JP2004109862A - Method for manufacturing semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the following problems with the case liquid crystal display devices and surface pressure distribution sensor devices existing in individual modules are set in information terminals, etc.; the man-hours for assembly increase; resembling parts, such as control circuits and FPCs (Flexible Printed Circuits), are many and illogical; casing members for fixing respective panels are necessary and therefore the terminals become large. <P>SOLUTION: The insulating substrate is provided thereon with liquid crystal display regions and surface pressure distribution sensor regions. The advance of liquid crystals into the surface pressure distribution sensor regions can be prevented by forming counter electrode films of the liquid crystal display regions as protective films in injecting the liquid crystals. Also, the counter electrode films of the surface pressure distribution sensor regions are fastened after the completion of the liquid crystal display regions requiring heat treatment of a high temperature and therefore the deterioration by the high-temperature heat treatment can be prevented. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention uses a thin film transistor (hereinafter, referred to as “TFT”) as a switching element, and a display device including a display electrode connected to the TFT and a surface pressure including a unit detection element including the TFT. The present invention relates to a method for manufacturing a semiconductor device with an integrated distribution sensor.
[0002]
[Prior art]
With the advancement of information security in recent years, there is a market demand for a notebook computer, a DPA, a mobile phone, and the like to be equipped with a login sensor, a password, and a fingerprint sensor for personal identification. On the other hand, a display device is indispensable for such an information terminal, and when a fingerprint sensor is mounted on the information terminal, a display device and a fingerprint sensor, which are individual module components, are employed as a set.
[0003]
Referring to FIG. 11, an example is shown in which an active matrix type surface pressure distribution sensor 20 for detecting a fingerprint pattern in a conventional semiconductor device is mounted together with a liquid crystal display device 10.
[0004]
As shown in FIG. 11A, the surface pressure distribution sensor 20 and the display device 10, which are individual modules, are set in the same housing 30.
[0005]
As shown in FIGS. 11B and 11C, the display device 10 is, for example, a liquid crystal display device that observes a display by reflecting light incident from an observer side with a reflective display electrode. The liquid crystal display device 10 includes an insulating substrate 11 made of glass or the like on which TFTs 14a to be a large number of display pixels 14 are formed, a counter electrode substrate 12, and a liquid crystal 19 sealed in both substrates (for example, see Patent Reference 1).
[0006]
As the TFT 14a, a silicon film or an amorphous silicon film is formed in a matrix on a substrate 11 made of glass or the like, and the TFT 14a is formed using this as an active layer. The reflective display electrode 14b is formed of a reflective material such as Al and is connected to the TFT 14a to form the display pixel 14.
[0007]
The counter electrode substrate 12 is opposed to and fixed to the substrate 11 provided with the TFT 14a by a sealant 13 applied to the outer periphery. On the counter electrode substrate 12, on the side where the liquid crystal 19 is disposed opposite to the substrate 11, a color filter or an alignment film for each color such as red (R), green (G), and blue (B) is disposed. I have. A liquid crystal 19 is sealed in a space formed by the substrate 11 and the counter electrode substrate 12.
[0008]
Further, on the substrate 11, a gate signal line and a drain signal line connected to the display pixel 14 are arranged to cross each other. The V scanner 15 and the H scanner 16 monitor a gate signal line and a drain signal line. Further, one side of the substrate 11 has an external circuit connection terminal in which wirings for transmitting various signals input to the gate signal line and the drain signal line are gathered, and an insulating property is provided via an FPC (Flexible Printed Circuit) 17. The board 11 and the external control circuit 18 are connected.
[0009]
As shown in FIGS. 11B and 11D, the surface pressure distribution sensor 20 includes an insulating substrate 21 such as glass on which TFTs 24a serving as a number of unit detecting elements are formed, and a counter electrode film 22 (for example, See Patent Document 2.).
[0010]
The unit detection element 24 has a TFT 24a and a contact electrode 24b connected thereto. The unit detecting elements 24 are arranged in a matrix on the substrate 11 made of glass or the like, the active layer of the TFT constituting the unit detecting element 24 is an amorphous silicon film, and the contact electrode 24b is formed of ITO (Indium Tin Oxide). You.
[0011]
The counter electrode film 22 is provided to face the substrate 21, and has a structure in which a conductive film 22b is deposited on the back surface (TFT side) of the flexible insulating film 22a. The counter electrode film 22 is fixed by a sealant 23 applied around the substrate 21 and is arranged separately from the substrate 21.
[0012]
An example of a method for manufacturing the surface pressure distribution sensor will be described. After the TFT is formed on the substrate 21, a sealing agent 23 made of a low-temperature thermosetting resin is applied around the substrate 21 in order to attach the counter electrode film 22. Thereafter, the counter electrode film 22 of the substrate 21 is attached, and heat treatment is performed. Thereby, the substrate 21 and the counter electrode film 22 are fixed.
[0013]
Further, a gate signal line and a drain signal line which cross each other are also arranged on the substrate 21, and are connected to the unit detection element 24. The V scanner 25 and the H scanner 26 monitor a gate signal line and a drain signal line. One side of the substrate 21 has external circuit connection terminals in which wirings for transmitting various signals input to the gate signal line and the drain signal line are collected, and the substrate 21 and the external control circuit 28 are connected via the FPC 27. Connect.
