JP2006169040A - Glass substrate with ito and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a glass substrate with ITO having electric resistance and visual light transmissivity proper as a counter substrate of a liquid crystal silicon (LCOS) chip. <P>SOLUTION: After a reflection preventing film 7 is formed on the rear surface of the glass substrate 1, a titanium oxide film 2 having 80-200 Å thickness, a silicon dioxide film 3 having 150-300 Å thickness, a titanium oxide film 4 having 1,000-1,200 Å thickness and a silicon dioxide film 5 having 200-400 Å are formed in this order on the surface of the glass substrate 1. An ITO film 6 having 100-350 Å thickness is formed on the surface of the outermost oxide film 5 by keeping the degree of vacuum and the temperature in a chamber respectively to 10<SP>-6</SP>Torr order and 125-230°C, passing oxygen at a flow rate of 1.5-3.5 sccm and argon at a flow rate of 150-450 sccm in the chamber and sputtering. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a glass substrate with ITO and a method for producing the same.

  Recently, LCOS (Liquid Crystal on Silicon) technology has attracted attention as a micro display used for large screen televisions such as rear projection televisions and large screen displays. In general, an LCOS chip has a single crystal silicon substrate having a MOSFET (insulated gate field effect transistor) manufactured by a semiconductor manufacturing technology and a glass substrate having a transparent electrode facing each other, and a liquid crystal is sealed between them. It has a structure. The glass substrate with a transparent electrode used for the LCOS chip is required to have a high light transmittance even at 1% while controlling the electric resistance value.

As a glass substrate having a transparent electrode, a translucent conductive film is known in which an ITO film and a SnO film are alternately laminated by a vacuum deposition method on a substrate in which an insulating film is formed on a glass substrate (for example, Patent Literature 1). Further, a transparent conductive laminate is known in which a TiO ₂ film is laminated on a glass substrate, a ZrSi _x O _y film is laminated thereon, and an ITO film is laminated thereon by an ion plating method (for example, , See Patent Document 2). Also, a heat ray shielding plate having a high visible light transmittance is known in which a TiO ₂ film and a SiO ₂ film are alternately laminated on a glass substrate (see, for example, Patent Document 3).

JP-A-60-205909 (Table 1) JP-A-4-154647 (Example 1) Japanese Patent Laid-Open No. 1-138159 (Example 4)

  However, in the translucent conductive film disclosed in Patent Document 1, not only the transmittance of light in a wavelength region other than the wavelength of 500 nm is unknown, but also the transmittance of light with a wavelength of 500 nm is high. Since it is 84%, there is a problem that the light transmittance is too low to be used as a glass substrate having a transparent electrode of an LCOS chip. In addition, the transparent conductive laminate disclosed in Patent Document 2 is not suitable for a glass substrate having a transparent electrode of an LCOS chip because the electrical resistance value and the light transmittance are unknown. Moreover, in the heat ray shielding plate disclosed in the above-mentioned Patent Document 3, not only the electric resistance value is unknown, but also the visible light transmittance is about 81% at the highest, so that the glass having the transparent electrode of the LCOS chip. There is a problem that the light transmittance is too low for use as a substrate.

  An object of the present invention is to provide a glass substrate with ITO having an appropriate electrical resistance and visible light transmittance as a counter substrate of an LCOS chip, for example, in order to eliminate the above-described problems caused by the prior art. Moreover, this invention aims at providing the manufacturing method of the glass substrate with ITO which has such a characteristic.

  In order to solve the above-mentioned problems and achieve the object, a glass substrate with ITO according to the present invention is laminated on a glass substrate, at least two oxide films laminated on the surface of the glass substrate, and the oxide film. And an ITO film having a thickness not less than 100 angstroms and not more than 350 angstroms. In the present invention, the oxide film may include an oxide film layer made of titanium oxide and an oxide film layer made of silicon dioxide. For example, the oxide film has a four-layer structure of an oxide film layer made of titanium oxide, an oxide film layer made of silicon dioxide, an oxide film layer made of titanium oxide, and an oxide film layer made of silicon dioxide in this order from the glass substrate side. May be.

  Alternatively, the oxide film may include an oxide film layer made of tantalum oxide and an oxide film layer made of silicon dioxide. The sheet resistance value of the ITO film is 200Ω / □ or more and 310Ω / □ or less, preferably 300Ω / □ or less. Further, an antireflection film may be provided on the back surface of the glass substrate. Furthermore, the light transmittance is preferably 90% or more over the entire wavelength range of visible light. According to the present invention, a glass substrate with ITO having a low electrical resistance value and a high visible light transmittance can be obtained.

