JP2011215458A - Method of manufacturing electro-optical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing an electro-optical device in which the occurrence of hillock can be suppressed with simple constitution.SOLUTION: The method for manufacturing electro-optical device including a transistor, a fourth interlayer dielectric covering the transistor in a pixel region, and external circuit connecting terminals at the surroundings of a pixel region includes: steps S2 and S3 for laminating a metal layer including aluminum at the surrounding of the pixel region, and laminating a barrier layer on the metal layer; a step 4 for forming the fourth interlayer dielectric so as to cover the metal layer and the barrier layer; steps 6 and 7 for removing the metal layer and the fourth interlayer dielectric on the barrier layer and performing heat treatment; and a step S8 for, after performing the steps 6 and 7, removing the barrier layer and forming the external circuit connecting terminals.

Description

  The present invention relates to a method for manufacturing an electro-optical device.

  Conventionally, pixel electrodes arranged in a matrix on a substrate, thin film transistors (hereinafter referred to as “TFTs” as appropriate) connected to each of the electrodes, connected to each of the TFTs, and rows and columns There is known an electro-optical device capable of so-called active matrix driving by including a data line, a scanning line, and the like provided in parallel in each direction. In addition to the above, the electro-optical device includes a counter substrate disposed to face the substrate, a counter electrode facing the pixel electrode on the counter substrate, and the pixel electrode and the counter electrode. By providing a liquid crystal layer sandwiched between the electrodes, a pixel electrode, a storage capacitor connected to the TFT, and the like, an image can be displayed.

The substrate in such an electro-optical device supplies an image display region provided with scanning lines, data lines, pixel electrodes, storage capacitors, and the like, a scanning line driving circuit, a data line driving circuit, and predetermined signals to these circuits. And a peripheral region in which external circuit connection terminals and the like are provided.
The external circuit connection terminal described above includes a metal layer containing aluminum.

By the way, in the manufacturing process of the external circuit connection terminal, a hillock generated on the metal layer becomes a problem. Here, the hillock is generated by locally plastically deforming the metal layer using a compressive stress applied by heating or the like on the metal layer as a driving force.
When hillocks are generated in the manufacturing process, the hillocks scrape off the metal layer when the alignment film is rubbed, and the scraped metal pieces are scattered in the image display area. The dispersed metal pieces cause a short circuit between pixels or cause burn-in.
Therefore, various studies for suppressing the occurrence of hillocks have been made (see, for example, Patent Document 1).

  This patent document 1 discloses the following method. That is, an aluminum electrode pad portion is formed on the substrate, and an insulating film such as a passivation film is formed so as to cover the electrode pad portion. Then, an opening is formed so that the insulating film remains in the central portion and the peripheral portion of the electrode pad portion, and no insulating film remains between the central portion and the peripheral portion. In this way, the generation of hillocks during heat treatment is suppressed by leaving the insulating film at the center of the electrode pad portion.

JP-A-8-124932

  However, when the method described in Patent Document 1 is applied to the manufacturing process of the electro-optical device, a step of forming an opening that is not performed in the general manufacturing process of the electro-optical device is required. Since the external circuit connection terminal of the electro-optical device is extremely small, high-precision control is required to form the opening. Therefore, a configuration that can suppress the occurrence of hillocks with a simple configuration is desired.

  An object of the present invention is to provide a method of manufacturing an electro-optical device that can suppress generation of hillocks with a simple configuration.

In order to achieve the above object, as a result of intensive studies by the present inventors, the following has been found and the present invention has been completed.
That is, in the conventional manufacturing process of the electro-optical device, first, a step of laminating a metal layer containing aluminum on a substrate and a barrier layer on the metal layer is performed. Next, after forming an interlayer insulating film so as to cover the metal layer and the barrier layer, the barrier layer and the interlayer insulating film are removed to form a connection terminal in which the metal layer is exposed. Thereafter, heat treatment was performed to recover plasma damage and crystal defects in Si. However, in such a method, it was confirmed that many hillocks were generated on the metal layer.
Therefore, after the heat treatment was performed after removing only the interlayer insulating film so that the barrier layer was exposed, and the connection layer was formed by removing the barrier layer, it was confirmed that the generation of hillocks was suppressed. .
The present invention has been devised based on such knowledge.

