannings are performed as necessary with the irradiation patterns prepared for each scan. It is preferable that the start time of each scan follows a fixed cycle. When the required number of scans is completed, the light irradiation process is completed.

9 to 12 are diagrams showing an example of an irradiation pattern of light irradiated to the substrate in this process and its transition. In the following description, of the surface regions of the substrate SB and the structure formed on the substrate, the regions that have already been irradiated with the light beam are referred to as “irradiated regions” and are shown by relatively coarse diagonal lines in the figure. In addition, the area that has not been irradiated yet is referred to as an "unirradiated area" and is represented by a white background in the figure. Further, the region that is collectively irradiated with the light beam in each scan is referred to as an “irradiation target region”, and is indicated by a relatively fine diagonal line in the figure.

FIG. 9 is a diagram showing an irradiation pattern in a case in which the relationship with the positions of pixels allocated on the substrate SB is represented as shown in FIG. 7. The irradiation pattern in the first scan is shown in FIG. As shown with diagonal lines, in the first scan, light irradiation is performed on one pixel including the peripheral portion of the pattern PT of the organic semiconductor. That is, the region R11 occupied by the pixels is set as the irradiation target region in the first scan. This region R11 will be referred to as a "primary irradiation region" below. In this example, the position of the pixel including the upper left corner of the peripheral edge of the rectangular pattern PT is defined as the primary irradiation region R11.

The primary irradiation region R11 is a minute partial region of the pattern PT including the peripheral portion thereof. When this region is first irradiated with a light beam, the liquid forming the pattern PT is locally heated in this region, and crystallization of the organic semiconductor begins. It is preferable that the primary irradiation region R11 is as small as possible in order to prevent crystallization from starting at a plurality of locations in a wide region. This requirement is satisfied by setting the region for one pixel, which is the smallest feasible size, as the primary irradiation region R11.

If the substrate SB is preheated by the stage 17 incorporating the heater 172, crystallization is further promoted. In order to prevent crystallization from being started by preheating, it is desirable that this preheating temperature is lower than the crystal transition temperature of the organic semiconductor material.

Since the irradiation region is small, the crystals at this time are minute. In other words, in order to start crystallization from such a minute region, the primary irradiation region R11 is located at the position of the pixel including the peripheral portion of the pattern PT, that is, the entire region is not included inside the pattern PT. Set. And at this point, most of the other patterns PT have not yet crystallized. As described above, in the first scan, crystallization is started only in a small part of the pattern PT. In the second and subsequent scans, single crystals are achieved by sequentially growing the crystals with the small crystals thus formed as nuclei.

When scanning the light beam is performed by moving the beam in a predetermined direction (for example, the X direction), for the primary irradiation region R11, among the pixels including the peripheral portion of the pattern PT, those on the most upstream side in the scanning direction It is desirable to set it to the occupied position. In this way, it is possible to continuously irradiate the irradiation target region set at the positions of the pixels continuous along the scanning direction in the subsequent scanning described below. In addition, crystal growth can proceed along the scanning direction of the light beam.

The irradiation pattern in the second scan is shown in FIG. Here, the region R11 irradiated with light in the first scan is indicated by a coarse diagonal line. On the other hand, it is the region R12 indicated by the fine diagonal lines that receives the light irradiation in the second scan. This region R12
(1) Not yet irradiated with light,
(2) At least a part is included in the pattern PT,
(3) Adjacent to the area that has been irradiated with light by the conventional light irradiation,
This is the area occupied by all the pixels that meet the conditions of. In this example, the pixels adjacent to the right side of the region R11 irradiated with light in the first scan, the pixels below the region R11, and the pixels immediately below the region R11 correspond to each other. Here, a region that shares only the vertices with a region that has already been irradiated with light is also included in the concept of "adjacent".

The second light irradiation is performed with the region R12 occupied by these pixels as the irradiation target region. The irradiation target region R12 is a region of the pattern PT that is adjacent to all the boundaries between the irradiated region R11 that was irradiated with light in the first scan and the other non-irradiated regions. As a result, crystallization of the organic semiconductor proceeds in the region, but crystals have already been formed in the adjacent region R11. Therefore, it is expected that crystal growth will proceed around this and large crystal grains will grow. In this example, crystal growth proceeds from the upper left corner of the pattern PT toward the right and downward.

The irradiation target area in the second and subsequent scans is referred to as a "secondary irradiation area" in the present specification. This is because the primary irradiation region where the light is irradiated in the first scan is a special region for forming the crystal nucleus, whereas the irradiation target regions in the second and subsequent scans are all. This is because they have the common feature of having the effect of further growing the crystals that have already been formed.

