JP2007305802A - Semiconductor device, electrooptic device, electronic appliance, and manufacturing method of semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor device wherein the breakdowns of its gate insulating layer are generated hardly which are caused by the electric-field concentrations to the corners of its source and drain electrodes, to provide an electrooptic device and an electrooptic appliance which use the semiconductor device, and to provide the manufacturing method of the semiconductor device. <P>SOLUTION: An organic TFT 1 of the semiconductor device has interdigital source and drain electrodes 21, 22 on a substrate 10 as to be separated from each other, a semiconductor layer and a gate insulating layer which are laminated successively on the electrodes 21, 22, and a gate electrode 50 disposed in such a region present on the gate insulating layer as to overlap with the respective one-portions of the source and drain electrodes 21, 22 when observing them from the normal direction of the substrate 10. Hereupon, corners 20a, 20b of the end and root of comb teeth 21p, 22p of the source and drain electrodes 21, 22 so have nearly arcuate shapes as to be able to relax the electric-field concentrations to the corners 20a, 20b. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a semiconductor device, an electro-optical device, an electronic apparatus, and a method for manufacturing a semiconductor device.

  In recent years, an organic semiconductor device such as an organic thin film transistor (hereinafter referred to as “organic TFT”) using an organic material for a semiconductor layer has attracted attention. The organic TFT can form a semiconductor layer by a liquid phase process that does not require high temperature and high vacuum, is suitable for thin and light weight, has flexibility, and has a low material cost. It is expected as a switching element for flexible displays and the like.

In such an organic TFT, it has become clear that SiO ₂ may not be used for the gate insulating layer as in the case of the inorganic TFT (see Non-Patent Document 1), and a polymer material is used as the gate insulating layer. Is known to be suitable (see Non-Patent Document 2).

A. Salleo et.al., APL, 81 (2002), 4383 T.Kawase et.al., JJAP, 44 (2005), 3649

However, in general, organic materials or polymer materials have a drawback that the dielectric breakdown voltage is lower than that of SiO ₂ . For this reason, there is a problem that it is difficult to reduce the thickness of the gate insulating layer in order to improve the FET characteristics of the organic TFT. Furthermore, when the source electrode and drain electrode are patterned so as to have sharp corners, electric field concentration occurs at the corners, so that insulation is performed at a voltage lower than the dielectric breakdown voltage of the polymer material itself. There was a problem that destruction occurred and the organic TFT was destroyed.

  According to one of the effects exhibited by the present invention, it is possible to suppress the occurrence of dielectric breakdown of the gate insulating layer and the like due to electric field concentration at the corners of the source electrode and the drain electrode.

  A semiconductor device of the present invention includes a source electrode and a drain electrode that are spaced apart from each other on a substrate, a semiconductor layer that is disposed on the source electrode and the drain electrode, and a gate insulating layer that is disposed on the semiconductor layer. A gate electrode that is insulated from the source electrode and the drain electrode by the gate insulating layer and disposed in a region that overlaps at least a part of each of the source electrode and the drain electrode when viewed from the normal direction of the substrate. The corners of the source electrode and the drain electrode in a region overlapping the gate electrode when viewed from the normal direction of the substrate are substantially arcuate when viewed from the normal direction of the substrate. It is characterized by that.

  According to such a configuration, in the portion where the electric field is applied among the source electrode and the drain electrode, there is no sharp corner such as a right angle or an acute angle at which the electric field tends to concentrate. Concentrated events are less likely to occur. As a result, a semiconductor device in which dielectric breakdown of the gate insulating layer due to electric field concentration at the corners of the source electrode and the drain electrode hardly occurs can be obtained.

  In the semiconductor device, it is preferable that a cross-sectional shape of a corner portion of the source electrode and the drain electrode in a plane perpendicular to the substrate includes a substantially arc-shaped portion. According to such a configuration, electric field concentration is less likely to occur by forming a smooth shape including a substantially arc-shaped portion of the cross section of the corner in the portion where the electric field is applied among the source electrode and the drain electrode. Can do.

  In the semiconductor device, it is preferable that the source electrode and the drain electrode have a comb-shaped portion and are arranged so that the teeth mesh with each other. According to such a configuration, alignment between the source and drain electrodes and the gate electrode is facilitated.

  In the semiconductor device, it is preferable that the shape of the end portions of the source electrode and the drain electrode forming a comb-teeth shape is a substantially arc shape when viewed from the normal direction of the substrate. According to such a configuration in which the shape of the entire end portion of the comb-like portion of the source electrode and the drain electrode is a substantially arc shape, as compared with a case where only the corner portion of the end portion is a substantially arc shape. Thus, since the shape of the end portion includes an arc having a larger radius, electric field concentration can be made more difficult to occur. Furthermore, the cross-sectional shape of the end portion in a plane perpendicular to the substrate is preferably configured to include a substantially arc-shaped portion.

  In the semiconductor device described above, it is preferable that the shape of the corner of the root portion of the comb-like portion of the source electrode and the drain electrode has a substantially arc shape when viewed from the normal direction of the substrate. According to such a configuration, since the corner of the root portion of the comb-like portion of the source electrode and the drain electrode does not have a sharp corner such as a right angle or an acute angle at which the electric field tends to concentrate, An event that an electric field concentrates on a part of the source electrode or the drain electrode is less likely to occur. Accordingly, a semiconductor device in which dielectric breakdown of the gate insulating layer due to electric field concentration at the corners of the source electrode and the drain electrode hardly occurs can be obtained. Further, the cross-sectional shape of the corner portion of the base portion in a plane perpendicular to the substrate is preferably configured to include a substantially arc-shaped portion.

  In the semiconductor device, it is preferable that a substantially entire shape of the portion of the source electrode and the drain electrode, which are comb-shaped, as viewed from the normal direction of the substrate, is formed by a curve. According to such a configuration, in the source electrode and the drain electrode, there is no corner portion where the electric field tends to concentrate, so that the electric field concentration can be made less likely to occur.

  An electro-optical device according to the present invention includes the above-described semiconductor device. Since the electro-optical device having such a configuration includes a semiconductor device that is not easily damaged by dielectric breakdown, high reliability can be obtained.

  According to another aspect of the present invention, there is provided an electronic apparatus including the above electro-optical device. According to such a configuration, a highly reliable electronic device can be obtained.

  A method of manufacturing a semiconductor device according to the present invention is a method of manufacturing a semiconductor device having a source electrode, a drain electrode, and a gate electrode, and a droplet is applied to a region on the substrate where the source electrode and the drain electrode are to be formed. Disposing a plurality of droplets of a functional liquid containing a conductive material by using a discharge device to dispose the functional liquid, and drying the functional liquid to provide the source electrode containing the conductive material And forming the drain electrode; forming a semiconductor layer on the source electrode and the drain electrode; forming a gate insulating layer on the semiconductor layer; and the substrate on the gate insulating layer Forming a gate electrode in a region overlapping at least a part of each of the source electrode and the drain electrode as viewed from the normal direction of the step, and the step A includes the source electrode and the drain electrode. In the region where the rain electrode is to be formed, the droplet is discharged so that the shape after the discharge becomes a substantially circular shape at a corner position in a region overlapping with the gate electrode when viewed from the normal direction of the substrate Including a process.