[0014]
When a finger is put on the surface pressure distribution sensor 20 and pressed lightly, the opposing electrode film 22 has different pressing force between the peak and the valley of the fingerprint, so that the unit located immediately below the peak or in the immediate vicinity thereof. The contact electrode 24b of the detection element 24 is in electrical contact with the counter electrode film 22. As described above, a signal at a portion where the counter electrode film 22 and the unit detection element 24 are in contact with each other is extracted to detect a fingerprint pattern.
[0015]
[Patent Document 1]
JP 2001-83547 A (Pages 2-3, FIGS. 5 and 6)
[Patent Document 2]
Japanese Patent No. 25557796 (Page 1-3, Figure 1-3)
[0016]
[Problems to be solved by the invention]
As described above, conventionally, the liquid crystal display area 10 and the surface pressure distribution sensor 20 are formed in separate manufacturing processes, respectively, and are mounted on the information terminal as individual module parts.
[0017]
This is because, for example, the liquid crystal display device 10 requires a heat treatment of 150 ° C. in the panel manufacturing process, but the component parts of the surface pressure distribution sensor 20 have a heat resistant temperature of 114 ° C. In addition, the liquid crystal display device 10 needs to be evacuated by vacuum in injecting the liquid crystal, and it is necessary to take measures for explosion-proof atmosphere in the sealing region of the surface pressure distribution sensor.
[0018]
Naturally, each of these two modules is formed in large numbers on the mother glass and scribed into individual products. Since the scribes are physically separated, for example, a margin of about 1 mm is provided between them, and even if two parts are arranged in contact with each other, an invalid area of at least 2 mm is generated.
[0019]
Further, since a housing for fixing each panel is required, there is a problem that the size of the device is not reduced and the number of assembling steps is increased.
[0020]
In addition, since the difference between the thickness of the liquid crystal display device 10 and the thickness of the surface pressure distribution sensor 20 is very large, there is a problem that fingerprint sensoring cannot be performed optimally.
[0021]
[Means for Solving the Problems]
The present invention has been made in view of the above problems, and firstly, a step of forming a plurality of thin film transistors on an insulating substrate, a step of applying a first sealant to at least an outer periphery of a region to be a liquid crystal display region, Fixing a counter electrode substrate to the entire surface of the substrate with a first sealant and injecting liquid crystal into a region to be the liquid crystal display region to form a liquid crystal display region; and an outer periphery of the region to be the surface pressure distribution sensor region. And a step of forming a surface pressure distribution sensor region by fixing a flexible conductive film with the second sealant.
[0022]
Second, a step of forming a thin film transistor in a region to be a liquid crystal display region and a surface pressure distribution sensor region on an insulating substrate; a step of forming a pixel electrode in the region to be the liquid crystal display region; Forming a contact electrode in a region to be formed, applying a first sealant at least surrounding the outer periphery of the region to be the liquid crystal display region, and forming a counter electrode substrate on the entire surface of the substrate with the first sealant. A step of forming a liquid crystal display region by injecting a liquid crystal into a region to be fixed to the liquid crystal display region, and removing the counter electrode substrate on the region to be the surface pressure distribution sensor region; and A step of applying a second sealant to an outer periphery of a region to be formed, and a step of fixing the insulating substrate and the flexible conductive film with the second sealant to form a surface pressure distribution sensor region. It is intended to resolve by the.
[0023]
The method may further include a step of thinning the counter electrode substrate after the completion of the liquid crystal display area.
[0024]
Further, the first sealant is applied so as to surround the area to be the surface pressure distribution sensor area.
[0025]
Further, the first sealing agent and the second sealing agent are thermosetting resins, and the first sealing agent is higher in temperature than the curing temperature of the second sealing agent. .
[0026]
Further, after the counter electrode substrate is fixed, the liquid crystal display area and the surface pressure distribution sensor area are divided into individual elements as one set.
[0027]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to FIGS.
[0028]
FIG. 1 is a schematic diagram showing the first embodiment. 1A is a perspective cross-sectional view showing the outline, FIG. 1B is a plan view, and FIG. 1C is a cross-sectional view taken along line AA of FIG. 1B.
[0029]
In the semiconductor device of the present invention, both a surface pressure distribution sensor area 200 and a liquid crystal display area 100 are provided on the same insulating substrate 101.
[0030]
Since there is no scribing between the liquid crystal display area 100 and the surface pressure distribution sensor area 200, the operation can be as close as possible in the process. These two regions 100 and 200 are integrally fixed to the housing 300.
[0031]
The liquid crystal display area 100 has a gate signal line and a drain signal line that cross each other, and a V scanner 155 for scanning the gate signal line and an H scanner 156 for scanning the drain signal line are arranged. Various signals supplied to the V scanner 155 and the H scanner 156 are connected to an external control IC 312 via the FPC 311.
[0032]
The surface pressure distribution sensor region 200 has a gate signal line and a drain signal line that cross each other, and a V scanner 225 that scans the gate signal line and an H scanner 226 that scans the drain signal line are arranged. Various signals supplied to the V scanner 225 and the H scanner 226 are connected to an external control IC 312 via the FPC 311.
