JP4352987B2 - Reflective liquid crystal display - Google Patents

Description

  The present invention relates to a reflective liquid crystal display device configured for each color corresponding to red light, green light, and blue light. Red light or green light incident on the liquid crystal through the counter electrode from the transparent substrate side or The plurality of switching elements and the plurality of reflective pixel electrodes are arranged so that a part of the blue light does not enter into the plurality of switching elements provided on the semiconductor substrate from the electrode gap formed between the adjacent reflective pixel electrodes. At least two or more metal light-shielding films are provided between them, and the thickness of the light-shielding insulating film provided in contact with at least one metal light-shielding film is changed according to each wavelength of red light, green light, or blue light. The present invention relates to a reflective liquid crystal display device that can reliably reduce a leakage current generated in a switching element by setting each.

  Recently, a projection type for displaying images on a large screen, such as a display for outdoor public use or control operations, or a display for displaying high-definition images typified by the high definition broadcasting standard or the SVGA standard for computer graphics. Liquid crystal display devices are actively used.

  This type of projection type liquid crystal display device can be broadly divided into a transmission type liquid crystal display device using a transmission method and a reflection type liquid crystal display device using a reflection method. In the case of the former transmission type liquid crystal display device, However, since the area of a TFT (Thin Film Transistor) provided in each pixel does not become a transmission area of a pixel that transmits light, the aperture ratio becomes small. A liquid crystal display device has attracted attention.

  Generally, in the above-described reflective liquid crystal display device, a plurality of switching elements are electrically separated from each other on a semiconductor substrate (Si substrate), and the multilayer film is stacked above the plurality of switching elements. In the uppermost layer, a plurality of reflective pixel electrodes corresponding to a plurality of switching elements are electrically separated from each other, and one reflective pixel electrode connected to one switching element and a storage capacitor portion for the switching element are provided. A plurality of pixels are arranged in a matrix on a semiconductor substrate, and a transparent counter electrode that is common to all the pixels and is opposed to the plurality of reflection pixel electrodes is formed on a transparent substrate (glass Film is formed on the lower surface of the substrate), and liquid crystal is sealed between a plurality of reflective pixel electrodes and a counter electrode, so that incident light for a color image is opposed from the transparent substrate side. The liquid crystal is incident on the liquid crystal via a pole, and the potential difference between the counter electrode and each reflective pixel electrode is changed for each reflective pixel electrode corresponding to the video signal by the switching element, thereby controlling the orientation of the liquid crystal. Then, the color image readout light is modulated, and the color image readout light reflected by each reflective pixel electrode is emitted from the transparent substrate.

FIG. 8 is a cross-sectional view schematically showing one pixel in the reflective liquid crystal display device of Conventional Example 1,
FIG. 9A is a block diagram for explaining an active matrix circuit in the reflection type liquid crystal display device of Conventional Example 1, and FIG. 9B is a schematic diagram showing an X portion in FIG. .

The reflective liquid crystal display device 10 of Conventional Example 1 shown in FIG. 8 is configured to be applicable to a reflective liquid crystal projector, and enlarges one pixel among a plurality of pixels for displaying an image. The semiconductor substrate 11 serving as a base uses a p-type Si substrate such as single crystal silicon (or an n-type Si substrate), and this semiconductor substrate (hereinafter referred to as a p-type Si substrate). ) On the left side in FIG. 11, one p ^- well region 12 is provided in a state where it is electrically separated in pixel units by left and right filled oxide films 13A and 13B. One switching element 14 is provided in one p ^- well region 12, and this switching element 14 is configured as a MOSFET (Metal Oxide Semiconductor Field Effect Transistor).

Further, one switching element (hereinafter referred to as MOSFET) 14 has a gate G 16 formed by forming a gate electrode 16 made of polysilicon on a gate oxide film 15 located substantially at the center on the p ⁻ well region 12. Is formed.

  Further, a drain region 17 is formed on the left side of the gate G of the MOSFET 14 in the figure, and a drain electrode 18 is formed on the drain region 17 by an aluminum wiring in the first via hole Via1, thereby forming a drain D. Has been.

  Further, a source region 19 is formed on the right side of the gate G of the MOSFET 14 in the figure, and a source electrode 20 is formed on the source region 19 by aluminum wiring in the first via hole Via1, thereby forming a source S. Has been.

Further, an ion-implanted diffusion capacitor electrode 21 is formed on the p-type Si substrate 11 on the right side of the p ^- well region 12 in the drawing, and this diffusion capacitor electrode 21 is also formed in pixel units by left and right filled oxide films 13B and 13C. The range from the filled oxide film 13A to the filled oxide film 13C corresponds to one pixel.

  Further, the insulating film 22 and the capacitor electrode 23 are sequentially formed on the diffusion capacitor electrode 21, and the capacitor electrode contact 24 is formed on the capacitor electrode 23 by the aluminum wiring in the first via hole Via 1. Thus, a storage capacitor portion C corresponding to one MOSFET 14 is formed.

  Above the field oxide films 13A to 13C, the gate electrode 16 and the capacitor electrode 23, a first interlayer insulating film 25, a first metal film 26, a second interlayer insulating film 27, and a second metal film 28 are provided. The multilayer films 25 to 30 each including the third interlayer insulating film 29 and the third metal film 30 are stacked in the order described above.

At this time, the first, second, and third interlayer insulating films 25, 27, and 29 are formed using insulating SiO ₂ (silicon oxide) or the like.

  The first, second, and third metal films 26, 28, and 30 are partitioned into a predetermined pattern shape for each pixel corresponding to one switching element 14 by conductive aluminum wiring or the like. In the same pixel, the first, second, and third metal films 26, 28, and 30 are electrically connected to each other, but the first and second metal films 26 and 28 are not connected to adjacent pixels. Openings 26a and 28a are respectively formed between the adjacent films, and an electrode gap 30a is formed between the adjacent films of the third metal film 30, so that one first and second one for each pixel. The third metal films 26, 28 and 30 are electrically separated from each other.

  The first metal film 26 at the lowermost stage in one pixel is formed by depositing an aluminum wiring in each first via hole Via1 obtained by etching the first interlayer insulating film 25, and the source electrode 20 and the source electrode 20 are formed. , Are connected to one switching element 14 and the storage capacitor C through a capacitor electrode contact 24.

  Further, in one pixel, the second metal film 28 in the middle stage is the MOSFET 14 on the p-type Si substrate 11 provided with a part of the incident light LI incident below from the transparent substrate 42 side described below disposed above. It is provided as a metal light shielding film for shielding light from the side. That is, the second metal film (metal light shielding film) 28 covers the electrode gap 30a so as to shield part of the incident light LI entering from the electrode gap 30a formed between the upper adjacent third metal films 30. In addition, the aluminum wiring is formed in the second via hole Via2 obtained by etching the second interlayer insulating film 27, thereby being connected to the lowermost first metal film 26.

  Further, in one pixel, the upper third metal film 30 is divided into a square shape by an electrode gap 30a formed between adjacent third metal films 30 corresponding to one pixel, and thus one reflective pixel. It is provided as an electrode, and is connected to the second metal film 28 in the middle stage by forming an aluminum wiring in the third via hole Via3 obtained by etching the third interlayer insulating film 29.

  A liquid crystal 40 is sealed above a third metal film (hereinafter referred to as a reflective pixel electrode) 30, and a transparent counter electrode 41 having a light transmission property through the liquid crystal 40 has a transparent substrate (glass). The substrate is formed on the lower surface of the substrate 42 by using ITO (Indium Tin Oxide) or the like as a common electrode for each of the reflective pixel electrodes 30 without being partitioned for each pixel. Yes.

  Then, the incident light LI is incident from the transparent substrate 42 side, and the incident light LI is transmitted through the counter electrode 41 and the liquid crystal 40, and then reflected by the reflection pixel electrode 30, the read light L is transmitted through the liquid crystal 40 and the counter electrode 41. Through the transparent substrate 42.

  Next, in the reflective liquid crystal display device 10 of the prior art example 1, an active matrix circuit when a plurality of the above-described MOSFETs (switching elements) 14 are arranged on the p-type Si substrate 11 in a matrix is shown in FIGS. This will be described with reference to b).

  As shown in FIGS. 9A and 9B, in the active matrix circuit 70 in the reflective liquid crystal display device 10 of Conventional Example 1, a plurality of MOSFETs (switching elements) 14 are on a p-type Si substrate (semiconductor substrate) 11. Are arranged in a matrix, and one pixel is formed by combining one reflective pixel electrode 30 connected to one MOSFET 14 and a holding capacitor C for the MOSFET. A plurality of elements are arranged in a matrix on the mold Si substrate 11.

  In order to specify one pixel among the plurality of pixels, the horizontal shift register circuit 71 and the vertical shift register circuit 75 are provided separately in the column direction and the row direction, respectively.