The irradiation pattern in the third scan is shown in FIG. Here, the regions R11 and R12 that have been irradiated with light in the scans up to the second scan are shown by coarse diagonal lines. On the other hand, it is the region R13 indicated by the fine diagonal lines that receives the light irradiation in the third scan. This area R13 is an area occupied by all the pixels corresponding to the above conditions (1) to (3). In this example, two pixels to the right of the area R12, one pixel below the area R12, and two pixels directly below the area R12 correspond to each other. The third light irradiation is performed with the region R13 occupied by these pixels as the irradiation target region. As a result, the crystallization of the organic semiconductor proceeds in this region, and it is expected that the crystal grains will grow even larger by growing with the crystals in the adjacent region R2 as nuclei.

By the light irradiation so far, crystallization of the left end portion of the pattern PT is completed from the upper end to the lower end. Therefore, in the subsequent scanning, as shown in FIGS. (D) to (f), the area occupied by the continuous pixels (3 pixels in this example) including the upper end to the lower end of the pattern PT is occupied by the irradiation target area (in the figure). As R14, R15, ... (Indicated by fine diagonal lines), light irradiation is sequentially performed while moving the irradiation target area to the right one pixel at a time. Finally, as shown in FIG. (G), light irradiation is completed for the entire pattern PT. In the figure, the movement of the irradiation target area is discrete because a part of the process in the middle is omitted, but the movement is actually one pixel at a time. The irradiation target area is sequentially set so as to gradually move away from the primary irradiation area, which is the first irradiation target area.

By repeating scanning with the light beam while sequentially moving the irradiation target region in this way, crystallization proceeds from the left end to the right end of the figure in the pattern PT. Therefore, for example, it is possible to form an organic semiconductor layer OS having remarkably excellent crystallinity as compared with the case where the entire pattern PT is irradiated with light all at once. If the amount of energy given to the pattern PT by one scan and the time interval between each scan are appropriate, the entire pattern PT can be single-crystallized.

If sufficient energy for crystallization cannot be given to one pixel by one light irradiation, the same irradiation target area is irradiated with light multiple times at time intervals. You may. According to the flowchart shown in FIG. 8, the scanning in step S303 may be repeatedly executed a predetermined number of times without reading out new irradiation data (step S302) in the middle. Even if it is possible to give sufficient energy with one light irradiation due to the device configuration, for example, the progress rate of crystallization can be adjusted by performing light irradiation in multiple times with relatively small power. It is also possible.

In order to avoid confusion, in this specification, when the scan of step S303 is repeatedly executed a plurality of times in this way, the plurality of scans are collectively referred to as "one scan". That is, for example, when the Nth scan is performed by changing the irradiation pattern from the previous scan and the scan is performed with the same irradiation pattern based on the same irradiation data, these scans are combined to form the "Nth scan". It is called "scanning".

Further, in the irradiation pattern shown in FIG. 9, only the pixels including at least a part of the pattern PT among the pixels on the substrate are targeted for irradiation. As a result, unnecessary light irradiation to the substrate can be minimized while reliably irradiating the organic semiconductor in the pattern PT, so that the temperature rise and damage to the substrate can be avoided. Therefore, for example, even a resin substrate having low heat resistance can be used without any problem. On the other hand, by targeting a pixel including at least a part of the pattern PT as an irradiation target, light irradiation is also performed on the outside of the pattern PT. Therefore, even if the positional relationship between the incident light beam L5 and the pattern PT deviates slightly from the design time, it is possible to accurately irradiate the pattern PT with light.

In addition, in order to make the correspondence to such a misalignment more reliable, for example, the following can be done.

FIG. 10 is a diagram showing an example of an irradiation pattern corresponding to the displacement of the pattern. Consider a case where the incident position of the light beam on the substrate SB and the position of the pattern PT on the substrate SB may be relatively displaced by, for example, within one pixel. At this time, as shown in FIG. 9A, the irradiation target region R21 to be first irradiated with light has a pattern further than the pixel including the peripheral edge of the pattern PT which is the primary irradiation region R11 in the example of FIG. It is set at a pixel position one pixel far from the PT. Light irradiation is started from this region R21.

Since this region R21 does not include a part of the pattern PT, it does not immediately correspond to the “primary irradiation target region”. The irradiation target area when at least a part of the pattern PT is included in the subsequent scanning becomes the “primary irradiation area” in a strict sense. When the region R21 includes a part of the pattern PT due to the misalignment, the region R21 corresponds to the primary irradiation target region.