  According to such a manufacturing method, since the source electrode and the drain electrode are obtained by drying the functional liquid disposed in the process A, the shape thereof is the shape of the region where the functional liquid is disposed in the process A. . Then, the shape of the corner portions of the source electrode and the drain electrode is substantially arc-shaped because a part of the shape of the substantially circular droplet discharged to the corner portion in the process A is reflected as it is. Further, since the surface of the functional liquid disposed on the substrate maintains a curved surface shape so as to minimize the surface area due to surface tension in the subsequent drying process, the source electrode formed by drying the functional liquid and The drain electrode also has a smooth shape including a substantially arc-shaped portion with respect to the cross section of the corner portion. In such a source electrode and a drain electrode, there is no sharp corner such as a right angle or an acute angle where the electric field tends to concentrate in a portion where the electric field is applied, and therefore, an event that the electric field concentrates on a part of the source electrode or the drain electrode hardly occurs. . Accordingly, a semiconductor device in which dielectric breakdown of the gate insulating layer due to electric field concentration at the corners of the source electrode and the drain electrode hardly occurs can be obtained.

  In the manufacturing method, the source electrode and the drain electrode may be formed in a comb-like shape and the teeth mesh with each other. Further, the shape of the end portion of the source electrode and the drain electrode having a comb-teeth shape may be a substantially arc shape when viewed from the normal direction of the substrate. Further, the corners of the roots of the source electrode and the drain electrode that are comb-shaped may be formed so as to form a substantially arc shape when viewed from the normal direction of the substrate. Furthermore, the source electrode and the drain electrode may be formed in a shape in which a substantially comb-shaped portion of the source electrode and the drain electrode viewed from the normal direction of the substrate is formed by a curve.

  A method for manufacturing a semiconductor device according to the present invention is a method for manufacturing a semiconductor device having a source electrode, a drain electrode, and a gate electrode, wherein a region on the substrate where the source electrode is to be formed and the drain electrode are formed. Forming a bank in a region sandwiched between regions to be formed, disposing a functional liquid containing a conductive material at least in a region in contact with the bank, and drying the functional liquid to form the conductive material Forming the source electrode and the drain electrode including: a step of forming a semiconductor layer on the source electrode and the drain electrode; a step of forming a gate insulating layer on the semiconductor layer; and the gate insulation Forming a gate electrode in a region on the layer that overlaps at least a part of each of the source electrode and the drain electrode when viewed from the normal direction of the substrate. In the region where the source electrode and the drain electrode are to be formed in the step B, the shape of the corners in the region overlapping the gate electrode when viewed from the normal direction of the substrate is substantially arc-shaped. Features.

  With the bank formed in the step B, the functional liquid is disposed in a region where no bank is formed. Therefore, the source electrode and the drain electrode obtained by drying the same are also formed in a region where no bank is formed. Here, since the bank is formed in a region where the corners of the source electrode and the drain electrode are substantially arc-shaped, as a result, the source electrode and the drain electrode have a substantially arc-shaped corner. Formed. In addition, since the surface of the functional liquid maintains a curved surface shape so as to minimize the surface area due to surface tension after the placement and in the drying process, the source electrode and the drain electrode formed by drying the functional liquid are: The corner cross section also has a smooth shape including a substantially arc-shaped portion. In such a source electrode and a drain electrode, there is no sharp corner such as a right angle or an acute angle where the electric field tends to concentrate in a portion where the electric field is applied, and therefore, an event that the electric field concentrates on a part of the source electrode or the drain electrode hardly occurs. . Accordingly, a semiconductor device in which dielectric breakdown of the gate insulating layer due to electric field concentration at the corners of the source electrode and the drain electrode hardly occurs can be obtained.

  In the manufacturing method, the source electrode and the drain electrode may be formed in a comb-like shape and the teeth mesh with each other. Further, the shape of the end portion of the source electrode and the drain electrode having a comb-teeth shape may be a substantially arc shape when viewed from the normal direction of the substrate. Further, the corners of the roots of the source electrode and the drain electrode that are comb-shaped may be formed so as to form a substantially arc shape when viewed from the normal direction of the substrate. Furthermore, the source electrode and the drain electrode may be formed in a shape in which a substantially comb-shaped portion of the source electrode and the drain electrode viewed from the normal direction of the substrate is formed by a curve.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings shown below, the dimensions and ratios of the components are appropriately different from the actual ones in order to make the components large enough to be recognized on the drawings.

<First Embodiment>
(A. Semiconductor device)
FIG. 1 is a plan view of an organic TFT 1 as a semiconductor device of the present invention. A cross-sectional view taken along line AA in FIG. 1 is shown in FIG. The organic TFT 1 is a top gate type thin film transistor, and is disposed so as to contact and cover the source electrode 21 and the drain electrode 22 which are disposed on the glass substrate 10 so as to be spaced apart from each other. The organic semiconductor layer 30 is formed, and the gate insulating layer 40 and the gate electrode 50 are sequentially stacked on the organic semiconductor layer 30. Here, the glass substrate 10 corresponds to the “substrate” in the present invention, and the organic semiconductor layer 30 corresponds to the “semiconductor layer” in the present invention. In FIG. 1, for convenience of explaining the shapes of the source electrode 21 and the drain electrode 22 and the positional relationship between the source electrode 21 and the drain electrode 22 and the gate electrode 50, the display of the organic semiconductor layer 30 and the gate insulating layer 40 is omitted. The source electrode 21 and the drain electrode 22 located on the back side of the electrode 50 are also indicated by solid lines.

  Hereinafter, the configuration of each part will be described in detail. The constituent material of the source electrode 21 and the drain electrode 22 is not particularly limited as long as it is a known electrode material. Specifically, metallic materials such as Cr, Al, Ta, Mo, Nb, Cu, Ag, Au, Pd, In, Ni, Nd, Co or alloys containing these, and oxides thereof, or conductivity An organic material or the like can be used. As a typical example of the conductive organic material, an aqueous dispersion of PEDOT (polyethylenedioxythiophene) doped with PSS (polystyrene sulfonic acid) (hereinafter referred to as “PEDOT-PSS”) is applied. A dried product can be used. In this embodiment, PEDOT-PSS is used. The average thickness of the source electrode 21 and the drain electrode 22 is not particularly limited, but is preferably about 10 to 2000 nm, and more preferably about 50 to 1000 nm.

  As shown in FIG. 1, the source electrode 21 and the drain electrode 22 have comb-shaped portions, respectively, and are arranged so that the teeth mesh with each other. More specifically, the source electrode 21 has three substantially rectangular comb teeth 21 p that protrude toward the drain electrode 22. Similarly, the drain electrode 22 protrudes toward the source electrode 21. There are three shaped comb teeth 22p. And the comb teeth 21p and 22p are arrange | positioned so that it may enter alternately and may not mutually contact. With this configuration, alignment between the source electrode 21 and the drain electrode 22 and the gate electrode 50 is facilitated.

  Further, the two corners 20a at the ends of the comb teeth 21p and 22p have a substantially arc shape. That is, the comb teeth 21p and 22p are not a perfect rectangle consisting of only a straight line, but the corners 20a at the ends are rounded. Further, the corners 20b of the roots of the comb teeth 21p and 22p are also substantially arcuate. That is, the roots of the comb teeth 21p and 22p do not rise at a right angle like a rectangular wave, but rise smoothly so that the corner 20b has a curved shape. Here, the “corner portion” in this paper refers to a portion of the boundary line defining the outer shape of the source electrode 21 and the drain electrode 22 where the direction of the straight line changes, in other words, two straight lines having different directions. This refers to the part where the border line is connected.

  Further, as shown in FIG. 3 (e), the cross-sectional shape of the source electrode 21 and the drain electrode 22 is formed of a smooth curve in which the outer peripheral portion 20d includes a substantially arc-shaped portion, and sharp corner portions are formed. There is no waste. Therefore, the cross-sectional shapes of the corners 20a at the ends of the comb teeth 21p and 22p and the corners 20b at the roots of the comb teeth 21p and 22p are formed by smooth curves including a substantially arc-shaped portion.