In order to solve the above-described problems and achieve the object, a method for manufacturing a glass substrate with ITO according to the present invention includes a step of laminating at least two oxide films on the surface of a glass substrate, and a chamber in a sputtering apparatus. After the degree of vacuum of 10 ⁻⁶ Torr is maintained, the temperature in the chamber is maintained at 125 ° C. or higher and 230 ° C. or lower, and oxygen is introduced into the chamber at a flow rate of 1.5 sccm or higher and 3.5 sccm or lower. And argon is introduced at a flow rate of 150 sccm or more and 450 sccm or less, and sputtering is performed to form an ITO film on the oxide film. In the present invention, the ITO film may be formed to a thickness of 100 angstroms or more and 350 angstroms or less.

  Further, as the oxide film, an oxide film layer made of one or more titanium oxides and an oxide film layer made of one or more silicon dioxides may be stacked. For example, as the oxide film, an oxide film layer made of titanium oxide, an oxide film layer made of silicon dioxide, an oxide film layer made of titanium oxide, and an oxide film layer made of silicon dioxide may be stacked in this order from the glass substrate side. . Alternatively, as the oxide film, an oxide film layer made of tantalum oxide and an oxide film layer made of silicon dioxide may be stacked in this order from the glass substrate side.

  Further, before the oxide film is laminated on the surface of the glass substrate, an antireflection film may be formed on the back surface of the glass substrate, or the glass substrate may be processed into a substantially circular shape in advance. According to the present invention, a glass substrate with ITO having a low electrical resistance value and a high visible light transmittance can be obtained at a lower cost than when an ITO film is formed by a CVD (chemical vapor deposition) method.

  According to the present invention, a glass substrate with ITO having a low electrical resistance value and a high visible light transmittance can be obtained. In particular, there is an effect that a glass substrate with ITO having an appropriate electrical resistance and visible light transmittance can be obtained as the counter substrate of the LCOS chip.

  Exemplary embodiments of a glass substrate with ITO and a method for manufacturing the same according to the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view showing an example of a glass substrate with ITO according to the present invention. As shown in FIG. 1, a first titanium oxide (TiO _x ) film 2, a first silicon dioxide (SiO ₂ ) film 3, and a second titanium oxide ( A TiO _x ) film 4, a second silicon dioxide film 5, and an ITO film 6 are laminated. The glass substrate 1 is not particularly limited, but is an alkali-free glass plate having a refractive index of 1.55 for light having a wavelength of 550 nm, for example.

  The thickness of the first titanium oxide film 2 is 80 to 200 angstroms. The thickness of the first silicon dioxide film 3 is 150 to 300 angstroms. The thickness of the second titanium oxide film 4 is 1000 to 1200 angstroms. The thickness of the second silicon dioxide film 5 is 200 to 400 angstroms. The thickness of the ITO film 6 is 100 to 350 angstroms.

An antireflection film (AR film) 7 is provided on the back surface of the glass substrate 1. The antireflection film 7 has a structure in which a silicon dioxide film 71, a titanium dioxide (TiO ₂ ) film 72, a silicon dioxide film 73, a titanium dioxide film 74, and a silicon dioxide film 75 are laminated in order from the back surface side of the glass substrate 1. ing.

  The glass substrate with ITO having the above-described configuration has the following characteristics. That is, the sheet resistance value of the ITO film 6 is 200 to 310Ω / □. Preferably, the sheet resistance value is 200 to 300Ω / □. In the visible light wavelength region, specifically in the wavelength region of 410 to 750 nm, the light transmittance is 90% or more.

  Next, the manufacturing method of the glass substrate with ITO concerning this invention is demonstrated. FIG. 2 is a process diagram showing an example of the manufacturing method. As shown in FIG. 2, first, the rectangular glass substrate 1 is processed into a substantially circular shape (step S1). Next, after washing the glass substrate 1, an antireflection film 7 is formed on the back surface of the glass substrate 1 (step S2). Next, after cleaning the glass substrate 1, a first titanium oxide film 2, a first silicon dioxide film 3, a second titanium oxide film 4, and a second silicon dioxide film 5 are sequentially formed on the surface of the glass substrate 1. Film is formed (step S3). In forming these four layers of oxide films 2, 3, 4, and 5, electron beam physical vapor deposition or sputtering can be used.