  First, on the horizontal shift register circuit 71 side, the signal line 73 is wired in the vertical direction via the video switch 72 for each column of pixels. Here, for convenience of illustration, one signal line 73 is provided. Only in the state connected to the horizontal shift register circuit 71 side. A video line 74 is connected to a signal line 73 provided between the horizontal shift register circuit 71 and the video switch 72. One signal line 73 is connected to the drain electrodes 18 of the plurality of MOSFETs 14 arranged in one column.

  Next, on the vertical shift register circuit 75 side, a gate line 76 is wired in the horizontal direction for each row of pixels. Here, for convenience of illustration, only one gate line 76 is provided in the vertical shift register circuit. Shown in a state connected to the 75 side. One gate line 76 is connected to the gate electrodes 16 of the plurality of MOSFETs 14 arranged in one row.

  Further, the source electrode 20 of each MOSFET 14 is connected to one reflective pixel electrode 30 and the capacitor electrode 23 via the capacitor electrode contact 24 of the storage capacitor portion C. At this time, the active matrix circuit 70 applies a well-known frame inversion driving method, and the video signal is inverted to a positive polarity and a negative polarity every frame period, that is, for example, the nth frame period of the video signal is positive. Writing is negative writing in the (n + 1) th frame period. Accordingly, when a video signal is input from the signal line 73, the signal line 73 may be connected to either the drain electrode 18 or the source electrode 20 of the MOSFET 14, but here, as described above, the signal line 73 73 is connected to the drain electrode 18. When the signal line 73 is connected to the source electrode 20, one reflective pixel electrode 30 and the capacitor electrode 23 are connected to the drain electrode 18 via the capacitor electrode contact 24 of the storage capacitor portion C. Is.

  Further, in the reflective liquid crystal display device 10 of the above-described conventional example 1, a well potential supplied to the MOSFET 14 as a fixed potential and a COM (common) potential supplied to the storage capacitor C are necessary.

That is, the well potential supplied to the MOSFET 14 is, for example, a fixed potential between the gate line 76 and a well potential contact on a p ⁺ region (not shown) formed in one p ⁻ well region 12 (FIG. 8). A voltage of 0V is applied. When an n-type Si substrate is used, for example, −15 V may be applied as the well potential.

  On the other hand, the COM potential supplied to the storage capacitor unit C is, for example, 8.5 V as a fixed potential between the capacitor electrode 24 of the storage capacitor unit C and a COM (common) potential contact (not shown) on the diffusion capacitor electrode 22. Is applied. At this time, the COM potential may basically be any number of volts in order to form the storage capacitor portion C. However, if the COM potential is set to the center value (for example, 8.5 V) of the video signal, the storage capacitor portion C The voltage applied to is about half of the power supply voltage. That is, since the storage capacitor withstand voltage may be approximately half of the power supply voltage, it is possible to increase the capacitance value by reducing only the thickness of the insulating film 22 of the storage capacitor portion C. Is large, it is possible to reduce the fluctuation of the potential of the reflective pixel electrode 30, which is advantageous for flicker, burn-in, and the like.

  The storage capacitor C accumulates electric charge according to the potential difference between the potential applied to one reflective pixel electrode 30 and the COM potential, and the voltage is maintained even when one MOSFET 14 is turned off during the non-selection period. And a function of continuing to apply the holding voltage to one reflective pixel electrode 30.

  Here, when one pixel is driven in the active matrix circuit 70 in the reflective liquid crystal display device 10 of the conventional example 1, the video signals input from the video line 74 with the timing shifted sequentially are passed through the video switch 72. Is supplied to one signal line 73 arranged in the column direction, and one MOSFET 14 at the position where this one signal line 73 and one gate line 76 arranged in the row direction intersect is selected and turned on. To do.

  When a video signal is input to the selected one reflective pixel electrode 30 via the signal line 73, the video signal is written in the storage capacitor C in the form of electric charge, and the selected one reflective pixel electrode 30 is provided. And a counter electrode 41 (FIG. 8), a potential difference is generated according to a video signal, and the optical characteristics of the liquid crystal 40 are modulated. As a result, the color image incident light LI (FIG. 8) incident from the transparent substrate 42 side is modulated for each pixel by the liquid crystal 40, reflected by the reflecting pixel electrode 30, and reflected by the reflecting pixel electrode 30. Read light L (FIG. 8) is emitted from the transparent substrate 42. For this reason, unlike the transmission method, the read light L (FIG. 8) corresponding to the incident light LI (FIG. 8) can be used almost 100%, and a structure that can achieve both high definition and high brightness for the projected image. It has become.

  At this time, as shown in FIG. 8, part of the color image incident light LI incident from the transparent substrate 42 side is separated from the electrode gap 30 a formed between the adjacent reflective pixel electrodes 30 by the third interlayer insulation. It penetrates into the film 29, and in this third interlayer insulating film 29, the lower surface of the reflective pixel electrode (third metal film) 30 made of aluminum wiring and the upper surface of the metal light shielding film (second metal film) 28 made of aluminum wiring After that, a part of the incident light LI penetrates into the second interlayer insulating film 27 from the opening 28a where the metal light shielding film 28 is not formed. Reflection is repeated between the lower surface of the metal light-shielding film 28 made of aluminum wiring and the upper surface of the first metal film 26 made of aluminum wiring. Further, the first interlayer insulating film 25 is formed from the opening 26a where the first metal film 26 is not formed. Invade inside. At this time, the opening 26a in which the first metal film 26 is not formed is formed in the upper part of the gate electrode 16 of the MOSFET 14 or the upper part of the capacitor electrode 23 of the storage capacitor part C. Part of the incident light LI that has entered the interlayer insulating film 25 reaches the gate electrode 16, the drain region 17, the source region 19 of the MOSFET 14, and the capacitor electrode 23 of the storage capacitor portion C.

Here, when a part of the incident light LI enters the drain region 17 and the source region 19 of the MOSFET 14, the p ⁻ well region 12, the drain region 17 and the source region 19 made of a high concentration n ⁺ impurity layer in the MOSFET 14, and Since the pn junction is used, the photodiode function works, and optical carriers are generated by a part of the incident light LI to cause a leakage current, which may cause the potential of the reflection pixel electrode 30 to fluctuate. Since the fluctuation of the potential of the reflection pixel electrode 30 causes flicker and image sticking, it is necessary to minimize light leakage in the MOSFET 14 due to a part of the incident light LI.

There is a liquid crystal display device that takes measures to suppress the occurrence of light leakage in the MOSFET 14 due to a part of the incident light LI (see, for example, Patent Document 1).
JP 2002-40482 (page 3-7, FIG. 1).

  FIG. 10 is a cross-sectional view schematically showing a liquid crystal display device of Conventional Example 2. The liquid crystal display device 100 of Conventional Example 2 shown in FIG. 10 is disclosed in the above-mentioned Patent Document 1 (Japanese Patent Laid-Open No. 2002-40482), and is briefly described here with reference to Patent Document 1. To do.

  As shown in FIG. 10, in the liquid crystal display device 100 of the second conventional example, a plurality of active elements 102 are provided on a first substrate (drive circuit substrate) 101. At this time, one active element 102 includes a gate electrode 103, a drain region 104 and a source region 105 provided on the left and right sides of the gate electrode 103, and one active element 102 is formed on the insulating film 106. The adjacent left and right field oxide films 107 and 107 are electrically isolated from the adjacent active element 102.

  In addition, above the active element 102, a first interlayer film 108, a first conductive film 109, a second interlayer film 110, a first light shielding film 111, a third interlayer film 112, A multilayer film of the second light-shielding film 113, the fourth interlayer film 114, and a second conductive film (hereinafter referred to as a reflective electrode) 115 serving as a reflective electrode is laminated in the order described above. Yes.

  At this time, the first conductive film 109, the first light-shielding film 111, the second light-shielding film 113, and the reflective electrode 115 each have conductivity and are partitioned into a predetermined pattern for each active element 102. Yes.

  The first conductive film 109 is connected to the drain region 104 and the source region 105 of one active element 102 through the first via hole Via1 formed in the first interlayer film 108. Further, the first light shielding film 111 needs to form a second via hole Via2 indicated by an imaginary line outside the illustrated frame in order to apply a voltage as will be described later. The second light shielding film 113 is connected to the first conductive film 109 through a third via hole Via3 formed in the second and third interlayer films 110 and 112. Further, the reflective electrode 115 is connected to the second light shielding film 113 through a fourth via hole Via4 formed in the fourth interlayer film 114. Accordingly, one reflective electrode 115 is connected to one active element 102 through the second light shielding film 113 and the first conductive film 109.