  The organic semiconductor layer 30 disposed so as to be in contact with and covering the source electrode 21 and the drain electrode 22 is composed mainly of an organic semiconductor material (an organic material exhibiting semiconducting electrical conduction). Examples of such organic semiconductor materials include naphthalene, anthracene, tetracene, pentacene, hexacene, phthalocyanine, perylene, hydrazone, triphenylmethane, diphenylmethane, stilbene, arylvinyl, pyrazoline, triphenylamine, triarylamine, or these Low molecular organic semiconductor materials such as derivatives, poly-N-vinylcarbazole, polyvinylpyrene, polyvinylanthracene, polythiophene, poly (p-phenylenevinylene), pyreneformaldehyde resin, ethylcarbazole formaldehyde resin, fluorene-bithiophene copolymer (F8T2) or polymeric organic semiconductor materials such as derivatives thereof can be used, and one or more of these can be used in combination. In particular, it is preferable to use an organic semiconductor material of a polymer as a main material. The organic semiconductor layer 30 composed mainly of a polymer organic semiconductor material can be reduced in thickness and weight, and has excellent flexibility. Therefore, the organic semiconductor layer 30 is applied to a thin film transistor used as a switching element of a flexible display. Suitable for

  The organic semiconductor layer 30 is preferable in that it can be formed at a low temperature. As a result, it is possible to manufacture at a low cost, and it is possible to obtain an effect that it is possible to use a plastic substrate which is an inexpensive flexible substrate.

  The average thickness of the organic semiconductor layer 30 is preferably about 0.1 to 1000 nm, more preferably about 1 to 500 nm, and further preferably about 1 to 100 nm.

  Note that the organic semiconductor layer 30 may not be provided so as to cover the source electrode 21 and the drain electrode 22, and may be provided at least in a region (channel region) between the source electrode 21 and the drain electrode 22. That's fine. In addition, the semiconductor layer in the present invention can be composed of an inorganic semiconductor layer instead of the organic semiconductor layer 30.

  A gate insulating layer 40 is provided on the organic semiconductor layer 30. The gate insulating layer 40 is made of an insulating polymer containing an acrylic resin, an epoxy resin, an ester resin, or the like. Examples of the insulating polymer include polymethyl methacrylate, polyvinyl phenol, polyimide, polystyrene, polyvinyl alcohol, polyvinyl acetate, and the like, and one or more of these can be used in combination.

  The average thickness of the gate insulating layer 40 is not particularly limited, but is preferably about 10 to 5000 nm, and more preferably about 50 to 1000 nm. By setting the thickness of the gate insulating layer 40 within the above range, the operating voltage of the organic TFT 1 can be lowered while reliably insulating the source electrode 21 and the drain electrode 22 from the gate electrode 50.

  A region overlapping at least a part of each of the source electrode 21 and the drain electrode 22 when viewed from a predetermined position on the gate insulating layer 40, that is, the normal direction of the glass substrate 10, A gate electrode 50 is formed in a region including the region between. As the constituent material of the gate electrode 50, the same conductive materials as those described for the source electrode 21 and the drain electrode 22 can be used. The average thickness of the gate electrode 50 is not particularly limited, but is preferably about 0.1 to 2000 nm, and more preferably about 1 to 1000 nm.

  In the organic TFT 1 configured as described above, when a gate voltage is applied to the gate electrode 50 in a state where a voltage is applied between the source electrode 21 and the drain electrode 22, the vicinity of the interface between the organic semiconductor layer 30 and the gate insulating layer 40. A channel is formed in the channel, and carriers (holes) move in the channel region, whereby a current flows between the source electrode 21 and the drain electrode 22.

  That is, in the OFF state in which no voltage is applied to the gate electrode 50, even if a voltage is applied between the source electrode 21 and the drain electrode 22, almost no carriers are present in the organic semiconductor layer 30. Only flows. On the other hand, in the ON state in which a voltage is applied to the gate electrode 50, charges are induced in the portion of the organic semiconductor layer 30 facing the gate insulating layer 40, and a channel (carrier flow path) is formed. When a voltage is applied between the source electrode 21 and the drain electrode 22 in this state, a current flows through the channel region.

  At this time, as described above, the corners 20a at the ends of the comb teeth 21p and 22p of the source electrode 21 and the drain electrode 22 and the corners 20b at the roots are substantially arc-shaped. The following effects can be obtained. That is, in the portion where the electric field is applied in the source electrode 21 and the drain electrode 22, there is no sharp corner such as a right angle or an acute angle at which the electric field tends to concentrate, so that the electric field concentrates on a part of the source electrode 21 or the drain electrode 22. Is hard to get up. Therefore, the dielectric breakdown of the gate insulating layer 40 due to the electric field concentration at the corners 20a and 20b of the source electrode 21 and the drain electrode 22 is unlikely to occur. In addition, since the cross-sectional shapes of the corners 20a and 20b are also composed of smooth curves including a substantially arc-shaped portion, the electric field concentration can be mitigated in the same manner, and the dielectric breakdown of the gate insulating layer 40 can be prevented. It is harder to happen. Thereby, the thickness of the gate insulating layer 40 can be further reduced, and the transistor characteristics can be improved. As described above, the organic TFT 1 of the present embodiment hardly causes dielectric breakdown of the gate insulating layer 40, and has high reliability and high transistor characteristics due to the breakdown.

(B. Manufacturing method of semiconductor device)
Then, the manufacturing method of organic TFT1 is demonstrated using FIGS. 2-6. 2 is a process diagram showing a method of manufacturing the organic TFT 1, FIGS. 3A to 3E are cross-sectional views of the organic TFT 1 in the manufacturing process, and FIG. 4 is for explaining the process P11 in FIG. FIG. More specifically, it is a schematic diagram showing a pattern of positions where droplets 24A of the functional liquid 24 are to be ejected in step P11. FIG. 5 is a perspective view of the droplet discharge device 100 used in step P11. 6A and 6B show the head 114 of the droplet discharge device 100, where FIG. 6A is a perspective view and FIG. 6B is a cross-sectional view.

  Hereinafter, it demonstrates along the process drawing of FIG. First, in step P11, the constituent material of the source electrode 21 and the drain electrode 22 is formed on the glass substrate 10 from the head 114 of the droplet discharge device 100 (FIG. 5) to the region where the source electrode 21 and the drain electrode 22 are to be formed. A plurality of droplets 24A of the functional liquid 24 containing the conductive material to be used are ejected by an ink jet method (FIG. 3A). As a result, the functional liquid 24 is disposed in the region. The functional liquid 24 is disposed with a contact angle corresponding to the liquid repellency of the surface of the glass substrate 10. This contact angle is preferably about 90 °. In this embodiment, PEDOT-PSS is used as the functional liquid 24, but in addition, as the constituent material of the source electrode 21 and the drain electrode 22, an aqueous dispersion or an alcohol dispersion of various conductive materials described above is used. You can also.

  Here, the droplet discharge device 100 used in the process P11 will be described with reference to FIGS. A droplet discharge device 100 shown in FIG. 5 includes a tank 101 that holds the functional liquid 24, a tube 110, a ground stage GS, a discharge head unit 103, a stage 106, a first position control device 104, A two-position control device 108, a control unit 112, and a support unit 104a are provided. The discharge head unit 103 holds a head 114 (FIG. 6). The head 114 ejects a droplet 24A (FIG. 6) of the functional liquid 24 in response to a signal from the control unit 112. Note that the head 114 in the ejection head unit 103 is connected to the tank 101 by the tube 110, and thus the functional liquid 24 is supplied from the tank 101 to the head 114. The stage 106 provides a plane for fixing the glass substrate 10.

  As shown in FIGS. 6A and 6B, the head 114 is an inkjet head having a plurality of nozzles 118. Specifically, the head 114 includes a diaphragm 126 and a nozzle plate 128 that defines the opening of the nozzle 118. A liquid pool 129 is located between the diaphragm 126 and the nozzle plate 128, and the functional liquid 24 supplied from an external tank (not shown) through the hole 131 is always in the liquid pool 129. Filled.