After that, the irradiation target areas R22, R23, ... Are set according to the same rule as in the example of FIG. 9, and scanning by the light beam is sequentially executed. FIGS. 10 (b) to 10 (g) show the transition between the irradiated region and the irradiated target region in the process. Here, for example, as shown in (e) and (f), the width of the irradiation region is set to include a margin of one pixel or more in each of the vertical directions with respect to the width of the pattern PT. As a result, if the amount of deviation between the incident position of the light beam and the position of the pattern PT is within one pixel, the problem that an unirradiated region remains in the pattern PT due to the displacement is surely avoided. In addition, it is possible to appropriately irradiate a pattern formed on a flexible film resin substrate that is easily distorted or stretched.

The only change from the example of FIG. 9 to make this possible is the content of the irradiation data. That is, by adding the amount of misalignment that can occur when creating irradiation data, the above function can be realized basically by the same control as in the example of FIG. In this example, a margin for one pixel is provided in each of the vertical and horizontal directions of the pattern PT, but if there is a difference in the occurrence mode of the positional deviation for each direction, an asymmetrical margin is added in consideration of that point. The irradiation pattern to have may be set. When the substrate SB is likely to be damaged by light irradiation, the smaller the margin, the better.

In the above example, the pattern PT is rectangular, and the pixel arrangement direction on the substrate SB and the extension direction of the pattern PT are the same. That is, each side forming the outline of the pattern PT is parallel to the pixel arrangement direction. However, this is not always the case with actual devices. That is, the contoured sides of the pattern PT may not be parallel to the pixel arrangement direction. Hereinafter, an example in which the pattern PT is non-parallel to the pixel arrangement direction will be described.

FIG. 11 is a diagram showing an example of an irradiation pattern when the arrangement direction of the pixels and the side direction of the pattern do not match. Here, an example is shown in which the pattern PT shown in FIG. 7 is arranged in a direction different from the pixel arrangement direction indicated by the direction of the dotted line. However, the same idea can be applied to all cases where at least one side of the pattern contour is non-parallel to the pixel arrangement direction. The amount of inclination of the pattern (more specifically, its contour) with respect to the pixel arrangement direction can be grasped in advance from the pattern design data.

As shown in FIG. (A), also in this case, the primary irradiation region R31 is set at the position of the pixel including the peripheral portion of the pattern PT, and the light irradiation is first performed in this region. Then, as shown in FIG. (B), in the next scan, the secondary irradiation region R32 is set at the position of the pixel adjacent to the primary irradiation region R31 and including at least a part of the pattern PT, and the light irradiation is performed in this region. Will be done. As a result, crystal growth proceeds with the crystal formed in the primary irradiation region R31 as a nucleus. After that, by executing scanning while sequentially moving the irradiation target regions R33, R34, ..., Crystallization proceeds in one direction as shown in FIGS. (C) to (f). Here, as shown in FIG. (E), the width of the irradiation target region is appropriately increased or decreased according to the outer shape of the pattern PT. As a result, the entire pattern PT can be crystallized while controlling the direction of crystal growth.

In each of the above examples, the crystallinity is improved by forming a core crystal in the region where the light irradiation is first performed and growing the crystal in one direction. Here, for example, considering the case where the size of the pattern PT is sufficiently larger than the size of the pixels set on the substrate SB by the light irradiation device 1, it is necessary to irradiate the entire pattern PT with light and crystallize it many times. It is necessary to repeat the scanning, and the processing time becomes long. In order to shorten the processing time, the following processing modes can be considered.

FIG. 12 is a diagram showing an example of an irradiation pattern capable of shortening the time required for crystallization. The pattern PT to be crystallized is the same as that shown in FIG. As shown in FIG. (A), the primary irradiation region R41 to which the light beam is first irradiated is set not in the corner of the pattern PT but in the region occupied by the pixels in the substantially central portion in the longitudinal direction of the pattern PT. Also in this case, as the pixel, a pixel including a part of the peripheral portion of the pattern PT is selected. In this example, the primary irradiation region R41 is set at the position of the pixel including the lower side of the pattern PT, but it may be at another position.