  Further, an alignment film 116, a liquid crystal composition 117, an alignment film 118, a counter electrode 119, and a second substrate (transparent substrate) 120 are provided above the reflective electrode (second conductive film) 115 in the order described above. The liquid crystal composition 117 is divided into one reflective electrode 115 (one pixel) by left and right spacers 121 and 121.

  At this time, the spacer 121 described above is disposed on the electrode gap 115 a formed between the adjacent reflection electrodes 115, and the second light shielding film 113 is substantially the same size as the reflection electrode 115 so as to cover the electrode gap 115 a. Furthermore, since the first light shielding film 111 is formed so as to cover the opening 113a formed between the adjacent second light shielding films 113, it is made incident from the second substrate (transparent substrate) 120. Even if a part of the incident light LI enters into the fourth interlayer film 114 from the electrode gap 115a formed between the adjacent reflective electrodes 115, a part of the incident light LI remains in the first and second light shielding films. Since the active element 102 provided on the first substrate 101 is blocked by the first and second substrates 101 and 113, light leakage in the active element 102 due to part of the incident light LI can be suppressed. Measures have been subjected to kill.

  In addition, with the above configuration, unnecessary light generated in the liquid crystal display element is prevented from being incident, and the read light L that is reflected from the reflective electrode 115 by the incident light LI incident from the second substrate (transparent substrate) 120 is generated. It is disclosed that a liquid crystal display device 100 with high image quality and a liquid crystal projector using the same can be realized by emitting light from the second substrate (transparent substrate) 120.

  By the way, in the reflective liquid crystal display device 10 of Conventional Example 1 shown in FIG. 8, as described above, a part of the incident light LI for color image incident from the transparent substrate 42 side is on the p-type Si substrate 11. Light leakage occurs in order to reach the formed MOSFET 14 side.

  On the other hand, in the reflective liquid crystal display device 100 of Conventional Example 2 shown in FIG. 10, a second light shielding film 113 is provided below the reflective electrode 115 so as to cover the electrode gap 115a formed between the adjacent reflective electrodes 115. Furthermore, the second substrate (transparent substrate) 120 is provided by providing the first light-shielding film 111 below the second light-shielding film 113 so as to cover the opening 113 a formed between the adjacent second light-shielding films 113. Recently, although a portion of the incident light LI incident from the side does not reach the active element 102 formed on the first substrate 101, light leakage hardly occurs, but recently, color images have been enlarged with high image quality and high definition. In the case of projection, a three-plate reflection type liquid crystal projector using three reflection type liquid crystal display devices corresponding to R (red), G (green), and B (blue) is used. Reflective LCD table It has not been considered in any way for the application to a reflective liquid crystal projector of the device 100 in three-plate type.

  Further, in the reflective liquid crystal display device 100 of Conventional Example 2, the step of forming the first via hole Via1 in the first conductive film 109 and the step of forming the second via hole Via2 in the first light shielding film 111 are performed. And a step of forming the third via hole Via3 in the second light shielding film 113 and a step of forming the fourth via hole Via4 in the reflective electrode (second conductive film) 115, particularly, As the number of processes for forming via holes increases, it takes time to manufacture the liquid crystal display device 100, and the yield tends to deteriorate, which is a problem.

  Therefore, when the reflective liquid crystal display device is configured exclusively for each color light corresponding to R (red), G (green), and B (blue), it is made to enter the liquid crystal through the counter electrode from the transparent substrate side. The red light, the green light, or a part of the blue light is generated in the switching element by preventing it from entering the switching element provided on the semiconductor substrate from the electrode gap formed between the adjacent reflection pixel electrodes. There is a demand for a reflective liquid crystal display device that can reliably reduce leakage current and can also reduce the formation of via holes.

The invention according to claim 1 is a plurality of switching elements formed for each pixel on a semiconductor substrate;
A multilayer film stacked above the plurality of switching elements;
A plurality of reflective pixel electrodes connected to each switching element in the uppermost layer of the multilayer film and having a predetermined electrode gap;
A transparent counter electrode formed on a transparent substrate;
The liquid crystal sealed between the semiconductor substrate side and the transparent substrate side arranged so that the plurality of reflective pixel electrodes and the transparent counter electrode face each other,
Red light, green light, or blue light incident from the transparent substrate side is light-modulated by the liquid crystal according to a signal from each switching element, and then reflected by the plurality of reflective pixel electrodes, and the transparent substrate In a reflective liquid crystal display device configured exclusively for each color light so as to be emitted from the side,
When the red light, the green light, or the blue light incident from the transparent substrate side enters the inside from between the adjacent reflection pixel electrodes, a part of the red light, the green light, or the blue light In order to shield light from the plurality of switching elements, at least two layers of metal light-shielding films are provided between the plurality of switching elements and the plurality of reflective pixel electrodes, and at least one of the metal light-shielding films is provided. A reflection type liquid crystal display device in which a film thickness of a light-shielding insulating film provided in contact with the film is set for each color light according to each wavelength of the red light, the green light, or the blue light .

According to a second aspect of the present invention, in the reflective liquid crystal display device according to the first aspect,
The metal material of the metal light-shielding film in contact with the light-shielding insulating film is TiN, Ti, or TiN / Ti, and the thickness of the light-shielding insulating film provided corresponding to the wavelength of the red light is 300 nm. The film thickness of the light-shielding insulating film set corresponding to the wavelength of the green light is set in the range of 200 nm to 500 nm, and the wavelength of the blue light is set. The reflective liquid crystal display device is characterized in that a thickness of the provided light shielding insulating film is set in a range of 100 nm to 400 nm.

  According to the reflective liquid crystal display device of claim 1, in particular, when red light, green light, or blue light incident from the transparent substrate side enters the inside from between adjacent reflective pixel electrodes, red light or green light is emitted. In order to shield part of the light or blue light from the plurality of switching elements, at least one metal light-shielding film is provided between the plurality of switching and the plurality of reflection pixel electrodes, and at least one Since the thickness of the light shielding insulating film provided in contact with the metal light shielding film is set for each color light according to each wavelength of red light, green light, or blue light, the red light, green light, or blue light is on the semiconductor substrate. Therefore, the occurrence of light leakage in the switching element due to red light, green light, or part of blue light can be suppressed.

  According to the reflection type liquid crystal display device according to claim 2, in particular, the metal material of the metal light-shielding film in contact with the light-shielding insulating film is TiN or Ti or TiN / Ti, and corresponds to the wavelength of red light. The thickness of the light-shielding insulating film provided is set in the range of 300 nm to 600 nm, and the thickness of the light-shielding insulating film provided corresponding to the wavelength of green light is set in the range of 200 nm to 500 nm. In addition, since the thickness of the light shielding insulating film provided corresponding to the wavelength of blue light is set in the range of 100 nm to 400 nm, the thickness of the light shielding insulating film is 400 nm regardless of red light, green light, and blue light. Since the film thicknesses of the light shielding insulating film for G light and the light shielding insulating film for R light are set to be larger than the film thickness of the light shielding insulating film for B light than when set as follows, G light shielding insulating film and R light shielding film Thereby improving the yield of each metal light-shielding film in contact respectively with the edge membrane.

  An embodiment of a reflective liquid crystal display device according to the present invention will be described in detail below in the order of Embodiments 1 to 3 with reference to FIGS.

FIG. 1 is a cross-sectional view schematically showing one pixel in a reflective liquid crystal display device according to a first embodiment of the present invention.
FIG. 2 is a view for explaining an optical system of a three-plate type reflection type liquid crystal projector to which the reflection type liquid crystal display device of Example 1 according to the present invention is applied;
FIG. 3 illustrates a third via hole for electrically connecting the first metal light shielding film (second metal film), the second metal light shielding film, and the reflection pixel electrode (third metal film) shown in FIG. FIG. 4 is a partially enlarged cross-sectional view for illustrating the case where (a) shows a case where the third via hole is formed of tungsten, and (b) shows a case where the third via hole is formed of aluminum wiring. Figure,
FIG. 4A shows a case where a second metal light-shielding film is formed above the light-shielding insulating film for R light, and FIG. 4B shows a second metal light-shielding film above the light-shielding insulating film for G light. (C) is a diagram showing a case where a second metal light-shielding film is formed above the light-shielding insulating film for B light,
FIG. 5 is a plan view showing the reflection pixel electrode (third metal film), the second metal light shielding film, and the third via hole shown in FIG.

  The reflective liquid crystal display devices 10R, 10G, and 10B according to the first embodiment of the present invention shown in FIG. 1 are partially the same as the configuration of the reflective liquid crystal display device 10 according to the first conventional example described with reference to FIG. Except for the sake of convenience of explanation, the same reference numerals are given to the constituent members shown above, and the constituent members shown above will be appropriately described as necessary. Different constituent members will be described with new reference numerals.