  A plurality of partition walls 122 are positioned between the diaphragm 126 and the nozzle plate 128. A portion surrounded by the diaphragm 126, the nozzle plate 128, and the pair of partition walls 122 is the cavity 120. The functional liquid 24 is supplied from the liquid pool 129 to the cavity 120 through the supply port 130 positioned between the pair of partition walls 122.

  Now, on the diaphragm 126, the vibrators 124 are positioned corresponding to the respective cavities 120. Each of the vibrators 124 includes a piezoelectric element 124C and a pair of electrodes 124A and 124B sandwiching the piezoelectric element 124C. The control unit 112 applies a driving voltage between the pair of electrodes 124A and 124B, whereby the droplet 24A of the functional liquid 24 is discharged from the corresponding nozzle 118. Here, the volume of the material discharged from the nozzle 118 is variable between 0 pl and 42 pl (picoliter). The shape of the nozzle 118 is adjusted so that the droplet 24A of the functional liquid 24 is discharged from the nozzle 118 in the Z-axis direction.

  Returning to FIG. 5, the first position control device 104 is fixed to a position at a predetermined height from the ground stage GS by the support portion 104a. In response to a signal from the control unit 112, the first position control device 104 moves the ejection head unit 103 including the head 114 along the X-axis direction and the Z-axis direction orthogonal to the X-axis direction. It has a function. The second position control device 108 moves the stage 106 on the ground stage GS in the Y-axis direction according to a signal from the control unit 112. As a result, the relative position of the head 114 with respect to the glass substrate 10 changes. More specifically, by these operations, the ejection head unit 103, the head 114, or the nozzle 118 maintains the predetermined distance in the Z-axis direction with respect to the glass substrate 10 fixed to the stage 106, while maintaining the X-axis. Relative movement in the direction and the Y-axis direction, that is, relatively scanning.

  The control unit 112 is configured to receive ejection data representing a relative position at which the droplet of the functional liquid 24 is to be ejected from the external information processing apparatus. The control unit 112 stores the received discharge data in an internal storage device, and controls the first position control device 104, the second position control device 108, and the head 114 in accordance with the stored discharge data. To do. The ejection data is data for applying the functional liquid 24 in a predetermined pattern on the glass substrate 10. In the present embodiment, the ejection data has the form of bitmap data.

  The droplet discharge device 100 having the above configuration moves the nozzle 118 of the head 114 relative to the glass substrate 10 according to the discharge data, and also drops the droplet 24A of the functional liquid 24 from the nozzle 118 toward the discharge target portion. Is discharged.

  In step P11, using such a droplet discharge device 100, droplets 24A of the functional liquid 24 are discharged on the glass substrate 10 according to the pattern shown in FIG. A small circle 60 in FIG. 4 indicates a range in which the droplet 24A spreads after discharging one droplet 24A, and the center of the small circle 60 corresponds to a position where the droplet 24A should be discharged. The small circles 60 are basically arranged so that the centers thereof form a matrix, and adjacent small circles 60 are arranged so as to partially overlap each other. The positions of the small circles 60 are set over the entire region in which the source electrode 21 and the drain electrode 22 are to be formed, and the comb teeth 21p and 22p are formed by the three rows of small circles 60. Information about the arrangement of the small circles 60 corresponds to the ejection data described above.

  In this way, one small circle 60a is necessarily arranged at a portion corresponding to the corner 20a (FIG. 1) at the ends of the comb teeth 21p and 22p. For this reason, after ejecting the droplet 24A, the functional liquid 24 has a substantially arcuate outer peripheral shape defined by a part of the small circle 60a in the corner portion 20a (broken line in FIG. 4). Will be placed.

  Further, one small circle 60b is also arranged at a portion corresponding to the corner 20b (FIG. 1) at the base of the comb teeth 21p and 22p. In other words, among the formation regions of the comb teeth 21p and 22p, five rows of small circles 60 obtained by adding a pair of small circles 60b to the above-described three rows are arranged only at the roots thereof. In this way, after discharging the droplet 24A, the corner portion 20b has a smooth substantially arc-shaped outer peripheral shape due to the effect of the droplet 24A discharged to the position of the small circle 60b. It will be arranged in a state (broken line in FIG. 4).

  As described above, the functional liquid 24 including the conductive material is disposed on the glass substrate 10 in the region where the source electrode 21 and the drain electrode 22 are to be formed. This process P11 corresponds to “process A” in the present invention.

  Next, in step P12, the functional liquid 24 disposed on the glass substrate 10 is dried to form the source electrode 21 and the drain electrode 22 (FIG. 3B). Specifically, the dispersion medium or solvent of the functional liquid 24 is evaporated to solidify the conductive material contained in the functional liquid 24, thereby forming the source electrode 21 and the drain electrode 22 on the glass substrate 10. To do. At this time, since the functional liquid 24 is disposed with a smooth substantially arc-shaped outer peripheral shape in the portions corresponding to the corners 20a and 20b at the ends of the comb teeth 21p and 22p, The source electrode 21 and the drain electrode 22 obtained by drying are also formed in a state where the corner portions 20a and 20b have a smooth substantially arc shape. Further, since the surface of the functional liquid 24 maintains a curved surface shape so as to minimize the surface area due to surface tension even during the drying process, the cross-sectional shapes of the source electrode 21 and the drain electrode 22 obtained after drying are the corner portions 20a. , 20b, the outer peripheral portion 20d has a smooth shape including a substantially arc-shaped portion.

  Next, in the process P13, the organic semiconductor layer 30 is formed so as to cover the source electrode 21 and the drain electrode 22 (FIG. 3C). More specifically, after the oxygen plasma treatment and the cleaning treatment are performed on the glass substrate 10, the semiconductor solution is ejected by a droplet ejection method such as an inkjet method, and an annealing treatment is performed. At this time, a channel region is formed between the source electrode 21 and the drain electrode 22. In addition to the above method, this step can also be performed by a coating method using a spin coating method, a dip method, or the like, or a printing method using an ink jet method, a screen printing method, or the like.

  The organic semiconductor layer 30 may be formed only in a region (channel region) between the source electrode 21 and the drain electrode 22. Thereby, when arranging a plurality of organic TFTs 1 on the same substrate, the leakage current and crosstalk between the elements can be suppressed by forming the organic semiconductor layer 30 of each organic TFT 1 independently. . Moreover, the usage-amount of organic-semiconductor material can be reduced and manufacturing cost can also be reduced.

  Next, in process P14, the gate insulating layer 40 is formed on the organic semiconductor layer 30 (FIG. 3D). This step is performed by forming the above-described insulating polymer on the entire surface using a coating method using a spin coating method, a dip method, or the like, or a printing method using an ink jet method or a screen printing method.

  Next, in step P15, the gate electrode 50 is formed on the gate insulating layer 40 in a region at least overlapping with the comb teeth 21p and 22p of the source electrode 21 and the drain electrode 22 when viewed from the normal direction of the glass substrate 10 ( FIG. 3 (e)). This step is performed by applying PEDOT-PSS using a printing method using an inkjet method, a screen printing method, or the like and then drying it.

  The organic TFT 1 is obtained through the above steps. According to such a manufacturing method, the shape of the corners 20a and 20b of the source electrode 21 and the drain electrode 22 can be made into a substantially arc shape. Further, the cross-sections of the corner portions 20a and 20b can also be smooth so as to include a substantially arc-shaped portion. In the organic TFT 1 of the present embodiment, the source electrode 21 and the drain electrode 22 and the organic semiconductor layer 30, the organic semiconductor layer 30 and the gate insulating layer 40, and the gate insulating layer 40 and the gate electrode 50 are interposed. In each case, one layer or two or more layers may be added for an arbitrary purpose.