Then, the secondary irradiation region R42 in the second scan is set in the region occupied by all the pixels satisfying the above conditions (1) to (3) with respect to the primary irradiation region R41 set in this way. As shown in FIG. (B), in this example, the secondary irradiation region R42 is set to surround the left, right, and above of the primary irradiation region R41. Hereinafter, as shown in FIGS. (c) and (d), the secondary irradiation regions R43, R44, ... Are sequentially set and light irradiation is performed, so that the crystal growth is directed from the central portion of the pattern PT to both the left and right sides. It will proceed. As a result, the time required to irradiate the entire pattern PT with light can be reduced to about half.

Not only can the processing time be shortened, but the method shown in FIG. 11 may exhibit better crystallinity depending on the shape of the pattern. For example, in the case of a pattern in which two relatively wide parts are interconnected in one narrow part, the whole is formed by generating a nucleus in the narrow part and growing toward the wide part. It may be possible to single crystallize. In this embodiment, since the direction in which the irradiated region spreads can be arbitrarily controlled by setting the irradiation pattern, such crystal growth can be realized.

Also in this case, only one primary irradiation region where light irradiation is first performed is set in a part of the pattern PT. When core crystals are generated at two or more locations in the pattern PT, grain boundaries will almost certainly occur at the sites where the crystals grown from each contact. In order to avoid this, it is desirable that the core crystal is generated at only one place in one pattern PT.

It is also not preferable that the primary irradiation region is set at the position of the pixel included inside the pattern PT, that is, not including the peripheral edge portion. The reason is as follows. The first crystal formed in the primary irradiation region is not necessarily a single crystal. By proceeding with crystallization in a certain direction with such a crystal as a nucleus, it is possible to selectively grow a crystal having a specific crystal orientation among the initially formed minute crystals and achieve single crystallization. It becomes. When a nucleus is formed inside the pattern PT, a grain boundary is generated in the process of crystal growth in each direction around this, and there is a high probability that the crystal becomes polycrystal as a whole. In order to limit the direction of crystal growth, it is desirable that the primary irradiation region is provided at a position including the peripheral portion of the pattern PT.

In each of the examples shown in FIGS. 11 and 12, it is possible to take measures to deal with the positional deviation that may occur between the pixel and the pattern shown in FIG.

In the above, the crystallization process of the organic semiconductor by irradiating the light beam has been described by taking the pattern PT having a specific shape as an example. However, for any other pattern shape, each part is described according to the shape. It is possible to create an irradiation pattern and perform light irradiation by applying any of the above technical ideas.

Even when a plurality of patterns separated from each other are formed on one substrate SB, each of them is irradiated with light as described above in the process of scanning the entire substrate SB by the light beam, so that the crystals are individually crystallized in each pattern. As the crystallization progresses, it is possible to obtain good crystallinity in each case. Even when the shapes and sizes of the plurality of patterns are different, good crystallinity can be obtained for each of them by setting the irradiation pattern according to each.

As described above, in the light irradiation device 1 of the above embodiment, the stage 17 functions as the "board holding unit" of the present invention, and the light source unit 11, the light modulation unit 13, and the projection optical system 15 are integrated into the present invention. It functions as a "light irradiation unit" of. Further, in the above-mentioned light irradiation treatment, the setting of the primary irradiation region and the first light irradiation based on the setting correspond to the "first step" of the present invention, while the setting of the secondary irradiation region and the second time based on the setting. Subsequent light irradiation corresponds to the "second step" of the present invention.

The present invention is not limited to the above-described embodiment, and various modifications other than those described above can be made without departing from the spirit of the present invention. For example, the light irradiation device 1 of the above embodiment scans the substrate SB with the light beam by modulating a single light beam emitted from the light source unit 11 by the light modulation unit 13. Instead of this, a device capable of simultaneously incident a light beam at each position of the substrate SB may be used. In this case, the above-mentioned irradiation pattern can be realized by individually controlling the on / off of the light beam incident on each position.

Further, for example, in the above embodiment, the incident position of the light beam on the substrate SB is controlled in pixel units, but for example, an irradiation device capable of adjusting the irradiation range in units smaller than the pixel size in the scanning direction of the light beam. It may be used. Further, an irradiation device that realizes a halftone by changing the output light intensity as well as turning on / off the light beam may be used, but at least in the primary irradiation region, in order not to generate a plurality of crystal nuclei at different positions, it is necessary to use an irradiation device. It is desirable that there is a clear difference in the amount of energy given between the area irradiated with light and the area around it.