  The above-described reflective liquid crystal display devices 10R, 10G, and 10B according to the first embodiment of the present invention are configured exclusively for each color corresponding to R (red), G (green), and B (blue). When applied to a three-plate-type reflective liquid crystal projector 80 as will be described later with reference to FIG. 2, the wavelength obtained by color-separating visible light (white light) in the reflective liquid crystal projector 80 is about 600 nm to 780 nm. Since the red light LR, the green light LG having a wavelength of about 500 nm to 600 nm, and the blue light LB having a wavelength of about 400 nm to 500 nm are incident on each color light from the transparent substrate 42 side, reflection for R light is performed. The type liquid crystal display device 10R reflects only the red light LR by the plurality of reflection pixel electrodes 30 to be read light, and the reflection type liquid crystal display device 10G for G light uses only the green light LG for the plurality of reflection pixel electrodes. 30 The reflected light is reflected as readout light, and the B-light reflective liquid crystal display device 10B reflects only the blue light LB at the plurality of reflection pixel electrodes 30 as readout light, and is read out by the devices 10R, 10G, and 10B. The red light LR, the green light LG, and the blue light LB are combined in the reflective liquid crystal projector 80 and emitted to the projection lens (not shown) side. In the reflective liquid crystal display devices 10R, 10G, and 10B, R, G, and B are added after the number only for the portions that are exclusively configured for each color light corresponding to the red light LR, the green light LG, and the blue light LB. This will be described below with an auxiliary code.

  Further, the reflective liquid crystal display devices 10R, 10G, and 10B according to the first embodiment of the present invention are the first technical ideas for preventing light leakage in the liquid crystal display device 100 according to the second conventional example described with reference to FIG. This is a partial application of the case where at least two or more light shielding films 111 and 113 are provided between a plurality of active elements 102 and a plurality of reflective electrodes 115 provided on one substrate 101. Then, as will be described later, two layers are provided between a plurality of switching elements (hereinafter referred to as MOSFETs) 14 provided on a semiconductor substrate (hereinafter referred to as a p-type Si substrate) 11 and a plurality of reflective pixel electrodes 30. The first and second metal light-shielding films 28 and 33 are provided with insulating films interposed between the upper and lower sides, and TiN or Ti or TiN / Ti having a low reflectance among the two metal light-shielding films 28 and 33 is used. Money The light shielding insulating film 32R for R light, the light shielding insulating film 32G for G light, or the light shielding insulating film 32B for B light provided in contact with the lower surface of the second metal light shielding film 33 formed using a material. Each film thickness is set for each color light according to each wavelength of the red light LR, the green light LG, or the blue light LB.

  At this time, when a multilayer film is formed on the p-type Si substrate 11, R is used for each p-type Si substrate 11 corresponding to the light-shielding insulating films 32 R, 32 G, and 32 B provided for each color light. An identification symbol for G or B is displayed.

  Here, before describing the reflective liquid crystal display devices 10R, 10, and 10B according to the first embodiment of the present invention, the reflective liquid crystal projector of the three-plate system to which the reflective liquid crystal display devices 10R, 10, and 10B are applied. The optical system will be described with reference to FIG.

  As shown in FIG. 2, the three-plate-type reflective liquid crystal projector 80 includes a light source unit 85 that emits visible light (white light), and visible light emitted from the light source unit 85 as red light LR, green light LG, The three primary color lights of blue light LB are color-separated, and the three primary color lights are led to the three-plate type reflective liquid crystal display devices 10R, 10G, and 10B corresponding to R, G, and B, respectively, and further, the reflective type of each color. A color separation and color synthesis optical system 90 that emits a color synthesized light obtained by color-combining each color light LR, LG, and LB light-modulated in accordance with the video signal by the liquid crystal display devices 10R, 10G, and 10B, and the color separation and color A projection lens (not shown) for projecting the color synthesized light emitted from the synthesis optical system 90 is configured.

  More specifically, the light source unit 85 includes a reflecting mirror 86 and a metal halide lamp, a xenon lamp, a halogen lamp and the like installed in the reflecting mirror 86 and emitting visible light (white light). The light source 87 used and a polarization conversion plate 88 provided in front of the light source 87 and having a transmission axis selected so as to transmit only visible s-polarized light. Therefore, when visible light from the light source 87 passes through the polarization conversion plate 88, three colors of Rs light, Gs light, and Bs light respectively corresponding to R, G, and B are incident on the color separation and color synthesis optical system 90. The

  Further, when the four first to fourth polarization beam splitters 91 to 94 are shown in plan view when viewed from the upper surface side, the color separation and color synthesis optical system 90 has the first to fourth polarization beam splitters 91 to 94. The polarization separation surfaces 91a to 94a are arranged in an X shape. At this time, the second polarization beam splitter 92 is disposed on the right side of the first polarization beam splitter 91, the third polarization beam splitter 93 is disposed above the first polarization beam splitter 91, and the second polarization beam A fourth polarizing beam splitter 94 is disposed above the beam splitter 92 and to the right of the third polarizing beam splitter 93. The first polarization beam splitter 91 side faces the polarization conversion plate 88 of the light source unit 85 through a G light polarization conversion plate 95 described later, while the fourth polarization beam splitter 94 side is a projection lens (not shown). Opposite. At this time, each of the polarization separating surfaces 91a to 94a of the first to fourth polarization beam splits 91 to 94 transmits a p-polarized light and reflects a s-polarized light in a rectangular shape. It is formed along the diagonal line.

  In addition, the first polarizing beam splitter 91 on the light source unit side where visible light from the light source unit 85 enters and the fourth polarizing beam splitter 94 on the projection lens side that emits color synthesized light are formed in a large size. The second and third polarizing beam splitters 92 and 93 are formed to be slightly smaller than the first and fourth polarizing beam splitters 91 and 94.

  Further, a reflective liquid crystal display device 10G for G light is disposed facing the right side surface of the small-sized second polarizing beam splitter 92, and is opposed to the upper surface and left side surface of the small-sized third polarizing beam splitter 93. Then, the reflection liquid crystal display device 10R for R light and the reflection liquid crystal display device 10B for B light are arranged orthogonally to each other, and each of the reflection liquid crystal display devices 10R, 10G, 10B is second, third. The size of the polarizing beam splitters 92 and 93 is reduced.

  Further, a G light polarization conversion plate 95 having a function of rotating the polarization plane of the G light by 90 ° is installed on the light incident surface of the first polarization beam splitter 91 on the light source unit 85 side. Further, between the first polarization beam splitter 91 and the third polarization beam splitter 93, an R light polarization conversion plate 96 having a function of rotating the polarization plane of the R light by 90 ° is installed. An R light polarization conversion plate 97 having a function of rotating the polarization plane of the R light by 90 ° is installed between the third polarizing beam splitter 93 and the fourth polarizing beam splitter 94. A G light polarization conversion plate 98 having a function of rotating the polarization plane of the G light by 90 ° is installed on the light exit surface of the fourth polarization beam splitter 94.

  When visible light composed of Rs light, Gs light, and Bs light of s-polarized light emitted from the light source unit 85 is incident on the first polarizing beam splitter 91 via the G light polarization conversion plate 95, each of the illustrated light sources is shown. The p-polarized Rp light is incident on the R-light reflective liquid crystal display device 10R through the optical path, the p-polarized light Gp light is incident on the G-light reflective liquid crystal display device 10G, and the B-light reflective type is displayed. The s-polarized Gs light is incident on the liquid crystal display device 10B, and after being modulated in accordance with the video signal by each of the reflective liquid crystal display devices 10R, 10G, and 10B, the G light polarization conversion on the fourth polarizing beam splitter 94 side. Since the color composite light combining the Rp, Gp light and Bp light of the p-polarized light is emitted from the plate 98 to the projection lens (not shown) side, the color composite light having no color unevenness is projected onto a screen (not shown). To be able toIn addition, since there are various structural forms as the color separation and color synthesis optical system, an appropriate color separation and color synthesis optical system may be applied in the first embodiment.

Returning to FIG. 1, in the reflective liquid crystal display devices 10R, 10G, and 10B according to the first embodiment of the present invention, one pixel among a plurality of pixels for displaying an image is enlarged and described. As in the reflection type liquid crystal display device 10 of the prior art 1 described with reference to FIG. 8, one p ^- well region 12 is formed in a p-type Si substrate (semiconductor substrate) 11 in pixel units by left and right filled oxide films 13A and 13B. In an electrically separated state. One MOSFET (switching element) 14 is provided in one p ⁻ well region 12. This MOSFET 14 includes a gate G having a gate electrode 16 formed on a gate oxide film 15, a drain D having a drain electrode 18 formed on a drain region 17, and a source having a source electrode 20 formed on a source region 19. S.

Further, on the p-type Si substrate 11, on the right side of the p ^- well region 12, a storage capacitor portion C 1 including a diffusion capacitor electrode 21, an insulating film 22, a capacitor electrode 23, and a capacitor electrode contact 24 is formed. The capacitor portion C1 is electrically separated in pixel units by the left and right filled oxide films 13B and 13C.