(C. Modification)
In the organic TFT 1, the shapes of the source electrode 21 and the drain electrode 22 are not limited to those described above. Below, the modification about the shape of the source electrode 21 and the drain electrode 22 of organic TFT1 is demonstrated using FIGS. 7-9.

  FIG. 7 is a plan view of an organic TFT 1A which is one of the modifications of the present embodiment. The organic TFT 1A is different from the organic TFT 1 in that the entire ends 20c of the comb teeth 21p and 22p of the source electrode 21 and the drain electrode 22 are substantially arc-shaped (substantially semicircular). According to such a configuration, the radius of curvature of the shape of the end portion 20c can be increased, so that electric field concentration and dielectric breakdown of the gate insulating layer 40 due to this can be made less likely to occur.

  The organic TFT 1A can be basically manufactured by the same manufacturing method as the organic TFT 1. However, in forming the source electrode 21 and the drain electrode 22, when the droplet 24A is ejected, the diameter of the ejected droplet 24A is set to be equal to the thickness of the comb teeth 21p and 22p. If it does in this way, the edge part 20c of the comb teeth 21p and 22p will be formed in the substantially semicircle shape using the half (semicircle) of the external shape of the droplet 24A discharged to the said site | part.

  FIG. 8 is a plan view of an organic TFT 1B which is one of the modifications of the present embodiment. The organic TFT 1B is different from the organic TFT 1 in that the entire shape of the comb teeth 21p and 22p of the source electrode 21 and the drain electrode 22 is formed by curves. According to such a configuration, the source electrode 21 and the drain electrode 22 do not have corners where the electric field tends to concentrate, so that the electric field concentration and the dielectric breakdown of the gate insulating layer 40 due to the electric field concentration are less likely to occur. can do.

  FIG. 9 is a plan view of an organic TFT 1 </ b> C that is one of modifications of the present embodiment. The organic TFT 1C is different from the organic TFT 1 in that the source electrode 21 and the drain electrode 22 do not have comb teeth 21p and 22p. However, the shape of the corner portion 20a of the source electrode 21 and the drain electrode 22 is substantially arc-shaped, and the cross-section of the corner portion 20a is also a smooth shape including a substantially arc-shaped portion. Similar to the organic TFT 1, the electric field concentration and the dielectric breakdown of the gate insulating layer 40 due to this are unlikely to occur.

<Second Embodiment>
(A. Semiconductor device)
Next, an organic TFT 1D according to the second embodiment of the present invention will be described. FIG. 10 is a plan view of an organic TFT 1D as a semiconductor device of the present invention. Further, FIG. 12F shows a cross-sectional view taken along line BB in FIG. Hereinafter, the organic TFT 1D of FIGS. 10 and 12F will be described focusing on differences from the organic TFT 1 according to the first embodiment shown in FIGS. 1 and 3E. The same elements as those in FIG. 1 and FIG. 3E are denoted by the same reference numerals, and the description thereof is omitted.

  The organic TFT 1D is disposed on the glass substrate 10 so as to be spaced apart from each other, the region on the glass substrate 10 between the source electrode 21 and the drain electrode 22 and the periphery thereof. The polyimide thin film 26 as a bank in the present invention, the source electrode 21, the drain electrode 22, the organic semiconductor layer 30 disposed so as to cover and cover the polyimide thin film 26, and the organic semiconductor layer 30 are sequentially stacked. A gate insulating layer 40 and a gate electrode 50. Here, the difference from the organic TFT 1 in the first embodiment is that a polyimide thin film 26 is disposed in and around a region sandwiched between the source electrode 21 and the drain electrode 22. In other words, the polyimide thin film 26 is formed in a region exclusive to the formation region of the source electrode 21 and the drain electrode 22. The polyimide thin film 26 functions as a bank that defines the formation region of the source electrode 21 and the drain electrode 22 in the manufacturing process of the organic TFT 1D.

  The organic TFT 1D has the same configuration as the organic TFT 1 of the first embodiment except for the above points. Accordingly, the shape of the corner 20a at the ends of the comb teeth 21p and 22p of the source electrode 21 and the drain electrode 22 and the corner 20b at the base are substantially arc-shaped, and thus gate insulation caused by electric field concentration. The dielectric breakdown of the layer 40 hardly occurs. In addition, since the cross-sectional shapes of the corners 20a and 20b are also composed of smooth curves including a substantially arc-shaped portion, the electric field concentration can be mitigated in the same manner, and the dielectric breakdown of the gate insulating layer 40 can be prevented. It is harder to happen. With such an effect, the thickness of the gate insulating layer 40 can be further reduced, and the transistor characteristics can be improved. That is, the organic TFT 1D of the present embodiment is also less likely to cause breakdown of the gate insulating layer 40, and has high reliability and high transistor characteristics due to the breakdown.

(B. Manufacturing method of semiconductor device)
Then, the manufacturing method of organic TFT1D is demonstrated using FIGS. 11-13. FIG. 11 is a process diagram showing a manufacturing method of the organic TFT 1D, FIGS. 12A to 12F are cross-sectional views of the organic TFT 1D in the manufacturing process, and FIG. 13 shows the process P21 and the process P23 in FIG. It is a top view for demonstrating.

  Hereinafter, the process will be described with reference to the process diagram of FIG. First, in step P21, a polyimide thin film 26 is formed on a part of the glass substrate 10 (FIG. 12A). Here, as shown in FIG. 13A, the region where the polyimide thin film 26 is formed includes a region sandwiched between regions where the source electrode 21 and the drain electrode 22 are to be formed (see FIG. 7). And a region around a region where the drain electrode 22 is to be formed. At this time, the shape of the region where the source electrode 21 and the drain electrode 22 are to be formed is set so that the shape of the corners 20a and 20b (FIG. 10) in the region overlapping with the gate electrode 50 later becomes a substantially arc shape. That is, the polyimide thin film 26 is formed so as to have a substantially arc shape at portions corresponding to the corner portions 20a and 20b.

  This step is performed by applying photosensitive polyimide on the glass substrate 10 by spin coating or the like and then patterning the photosensitive polyimide by photolithography. This step P21 corresponds to “step B” in the present invention.

  In a subsequent process P22, the polyimide thin film 26 is subjected to a liquid repellency treatment. More specifically, after the glass substrate 10 is subjected to oxygen plasma treatment to remove carbon components on the surface and subjected to hydrophilic treatment, the polyimide thin film 26 is subjected to water repellent treatment by performing fluorine plasma treatment.

  Next, in step P23, the functional liquid 24 containing a conductive material is disposed in the region where the source electrode 21 and the drain electrode 22 are to be formed, including the region in contact with the polyimide thin film 26 on the glass substrate 10 (FIG. 12 (b)). This step is performed by an ink jet method. That is, it is performed by discharging a plurality of droplets 24A of the functional liquid 24 containing a conductive material as a constituent material of the source electrode 21 and the drain electrode 22 from the head 114 of the droplet discharge device 100 (FIG. 5). In this embodiment, PEDOT-PSS is used as the functional liquid 24, but in addition, as the constituent material of the source electrode 21 and the drain electrode 22, an aqueous dispersion or an alcohol dispersion of various conductive materials described above is used. You can also.

  At this time, since the polyimide thin film 26 has liquid repellency with respect to the functional liquid 24 and repels the functional liquid 24, the functional liquid 24 is not disposed on the polyimide thin film 26, as shown in FIG. Are disposed exclusively with respect to the formation region of the polyimide thin film 26. That is, the functional liquid 24 is disposed only in a region where the source electrode 21 and the drain electrode 22 are to be formed. In other words, the polyimide thin film 26 functions as a bank that defines the formation region of the source electrode 21 and the drain electrode 22. The functional liquid 24 is arranged with a contact angle corresponding to the liquid repellency of the polyimide thin film 26. This contact angle is preferably about 90 °.