Regarding this, since the incident position of the light beam is set for each pixel in the above embodiment, the secondary irradiation region is set to the region adjacent to the irradiated region where the light irradiation has already been performed, and overlaps at the same position. No light irradiation is performed. However, since the energy density of the irradiated light beam is generally lower in the peripheral portion of the beam spot than in the central portion, the irradiation ranges are partially overlapped in order to avoid insufficient irradiation in the peripheral portion of the beam spot. May be good. In order to make this possible, the secondary irradiation region at each time may be set so as to include the entire boundary between the irradiated region and the non-irradiated region.

Further, for example, in the above-mentioned light irradiation treatment, the irradiated area that has already been irradiated with light is excluded from the subsequent irradiation target areas, and the irradiated area is not irradiated with light in the subsequent scanning. This is to prevent damage to the crystal and the substrate by applying excessive energy to the already crystallized region. If such a problem does not occur, further light irradiation may be performed on the irradiated area. For example, by including the irradiated area in the setting of the secondary irradiation area, it is possible to expand the irradiation range for each scan.

Further, for example, in the above embodiment, the light irradiation position is determined by the light modulation by the light modulation unit 13 and the movement of the substrate SB by the stage moving mechanism 171. However, the light irradiation position is determined by only one of them. You may.

Further, for example, in the manufacturing method of the above embodiment, a so-called top gate type thin film transistor is manufactured by forming an organic semiconductor layer OS on a substrate on which a source electrode and a drain electrode are formed in advance and finally forming a gate electrode. How to do it. However, the method for producing an organic semiconductor according to the present invention is characterized by a process of forming an organic semiconductor layer on some substrate, and the content and order of the processes provided before and after the process, and the type and shape of the element to be formed. Is optional, not limited to the above.

As described above by exemplifying a specific embodiment, in the method for producing an organic semiconductor according to the present invention, for example, the secondary irradiation region covers all the boundaries between the irradiated region and the non-irradiated region. It can be set to include or be adjacent to all of the boundaries. According to such a configuration, it is possible to prevent a region in the pattern from which sufficient light irradiation is not received and good crystallization is not performed.

Further, for example, the primary irradiation region can be set to include a part of the peripheral portion of the pattern and a part of the exposed surface of the substrate adjacent to the peripheral portion. With such a setting, even if the relationship between the pattern position on the substrate and the irradiation position of the light beam deviates slightly from the design value, crystallization can be reliably started from the peripheral portion of the pattern.

Further, for example, the irradiation in the first step and the irradiation in the second step can be configured to be intermittent in time. According to such a configuration, the progress of crystal growth can be controlled by the time interval of irradiation.

Further, for example, it is possible to configure the settings of the secondary irradiation regions to be different from each other so that the second step is executed a plurality of times. According to such a configuration, even if the size of the pattern is sufficiently larger than the spot size of the light beam, the entire pattern can be finally irradiated with light by sequentially moving the secondary irradiation region and performing light irradiation. It is possible.

In this case, the secondary irradiation region can be set to move away from the primary irradiation region, for example, each time the second step is executed. According to such a configuration, the crystal growth can be promoted in a specific direction from the crystal initially formed by irradiating the primary irradiation region with light, so that the crystallinity can be improved. ..

Further, for example, the secondary irradiation region can be set so as to substantially not include the irradiated region. According to such a configuration, it is possible to prevent damage to the crystal and the substrate in the specific region due to the excessive energy being applied by irradiating the specific region with light a plurality of times.

Further, for example, in the first step, the irradiation to the primary irradiation region may be executed a plurality of times with a time lag. Further, in one second step, irradiation to the same secondary irradiation region may be performed a plurality of times with a time lag. According to such a configuration, crystallization can proceed satisfactorily even when sufficient energy for crystallization cannot be given by one light irradiation. Further, by applying energy in a plurality of times, it is possible to adjust the progress rate of crystallization.

Further, for example, the size of the primary irradiation region can be the same as the beam size of the light beam on the substrate surface. The beam size is the minimum size that can be realized as the irradiation target region, and by making the size of the primary irradiation region as small as possible in this way, it is possible to suppress the generation of a plurality of crystal nuclei in a wide region.

Further, for example, the substrate may be configured to irradiate a light beam on a substrate on which a plurality of patterns separated from each other are formed. In the present invention, the pattern of light irradiation on the substrate is specified by the irradiation data, and the irradiation pattern is not limited to the continuous one on the substrate, and the discrete one can be set. Therefore, even when a plurality of patterns are formed on the substrate, they can be individually irradiated with light to promote good crystallization.