  In addition, when the reflective pixel electrode 30 corresponding to the MOSFET 14 is electrically separated and provided in the uppermost layer among the multilayer films stacked above the field oxide films 13A to 13C, the gate electrode 16, and the capacitor electrode 23, From the first interlayer insulating film 25 to the first metal film 26, the second interlayer insulating film 27, and the second metal film 28 are formed in the same manner as in the conventional example 1 (FIG. 8) and are formed by aluminum wiring. The one metal film 26 is connected to one switching element 14 and the storage capacitor portion C1 through the drain electrode 18, the source electrode 20, and the capacitor electrode contact 24 by the aluminum wiring in the first via hole Via 1. Furthermore, one second metal film 28 is electrically separated by an opening 28a formed between adjacent second metal films 28 and connected to the first metal film 26 by an aluminum wiring in the second via hole Via2. This is also the same as in Conventional Example 1. Further, TiN (not shown) having a low reflectance is disposed above and below the first metal film 26 and above and below the second metal film 28.

  Here, the difference from the conventional example 1 (FIG. 8) will be described. The second metal film 28 is formed between the adjacent reflective pixel electrodes 30 among the reflective pixel electrodes 30 formed thereon. In order to shield a part of the red light LR, the green light LG, or the blue light LB entering from the electrode gap 30a toward the p-type Si substrate 11, the first metal light shielding film is formed so as to cover the electrode gap 30a. It is what is filmed.

  Further, as shown in an enlarged view in FIG. 3A or 3B, the antireflection film 31 and the R light are disposed above the second metal film (hereinafter referred to as the first metal light shielding film) 28. The second metal light-shielding film 33 is formed in this order through the light-shielding insulating film 32R, the G-light light-shielding insulating film 32G, or the B-light light-shielding insulating film 32B. 33 covers the opening 28a (FIGS. 1 and 4) formed between the first metal light shielding films 28 adjacent to each other. At this time, the second metal light-shielding film 33 is electrically separated for each pixel similarly to the reflective pixel electrode 30 as described later.

  A third interlayer insulating film 29 is formed on the second metal light-shielding film 33, and a reflection pixel electrode 30 is formed on the third interlayer insulating film 29 via an antireflection film 34. Further, the second metal light shielding film 33 is electrically connected to the reflection pixel electrode 30 via the antireflection film 34 by the third via hole Via3 using tungsten as shown in FIG. Alternatively, it is electrically connected to the reflection pixel electrode 30 through the antireflection film 34 by the third via hole Via3 using the aluminum wiring as shown in FIG. The antireflection films 31 and 34 are not shown in FIG. 1 for convenience of illustration.

  At this time, the antireflection film 31 formed on the upper surface of the first metal light shielding film (second metal film) 28 and the antireflection film 34 formed on the lower surface of the reflection pixel electrode 30 are both conductive TiN. Red light LR, green light LG, or blue light that has entered the third interlayer insulating film 29 from each electrode gap 30a (FIG. 1) formed between adjacent reflective pixel electrodes 30 using (titanium nitride: titanium nitride). It is provided to prevent reflection of a part of the light LB and absorb a part of the invading red light LR, green light LG, or blue light LB.

  The second metal light shielding film 33 described above is one of the red light LR, the green light LG, or the blue light LB that has entered the third interlayer insulating film 29 from the electrode gap 30a formed between the adjacent reflective pixel electrodes 30. In order to absorb the part, it is important to form a film using a metal material having a low reflectance. Specifically, TiN (titanium nitride: titanium nitride), Ti (titanium), TiN and Ti are used. A film is formed with a film thickness in the range of 50 nm to 200 nm using laminated TiN / Ti or the like. Accordingly, when the second metal light shielding film 33 absorbs part of the red light LR, the green light LG, or the blue light LB, the reflectance of the second metal light shielding film 33 can be set low, so that the adjacent reflections The red light LR, the green light LG, or the blue light LB that has entered from the electrode gap 30a formed between the pixel electrodes 30 can be absorbed.

Here, on the lower surface of the second metal light-shielding film 33 formed using a metal material such as TiN or Ti or TiN / Ti having a low reflectance among the first and second metal light-shielding films 28 and 33 of the two layers. The R light shielding insulating film 32R, the G light shielding insulating film 32G, or the B light shielding insulating film 32B provided in contact with each color light constitutes a part of the main part of the first embodiment. It is normally formed on the first metal light-shielding film (second metal film) 28 / antireflection film 31 using an oxide film such as SiO ₂ (silicon oxide), but it is not an oxide film. Needless to say, SiN (silicon nitride) or SiON (silicon nitride oxide) having a dielectric constant larger than that of SiO ₂ can be used other than the oxide film.

  In addition, the light shielding insulating film 32R for R light has a film thickness of, for example, 600 nm or less and a range of 300 nm to 600 nm corresponding to the red light LR having a wavelength of about 600 nm to 780 nm. Further, the light shielding insulating film 32G for G light has a film thickness of, for example, 500 nm or less and 200 nm to 500 nm corresponding to the green light LG having a wavelength of about 500 nm to 600 nm. Furthermore, the light-shielding insulating film 32B for B light has a film thickness of, for example, 400 nm or less and a range of 100 nm to 400 nm corresponding to the blue light LB having a wavelength of about 400 nm to 500 nm.

  Therefore, the film thicknesses of the light shielding insulating film 32R, the light shielding insulating film 32G, and the light shielding insulating film 32B are 600 nm or less, 500 nm or less, and 400 nm corresponding to the wavelengths of the red light LR, the green light LG, and the blue light LB, respectively. If each color light is set as follows, the light shielding insulating film 32R, the light shielding insulating film 32G, and the light shielding insulating film 32B enter from the opening 33a formed between the adjacent second metal light shielding films 33, respectively. Part of the red light LR, green light LG, and blue light LB is formed on the light shielding insulating film 32R, the light shielding insulating film 32G, and the first metal light shielding film formed below and above the light shielding insulating film 32B. Therefore, the light shielding effect of the light shielding insulating film 32R, the light shielding insulating film 32G, and the light shielding insulating film 32B can be maximized.

  By the way, if the respective film thicknesses of the light shielding insulating films 32R, 32G, and 32B are all set to 400 nm or less regardless of the red light LR, the green light LG, and the blue light LB, the reflective liquid crystal display devices 10R, 10G, 10B can be shared, but in this case, the yield to the second metal light shielding film 33 formed above the light shielding insulating films 32R, 32G, and 32B is significantly reduced. In the first embodiment, the thickness of each of the light shielding insulating films 32R, 32G, and 32B is set for each color light according to each wavelength of the red light LR, the green light LG, and the blue light LB in order to suppress the decrease. Yes, the reason for this will be described with reference to FIGS.

  As shown in FIG. 4A, first, a photoresist is formed on the antireflection film 31 formed using TiN (titanium nitride) on the first metal light-shielding film (second metal film) 28 made of aluminum wiring. Apply.

  Next, a photomask is placed on the photoresist, and exposure / development is performed from above the photomask using a photolithography method to form a photoresist pattern (opening) on the photoresist.

  Next, when dry etching is performed from the antireflection film 31 exposed from the photoresist pattern (opening) through the first metal light-shielding film (second metal film) 28 to the second interlayer insulating film 27, the first metal is obtained. An opening 28 a wider than the opening 31 a in the antireflection film 31 is formed concentrically in the light shielding film 28.

  The dry etching described above is performed by applying a microwave power with chlorine and boron chloride as etching gases in a vacuum atmosphere to generate plasma. At this time, since the above-described photoresist is also etched at the same time, hydrocarbons and chlorine, which are main components of the photoresist, are applied to the antireflection film 31 and the first metal light-shielding film (second metal film) 28 to be etched. By attaching, anisotropic etching becomes possible, and a fine wiring pattern can be formed.

  From the above, when the antireflection film 31 is formed on the first metal light-shielding film (second metal film) 28, since the exposure light can suppress irregular reflection by the antireflection film 31, only the exposure region is exposed. Since the photoresist pattern (opening) formed can be formed, the opening 31a in the antireflection film 31 and the opening 28a in the first metal light-shielding film 28 etched using the photoresist pattern as a mask have dimensional accuracy. Will be good.

  However, in the dry etching process described above, the anti-reflection film 31 using TiN (titanium nitride) and the first metal light-shielding film (second metal film) 28 using aluminum wiring are different in etching gas. The cross-sectional shape of the opening 28a formed in the first metal light-shielding film 28 after dry etching is as shown in the figure, that is, the upper portion in the opening 28a in which the antireflection film 31 is formed in the first metal light-shielding film 28. It remains in a state of protruding in a “eave shape”.