  By this step, the functional liquid 24 is disposed in a state having a substantially arcuate outer peripheral shape at a portion corresponding to the corner 20a (FIG. 10) at the end of the comb teeth 21p and 22p. In addition, the functional liquid 24 is arranged in a state having a smooth substantially arc-shaped outer peripheral shape also at a portion corresponding to the corner portion 20b (FIG. 10) of the root portions of the comb teeth 21p and 22p.

  Note that this step can be performed by a dipping method, a spin coating method, or the like instead of the ink jet method as long as the polyimide thin film 26 has sufficient liquid repellency. Even if the functional liquid 24 is applied to the entire surface of the glass substrate 10 by such a method, the polyimide thin film 26 repels the functional liquid 24. Therefore, the functional liquid 24 is disposed only in the region where the source electrode 21 and the drain electrode 22 are to be formed. can do.

  Next, in the process P24, the functional liquid 24 arranged on the glass substrate 10 is dried to form the source electrode 21 and the drain electrode 22 (FIG. 12C). Specifically, the dispersion medium or solvent of the functional liquid 24 is evaporated to solidify the conductive material contained in the functional liquid 24, thereby forming the source electrode 21 and the drain electrode 22 on the glass substrate 10. To do. At this time, since the functional liquid 24 is disposed with a smooth substantially arc-shaped outer peripheral shape in the portions corresponding to the corners 20a and 20b at the ends of the comb teeth 21p and 22p, The source electrode 21 and the drain electrode 22 obtained by drying are also formed in a state where the corner portions 20a and 20b have a smooth substantially arc shape. Further, since the surface of the functional liquid 24 maintains a curved surface shape so as to minimize the surface area due to surface tension even during the drying process, the cross-sectional shapes of the source electrode 21 and the drain electrode 22 obtained after drying are the corner portions 20a. , 20b, the outer peripheral portion 20d has a smooth shape including a substantially arc-shaped portion.

  Next, in step P25, the organic semiconductor layer 30 is formed so as to cover the source electrode 21, the drain electrode 22, and the polyimide thin film 26 (FIG. 12D). This process is performed in the same manner as the process P13 of the first embodiment.

  Next, in process P26, the gate insulating layer 40 is formed on the organic semiconductor layer 30 (FIG. 12E). This process is performed in the same manner as the process P14 of the first embodiment.

  Next, in step P27, the gate electrode 50 is formed on the gate insulating layer 40 in a region at least overlapping with the comb teeth 21p and 22p of the source electrode 21 and the drain electrode 22 when viewed in the normal direction of the glass substrate 10 ( FIG. 12 (f)). This step is performed in the same manner as the step P15 of the first embodiment.

  Through the steps as described above, the organic TFT 1D is obtained. According to such a manufacturing method, the shape of the corners 20a and 20b of the source electrode 21 and the drain electrode 22 can be made into a substantially arc shape. Further, the cross-sections of the corner portions 20a and 20b can also be smooth so as to include a substantially arc-shaped portion. In the organic TFT 1D of this embodiment, between the source electrode 21 and the drain electrode 22 and the organic semiconductor layer 30, between the organic semiconductor layer 30 and the gate insulating layer 40, and between the gate insulating layer 40 and the gate electrode 50. In each case, one layer or two or more layers may be added for an arbitrary purpose.

(C. Modification)
In the organic TFT 1D, the shapes of the source electrode 21 and the drain electrode 22 are not limited to those described above. Below, the modification about the shape of the source electrode 21 and the drain electrode 22 of organic TFT1D is demonstrated using FIGS. 14-16.

  FIG. 14 is a plan view of an organic TFT 1E which is one of the modifications of the present embodiment. The organic TFT 1E is different from the organic TFT 1D in that the entire ends 20c of the comb teeth 21p and 22p of the source electrode 21 and the drain electrode 22 are substantially arc-shaped (substantially semicircular). According to such a configuration, the radius of curvature of the shape of the end portion 20c can be increased, so that electric field concentration and dielectric breakdown of the gate insulating layer 40 due to this can be made less likely to occur.

  FIG. 15 is a plan view of an organic TFT 1F which is one of the modifications of the present embodiment. The organic TFT 1F is different from the organic TFT 1D in that the entire shape of the comb teeth 21p and 22p of the source electrode 21 and the drain electrode 22 is formed by curves. According to such a configuration, the source electrode 21 and the drain electrode 22 do not have corners where the electric field tends to concentrate, so that the electric field concentration and the dielectric breakdown of the gate insulating layer 40 due to the electric field concentration are less likely to occur. can do.

  FIG. 16 is a plan view of an organic TFT 1G which is one of modifications of the present embodiment. The organic TFT 1G is different from the organic TFT 1D in that the source electrode 21 and the drain electrode 22 do not have comb teeth 21p and 22p. However, the shape of the corner portion 20a of the source electrode 21 and the drain electrode 22 is substantially arc-shaped, and the cross-section of the corner portion 20a is also a smooth shape including a substantially arc-shaped portion. Similar to the organic TFT 1D, the electric field concentration and the dielectric breakdown of the gate insulating layer 40 due to this are unlikely to occur.

  In order to manufacture the organic TFTs 1E, 1F, and 1G according to the above modifications, the formation region of the polyimide thin film 26 may be changed in accordance with the shapes of the source electrode 21 and the drain electrode 22 in all cases.

<Electro-optical device>
Next, an electrophoretic display device will be described as an example of an electro-optical device in which an active matrix device including the organic TFT 1 (including organic TFTs 1A to 1G) as described above is incorporated.

  17 is a cross-sectional view showing an embodiment of an electrophoretic display device 200 as an electro-optical device of the present invention, and FIG. 18 is a block diagram showing a configuration of an active matrix device 300 included in the electrophoretic display device 200 shown in FIG. FIG. 19 is an enlarged plan view of the active matrix device 300. In FIG. 19, for convenience of explanation, the display of the organic semiconductor layer 30 and the gate insulating layer 40 included in the organic TFT 1 is omitted.

  An electrophoretic display device 200 shown in FIG. 17 includes an active matrix device 300 provided on a substrate 500 and an electrophoretic display unit 400 electrically connected to the active matrix device 300.

  As shown in FIGS. 18 and 19, the active matrix device 300 is provided near a plurality of data lines 301 orthogonal to each other, a plurality of scanning lines 302, and intersections of these data lines 301 and the scanning lines 302. And a plurality of organic TFTs 1. The scanning line 302 is a wiring formed by connecting the gate electrodes 50 of the plurality of organic TFTs 1 arranged in the row direction. Further, the source electrode 21 of the organic TFT 1 is connected to the data line 301, and the drain electrode 22 is connected to the pixel electrode (individual electrode) 401.

  As illustrated in FIG. 17, the electrophoretic display unit 400 includes a pixel electrode 401, a microcapsule 402, a transparent electrode (common electrode) 403, and a transparent substrate 404 that are sequentially stacked on the substrate 500. . The microcapsule 402 is fixed between the pixel electrode 401 and the transparent electrode 403 by a binder material 405. The pixel electrodes 401 are divided so as to be regularly arranged in a matrix, that is, vertically and horizontally. Within each microcapsule 402, there is an electrophoretic dispersion liquid 420 including a plurality of types of electrophoretic particles having different characteristics, in this embodiment, two types of electrophoretic particles 421 and 422 having different charges and colors (hues). It is enclosed.