That is, the electro-optical device manufacturing method of the present invention is a method for manufacturing an electro-optical device including a transistor in a pixel region, an interlayer insulating film covering the transistor, and a connection terminal around the pixel region, A step of laminating a metal layer containing aluminum and a barrier layer on the metal layer around the pixel region; a step of forming the interlayer insulating film so as to cover the metal layer and the barrier layer; Removing the interlayer insulating film on the barrier layer and performing heat treatment, and then removing the barrier layer to form connection terminals.
According to the present invention, since only the interlayer insulating film is removed and then the heat treatment is performed, the barrier layer is removed and the connection terminal is formed, so that generation of hillocks can be suppressed. Accordingly, the timing for removing the barrier layer and the timing for performing the heat treatment need only be changed with respect to the conventional method for manufacturing an electro-optical device. Therefore, it is not necessary to provide a new process or a process that requires high-precision control, and generation of hillocks can be suppressed with a simple configuration.

In the method of manufacturing the electro-optical device according to the aspect of the invention, it is preferable that a step of forming a pixel electrode is provided between the step of forming the interlayer insulating film and the step of removing the interlayer insulating film.
According to the present invention, since the pixel electrode is formed before the heat treatment, a thin film constituting the pixel electrode is not formed on the metal layer of the connection terminal, and the increase in resistance of the connection terminal can be suppressed.

In the method of manufacturing the electro-optical device according to the aspect of the invention, after the step of forming the connection terminal, a step of forming an alignment film so as to cover the connection terminal and a step of rubbing the alignment film are provided. Is preferred.
According to the present invention, since the rubbing process can be performed in a state where no hillock is generated, the problem of scraping off the metal layer during the rubbing process can be eliminated, and a high-quality electro-optical device can be provided.

FIG. 3 is a plan view of the electro-optical device when the element substrate according to the present embodiment is viewed from the side of the counter substrate together with each component formed thereon. Sectional drawing along the II-II line of FIG. The enlarged view of the principal part in FIG. FIG. 2 is a cross-sectional view illustrating a schematic configuration of a projection type projector according to the embodiment. 6 is a flowchart showing a method for manufacturing the electro-optical device in the embodiment. Sectional drawing which shows the state at the time of the heat processing of the element substrate in the said embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the electro-optical device of the invention is applied to a liquid crystal device.

[Overall configuration of electro-optical device]
First, an overall configuration of an embodiment according to an electro-optical device of the invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a plan view of the electro-optical device when the element substrate is viewed from the side of the counter substrate together with each component formed thereon, and FIG. 2 is taken along the line II-II in FIG. FIG. 3 is an enlarged view of a main part in FIG. 2. Here, a TFT active matrix driving type liquid crystal device with a built-in driving circuit, which is an example of an electro-optical device, is taken as an example.

1 and 2, in the electro-optical device 100 according to the present embodiment, the element substrate 10 and the counter substrate 30 are disposed to face each other. A liquid crystal layer 40 is sealed between the element substrate 10 and the counter substrate 30, and the element substrate 10 and the counter substrate 30 are mutually connected by a sealing material 51 provided in a seal region located around the image display region 50. It is glued to.
The sealing material 51 is made of, for example, an ultraviolet curable resin, a thermosetting resin, or the like for bonding the two substrates, and is applied on the element substrate 10 in the manufacturing process and then cured by ultraviolet irradiation, heating, or the like. is there. Further, in the sealing material 51, a gap material such as glass fiber or glass beads for dispersing the distance between the element substrate 10 and the counter substrate 30 (inter-substrate gap) to a predetermined value is dispersed.

A light-shielding frame light-shielding film 52 that defines the frame area of the image display region 50 is provided on the counter substrate 30 side in parallel with the inside of the seal region where the seal material 51 is disposed. Particularly in the present embodiment, when viewed from the center of the element substrate 10, the distance from the frame light shielding film 52 is defined as the peripheral region.
Of the peripheral region, a data line driving circuit 53 and an external circuit connection terminal 54 are provided along one side of the element substrate 10 particularly in a region located outside the sealing region where the sealing material 51 is disposed. The scanning line driving circuit 55 is provided along two sides adjacent to the one side so as to be covered with the frame light shielding film 52. Further, in order to connect the two scanning line driving circuits 55 provided on both sides of the image display region 50 in this way, a plurality of the plurality of the substrate substrates 10 are covered with the frame light-shielding film 52 along the remaining side of the element substrate 10. Wiring 56 is provided. Among these, the data line driving circuit 53 and the scanning line driving circuit 55 are connected to the external circuit connection terminal 54 via the extended capacitance wiring 16. The detailed configuration of the external circuit connection terminal 54 and the extended capacitor wiring 16 will be described later.