Thereafter, a light shielding insulating film 32B for B light is formed on the antireflection film 31 with a thin film thickness of 400 nm or less corresponding to the wavelength of the blue light LB using SiO ₂ , and further for B light. When the second metal light-shielding film 33 is formed on the light-shielding insulating film 32B using, for example, TiN (titanium nitride), the second metal light-shielding film 33 passes through the first light metal through the light-shielding insulating film 32B for B light. Although the film is formed substantially along the opening 28a formed in the light shielding film 28, the “lower part of the eaves” of the antireflection film 31 projecting in an “eave shape” at the upper portion in the opening 28a at this time. Therefore, the B light shielding insulating film 32B and the second metal light shielding film 33 are not normally formed in the opening 28a, so that the first and second films are formed in the opening 28a. Since the metal light shielding films 28 and 33 are in contact with each other and short-circuit, the second metal The yield on the light shielding film 33 may be reduced.

  On the other hand, as shown in FIG. 4B, the G light shielding insulating film 32G is formed with a film thickness of 500 nm or less corresponding to the wavelength of the green light LG, and FIG. As shown in (c), in any case where the light shielding insulating film 32R for R light is formed with a film thickness of 600 nm or less corresponding to the wavelength of the red light LR, light shielding for G light is performed. The film thickness of each of the insulating film 32G and the light shielding insulating film 32R for R light is set larger than the film thickness of the light shielding insulating film 32B for B light. Since the “lower part” does not become a shadow, the first and second metal light shielding films 28 and 33 do not contact each other and do not short-circuit.

  Therefore, the light-shielding insulating films 32R, 32G, and 32B are all set to 400 nm or less regardless of the red light LR, the green light LG, and the blue light LB, as compared with the case where all the film thicknesses of the light-shielding insulating films 32R, 32G, and 32B are set. The yield to the second metal light-shielding film 33 can be improved by setting each film thickness for each color light according to each wavelength of the red light LR, the green light LG, and the blue light LB.

  Further, as shown in FIG. 5, the shape of the second metal light-shielding film 33 is formed in a square shape that is slightly smaller than the reflective pixel electrode 30 formed in a square shape, and the reflective pixel electrode. Similarly to 30, each pixel is electrically separated. At this time, when the second metal light shielding film 33 is separated for each pixel, the opening 33a is formed between the adjacent second metal light shielding films 33 as shown in FIG. Since the first metal light-shielding film 28 covers the electrode gap 30a formed between the adjacent reflective pixel electrodes 30, the opening 33a formed between the second metal light-shielding films 33 is located with respect to the electrode gap 30a. Even if the opening positions substantially coincide with each other at the top and bottom, no trouble occurs.

  In the first embodiment, the first metal light shielding film 28 covers the electrode gap 30a formed between the adjacent reflection pixel electrodes 30, but one of the first and second metal light shielding films 28 and 33 is covered. The electrode gap 30a may be covered with. Accordingly, the positions of the first and second metal light shielding films 28 and 33 with respect to the reflective pixel electrode 30 are slightly shifted from the illustration, and the positions of the second and third via holes Via2 and Via3 are also slightly different from the illustration. There may be a case of deviation.

  Further, when the second metal light shielding film 33 is formed above the first metal light shielding film (second metal film) 28 via the light shielding insulating film 32R, the light shielding insulating film 32G, or the light shielding insulating film 32B, FIG. 1, since the first metal light-shielding film (second metal film) 28 and the second metal light-shielding film 33 also function as a storage capacitor, the storage capacitor portions C2 and C3 are connected to the third via hole Via3. It is divided into left and right sides. The reflective pixel electrode (third metal film) 30, the second metal light-shielding film 33, the first metal light-shielding film (second metal film) 28, and the first metal film 26 are composed of one MOSFET 14 and the storage capacitor portions C1 to C1. It is electrically connected to C3.

At this time, if SiN or SiON having a large dielectric constant is used as the light shielding insulating film 32R, the light shielding insulating film 32G, or the light shielding insulating film 32B, the retention capacitance values of the retention capacitor portions C2 and C3 can be further increased. For example, the light shielding insulating film 32R, 32G, in the case of using SiN is the dielectric constant of the SiN 9 as 32B, the other hand, the light shielding insulating film 32R, in the case of using 32G, SiO ₂ as 32B is SiO ₂ for a dielectric constant of 4.2, in the case of using SiN as the light shielding insulating film 32 can be increased more than twice the holding capacitance value than with the SiO _2.

  Thus, in the first embodiment, the total storage capacity value of the three locations can be set larger than that in the case of the conventional example 1 (FIG. 8) by the total of the storage capacitance sections C1 to C3. Since the voltage fluctuation of the reflection pixel electrode 30 can be reduced, display defects such as flicker and burn-in can be reduced. Further, even when the pixels are miniaturized, stable display characteristics can be obtained by forming the storage capacitor portions C1 to C3 at three locations.

  Compared with the structure of the conventional example 2 described above with reference to FIG. 10, the first and second metal light shielding films 28, 33 are arranged above and below between the p-type Si substrate 11 and the reflection pixel electrode 30. Even if the insulating films 27, 32, and 29 are provided, the via hole formation process can be reduced by one process compared to the conventional example 2, and can be accommodated in the first to third via holes Via1 to Via3. Thus, the productivity of each of the devices 10R, 10G, and 10B can be improved as compared with the conventional example 2.

  As described above, the first and second metal light shielding films 28 and 33 are provided between the p-type Si substrate 11 and the reflection pixel electrode 30, and are provided between the first and second metal light shielding films 28 and 33. By setting the film thickness of the light shielding insulating film 32R, the light shielding insulating film 32G, or the light shielding insulating film 32B for each color light according to each wavelength of the red light LR, the green light LG, or the blue light LB, the transparent substrate Even if a part of the red light LR, the green light LG, or the blue light LB incident from the side 42 enters the third interlayer insulating film 29 from the electrode gap 30a formed between the adjacent reflection pixel electrodes 30, the red light A part of LR or green light LG or blue light LB is reflected and reflected by the reflective pixel electrode 30 and the second metal light shielding film 33 provided above and below in the third interlayer insulating film 29 as shown by dotted lines in FIG. It will only repeat absorption, red light LR or Since part of the color light LG or blue light LB does not reach the side of the MOSFET 14 provided on the p-type Si substrate 11, the occurrence of light leakage in the MOSFET 14 due to the red light LR, green light LG, or part of the blue light LB. Can be suppressed.

  FIG. 6 is a cross-sectional view schematically showing one pixel in the reflective liquid crystal display device according to the second embodiment of the present invention.

  The reflective liquid crystal display devices 10R ′, 10G ′, and 10B ′ of the second embodiment according to the present invention shown in FIG. 6 also have the same R as the reflective liquid crystal display devices 10R, 10G, and 10B of the first embodiment described above. (Red), G (Green), and B (Blue) are configured exclusively for each color, and can be applied to the three-plate type reflective liquid crystal projector 80 as described above with reference to FIG. It is a thing.

  Further, the reflective liquid crystal display devices 10R ′, 10G ′, and 10B ′ according to the second embodiment of the present invention are the positions of the first and second metal light-shielding films in the reflective liquid crystal display devices 10R, 10G, and 10B according to the first embodiment. Here, a brief description will be given centering on differences from the first embodiment.

  In Example 2, the second metal light-shielding film is not formed above the first metal light-shielding film (second metal film) 28, and the red light LR, the green light LG, or the blue light is formed on the first metal film 26. The second metal light-shielding film through the light-shielding insulating film 36R for R light, the light-shielding insulating film 36G for G light, or the light-shielding insulating film 36B for B light, each film thickness set according to each wavelength of LB 37 is formed. Accordingly, the first metal light shielding film 28 is formed on the second metal light shielding film 37 via the second interlayer insulating film 27, and the first metal light shielding film 28 is adjacent to the first metal light shielding film 28 provided above this. The electrode gap 30 a formed between the reflective pixel electrodes 30 is covered.

  The first and second metal light shielding films 28 and 37 are not named in the order of film formation, but the same reference numerals are assigned to the first metal light shielding films 28 corresponding to the same positions as in the first embodiment.

  The second metal light-shielding film 37 is formed from the electrode gap 30a formed between the adjacent reflective pixel electrodes 30 to the third interlayer insulating film 29, the first metal light-shielding film (second metal film) 28, and the second interlayer. In order to absorb part of the red light LR, the green light LG, or the blue light LB that sequentially enters the insulating film 27, it is important to form a film using a metal material having a low reflectivity. Specifically, TiN (titanium nitride: titanium nitride), Ti (titanium), TiN / Ti in which TiN and Ti are laminated, and the like are formed with a film thickness in the range of 50 nm to 200 nm. ing. Thereby, when the second metal light-shielding film 37 absorbs part of the red light LR, the green light LG, or the blue light LB, the reflectance of the second metal light-shielding film 37 can be set low. The red light LR or the green light LG that sequentially enters the third interlayer insulating film 29, the first metal light shielding film (second metal film) 28, and the second interlayer insulating film 27 from the electrode gap 30 a formed between the pixel electrodes 30. Alternatively, a part of the blue light LB can be absorbed.