[0033]
As described above, by forming the liquid crystal display area 100 and the surface pressure distribution sensor area 200 on the common insulating substrate 101, scribing of an adjacent portion becomes unnecessary, and a margin for scribing is reduced to a necessary minimum. it can.
[0034]
For example, in the present invention, a margin between the liquid crystal display region 100 and the surface pressure distribution sensor region 200 is almost unnecessary in operation, and it is sufficient to secure only a margin required in a manufacturing process. However, in practice, it is better to provide the partition P having a predetermined width in consideration of the visual viewpoint and the availability when the device is set as a device. In this case, as shown in FIG. 1B, if necessary components such as the V scanners 155 and 225 are arranged between the liquid crystal display area 100 below the partition P and the surface pressure distribution sensor area 200, wiring can be routed. Is also simplified, and the area overlapping the partition P can be used effectively.
[0035]
In the past, since each module was individually set after being set, each frame was a completely invalid area, so that nothing could be arranged in the portion corresponding to the partition P. However, according to the present invention, the invalid frame area can be reduced, which can contribute to downsizing of the device.
[0036]
Further, conventionally, a housing for fixing each of them is separately required, and the size of the set device is large. However, according to the present invention, since the housing 300 can be integrated, the size of the device can be reduced. .
[0037]
The liquid crystal display area 100 will be described in more detail with reference to FIGS. The liquid crystal display area 100 is, for example, a reflection type liquid crystal display device, in which light incident from the observer side is reflected by a reflection display electrode to observe a display.
[0038]
As shown in FIG. 1C, the liquid crystal display region 100 includes an insulating substrate 101 such as quartz glass or non-alkali glass on which TFTs 114 a to be a large number of display pixels 114 are formed, and a counter electrode substrate fixed by a sealant 140. 130, and a liquid crystal 136 sealed in both substrates. The substrate 101 and the counter electrode substrate 130 have a thickness of about 1 mm, and the liquid crystal 136 has a thickness of several to several tens μm.
[0039]
FIG. 2 is an enlarged view of the vicinity of the display pixel area of the liquid crystal display area 100. FIG. 2A is a plan view, and FIG. 2B is a cross-sectional view taken along line BB of FIG. 2A. A TFT 114a is provided near an intersection between a gate signal line 151 partially having a gate electrode 151a and supplying a gate signal to a gate and a drain signal line 152 partially including a drain electrode 116 and supplying a drain signal to a drain. Have been. The gate 151a of the TFT 114a is connected to the gate signal line 151, the drain 113d is connected to the drain signal line 152, and the source 113s is connected to the reflective display electrode 114b.
[0040]
The drain signal line 152 is connected to the H scanner 156 shown in FIG. 1B, and the gate signal line 151 is connected to the V scanner 155. From the V scanner 155, scanning signals are sequentially switched and output to the gate signal line 151 at a predetermined timing. Now, it is assumed that a gate signal of a certain potential (“H” level) is applied to a certain gate signal line 151. All the TFTs connected to the gate signal line 151 to which the gate signal is applied become conductive (ON). In the meantime, a video signal is switched and applied from the H scanner 156 to the drain signal line 152 at a predetermined timing, and sent to the liquid crystal layer and the storage capacitor.
[0041]
Next, a method for manufacturing the liquid crystal display area 100 will be described. On an insulating substrate 101 made of glass or the like, an active layer 113 made of an island-shaped polycrystalline silicon film, a gate insulating film 112 made of a SiN film and a SiO2 film, and a gate electrode 151a made of a refractory metal such as Cr and Mo are formed. Form in order. The active layer 113 is provided with a source 113s and a drain 113d formed by ion implantation. Then, an interlayer insulating film 115 in which a SiO 2 film, a SiN film, and a SiO 2 film are stacked is formed on the entire surface of the gate insulating film 112 and the active layer 113. Next, Al alone or Mo and Al are sequentially stacked at positions corresponding to the drains 113d in the contact holes provided in the interlayer insulating film 115 and filled with metal to form a drain electrode 116. The drain signal line 152 is provided on the interlayer insulating film 115. Then, a flattening insulating film 119 made of, for example, an organic resin is formed on the entire surface. Further, a contact hole is formed at a position corresponding to the source 113s of the flattening insulating film 119 to provide the reflective display electrode 114b, and the reflective display electrode 114b is connected to the source 113s through the contact part CT. The reflective display electrode 114b is made of a reflective conductive material such as Al and also serves as a source electrode. An alignment film 121 for aligning the liquid crystal 136 is formed thereon. In FIG. 2A, the reflective display electrode 114b is indicated by a dotted line for simplicity, but is formed at the upper layer of the planarization insulating film 119 as shown in FIG. 2B.
[0042]
An insulating substrate 101 having the TFT thus manufactured and a color filter 131 exhibiting each color such as red (R), green (G), and blue (B) are provided on the side facing the substrate 101 on which the liquid crystal 136 is disposed. , A counter electrode 132 and an alignment film 133, and a counter electrode substrate 130 provided with a retardation plate 134 and a polarizing plate 135 on the opposite side of the substrate 130, which is formed by bonding the periphery with a first sealant 140. The liquid crystal 136 is filled in the space thus formed to form a liquid crystal display area.