Next, after cleaning the glass substrate 1 with the four layers of oxide film, an ITO film 6 is formed on the surface of the second silicon dioxide film 5 as the uppermost layer by a sputtering method (step S4). The sputtering conditions at this time are as follows. An in-line sputtering apparatus is used. Indium and tin are used for the target. The degree of vacuum in the chamber of the sputtering apparatus is on the order of 10 ⁻⁶ Torr. Moreover, the temperature in a chamber is 125-230 degreeC.

Then, after maintaining the vacuum level and temperature in the chamber, oxygen is introduced into the chamber at a flow rate of 1.5 to 3.5 sccm, and argon is introduced into the chamber at a flow rate of 150 to 450 sccm. . In the chamber when oxygen and argon are flowing in, the degree of vacuum decreases to the order of 1 × 10 ⁻¹ Torr. The current value of the target current and the substrate transport speed are appropriately controlled according to the film thickness of the ITO film 6. In other words, the film thickness of the ITO film 6 can be controlled by controlling the current value of the target current and the substrate transport speed. The film thickness of the ITO film 6 is appropriately selected within the above-mentioned range in consideration of the light transmittance and the electric resistance value.

  Here, when the four layers of oxide films 2, 3, 4, and 5 below the ITO film 6 are formed by sputtering, the glass substrate 1 is placed in the chamber while the ITO film 6 is placed. Since the four oxide films 2, 3, 4, 5 and the ITO film 6 can be continuously formed, it is not necessary to clean the substrate before the ITO film 6 is formed. In addition to indium and tin, silicon and titanium are also used as targets for the sputtering apparatus in this case.

  Next, the process by which the inventors derived the above-described sputtering conditions will be described. The characteristics of the ITO film 6 that the present inventors desire are high light transmittance in the visible light region and low electrical resistance. In order to increase the light transmittance, the ITO film 6 may be thinned. However, if the ITO film 6 is thin, the electrical resistance value becomes high. That is, the light transmittance of the ITO film 6 and the electric resistance value are in a trade-off relationship. Therefore, the present inventors conducted the following experiment in order to obtain sputtering conditions that can reduce the electrical resistance value in a state where the light transmittance of the ITO film 6 in the visible light region is high.

First, an ITO film having a thickness of 220 Å is formed on a glass substrate using a general sputtering condition when a conventional thick ITO film (sheet resistance value: 10 to 30Ω / □) is produced by a sputtering method. did. The target DC power was 0.4 kW, and the degree of vacuum in the chamber was set to 6 × 10 ⁻⁶ Torr, and then oxygen and argon were introduced. The flow rate of argon was 780 sccm. FIG. 3 shows how the sheet resistance value changes when the oxygen flow rate is changed to 2.5 sccm, 3.0 sccm, 3.5 sccm, 4.0 sccm, and 4.5 sccm. As shown in FIG. 3, it was found that the sheet resistance value was the smallest when the oxygen flow rate was 3.0 sccm. Accordingly, the present inventors tentatively set the oxygen flow rate to 3.0 sccm.

Next, an ITO film having a thickness of 220 Å was formed on a glass substrate by a sputtering method with the oxygen flow rate fixed at 3.0 sccm and the argon flow rate varied. The target DC power was 0.4 kW, and the degree of vacuum in the chamber was set to 6 × 10 ⁻⁶ Torr, and then oxygen and argon were introduced. The temperature in the chamber was 200 ° C. FIG. 4 shows changes in sheet resistance when the argon flow rate is changed to 50 sccm, 150 sccm, 300 sccm, 450 sccm, 600 sccm, 780 sccm, and 900 sccm. As shown in FIG. 4, it was found that the sheet resistance value was the smallest when the argon flow rate was 300 sccm, and the sheet resistance value was relatively small in the range of 150 to 450 sccm. Thus, the inventors set the flow rate of argon to 150 to 450 sccm.

Next, the argon flow rate was fixed at 300 sccm, the oxygen flow rate was changed, and an ITO film having a thickness of 220 angstroms was formed on the glass substrate by sputtering. The target DC power was 0.4 kW, and the degree of vacuum in the chamber was set to 6 × 10 ⁻⁶ Torr, and then oxygen and argon were introduced. The temperature in the chamber was 200 ° C. FIG. 5 shows how the sheet resistance value changes when the oxygen flow rate is changed to 1.0 sccm, 1.5 sccm, 2.5 sccm, 3.0 sccm, 3.5 sccm, and 4.5 sccm. As shown in FIG. 5, it was found that the sheet resistance value was relatively small when the oxygen flow rate was in the range of 1.5 to 3.5 sccm, and the sheet resistance value was the smallest when the oxygen flow rate was 2.5 sccm. Accordingly, the inventors set the flow rate of oxygen to 1.5 to 3.5 sccm.