Here, of the two layers of the first and second metal light shielding films 28 and 37, the lower metal light shielding film 37 is in contact with the lower surface of the second metal light shielding film 37 formed using a metal material such as TiN or Ti or TiN / Ti having a low reflectance. The light shielding insulating film 36R for R light, the light shielding insulating film 36G for G light, or the light shielding insulating film 36B for B light constitutes a part of the main part of the second embodiment. Although it is usually formed on the first metal film 26 using an oxide film such as SiO ₂ (silicon oxide), it does not have to be an oxide film, and other than the oxide film, SiN having a dielectric constant larger than that of SiO _2. (Silicon nitride) or SiON (silicon nitride oxide) can be used.

  In addition, the light shielding insulating film 36R for R light has a film thickness of, for example, 600 nm or less and 300 nm to 600 nm corresponding to the red light LR having a wavelength of about 600 nm to 780 nm. Further, the G light shielding insulating film 36G has a film thickness of, for example, 500 nm or less and a range of 200 nm to 500 nm corresponding to the green light LG having a wavelength of about 500 nm to 600 nm. Further, the light-shielding insulating film 36B for B light is set to have a film thickness of, for example, 400 nm or less and 100 nm to 400 nm corresponding to the blue light LB having a wavelength of about 400 nm to 500 nm.

  Therefore, as in the first embodiment, the light shielding insulating films 36R, 36G, and 36B are all light-shielded compared to the case where the film thickness is set to 400 nm or less regardless of the red light LR, the green light LG, and the blue light LB. If the thickness of each of the insulating films 36R, 36G, and 36B is set for each color light according to each wavelength of the red light LR, the green light LG, and the blue light LB, the yield to the second metal light shielding film 37 is improved. Can do.

  The film thicknesses of the light shielding insulating film 36R, the light shielding insulating film 36G, and the light shielding insulating film 36B are 600 nm or less, 500 nm or less, and 400 nm corresponding to the wavelengths of the red light LR, the green light LG, and the blue light LB. If each is set as follows, the red light LR incident on the light shielding insulating film 36R, the light shielding insulating film 36G, and the light shielding insulating film 36B from the opening 37a formed between the adjacent second metal light shielding films 37, respectively. , Green light LG, and part of blue light LB are the first metal film 26 and the second metal formed below and above the light shielding insulating film 36R, the light shielding insulating film 36G, and the light shielding insulating film 36B. Since it is absorbed or reflected by the light shielding film 37, the light shielding effect of the light shielding insulating film 36R, the light shielding insulating film 36G, and the light shielding insulating film 36B can be maximized.

  In the second embodiment, when the second via hole Via2 for connecting the first metal light shielding film (second metal film) 28 to the first metal film 26 is formed, tungsten or aluminum wiring in the second via hole Via2 is formed. Thus, the first metal light shielding film 28, the second metal light shielding film 37, and the first metal film 26 are electrically connected. Accordingly, in the second embodiment, the process of forming the via hole can be reduced by one process compared to the conventional example 2 (FIG. 10) and can be included in the three processes of the first to third via holes Via1 to Via3. Also, the productivity of each device 10R ′, 10G ′, 10B ′ can be improved.

  When the reflective liquid crystal display devices 10R ′, 10G ′, and 10B ′ of Example 2 are configured as described above, a part of the red light LR, the green light LG, or the blue light LB incident from the transparent substrate 42 side is Then, it penetrates into the third interlayer insulating film 29 from the electrode gap 30a formed between the adjacent reflecting pixel electrodes 30, and the reflecting pixel electrode (third metal film) 30 made of aluminum wiring in the third interlayer insulating film 29. Is repeatedly reflected between the lower surface of the first metal light-shielding film (second metal film) 28 by the aluminum wiring, and thereafter, part of the red light LR, the green light LG, or the blue light LB is adjacent to the first light shielding film (second metal film) 28. Although entering the second interlayer insulating film 27 through the opening 28a formed between the metal light shielding films 28, a part of the red light LR, the green light LG, or the blue light LB is shown as a dotted line in FIG. The second interlayer insulating film 27 The first metal light-shielding film 28 and the second metal light-shielding film 37 provided above and below only repeat reflection and absorption, and part of the red light LR, green light LG, or blue light LB is formed on the p-type Si substrate 11. Since it does not reach the provided MOSFET 14 side, the occurrence of light leakage in the MOSFET 14 due to part of the red light LR, the green light LG, or the blue light LB can be suppressed.

  FIG. 7 is a cross-sectional view schematically showing one pixel enlarged in the reflective liquid crystal display device of Example 3 according to the present invention.

  The reflective liquid crystal display devices 10R ″, 10G ″, and 10B ″ of the third embodiment according to the present invention shown in FIG. 7 are also the reflective liquid crystal display devices 10R, 10G, and 10B of the first embodiment described above. Similar to the reflective liquid crystal display devices 10R ′, 10G ′, and 10B ′ of the second embodiment, each color is configured correspondingly to R (red), G (green), and B (blue). The present invention can be applied to the three-plate reflection type liquid crystal projector 80 described with reference to FIG.

  Further, the reflective liquid crystal display devices 10R ″, 10G ″, and 10B ″ according to the third embodiment of the present invention are the reflective liquid crystal display devices 10R, 10G, and 10B according to the first embodiment of the present invention described above. The reflection type liquid crystal display devices 10R ′, 10G ′, and 10B ′ of the second embodiment are combined with metal light shielding films. Here, the differences from the first and second embodiments will be mainly described.

  In the third embodiment, similarly to the second embodiment, the first light shielding for R light in which each film thickness is set on the first metal film 26 according to each wavelength of the red light LR, the green light LG, or the blue light LB. A second metal light-shielding film 37 is formed via the insulating film 36R, the first light-shielding insulating film 36G for G light, or the first light-shielding insulating film 36B for B light. On the first metal light-shielding film (second metal film) 28, a second light-shielding insulating film 38R for R light or G having a film thickness set according to each wavelength of the red light LR, the green light LG, or the blue light LB. A third metal light shielding film 39 is formed through the second light shielding insulating film 38G for light or the second light shielding insulating film 38B for B light, and the first metal adjacent to the third metal light shielding film 39 is formed. The openings 28a formed between the light shielding films 28 are covered.

  The first, second, and third metal light shielding films 28, 37, and 39 are not names of the order of film formation, but are the first and second metal light shielding films 28 and 37 that correspond to the same positions as in the first and second embodiments. The same reference numerals are assigned to the third metal light shielding films 37 corresponding to the same positions as in the first embodiment.

  At this time, the second metal light-shielding film 37 and the third metal light-shielding film 39 are in the range of 50 nm to 200 nm using a metal material such as TiN or Ti or TiN / Ti having a low reflectance, as in the first and second embodiments. The film is formed with the inner film thickness.

Here, of the first to third metal light shielding films 28, 37, and 39 of the three layers, the second and third metal light shielding films formed using a metal material such as TiN having a low reflectance or Ti or TiN / Ti. First and second light shielding insulating films 36R and 38R for R light provided in contact with the lower surfaces of the films 37 and 39, or first and second light shielding insulating films 36G, 38G for G light, and B light The first and second light shielding insulating films 36B and 38B constitute a part of the main part of the third embodiment, and are usually formed using an oxide film such as SiO ₂ (silicon oxide). The oxide film may not be an oxide film, and other than the oxide film, SiN (silicon nitride) or SiON (silicon nitride oxide) having a dielectric constant larger than that of SiO ₂ can be used.

  The first and second light shielding insulating films 36R and 38R for R light are set in a range of, for example, 600 nm or less and 300 nm to 600 nm corresponding to the red light LR having a wavelength of about 600 nm to 780 nm. Yes. The first and second light shielding insulating films 36G and 38G for G light are set in a range of, for example, 500 nm or less and 200 nm to 500 nm corresponding to the green light LG having a wavelength of about 500 nm to 600 nm. Yes. Further, the first and second light shielding insulating films 36B and 38B for B light are set in a range of, for example, 400 nm or less and 100 nm to 400 nm corresponding to the blue light LB having a wavelength of about 400 nm to 500 nm. Yes.

  Accordingly, the thicknesses of the first light shielding insulating films 36R, 36G, and 36B and the second light shielding insulating films 38R, 38G, and 38B are all set to 400 nm or less regardless of the red light LR, the green light LG, and the blue light LB. In the same manner as in the first and second embodiments, the thicknesses of the first light shielding insulating films 36R, 36G, and 36B and the second light shielding insulating films 38R, 38G, and 38B are set to be red light LR and green light LG. Therefore, the yield to the second metal light shielding film 37 and the third metal light shielding film 39 can be improved by setting each color light according to each wavelength of the blue light LB.