[0043]
Further, one side of the substrate 101 has an external circuit connection terminal in which wirings for transmitting various signals input to the gate signal line 151 and the drain signal line 152 are collected. The external circuit connection terminal is connected to the substrate 101 via the FPC 157. Connect to control circuit.
[0044]
Next, the surface pressure distribution sensor area 200 will be described with reference to FIGS. 1, 3, and 4. FIG.
[0045]
As shown in FIG. 1C, the surface pressure distribution sensor region 200 has a structure in which the substrate 101 and the counter electrode film 202 made of a flexible conductive film are fixed by a second sealant 203.
[0046]
The substrate 101 is integrated with the liquid crystal display area 100, and a large number of unit detection elements 204 are arranged in a matrix on the inside of the substrate 101 surrounded by the second sealant 203. A contact 206 disposed inside the second sealant 203 is connected to the unit detection element 204, and a wiring (not shown) for transmitting various signals input to the gate signal line 208, the drain signal line 252, etc. And connects the board 101 and an external control circuit 228 via the FPC 227.
[0047]
The counter electrode film 202 has a structure in which a conductive film 202b of a metal such as gold is deposited on the back surface (TFT side) of a flexible insulating film 202a such as PET (polyethylene terephthalate) or PEN (polyethylene naphthalate).
[0048]
The second sealant 203 is a thermosetting resin which is in a liquid state before being cured and is cured by heating, and is cured at a lower temperature than the first sealant 140, as described later.
[0049]
The unit detection element 204 has a TFT 204a as a switching element and a contact electrode 204b connected to the TFT 204a. The active layer of the TFT 204a is a silicon film, particularly preferably a polysilicon film. The contact electrode 204b is a conductive film formed on an insulating film covering the TFT 204a, and is formed of, for example, ITO (Indium Tin Oxide).
[0050]
The gap G between the counter electrode film 202 and the substrate 101 is 10 μm to 40 μm. If the gap G is small, the sensing sensitivity is high (the fingerprint can be detected even if the gap G is weakened), and if the gap G is large, the variation in the sensing sensitivity is small. In this embodiment, 25 μm is adopted as the optimum value.
[0051]
The contact 206 is provided to apply a GND potential to the counter electrode film 202, and is arranged inside the second sealant 203. The contact 206 is composed of a contact pad made of Al and a contact resin provided on the contact pad and containing thermosetting conductive particles.
[0052]
Next, dry air from which moisture has been removed or nitrogen gas may be sealed between the counter electrode film 202 and the substrate 101. If the internal air contains moisture, the TFT 204a is always exposed to this air atmosphere, which causes deterioration and characteristic shift.
[0053]
FIG. 3 is a circuit conceptual diagram of the surface pressure distribution sensor 100.
[0054]
The conductive film 202b of the counter electrode film 202 is grounded via the resistor 217. The drain signal line 252 of the surface pressure distribution sensor area 200 is connected to the H scanner 226, and the gate signal line 251 is connected to the V scanner 225. From the V scanner 225, scanning signals are sequentially switched and output to the gate signal line 251 at a predetermined timing. Now, it is assumed that a gate signal of a certain potential (“H” level) is applied to a certain gate signal line 251. All the TFTs 204a connected to the gate signal line 251 to which the gate signal is applied are turned on (ON). In the meantime, the scanning signal is sequentially switched and applied to the drain signal line 252 from the H scanner 226 at a predetermined timing.
[0055]
When the counter electrode film 202 is bent by the finger peak and is in contact with the contact electrode 204b, even if the voltage once rises as a scanning signal, the current drops through the TFT 204a and the resistor 217, so the voltage drops. When the opposing electrode film 202 is not in contact with the contact electrode 204b at the valley of the finger, the voltage of the scanning signal is maintained without lowering. When this is read out as a voltage signal by the detector 216, the surface pressure distribution for one row can be measured. Then, a gate signal is applied by sequentially switching the gate signal line 251 to be selected, signals from all the unit detection elements 204 in the surface pressure distribution sensor area are read, and the surface pressure distribution on the entire surface can be measured.
[0056]
The detector 216 may be a voltage measuring device branched from the drain signal line 252 and connected as described above, or may be a current measuring device inserted in series with the drain signal line 252, but the voltage measuring device is Since the configuration can be simplified, the present embodiment employs a voltage measuring device.
[0057]
Next, the unit detection element 204 will be described with reference to FIG. FIG. 4A is a plan view of one unit detection element 204, and FIG. 4B is a cross-sectional view taken along line CC of FIG. 4A. The same reference numerals as those in FIG. 1 indicate the same components.
[0058]
In the TFT 204a of the unit detection element 204, an active layer 213 made of a polysilicon layer is formed on the substrate 101, and a source 213s and a drain 213d are formed by introducing impurities by a known method. A gate insulating film 112 is formed to cover the entire surface of the active layer 213, and a gate electrode 251a is formed thereon. The gate electrode 251a is formed integrally with the gate signal line 251. The interlayer insulating film 115 is provided over the gate electrode 251a, the drain 213d of the active layer 213 is connected to the drain signal line 252 via the contact hole, and the source 213s is connected to the extraction electrode 252a. The extraction electrode 252a is made of, for example, Al in the same layer as the drain signal line 252. A flattening film 119 is further laminated thereon to flatten the unevenness of the lower layer. On the flattening film 119, a contact electrode 204b made of ITO which is in contact with the extraction electrode 252a via a contact hole is arranged.