  In such an electrophoretic display device 200, when a selection signal (selection voltage) is supplied to one or a plurality of scanning lines 302, an organic substance connected to the scanning line 302 to which the selection signal (selection voltage) is supplied. TFT1 is turned on. Thereby, the data line 301 connected to the organic TFT 1 and the pixel electrode 401 are substantially conducted. At this time, if desired data (voltage) is supplied to the data line 301, this data (voltage) is supplied to the pixel electrode 401. As a result, an electric field is generated between the pixel electrode 401 and the transparent electrode 403, and the electrophoretic particles 421 and 422 are either one of the electrophoretic particles 421 and 422 depending on the direction and strength of the electric field and the characteristics of the electrophoretic particles 421 and 422. Electrophoresis in the direction of the electrode.

  On the other hand, when the supply of the selection signal (selection voltage) to the scanning line 302 is stopped from this state, the organic TFT 1 is turned off, and the data line 301 and the pixel electrode 401 connected to the organic TFT 1 are in a non-conductive state. Become.

  Therefore, by appropriately combining the supply and stop of the selection signal to the scanning line 302 or the supply and stop of the data to the data line 301, the display surface side (transparent substrate 404 side) of the electrophoretic display device 200 can be obtained. A desired image (information) can be displayed.

  In particular, in the electrophoretic display device 200 of the present embodiment, it is possible to display a multi-tone image by making the colors of the electrophoretic particles 421 and 422 different. In addition, since the electrophoretic display device 200 of the present embodiment includes the active matrix device 300, the organic TFT 1 connected to the specific scanning line 302 can be selectively turned on / off. And the circuit operation can be speeded up, so that a high quality image (information) can be obtained. In addition, since the electrophoretic display device 200 according to the present embodiment operates with a low driving voltage, power saving can be achieved.

  The electro-optical device of the present invention is not limited to application to such an electrophoretic display device 200, but can also be applied to a liquid crystal display device, an organic or inorganic EL display device, and the like.

<Electronic equipment>
Such an electrophoretic display device 200 can be incorporated into various electronic devices. Hereinafter, an electronic apparatus of the present invention including the electrophoretic display device 200 will be described.

(A. Electronic paper)
First, an embodiment when the electronic apparatus of the present invention is applied to electronic paper will be described. FIG. 20 is a perspective view of an electronic paper 600 according to an embodiment of the electronic apparatus of the present invention. An electronic paper 600 shown in this figure includes a main body 601 composed of a rewritable sheet having the same texture and flexibility as paper, and a display unit 602. In such electronic paper 600, the display unit 602 includes the electrophoretic display device 200 as described above.

(B. Display)
Next, an embodiment when the electronic apparatus of the present invention is applied to a display will be described. FIG. 21 is a view showing a display 800 according to an embodiment of the electronic apparatus of the present invention, where (a) is a cross-sectional view and (b) is a plan view. A display 800 shown in this figure includes a main body 801 and an electronic paper 600 that is detachably provided to the main body 801. The electronic paper 600 has the same configuration as described above, that is, the configuration shown in FIG.

  The main body 801 has an insertion port 805 into which the electronic paper 600 can be inserted on the side (right side in the drawing), and two pairs of conveying rollers 802a and 802b are provided inside. When the electronic paper 600 is inserted into the main body 801 through the insertion port 805, the electronic paper 600 is installed in the main body 801 in a state of being sandwiched between the pair of conveyance rollers 802a and 802b.

  Further, a rectangular hole 803 is formed on the display surface side of the main body 801 (the front side in the drawing (b) below), and a transparent glass plate 804 is fitted into the hole 803. Thereby, the electronic paper 600 installed in the main body 801 can be viewed from the outside of the main body 801. That is, in the display 800, the display surface is configured by visually recognizing the electronic paper 600 installed in the main body 801 on the transparent glass plate 804.

  In addition, a terminal portion 806 is provided at the leading end portion (left side in the drawing) of the electronic paper 600, and the terminal portion with the electronic paper 600 installed on the main body portion 801 is provided inside the main body portion 801. A socket 807 to which 806 is connected is provided. A controller 808 and an operation unit 809 are electrically connected to the socket 807.

  In such a display 800, the electronic paper 600 is detachably installed on the main body 801, and can be carried and used while being detached from the main body 801. Further, in such a display 800, the electronic paper 600 is configured by the electrophoretic display device 200 as described above.

  Note that the electronic apparatus of the present invention is not limited to the application to the above, and for example, a television, a viewfinder type, a monitor direct view type video tape recorder, a car navigation device, a pager, an electronic notebook, a calculator, an electronic Examples include newspapers, word processors, personal computers, workstations, videophones, POS terminals, and devices equipped with touch panels. The electrophoretic display device 200 can be applied to the display units of these various electronic devices. is there.

  As mentioned above, although embodiment of this invention was described, various deformation | transformation can be added with respect to the said embodiment in the range which does not deviate from the meaning of this invention. As modifications, for example, the following can be considered.

(Modification 1)
When the source electrode 21 and the drain electrode 22 are formed, the source electrode 21 and the drain electrode 22 are formed by a droplet discharge method in the first embodiment. In the second embodiment, the source electrode 21 and the drain electrode 22 are formed by a combination of the bank formation of the polyimide thin film 26 and the droplet discharge method. However, the present invention is not limited to these. As the bank material, not only an imide resin typified by polyimide but also an acrylic resin, an epoxy resin, or an ester resin may be used. The source electrode 21 and the drain electrode 22 may be formed by the following method instead.

  That is, first, a metal film (metal layer) is formed on the glass substrate 10. This includes, for example, chemical vapor deposition (CVD) such as plasma CVD, thermal CVD, and laser CVD, vacuum deposition, sputtering (low temperature sputtering), dry plating methods such as ion plating, electrolytic plating, immersion plating, and electroless plating. It can be formed by a wet plating method such as a thermal spraying method, a sol-gel method, a MOD method, or a metal foil bonding.

  On this metal film, a resist material is applied and then cured to form a resist layer having a shape corresponding to the shape of the source electrode 21 and the drain electrode 22. At this time, the resist layer is formed so that the portions corresponding to the corner portions 20a and 20b of the source electrode 21 and the drain electrode 22 have a substantially arc shape. Using this resist layer as a mask, unnecessary portions of the metal film are removed. For the removal of the metal film, for example, one or more of physical etching methods such as plasma etching, reactive ion etching, beam etching, and light-assisted etching, and chemical etching methods such as wet etching are used. They can be used in combination. Then, the source electrode 21 and the drain electrode 22 are obtained by removing the resist layer.

  Also by such a method, the organic TFT 1 in which the corners 20a and 20b of the source electrode 21 and the drain electrode 22 have a substantially arc shape can be manufactured, and the same effects as those of the above embodiments can be obtained.

(Modification 2)
In each of the embodiments described above, the shape of the corner portions 20a and 20b of the source electrode 21 and the drain electrode 22 and the end portions 20c of the comb teeth 21p and 22p does not necessarily have to be an accurate arc shape, and may be an approximately arc shape. Thus, the electric field concentration can be reduced. Specifically, it may be a combination of a plurality of arcs having different radii of curvature, a part of an ellipse, or other smooth curved shape.

(Modification 3)
In each of the above embodiments, an insulating polymer is used for the gate insulating layer 40, but an inorganic substance such as an inorganic oxide may be used instead. Examples of the inorganic oxide suitable for the gate insulating layer 40 include silicon oxide, aluminum oxide, zirconium oxide, cerium oxide, zinc oxide, cobalt oxide, lead zirconate titanate, lead titanate, titanium oxide, tantalum oxide, and the like. One or a combination of two types can be mentioned, and in particular, silicon oxide, aluminum oxide, zirconium oxide, cerium oxide, zinc oxide, cobalt oxide, lead zirconate titanate, lead titanate, titanium oxide, oxidation At least one of tantalum is preferred. These oxides have a particularly high dielectric constant, and by using these insulating inorganic particles, it becomes possible to suppress the driving voltage of the organic TFT 1, thereby reducing the power consumption and further improving the reliability of the organic TFT 1. Can be planned.