  The film thicknesses of the first and second light-shielding insulating films 36R and 38R, the first and second light-shielding insulating films 36G and 38G, and the first and second light-shielding insulating films 36B and 38B are set to be red light LR, If each of the wavelengths of green light LG and blue light LB is set to 600 nm or less, 500 nm or less, and 400 nm or less, one of red light LR, green light LG, or blue light LB incident from the transparent substrate 42 side is set. Even if the portion enters the third interlayer insulating film 29 from the electrode gap 30a formed between adjacent reflective pixel electrodes 30, a part of the red light LR, the green light LG, or the blue light LB is indicated by a dotted line in FIG. As shown, only reflection and absorption are repeated between the reflective pixel electrode (third metal film) 30 and the third metal light-shielding film 39 provided above and below in the third interlayer insulating film 29, and further, red light LR or green light LG or blue In the unlikely event that a part of LB enters from the opening 39a of the adjacent third metal light shielding film 39, a first metal light shielding film (second metal film) 28 provided above and below in the second interlayer insulating film 27. And the second metal light-shielding film 37 are only repeatedly reflected and absorbed, and a part of the red light LR, green light LG, or blue light LB hardly penetrates into the opening 37a of the second metal light-shielding film 37, so that the p-type It does not reach the side of the MOSFET 14 provided on the Si substrate 11 at all, and the occurrence of light leakage in the MOSFET 14 due to a part of the red light LR, the green light LG, or the blue light LB is further suppressed as compared with the first and second embodiments. Can do.

  In the third embodiment, the second light-shielding insulating film 38R, the second light-shielding insulating film 38G, or the second light-shielding insulating film 38R is disposed above the first metal light-shielding film (second metal film) 28, as in the first embodiment. When the third metal light-shielding film 39 is formed through the insulating film 38B, the first metal light-shielding film (second metal film) 28 and the third metal light-shielding film 39 also function as a storage capacitor. The storage capacitor portions C2 and C3 are formed on the left and right sides of the third via hole Via3. The reflective pixel electrode (third metal film) 30, the third metal light-shielding film 39, the first metal light-shielding film (second metal film) 28, and the first metal film 26 are composed of one MOSFET 14 and the storage capacitor portions C1 to C1. It is electrically connected to C3.

  As a result, even in the third embodiment, the total storage capacitance value of the three locations can be set larger than that of the conventional example 1 by the total storage capacitance portions C1 to C3 in the third embodiment, and the reflection pixel electrode due to the leakage current due to light or the like. Since the voltage fluctuation of 30 can be reduced, display defects such as flicker and burn-in can be reduced. Further, even when the pixels are miniaturized, stable display characteristics can be obtained by forming the storage capacitor portions C1 to C3 at three locations.

  Further, in the third embodiment, similarly to the first and second embodiments, the via hole formation process is reduced by one process compared to the conventional example 2 (FIG. 10), and the first to third via holes Via1 to Via3 are performed. Therefore, the productivity of each of the devices 10R ″, 10G ″, and 10B ″ can be improved as compared with the second conventional example.

In the reflective liquid crystal display device of Example 1 according to the present invention, it is a cross-sectional view schematically showing one pixel enlarged. It is a figure for demonstrating the optical system of the reflection type liquid crystal projector of the 3 plate system to which the reflection type liquid crystal display device of Example 1 which concerns on this invention is applied. To describe the third via hole for electrically connecting the first metal light shielding film (second metal film), the second metal light shielding film, and the reflective pixel electrode (third metal film) shown in FIG. It is sectional drawing expanded partially. (A) shows the case where the second metal light-shielding film is formed above the light-shielding insulating film for R light, and (b) shows the second metal light-shielding film formed above the light-shielding insulating film for G light. (C) is a diagram showing a case where a second metal light-shielding film is formed above the light-shielding insulating film for B light. FIG. 2 is a plan view illustrating the pixel electrode for reflection (third metal film), the second metal light shielding film, and the third via hole shown in FIG. 1 in a plan view. In the reflective liquid crystal display device of Example 2 according to the present invention, it is a cross-sectional view schematically showing one pixel enlarged. In the reflective liquid crystal display device of Example 3 according to the present invention, it is a cross-sectional view schematically showing one pixel enlarged. In the reflective liquid crystal display device of the prior art example 1, it is sectional drawing which expanded and showed one pixel typically. (A) is a block diagram for demonstrating the active matrix circuit in the reflection type liquid crystal display device of the prior art example 1, (b) is the schematic diagram which expanded and showed the X section in (a). It is sectional drawing which showed the liquid crystal display device of the prior art example 2 typically.

Explanation of symbols

10R, 10G, 10B ... the reflective liquid crystal display device of Example 1 according to the present invention,
10R ', 10G', 10B '... reflective liquid crystal display device of Example 2 according to the present invention,
10R '', 10G '', 10B '' ... reflective liquid crystal display device of Example 3 according to the present invention, 11 ... semiconductor substrate (p-type Si substrate), 12 ... p ^- well region,
13A to 13C: Field oxide film,
14 ... switching element (MOSFET), 15 ... gate oxide film,
16 ... gate electrode, 17 ... drain region, 18 ... drain electrode,
19 ... source region, 20 ... source electrode,
21 ... diffusion capacitance electrode, 22 ... insulating film, 23 ... capacitance electrode,
24: Contact for capacitive electrode,
25-30 ... multilayer film,
25 ... 1st interlayer insulation film, 26 ... 1st metal film, 27 ... 2nd interlayer insulation film,
28 ... 1st metal light shielding film (2nd metal film) of Example 1-3 Example, 28a ... Opening part,
29 ... third interlayer insulating film,
30 ... reflective pixel electrode (third metal film), 30a ... electrode gap,
31 ... Antireflection film, 31a ... Opening,
32R, 32G, 32B ... light shielding insulating film of Example 1,
33 ... the second metal light-shielding film of Example 1,
34 ... Antireflection film, 35 ... Tungsten,
36R, 36G, 36B ... the light shielding insulating film of Example 2, the first light shielding insulating film of Example 3,
37 ... 2nd metal light shielding film of 2nd, Example 3,
38R, 38G, 38B ... second light-shielding insulating film of Example 3,
39. Third metal light-shielding film of Example 3,
41 ... Liquid crystal, 42 ... Transparent counter electrode, 43 ... Transparent substrate (glass substrate),
70: Active matrix circuit,
71 ... Horizontal shift register circuit, 72 ... Video switch, 73 ... Signal line,
74 ... Video line, 75 ... Vertical shift register circuit, 76 ... Gate line,
C1 to C3 ... holding capacity part,
D ... Drain, G ... Gate, S ... Source,
Via1 to Via3 ... first to third via holes,
LR ... red light, LG ... green light, LB ... blue light, LI ... incident light, L ... reading light.

Claims (2)

A plurality of switching elements formed for each pixel on a semiconductor substrate;
A multilayer film stacked above the plurality of switching elements;
A plurality of reflective pixel electrodes connected to each switching element in the uppermost layer of the multilayer film and having a predetermined electrode gap;
A transparent counter electrode formed on a transparent substrate;
The liquid crystal sealed between the semiconductor substrate side and the transparent substrate side arranged so that the plurality of reflective pixel electrodes and the transparent counter electrode face each other,
Red light, green light, or blue light incident from the transparent substrate side is light-modulated by the liquid crystal according to a signal from each switching element, and then reflected by the plurality of reflective pixel electrodes, and the transparent substrate In a reflective liquid crystal display device configured exclusively for each color light so as to be emitted from the side,
When the red light, the green light, or the blue light incident from the transparent substrate side enters the inside from between the adjacent reflection pixel electrodes, a part of the red light, the green light, or the blue light In order to shield light from the plurality of switching elements, at least two layers of metal light-shielding films are provided between the plurality of switching elements and the plurality of reflective pixel electrodes, and at least one of the metal light-shielding films is provided. A reflective liquid crystal display device, wherein the thickness of a light-shielding insulating film provided in contact with the film is set for each color light according to each wavelength of the red light, the green light, or the blue light. The reflective liquid crystal display device according to claim 1,
The metal material of the metal light-shielding film in contact with the light-shielding insulating film is TiN, Ti, or TiN / Ti, and the thickness of the light-shielding insulating film provided corresponding to the wavelength of the red light is 300 nm. The film thickness of the light-shielding insulating film set corresponding to the wavelength of the green light is set in the range of 200 nm to 500 nm, and the wavelength of the blue light is set. A reflective liquid crystal display device, wherein a thickness of the provided light shielding insulating film is set in a range of 100 nm to 400 nm.

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