[0059]
As described above, in the present invention, the liquid crystal display region 100 and the surface pressure distribution sensor region 200 are focused on the fact that the configuration up to the TFT is almost common, and it is necessary to form them on the same substrate. did. As a result, the ineffective area can be reduced as compared with the conventional case where each module is set as an individual module, thereby contributing to downsizing of the device. In addition, the number of assembly steps and the number of parts can be reduced, and the cost can be reduced.
[0060]
Further, the liquid crystal display area 100 and the surface pressure distribution sensor area 200 are both operated by the scanning signals from the V scanners 155 and 225 and the V scanners 156 and 226, and are the same except that the clock timing is different due to the difference in the number of pixels. Can be used. That is, the control signals VCLK, HCLK, VST, and HST can be shared, and the control circuit 312 such as a timing controller and the FPC 311 can be shared. This greatly contributes to cost reduction by reducing the number of parts and the number of assembly steps.
[0061]
In this case, the wiring may be routed on the substrate 101 or may be routed on the FPC 311. If the substrate 101 can be routed on the FPC 311, the size of the substrate 101 can be further reduced.
[0062]
Here, the liquid crystal display area 100 is about 1 mm thicker as a finished product than the surface pressure distribution sensor area 200. The gap is 3 μm to 5 μm in the liquid crystal display area, which is smaller than the gap of 25 μm in the surface pressure distribution sensor area. However, the counter electrode film 2 in the surface pressure distribution sensor area is about 30 μm, while the counter electrode substrate in the liquid crystal display area is about 600 μm to 700 μm.
[0063]
If these are formed on the same substrate and they are close to each other, a problem may occur in fingerprint sensoring. When the difference between the thicknesses of the two regions is large, if a part of the finger is applied to the liquid crystal display region 100 when the finger is put thereon, the non-contact surface of the finger is increased by the thickness, so that the sensoring can be appropriately performed. I can't.
[0064]
Therefore, it is more preferable that the liquid crystal display region 100 be thinned by etching the counter electrode substrate 130 after the liquid crystal is filled. Specifically, it is desirable that the difference between these thicknesses is 0.5 mm or less. If the thickness is about 0.5 mm, a predetermined resolution can be obtained because the non-contact area corresponding to the thickness is reduced even if a part of the finger hangs over the liquid crystal display area during sensoring.
[0065]
Further, the control circuit 310 may be arranged in a region generated by a difference in the occupied area on the substrate 101 between the liquid crystal display region 100 and the surface pressure distribution sensor region 200. The control circuit 310 may control the V scanners 155 and 225 and the H scanners 156 and 226, or may be another control circuit such as a DRAM. By using this invalid area, the size of the device in which the semiconductor device is set can be further reduced.
[0066]
Further, the scanner may be shared by the liquid crystal display area and the surface pressure distribution sensor area. For example, the gate signal lines 314 of the liquid crystal display area 100 extend to the surface pressure distribution sensor area 200 and are shared. Thereby, the vertical clock VCLK and the vertical start signal VST input to the gate signal line can be shared. That is, since the V scanner 315 can be shared, the circuit can be simplified and the yield is improved. Also, the number of parts can be reduced.
[0067]
A method for manufacturing a semiconductor device according to the present invention will be described with reference to FIGS.
[0068]
The method for manufacturing a semiconductor device according to the present invention includes the steps of: forming a thin film transistor in a region to be a liquid crystal display region and a surface pressure distribution sensor region on an insulating substrate; forming a pixel electrode in a region to be a liquid crystal display region; A step of forming a contact electrode in a region to be a pressure distribution sensor region, a step of applying a first sealant at least surrounding an outer periphery of the region to be a liquid crystal display region, and a counter electrode substrate over the entire surface of the substrate with the first sealant A step of injecting liquid crystal into a region to be a liquid crystal display region by fixing the liquid crystal display region and forming a liquid crystal display region; It comprises a step of applying a second sealant to the outer periphery, and a step of fixing the insulating substrate and the flexible conductive film with the second sealant to form a surface pressure distribution sensor region.
[0069]
First step: a step of forming the thin film transistors 114a and 204a on the insulating substrate 101 in a region to be the liquid crystal display region 100 and the surface pressure distribution sensor region 200.
[0070]
First, as shown in FIG. 5, TFTs 114a and 204a to be the liquid crystal display area 100 and the surface pressure distribution sensor area 200 are formed on the insulating substrate 1. 5A is a cross-sectional view of the entire substrate 101, FIG. 5B is an enlarged cross-sectional view of the liquid crystal display area 100, and FIG. These two regions are formed on the same substrate 101 as shown. In addition, a cross-sectional view in which the liquid crystal display region 100 and the surface pressure distribution sensor region 200 are set as one set is shown below, but it is assumed that a plurality of these are provided on a large mother glass until the fourth step.