(Modification 4)
In each of the above embodiments, the glass substrate 10 is used as the “substrate” in the present invention, but in addition to this, polyethylene terephthalate (PET), polycarbonate (PC), polyethylene naphthalate (PEN), polyethersulfone (PES). ), A plastic substrate (resin substrate) made of aromatic polyester (liquid crystal polymer) polyimide (PI) or the like, a quartz substrate, a silicon substrate, a metal substrate, a gallium arsenide substrate, or the like can be used. When the organic TFT 1 is provided with flexibility, a plastic substrate or a thin (relatively small film thickness) metal substrate is selected as the substrate of the present invention. In the glass substrate 10, a method of forming a bank using the polyimide thin film 26 is used. However, when another substrate, particularly a plastic substrate, is used, a metal oxide that also serves as an insulating layer is formed on the surface of the substrate, and glass You may perform the process similar to the board | substrate 10. FIG. Alternatively, when a plastic substrate is used as the substrate, a fluororesin typified by fluorinated polyimide may be used for the bank. In the case of using a fluororesin, after patterning the fluororesin to form a bank and performing oxygen plasma treatment, only the inside of the bank can be made hydrophilic, and the source electrode 21 and the drain electrode 22 can be patterned. It becomes possible.

The top view of the organic TFT which concerns on 1st Embodiment. Process drawing which shows the manufacturing method of the organic TFT which concerns on 1st Embodiment. (A) to (e) are cross-sectional views in the manufacturing process of the organic TFT according to the first embodiment. The schematic diagram which shows the pattern of the position which should eject the droplet of a functional liquid. The perspective view of a droplet discharge device. The head of a droplet discharge apparatus is represented, (a) is a perspective view, (b) is sectional drawing. The top view of the organic TFT which concerns on the modification of 1st Embodiment. The top view of the organic TFT which concerns on the modification of 1st Embodiment. The top view of the organic TFT which concerns on the modification of 1st Embodiment. The top view of the organic TFT which concerns on 2nd Embodiment. Process drawing which shows the manufacturing method of the organic TFT which concerns on 2nd Embodiment. (A) to (f) is a cross-sectional view in the manufacturing process of the organic TFT according to the second embodiment. (A) And (b) is a top view for demonstrating the formation position of a polyimide thin film. The top view of the organic TFT which concerns on the modification of 2nd Embodiment. The top view of the organic TFT which concerns on the modification of 2nd Embodiment. The top view of the organic TFT which concerns on the modification of 2nd Embodiment. 1 is a cross-sectional view of an electrophoretic display device as an electro-optical device of the present invention. FIG. 18 is a block diagram illustrating a configuration of an active matrix device included in the electrophoretic display device illustrated in FIG. 17. FIG. 18 is an enlarged plan view of an active matrix device included in the electrophoretic display device shown in FIG. 17. The perspective view of the electronic paper as an electronic device of this invention. The display as an electronic device of this invention is shown, (a) is sectional drawing, (b) is a top view.

Explanation of symbols

1, 1A, 1B, 1C, 1D, 1E, 1F, 1G ... Organic TFT as "semiconductor device", 10 ... Glass substrate, 20a, 20b ... Corner, 20c ... End of comb tooth, 20d ... Source electrode or Peripheral portion of drain electrode, 21 ... source electrode, 21p ... comb teeth of source electrode, 22 ... drain electrode, 22p ... comb teeth of drain electrode, 24 ... functional liquid, 24A ... droplet of functional liquid, 26 ... polyimide thin film, DESCRIPTION OF SYMBOLS 30 ... Organic-semiconductor layer, 40 ... Gate insulating layer, 50 ... Gate electrode, 60, 60a, 60b ... Small circle which shows the discharge position of a droplet, 100 ... Droplet discharge apparatus, 114 ... Head, 200 ... "Electro-optical apparatus Electrophoretic display device as 300 "active matrix device" 600 as electronic paper as "electronic device", 800 as display as "electronic device".

Claims (10)

A source electrode and a drain electrode spaced apart on the substrate;
A semiconductor layer disposed on the source electrode and the drain electrode;
A gate insulating layer disposed on the semiconductor layer;
A gate electrode insulated from the source electrode and the drain electrode by the gate insulating layer, and disposed in a region overlapping at least a part of each of the source electrode and the drain electrode when viewed from the normal direction of the substrate. ,
The shape of the corner of the source electrode and the drain electrode in the region overlapping with the gate electrode when viewed from the normal direction of the substrate is substantially arcuate when viewed from the normal direction of the substrate. A featured semiconductor device. The semiconductor device according to claim 1,
A semiconductor device, wherein a cross-sectional shape of a corner portion of the source electrode and the drain electrode in a plane perpendicular to the substrate includes a substantially arc-shaped portion. The semiconductor device according to claim 1 or 2,
The semiconductor device according to claim 1, wherein the source electrode and the drain electrode have a comb-like portion and are arranged so that the teeth mesh with each other. A semiconductor device according to claim 2 or 3,
2. A semiconductor device according to claim 1, wherein a shape of an end portion of the source electrode and the drain electrode forming a comb-like shape is substantially an arc shape when viewed from a normal direction of the substrate. A semiconductor device according to any one of claims 2 to 4,
2. A semiconductor device according to claim 1, wherein a shape of a corner portion of a base portion of the source electrode and the drain electrode forming a comb shape is substantially an arc shape when viewed from a normal direction of the substrate. A semiconductor device according to any one of claims 2 to 5,
A semiconductor device characterized in that substantially the entire shape of the portion of the source electrode and the drain electrode that are formed in a comb-teeth shape as viewed from the normal direction of the substrate is formed by a curve.   An electro-optical device comprising the semiconductor device according to claim 1.   An electronic apparatus comprising the electro-optical device according to claim 7. A method for manufacturing a semiconductor device including a source electrode, a drain electrode, and a gate electrode,
Step A of disposing a plurality of droplets of a functional liquid containing a conductive material by using a droplet discharge device to dispose the functional liquid in a region on the substrate where the source electrode and the drain electrode are to be formed. When,
Drying the functional liquid to form the source electrode and the drain electrode containing the conductive material;
Forming a semiconductor layer on the source electrode and the drain electrode;
Forming a gate insulating layer on the semiconductor layer;
Forming a gate electrode on a region of the gate insulating layer that overlaps at least a part of each of the source electrode and the drain electrode when viewed from the normal direction of the substrate;
In the step A, the shape after discharge is substantially circular at a position that becomes a corner portion in a region that overlaps the gate electrode when viewed from the normal direction of the substrate, in a region where the source electrode and the drain electrode are to be formed. A method for manufacturing a semiconductor device, comprising: a step of discharging the droplets so that A method for manufacturing a semiconductor device including a source electrode, a drain electrode, and a gate electrode,
Forming a bank in a region on the substrate sandwiched between a region where the source electrode is to be formed and a region where the drain electrode is to be formed;
Disposing a functional liquid containing a conductive material at least in a region in contact with the bank;
Drying the functional liquid to form the source electrode and the drain electrode containing the conductive material;
Forming a semiconductor layer on the source electrode and the drain electrode;
Forming a gate insulating layer on the semiconductor layer;
Forming a gate electrode on a region of the gate insulating layer that overlaps at least a part of each of the source electrode and the drain electrode when viewed from the normal direction of the substrate;
In the region where the source electrode and the drain electrode are to be formed in the step B, the shape of the corners in the region overlapping the gate electrode when viewed from the normal direction of the substrate is substantially arc-shaped. A method for manufacturing a semiconductor device.

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