  In addition, vertical conduction members 57 functioning as vertical conduction terminals between the two substrates are disposed at the four corners of the counter substrate 30. On the other hand, the element substrate 10 is provided with vertical conduction terminals in a region facing these corners. Thus, electrical conduction can be established between the element substrate 10 and the counter substrate 30.

  In FIG. 2, an alignment film 18 is formed on the pixel electrode 17 on the element substrate 10. On the other hand, on the counter substrate 30, in addition to the counter electrode 31, a lattice-shaped or striped light-shielding film 32 and an alignment film 33 are formed in the uppermost layer portion. The liquid crystal layer 40 is made of, for example, a liquid crystal in which one kind or several kinds of nematic liquid crystals are mixed, and takes a predetermined alignment state between the pair of alignment films.

  Next, a detailed configuration of the element substrate 10 will be described. In FIG. 3, various configurations are provided in a stacked structure on the element substrate 10. This stacked structure includes a first layer including a scanning line 12, a second layer including a pixel switching TFT 13, a third layer including a storage capacitor (not shown), a data line 14, and the like, each formed on the substrate 11. The fourth layer includes a fifth layer including the capacitor wiring 15 and the like, and the sixth layer including the pixel electrode 17 and the alignment film 18 and the like.

Also, a base insulating film 20 is provided between the first layer and the second layer, a first interlayer insulating film 21 is provided between the second layer and the third layer, and a second interlayer insulating film 22 is provided between the third layer and the fourth layer. A third interlayer insulating film 23 is provided between the fourth layer and the fifth layer, and a fourth interlayer insulating film 24 is provided between the fifth layer and the sixth layer, so that the above-described elements are short-circuited. Is preventing. The fourth interlayer insulating film 24 is composed of a silicate glass film such as NSG (non-silicate glass), PSG (phosphorus silicate glass), BSG (boron silicate glass), BPSG (boron phosphorus silicate glass), silicon nitride film or silicon oxide. It is made of a film or the like, or preferably NSG, and is provided so as to cover the TFT 13.
Further, in these various insulating films 20, 21, 22, 23, 24, for example, contact holes for electrically connecting the high concentration source region of the TFT 13 and the data line 14 are also provided.

Further, in this embodiment, in particular, also in the peripheral region, as shown in FIG. 3, the capacitor wiring 15 is extended (hereinafter, in order to distinguish from the capacitor wiring on the image display region 50, this peripheral region The upper capacitor wiring is called “extended capacitor wiring 16”). The extended capacitor wiring 16 is formed on the third interlayer insulating film 23 as the same film as the capacitor wiring 15 and the like. The extended capacitor wiring 16 and the capacitor wiring 15 include a metal layer 161 formed on the third interlayer insulating film 23 and a barrier layer 162 formed on the metal layer 161. The metal layer 161 is formed of a material containing aluminum. The barrier layer 162 is formed of a material containing titanium nitride.
A contact hole 241 is formed in a part of the fourth interlayer insulating film 24 and the barrier layer 162 by etching. The portion provided with the contact hole 241 constitutes an external circuit connection terminal 54.

〔Electronics〕
Next, an overall configuration, particularly an optical configuration, of an embodiment of a projection type projector that is an example of an electronic apparatus using the electro-optical device 100 described above in detail as a light valve will be described. FIG. 4 is a cross-sectional view showing a schematic configuration of a projection type projector.

  In FIG. 4, a projection type projector 1100 according to the present embodiment prepares three liquid crystal modules including a liquid crystal device having a drive circuit mounted on an element substrate, which are used as RGB light valves 100R, 100G, and 100B, respectively. Configured as a projector. In the projector 1100, when projection light is emitted from a lamp unit 1102 of a white light source such as a metal halide lamp, the light components R, G, and B corresponding to the three primary colors of RGB are generated by three mirrors 1106 and two dichroic mirrors 1108. Divided and guided to the light valves 100R, 100G, and 100B corresponding to the respective colors. At this time, in particular, the B light is guided through a relay lens system 1121 including an incident lens 1122, a relay lens 1123, and an exit lens 1124 in order to prevent light loss due to a long optical path. The light components corresponding to the three primary colors modulated by the light valves 100R, 100G, and 100B are synthesized again by the dichroic prism 1112 and then projected as a color image on the screen 1120 via the projection lens 1114.

[Method of manufacturing electro-optical device]
Next, a method for manufacturing an element substrate will be described as a method for manufacturing the electro-optical device 100. FIG. 5 is a flowchart showing a method for manufacturing the electro-optical device. FIG. 6 is a cross-sectional view showing a state during heat treatment of the element substrate.