[0071]
Active layers 113 and 213 made of an island-shaped polysilicon film are formed on an insulating substrate 101 made of a large mother glass such as quartz glass or non-alkali glass. In this method, an amorphous silicon film is deposited and crystallized by laser annealing to form a polysilicon film. A gate insulating film 112 made of a SiN film and a SiO2 film, and gate electrodes 151a and 251a made of a refractory metal such as Cr and Mo are sequentially formed. At this time, a gate signal line connected to the gate electrodes 151a and 251a and an external connection terminal (not shown) are formed at the same time. The active layers 113 and 213 are provided with sources 113s and 213s and drains 113d and 213d formed by ion implantation. Then, an interlayer insulating film 115 in which a SiO2 film, a SiN film, and a SiO2 film are stacked is formed on the entire surface of the active layers 113 and 213 and the gate insulating film 112.
[0072]
Next, in the liquid crystal display region 100, Mo and Al are sequentially laminated and metal is filled in the contact holes provided in the interlayer insulating film 115 at positions corresponding to the drains 113d to form drain electrodes 116 and drain signal lines 152. It is formed. Further, in the surface pressure distribution sensor region 200, a drain signal line 252, an extraction electrode 252a, and a contact pad (not shown) around the substrate are formed. The contact pad is provided with an opening in the interlayer insulating film 115 at the corner of the surface pressure distribution sensor region 200, and forms a contact 206 with a contact resin containing conductive particles provided in a later step. This is for applying a GND potential.
[0073]
Thus, in the first step, the TFTs arranged in the liquid crystal display area 100 and the surface pressure distribution sensor area 200 can be formed by exactly the same process.
[0074]
Second step: a step of forming the pixel electrode 114 in a region to be the liquid crystal display region 100.
[0075]
FIG. 6 shows a sectional view of the second step. FIG. 6A shows the entire substrate, and FIG. 6B shows the liquid crystal display area 100.
[0076]
In a region to be the liquid crystal display region 100, a flattening insulating film 119 made of, for example, an organic resin is formed on the entire surface. Further, a contact hole is formed at a position corresponding to the source 113s of the planarization insulating film 119, and a reflective display electrode 114b is provided. As a result, the display pixels 114 are formed. An alignment film 121 for aligning the liquid crystal 136 is formed thereon.
[0077]
Third step: a step of forming a contact electrode in a region to be a surface pressure distribution sensor region.
[0078]
The third step will be described with reference to the cross-sectional view of FIG. FIG. 6A shows the entire substrate, and FIG. 6C shows the surface pressure distribution sensor area.
[0079]
In the planned surface pressure distribution sensor region 200, a contact electrode 204b made of ITO is formed at a position corresponding to the extraction electrode 252a of the planarization insulating film 119, and the unit detection element 204 is formed. When the contact electrode 204b comes into contact with the counter electrode film 202 formed in a later step, a signal from the unit detection element 204 is extracted, and a fingerprint pattern can be detected.
[0080]
Further, if a transmission type liquid crystal display device in which the display electrode 114b is formed of ITO, the display electrode 114b and the contact electrode 204b can be formed in the same process.
[0081]
Fourth step: a step of applying a first sealant 140 that surrounds at least the outer periphery of the area to be the liquid crystal display area 100.
[0082]
As shown in FIG. 7, the first sealant 140 is applied. This surrounds the outer peripheries of the two regions 100 and 200 on the substrate 101 and is also applied to the boundary between the two regions. In the planned liquid crystal display region 100, a part is opened to serve as a liquid crystal injection port, but the planned surface pressure distribution sensor region 200 is applied so as to completely surround the periphery. The first sealant 140 is a thermosetting resin that cures at about 150 ° C.
[0083]
Here, in order to prevent the infiltration of the etching solution in a later step, a sealant (not shown) completely surrounding the outermost periphery of the large mother glass provided with a plurality of sets of the liquid crystal display region 100 and the surface pressure distribution sensor region 200 is provided. ) Is also applied.
[0084]
Fifth step: a step of fixing the counter electrode substrate 130 to the entire surface of the substrate 101 with the first sealant 140 and injecting the liquid crystal 136 into a region to be inside the liquid crystal display region 100 to form the liquid crystal display region 100.
[0085]
From this step, the liquid crystal display area 100 is formed. As shown in FIG. 8A, the counter electrode substrate 130 in the liquid crystal display area 100 is fixed to the entire surface 1 of the substrate with the first sealant 140. As shown in FIG. 2, the counter electrode substrate 130 includes, on the TFT side, a color filter 131 for each color such as red (R), green (G), and blue (B), a counter electrode 132, and an alignment film 133. I have. Thereafter, the counter electrode substrate 130 is fixed to the insulating substrate 101 by a heat treatment at about 150 ° C.
[0086]
Thus, the liquid crystal display region 100 and the surface pressure distribution sensor region 200 have a structure in which the outer periphery of each region is surrounded by the sealant, and the common electrode substrate 130 is fixed thereon in common.
[0087]
Thereafter, an etching process is performed to reduce the thickness of the counter electrode substrate 130 covering the liquid crystal display region 100, and the glass is reduced to such an extent that the thickness difference from the completed surface pressure distribution sensor region 200 becomes 0.5 mm or less.