Further, for example, the substrate may be preheated, and by doing so, crystallization can be started immediately by light irradiation. The substrate temperature at this time is preferably a temperature lower than the crystal transition temperature of the organic semiconductor material. According to such a configuration, it is possible to prevent the organic semiconductor material from crystallizing before being irradiated with light, and it is possible to more effectively control the crystal growth by light irradiation.

Further, for example, in the light irradiation device according to the present invention, the light irradiation unit is configured to two-dimensionally control the incident position of light on the substrate by a two-dimensional optical element or a plurality of arranged one-dimensional optical elements. You may. According to such a configuration, it is possible to realize optimum light irradiation according to the shape and structure of the pattern to be irradiated with light.

The present invention can be applied to all the techniques for manufacturing an organic semiconductor on a substrate, and is particularly suitable for forming a plurality of semiconductor elements on one substrate.

1 Light irradiation device 11 Light source unit (light irradiation unit)
13 Light modulation section (light irradiation section)
15 Projection optical system (light irradiation unit)
17 Stage (board holding part)
20 Control unit PT pattern R11 Primary irradiation area R12, R13 Secondary irradiation area SB substrate

Claims (13)

A process of forming a pattern with a liquid containing an organic semiconductor material on a substrate,
A step of irradiating the coated liquid with a light beam to crystallize the organic semiconductor is provided.
The irradiation of the light beam is performed by performing intermittent emission of the light beam and control of the incident position of the emitted light beam on the substrate, thereby using irradiation data according to the pattern of the substrate. It is executed by an irradiation device capable of selectively irradiating the specified irradiation target area with the light beam.
The irradiation device is used for one continuous pattern.
After performing the first step of irradiating the light beam with the primary irradiation region, which is a partial region including the peripheral portion of the pattern, as the irradiation target region, the light beam is irradiated.
The second step of irradiating the light beam with the secondary irradiation area including the boundary between the irradiated area and the unirradiated area irradiated with the light beam or adjacent to the boundary as the irradiation target area in the pattern. , A method for producing an organic semiconductor, which crystallizes the entire pattern by executing it at least once. The method for producing an organic semiconductor according to claim 1, wherein the secondary irradiation region includes all of the boundaries between the irradiated region and the unirradiated region, or is set so as to be adjacent to all of the boundaries. The method for producing an organic semiconductor according to claim 1 or 2, wherein the primary irradiation region includes a part of a peripheral portion of the pattern and a part of an exposed surface of the substrate adjacent to the peripheral portion. The method for producing an organic semiconductor according to any one of claims 1 to 3, wherein the irradiation in the first step and the irradiation in the second step are intermittent in time. The method for producing an organic semiconductor according to any one of claims 1 to 4, wherein the second step is performed a plurality of times with different settings of the secondary irradiation region. The method for manufacturing an organic semiconductor according to claim 5, wherein the secondary irradiation region is set so as to move away from the primary irradiation region each time the second step is executed. The method for producing an organic semiconductor according to any one of claims 1 to 6, wherein the secondary irradiation region is set so as not to substantially include the irradiated region. The method for producing an organic semiconductor according to any one of claims 1 to 7, wherein in the first step, irradiation of the primary irradiation region is performed a plurality of times with a time interval. The method for producing an organic semiconductor according to any one of claims 1 to 8, wherein in the second step once, irradiation of the same secondary irradiation region is performed a plurality of times with a time lag. The method for producing an organic semiconductor according to any one of claims 1 to 9, wherein the size of the primary irradiation region is the same as the beam size of the light beam on the surface of the substrate. The method for producing an organic semiconductor according to any one of claims 1 to 10, wherein the substrate on which the plurality of patterns separated from each other are formed is irradiated with the light beam. A substrate holding part that holds a substrate on which a liquid pattern containing an organic semiconductor material is formed,
A light irradiation unit that performs intermittent emission of the light beam and adjustment of the incident position of the emitted light beam on the substrate, and
The light irradiation unit is controlled based on the irradiation data according to the pattern, and the substrate is provided with a control unit for selectively irradiating the irradiation target region specified by the irradiation data with the light beam.
For one continuous pattern
After irradiating the light beam with the primary irradiation region, which is a partial region including the peripheral portion of the pattern, as the irradiation target region,
Of the pattern, the irradiation of the light beam including the boundary between the irradiated area and the unirradiated area irradiated with the light beam or the secondary irradiation area adjacent to the boundary is set as the irradiation target area at least once. A light irradiator that crystallizes the entire pattern by executing it. The light irradiation device according to claim 12, wherein the substrate holding portion heats the substrate to a temperature lower than the crystal transition temperature of the organic semiconductor material.

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