  Next, the flow rates of oxygen and argon were fixed to 2.5 sccm and 300 sccm, respectively, and the temperature in the chamber was changed, and an ITO film having a thickness of 140 to 160 angstroms was formed on the glass substrate by sputtering. The target DC power was 0.2 kW. FIG. 6 shows how the sheet resistance value changes when the temperature in the chamber is changed to 100 ° C., 125 ° C., 150 ° C., 170 ° C., 190 ° C., 200 ° C., 210 ° C., 230 ° C., and 300 ° C. As shown in FIG. 6, it was found that the sheet resistance value was relatively small (310Ω / □ or less) when the temperature in the chamber was 125 to 230 ° C., and the sheet resistance value was the smallest at 190 ° C. . Accordingly, the inventors set the chamber temperature to 125 to 230 ° C. In addition, when the transmittance | permeability of light was measured about each sample which changed the temperature in a chamber, there was no change. That is, it was found that the light transmittance does not depend on the temperature in the chamber.

  Next, the flow rates of oxygen and argon were fixed to 2.5 sccm and 300 sccm, respectively, the target DC power was changed, and an ITO film was formed on the glass substrate by a sputtering method. FIG. 7 shows how the sheet resistance value changes when the target DC power is changed to 0.20 kW, 0.25 kW, 0.30 kW, and 0.35 kW. As shown in FIG. 7, it was confirmed that as the target DC power increases, the ITO film becomes thicker and the sheet resistance value decreases accordingly. FIG. 8 shows changes in transmittance of blue light (wavelength: 450 nm), green light (wavelength: 550 nm), and red light (wavelength: 660 nm) when the target DC power is changed. As shown in FIG. 8, it can be seen that as the target DC power increases, the ITO film becomes thicker, and thus the transmittance decreases. Based on the above experimental results, the present inventors have determined that the above sputtering conditions are appropriate.

  As described above, according to the embodiment, a glass substrate with ITO having a low electrical resistance value and a high visible light transmittance can be obtained. In particular, a glass substrate with ITO having an appropriate electrical resistance value and visible light transmittance can be obtained as the counter substrate of the LCOS chip. Further, by forming the ITO film 6 by a sputtering method, the ITO film 6 can be formed at a lower cost than when the ITO film 6 is formed by a CVD method.

  The present inventors produced a glass substrate with ITO according to the manufacturing method described above. As the glass substrate 1, an alkali-free glass plate having a refractive index of 1.55 with respect to light having a wavelength of 550 nm was used. The thicknesses of the first titanium oxide film 2, the first silicon dioxide film 3, the second titanium oxide film 4, the second silicon dioxide film 5 and the ITO film 6 are 100 angstroms, 200 angstroms, 1100 angstroms, respectively. 250 angstroms and 180 angstroms. An antireflection film 7 was provided on the back surface of the glass substrate 1.

The four oxide films 2, 3, 4, and 5 below the ITO film 6 were formed by electron beam physical vapor deposition. The sputtering conditions for forming the ITO film 6 were as follows. An inline sputtering apparatus (model number: ILC-3939S) manufactured by Nidec Anelva Co., Ltd. was used, and indium and tin were used as targets. After the degree of vacuum in the chamber was 6 × 10 ⁻⁶ Torr, oxygen and argon were introduced. At this time, the flow rate of oxygen was 2.5 sccm, and the flow rate of argon was 300 sccm. The substrate transfer speed was 180 mm / min. The result of having measured the light transmittance of the produced glass substrate with ITO is shown in FIG. As shown in FIG. 9, it was confirmed that the light transmittance was 90% or more in the wavelength region of 410 to 750 nm.

  The present invention is not limited to the above-described embodiments and examples, and various modifications can be made. For example, the refractive index and material of the glass substrate 1, the thicknesses of the films 2, 3, 4, 5, 6, the sheet resistance value, and the light transmittance are examples, and the present invention is limited to these values It is not something. Further, the number of oxide films under the ITO film 6 is not limited to four but may be an even number. Furthermore, the oxide films 2, 3, 4, and 5 below the ITO film 6 are not limited to silicon dioxide and titanium oxide. For example, when the number of oxide films under the ITO film 6 is two, tantalum oxide and silicon dioxide may be stacked in order from the surface side of the glass substrate 1.