[0088]
Here, as shown in FIG. 8B, a large number of liquid crystal display areas 100 and surface pressure distribution sensor areas 200 formed on a large mother glass are replaced with one liquid crystal display area 100 and one surface pressure distribution sensor area. 200 are scribed as a set, and are divided individually. At this time, the counter electrode substrate 130 functions as a protective film that protects the unit detection element portion in the surface pressure distribution sensor area from physical impact due to scribe.
[0089]
Thereafter, the liquid crystal 136 is filled from the liquid crystal injection port of the planned liquid crystal display area 100, and the liquid crystal display area 100 is completed. At this time, since the inside of the surface pressure distribution sensor region 200 is filled with air, an inert gas, or the like, the intrusion of the liquid crystal 136 must be prevented. Further, since the liquid crystal is injected by sucking and sucking the inside of the liquid crystal in a vacuum state, it is necessary to cope with explosion-proof atmosphere in the surface pressure distribution sensor. In the present embodiment, the area around the intended surface pressure distribution sensor area is protected by the first sealant 140 and the counter electrode substrate 130 covering the entire surface. That is, the interior of the planned surface pressure distribution sensor area 200 is sealed by the counter electrode substrate 130 and the first sealant 140, and the liquid crystal 136 does not enter. Further, even if the liquid crystal display area 100 is evacuated, the surface pressure distribution sensor area 200 is not affected.
[0090]
As described above, the counter electrode substrate 130 extending from the liquid crystal display region 100 and the first sealing agent 140 surrounding the periphery can protect the surface pressure distribution sensor region 200 from physical impact due to scribe and trouble in the liquid crystal injection process. Therefore, these two regions can be formed on the same substrate.
[0091]
Sixth step: a step of applying a second sealant to the outer periphery of the area to be the surface pressure distribution sensor area 200 after removing the counter electrode substrate 130 on the area to be the surface pressure distribution sensor area 200.
[0092]
As shown in FIG. 9, after the liquid crystal display area 100 is completed, the counter electrode substrate 130 provided as a protective film for the surface pressure distribution sensor area 200 is removed. The boundary between the already completed liquid crystal display region 100 and the planned surface pressure distribution sensor region 200 is scribed, the counter electrode substrate 130 on the planned surface pressure distribution sensor region 200 is removed, and the unit detection element 4 is exposed. .
[0093]
As shown in FIG. 10, a second sealant 203 mixed with a fiber resin having a diameter of 25 μm is applied in a window frame shape around the intended surface pressure distribution sensor area 200. Further, a contact resin containing thermosetting conductive particles for forming the contact 206 is potted on a contact pad (not shown) formed simultaneously with the drain signal line. As a resin serving as a base material of the contact 206 and the second sealant 203, a thermosetting resin whose temperature is lower than that of the first sealant 140 is used. Here, the first sealant 140 is cured at a height of about 3 to 5 μm, which is the gap of the liquid crystal display area 100, and the second sealant 203 is 25 μm. That is, even if the first sealant 140 applied to protect the surface pressure distribution sensor region 200 remains, there is no problem because it is buried therein. Also, the counter electrode substrate 130 may be removed in a removing step.
[0094]
Seventh step: a step of fixing the insulating substrate 101 and the flexible conductive film 202 with the second sealant 203 to form the surface pressure distribution sensor region 200.
[0095]
The substrate 201 is placed in a nitrogen atmosphere containing no water, the counter electrode film 202 is placed on the substrate 201, and the substrate 201 is moved on the counter electrode film 202 while rotating the roller to be attached. Next, heat treatment is performed while applying a load at about 90 ° C. for about 30 minutes at which the low-temperature thermosetting resin as the second sealant 203 is fully cured to cure the resin for the contact 206 and the resin for the second sealant 203. Then, the counter electrode film 202 and the substrate 201 are fixed to each other, and at the same time, a contact 206 for connecting the counter electrode film 202 is formed. Thus, the surface pressure distribution sensor region 200 is completed, and the final structure shown in FIG. 1C is obtained.
[0096]
The low-temperature thermosetting resin is used for the sealing agent 203 and the contact 206 because the heat-resistant temperature (softening temperature) of PET used for the flexible insulating film 202a of the counter electrode film 202 is about 114 ° C. This is because the above heat treatment cannot be performed.
[0097]
In the manufacturing process of the liquid crystal display device 100, a heat treatment at 150 ° C. is performed in the fixing step of the counter electrode substrate 130, but by performing the high-temperature heat treatment step first, the flexible film 202a having a lower heat-resistant temperature is protected. be able to.
[0098]
【The invention's effect】
As described above, according to the manufacturing method of the present invention, the liquid crystal display region and the surface pressure distribution sensor region can be formed on the same insulating substrate.
[0099]
At this time, the same process is performed up to the formation of the TFT 114a serving as the display pixel 114 of the liquid crystal display area 100 and the TFT 4a serving as the unit detection element 4a of the surface pressure distribution sensor area 200. In the past, they were individually manufactured by completely different processes, but by manufacturing them in the same process on the same substrate, the number of assembling steps can be significantly reduced.
[0100]
When scribing one large liquid crystal display device and one surface pressure distribution sensor region as a set from a large mother glass, the counter electrode substrate is fixed on the surface pressure distribution sensor region 200 by the first sealant. ing. At this time, the TFT region can be protected from the physical impact of the scribe by the counter electrode substrate.