In the manufacture of the element substrate 10 of the electro-optical device 100, as shown in FIG. 5, first, the components up to the third interlayer insulating film 23 as shown in FIG. 3 are formed on the substrate 11 (step S1). . Next, the capacitor wiring 15 and the extended capacitor wiring 16 are formed on the third interlayer insulating film 23, and a metal layer 161 containing aluminum is formed in a predetermined pattern (step 2). Next, the capacitor wiring 15 and the extended capacitor wiring 16 are formed on the metal layer 161, and the barrier layer 162 containing titanium nitride is formed (step S3). Further, a fourth interlayer insulating film 24 is formed so as to cover the metal layer 161 and the barrier layer 162 (step S4). Thereafter, the pixel electrode 17 is formed in a predetermined pattern (step S5).
In addition, the process of the above-mentioned step S1-S5 is a process generally performed conventionally.

Next, in order to form the external circuit connection terminal 54, as shown in FIG. 6, the portion located in the peripheral region in the fourth interlayer insulating film 24 is etched (step S6), and the contact hole 241 is formed. At this time, only the fourth interlayer insulating film 24 is etched, and the barrier layer 162 is not etched.
And after performing the process which adds the heat | fever H of 200 to 350 degreeC to the element substrate 10 in which various structures were formed (step S7), the barrier layer 162 exposed from the contact hole 241 is etched (step S8). .
By performing the above steps, an external circuit connection terminal 54 as shown in FIG. 3 is formed.
Thereafter, an alignment film 18 is formed (step S9), a rubbing process is performed (step S10), and the alignment film 18 in the peripheral region is removed, thereby completing the manufacture of the element substrate 10.
The etching in steps S6 and S8 is preferably wet etching, but may be dry etching.

[Effects of electro-optical device manufacturing method]
According to this embodiment described above, the following effects are obtained.
In this embodiment, after forming the metal layer 161, the barrier layer 162, and the fourth interlayer insulating film 24 on the substrate 11, only the fourth interlayer insulating film 24 is etched. Then, after the heat treatment, the external circuit connection terminal 54 is formed by etching the barrier layer 162. As a result, it is only necessary to change the timing of removing the barrier layer 162 and the timing of performing the heat treatment with respect to the conventional method of manufacturing an electro-optical device, so that a new process or a process requiring high-precision control is required. The generation of hillocks can be suppressed with a simple configuration.

Further, since the pixel electrode 17 is formed before the heat treatment, it is possible to suppress an increase in resistance of the external circuit connection terminal 54.
Since the alignment film 18 is formed and the rubbing process is performed on the element substrate 10 in which the generation of hillocks is suppressed, the problem of scraping off the metal layer 161 during the rubbing process can be eliminated, and high-quality electro-optics can be obtained. An apparatus 100 can be provided.

[Modification]
It should be noted that the present invention is not limited to the above-described embodiments, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.
That is, in the above-described embodiment, only an example in which the electro-optical device is used for the front projection type projector is described. However, the electro-optical device of the present invention includes a screen, and is a rear type that projects from the back side of the screen. It can also be applied to projectors. Moreover, it is applicable also to electronic devices other than a projector.

  DESCRIPTION OF SYMBOLS 13 ... TFT (transistor), 17 ... Pixel electrode, 18 ... Orientation film, 24 ... 4th interlayer insulation film (interlayer insulation film), 54 ... External circuit connection terminal, 100 ... Electro-optical device, 161 ... Metal layer, 162 ... Barrier layer.

Claims (3)

A method of manufacturing an electro-optical device comprising a transistor in a pixel region, an interlayer insulating film covering the transistor, and a connection terminal around the pixel region,
Laminating a metal layer containing aluminum and a barrier layer on the metal layer around the pixel region;
Forming the interlayer insulating film so as to cover the metal layer and the barrier layer;
Removing the interlayer insulating film on the metal layer and the barrier layer and performing a heat treatment, and then removing the barrier layer to form a connection terminal;
A method for manufacturing an electro-optical device. The method of manufacturing the electro-optical device according to claim 1,
A method for manufacturing an electro-optical device, comprising: forming a pixel electrode between the step of forming the interlayer insulating film and the step of removing the interlayer insulating film. In the manufacturing method of the electro-optical device according to claim 1 or 2,
After the step of forming the connection terminal, a step of forming an alignment film so as to cover the connection terminal, a step of rubbing the alignment film,
A method for manufacturing an electro-optical device.

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