  Further, values such as the degree of vacuum and temperature in the chamber when forming the ITO film 6 and the flow rates of oxygen and argon are examples, and the present invention is not limited to these values. The use of the glass substrate with ITO according to the present invention is not limited to the counter substrate for the LCOS chip. Since the present invention exhibits high transmittance in the visible light region in general, particularly in the wavelength region of blue light, it is also suitable as a liquid crystal panel substrate to which blue light is applied. For example, a liquid crystal lens that has a lens effect by changing the in-plane refractive index distribution of the liquid crystal by changing the in-plane distribution of the voltage applied to the liquid crystal, and other well-known reflective and transflective types It can also be applied to TFT liquid crystal devices.

  As described above, the glass substrate with ITO and the manufacturing method thereof according to the present invention are useful for an image display device such as a display, and are particularly suitable for a counter substrate of an LCOS chip.

It is sectional drawing which shows an example of the glass substrate with ITO concerning this invention. It is process drawing which shows an example of the manufacturing method of the glass substrate with ITO concerning this invention. It is a characteristic view which shows the result of the experiment conducted in order to derive | require sputtering conditions. It is a characteristic view which shows the result of the experiment conducted in order to derive | require sputtering conditions. It is a characteristic view which shows the result of the experiment conducted in order to derive | require sputtering conditions. It is a characteristic view which shows the result of the experiment conducted in order to derive | require sputtering conditions. It is a characteristic view which shows the result of the experiment conducted in order to derive | require sputtering conditions. It is a characteristic view which shows the result of the experiment conducted in order to derive | require sputtering conditions. It is a characteristic view which shows the light transmittance characteristic of an Example.

Explanation of symbols

1 Glass substrate 2, 4 Titanium oxide film 3, 5 Silicon dioxide film 6 ITO film 7 Antireflection film

Claims (14)

A glass substrate;
At least two oxide layers laminated on the surface of the glass substrate;
An ITO film having a thickness of not less than 100 angstroms and not more than 350 angstroms laminated on the oxide film;
A glass substrate with ITO, comprising:   The glass substrate with ITO according to claim 1, wherein the oxide film includes an oxide film layer made of titanium oxide and an oxide film layer made of silicon dioxide.   The oxide film has a four-layer structure of an oxide film layer made of titanium oxide, an oxide film layer made of silicon dioxide, an oxide film layer made of titanium oxide, and an oxide film layer made of silicon dioxide in this order from the glass substrate side. The glass substrate with ITO according to claim 2.   The glass substrate with ITO according to claim 1, wherein the oxide film includes an oxide film layer made of tantalum oxide and an oxide film layer made of silicon dioxide.   5. The glass substrate with ITO according to claim 1, wherein a sheet resistance value of the ITO film is 200Ω / □ or more and 310Ω / □ or less, preferably 300Ω / □ or less.   The glass substrate with ITO according to any one of claims 1 to 5, wherein an antireflection film is provided on a back surface of the glass substrate.   The glass substrate with ITO according to any one of claims 1 to 6, wherein the transmittance of light is 90% or more in the entire wavelength region of visible light. Laminating at least two oxide layers on the surface of the glass substrate;
After setting the degree of vacuum in the chamber of the sputtering apparatus to the order of 10 ⁻⁶ Torr, the temperature in the chamber is maintained at 125 ° C. or higher and 230 ° C. or lower, and oxygen is flowed in the chamber at a flow rate of 1.5 sccm or higher and 3.5 sccm or lower. And injecting argon into the chamber at a flow rate of 150 sccm or more and 450 sccm or less and performing sputtering to form an ITO film on the oxide film;
The manufacturing method of the glass substrate with ITO characterized by including.   9. The method for producing a glass substrate with ITO according to claim 8, wherein the ITO film is formed to a thickness of 100 angstroms or more and 350 angstroms or less.   10. The method for producing a glass substrate with ITO according to claim 8, wherein an oxide film layer made of one or more titanium oxides and an oxide film layer made of one or more silicon dioxides are laminated as the oxide film.   As the oxide film, an oxide film layer made of titanium oxide, an oxide film layer made of silicon dioxide, an oxide film layer made of titanium oxide, and an oxide film layer made of silicon dioxide are laminated in this order from the glass substrate side. The manufacturing method of the glass substrate with ITO of Claim 10.   10. The method for producing a glass substrate with ITO according to claim 8, wherein an oxide film layer made of tantalum oxide and an oxide film layer made of silicon dioxide are laminated in order from the glass substrate side as the oxide film. .   The glass substrate with ITO according to any one of claims 8 to 12, wherein an antireflection film is formed on the back surface of the glass substrate before the oxide film is laminated on the surface of the glass substrate. Manufacturing method. The method for producing a glass substrate with ITO according to any one of claims 8 to 13, wherein the glass substrate is processed into a substantially circular shape in advance.

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