[0101]
The surface pressure distribution sensor region is filled with air or an inert gas to prevent the intrusion of liquid crystal. However, the surface pressure distribution sensor region is sealed with the first sealant and the counter electrode substrate. Since the liquid crystal can be injected in the state, the area of the surface pressure distribution sensor can be protected. Further, the liquid crystal is sucked and injected by applying a vacuum. At this time, since the surface pressure distribution sensor is in a sealed state, it is not necessary to perform explosion proof by a separate process.
[0102]
Further, the counter electrode film in the area of the surface pressure distribution sensor needs to have a high resolution, and the flexible conductive film capable of obtaining this resolution has a heat resistance temperature of 114 ° C. On the other hand, in the manufacturing process of the liquid crystal display device, there is a high-temperature heat treatment step of about 150 ° C. Therefore, after the liquid crystal display area is completed, the counter electrode film is fixed using the low-temperature thermosetting resin as a sealant. By performing a flow requiring a high-temperature heat treatment first, two devices can be manufactured on the same substrate.
[0103]
Further, the liquid crystal display area is thinned by etching the glass after the liquid crystal is filled. Specifically, the difference between the thickness of the liquid crystal display area and the thickness of the surface pressure distribution sensor area is desirably 0.5 mm or less. If the difference in thickness is large, if a part of the finger touches the liquid crystal display area when a finger is put on the part, the part in contact with the liquid crystal display area cannot properly perform fingerprint sensoring due to the difference in thickness. If it is about 0.5 mm, a predetermined resolution can be obtained even if a part of the finger is over the liquid crystal display area.
[Brief description of the drawings]
FIG. 1A is a perspective view, FIG. 1B is a plan view, and FIG. 1C is a sectional view showing an embodiment of the present invention.
FIGS. 2A and 2B are a plan view and a cross-sectional view illustrating an embodiment of the present invention.
FIG. 3 is a schematic circuit diagram showing an embodiment of the present invention.
4A and 4B are a plan view and a cross-sectional view, respectively, showing an embodiment of the present invention.
FIG. 5 is a sectional view showing an embodiment of the present invention.
FIG. 6 is a sectional view showing an embodiment of the present invention.
FIG. 7 is a sectional view showing an embodiment of the present invention.
8A is a cross-sectional view and FIG. 8B is a plan view showing the embodiment of the present invention.
FIG. 9 is a sectional view showing an embodiment of the present invention.
FIG. 10 is a sectional view showing an embodiment of the present invention.
11A is a perspective view, FIG. 11B is a plan view, FIG. 11C is a cross-sectional view, and FIG.
[Explanation of symbols]
Reference Signs List 100 liquid crystal display area 101 insulating substrate 112 gate insulating film 113 active layer 113s source 113d drain 114 display pixel 114a TFT
114b Reflective display electrode 115 Interlayer insulating film 119 Flattening film 130 Counter electrode substrate 136 Liquid crystal 140 First sealant 151 Gate signal line 152 Drain signal line 200 Surface pressure distribution sensor area 202 Counter electrode film 203 Second sealant 204 Unit Detection element 204a TFT
204b Contact electrode 251 Gate signal line 251a Gate electrode 252 Drain signal line 252a Extraction electrode 213 Active layer 213s Source 213d Drain 300 Case

Claims (6)

Forming a plurality of thin film transistors on an insulating substrate,
A step of applying the first sealant to at least the outer periphery of a region to be a liquid crystal display region;
Fixing a counter electrode substrate to the entire surface of the substrate with the first sealant and injecting liquid crystal into a region to be the liquid crystal display region to form a liquid crystal display region;
A step of applying a second sealant to an outer periphery of an area to be the surface pressure distribution sensor area;
Fixing the flexible conductive film with the second sealant to form a surface pressure distribution sensor region. Forming a thin film transistor in a region to be a liquid crystal display region and a surface pressure distribution sensor region on the insulating substrate;
Forming a pixel electrode in a region to be the liquid crystal display region;
Forming a contact electrode in an area to be the surface pressure distribution sensor area,
Applying a first sealant at least surrounding the outer periphery of the area to be the liquid crystal display area;
Fixing a counter electrode substrate to the entire surface of the substrate with the first sealant, injecting liquid crystal into a region to be the liquid crystal display region, and forming a liquid crystal display region;
Applying a second sealant to the outer periphery of the area to be the surface pressure distribution sensor area after removing the counter electrode substrate on the area to be the surface pressure distribution sensor area;
Fixing the insulating substrate and the flexible conductive film with the second sealant to form a surface pressure distribution sensor region. The method according to claim 1, further comprising a step of thinning the counter electrode substrate after fixing the counter electrode substrate. 3. The method according to claim 1, wherein the first sealant is applied so as to surround an area to be the surface pressure distribution sensor area. 4. 5. The method according to claim 4, wherein the first sealant and the second sealant are thermosetting resins, and the first sealant is higher than a curing temperature of the second sealant. Manufacturing method of a semiconductor device. 3. The device according to claim 1, wherein after fixing the counter electrode substrate, the liquid crystal display region and the surface pressure distribution sensor region are divided into individual elements as one set. 4. The manufacturing method of the semiconductor device described in the above.

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