JP4289143B2 - Reflective liquid crystal display device and method of manufacturing reflective liquid crystal display device - Google Patents

Description

  According to the present invention, in a reflective liquid crystal display device, a part of the readout light incident on the liquid crystal through the counter electrode from the transparent substrate side is changed from the opening formed between the adjacent reflective pixel electrodes to the reflective pixel electrode. The present invention relates to a reflective liquid crystal display device capable of reducing leakage current generated in a switching element provided on a semiconductor substrate by a part of the readout light when entering into an adjacent insulating film, and a method for manufacturing the reflective liquid crystal display device It is.

  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.

  In general, in the above-described reflective liquid crystal display device, a plurality of switching elements are provided on a semiconductor substrate (Si substrate) so as to be electrically separated from each other, and are stacked and formed above the plurality of switching elements. Among the plurality of functional films, a plurality of reflective pixel electrodes corresponding to a plurality of switching elements are provided on the uppermost layer so as to be electrically separated from each other, and one reflective pixel electrode and switching element connected to one switching element One pixel is formed in combination with a storage capacitor section for a plurality of pixels, and a plurality of pixels are arranged in a matrix on a semiconductor substrate, and a transparent facing common to all pixels facing a plurality of reflecting pixel electrodes. By forming a film on the lower surface of a transparent substrate (glass substrate) and encapsulating liquid crystal between a plurality of pixel electrodes for reflection and a counter electrode, it can be used for color images from the transparent substrate side. The readout light is incident on the liquid crystal through the counter electrode, and the potential difference between the counter electrode and each reflection pixel electrode is changed by the switching element for each reflection pixel electrode corresponding to the video signal, thereby aligning the liquid crystal. By controlling the above, 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. 1 is a cross-sectional view schematically showing one pixel in a reflection type liquid crystal display device according to a conventional example 1,
FIG. 2A is a block diagram for explaining an active matrix driving circuit in the reflection type liquid crystal display device of Conventional Example 1, and FIG. 2B is a schematic diagram showing an X portion in FIG. is there.

The reflective liquid crystal display device 10A of Conventional Example 1 shown in FIG. 1 is configured to be applicable to a general reflective projector, and one pixel among a plurality of pixels for displaying an image. The semiconductor substrate 11 serving as a base is 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). A p ^- well region 12 is provided on the left side in FIG. 11 in a state where the p ^- well region 12 is electrically separated pixel by pixel by left and right field 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, on the p-type Si substrate 11, an ion-implanted diffusion capacitor electrode 21 is formed on the right side of the p ^- well region 12 in the figure, and this diffusion capacitor electrode 21 is also formed in pixel units by left and right field oxide films 13B and 13C. The field oxide film 13A to the field oxide film 13C correspond 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. A plurality of functional films 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, second, and third metal films 26 are adjacent to adjacent pixels. , 28, 30 are formed with openings 26a, 28a, 30a, respectively, so that each of the first, second, and third metal films 26, 28, 30 is electrically connected to each pixel. It is separated.

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

  Further, in one pixel, the second metal film 28 in the middle stage has the MOSFET 14 on the p-type Si substrate 11 provided with a part of the readout light L incident below from the transparent substrate 42 side described later disposed on the upper side. 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 opening 30a so as to shield a part of the readout light L entering from the opening 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 opening 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 reflection pixel electrode) 30, and a transparent counter electrode 41 is placed on the lower surface of the transparent substrate (glass substrate) 42 through the liquid crystal 40. In addition, it is formed 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.

  Next, in the reflective liquid crystal display device 10A of Conventional Example 1, an active matrix drive circuit when a plurality of the above-described MOSFETs (switching elements) 14 are arranged in a matrix on the p-type Si substrate 11 is shown in FIGS. A description will be given using (b).

  As shown in FIGS. 2A and 2B, in the active matrix driving circuit 70 in the conventional reflective liquid crystal display device 10A, a plurality of MOSFETs (switching elements) 14 are formed on a p-type Si substrate (semiconductor substrate) 11. One pixel is formed by combining one reflective pixel electrode 30 connected to one MOSFET 14 and a storage capacitor C for the MOSFET, which are arranged in a matrix, and this pixel set is a p-type. A plurality of elements are arranged in a matrix on the 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 contact 24 and the capacitor electrode 23 of the storage capacitor C. At this time, the active matrix driving 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 and (n + 1) th frame period are negative writing. 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 pixel electrode 30 for reflection and the capacitor electrode contact 24 and the capacitor electrode 23 of the storage capacitor C are connected to the drain electrode 18. is there.

  Further, in the above-described conventional reflective liquid crystal display device 10A, 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 MOSFET14 includes a gate line 76, one of the p ^- for example as a fixed potential between the well potential contact well region 12 (FIG. 1) (not shown) formed in the p ⁺ region A voltage of 15V is applied. When an n-type Si substrate is used, for example, 0 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. A voltage 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, in the case of driving one pixel in the active matrix driving circuit 70 in the conventional reflective liquid crystal display device 10A, video signals input from the video line 74 sequentially shifted in timing are transmitted via the video switch 72. One MOSFET 14 that is supplied to one signal line 73 arranged in the column direction and crosses the one signal line 73 and one gate line 76 arranged in the row direction is selected and turned on. .

  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. 1), 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 readout light L (FIG. 1) incident from the transparent substrate 42 side is modulated for each pixel by the liquid crystal 40, reflected by the reflective pixel electrode 30, and emitted from the transparent substrate 42. For this reason, unlike the transmission method, the reading light L (FIG. 1) can be used nearly 100%, and the structure can achieve both high definition and high luminance for the projected image.

  At this time, as shown in FIG. 1, a part of the color image readout light L incident from the transparent substrate 42 side passes through the opening 30 a formed between the adjacent reflective pixel electrodes 30 to 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 readout light L enters 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 readout light L 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 part of the read light L 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 photocarriers are generated by a part of the readout light L 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 flickering and image sticking, it is necessary to minimize light leakage in the MOSFET 14 due to a part of the readout light L.

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 readout light L described above (see, for example, Patent Document 1).
JP 2002-40482 (page 3-7, FIG. 1).

  FIG. 3 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. 3 is disclosed in the above-mentioned Patent Document 1 (Japanese Patent Laid-Open No. 2002-40482). Here, the liquid crystal display device 100 will be briefly described with reference to Patent Document 1. To do.

  As shown in FIG. 3, 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 plurality of functional films each including a second light-shielding film 113, a fourth interlayer film 114, and a second conductive film (hereinafter referred to as a reflective electrode) 115 serving as a reflective electrode are stacked in the order described above. Has been.

  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 opening 115 a formed between the adjacent reflecting electrodes 115, and the second light shielding film 113 is substantially the same size as the reflecting electrode 115 so as to cover the opening 115 a. Furthermore, since the first light shielding film 111 is formed so as to cover the opening 113 a 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 readout light L enters the fourth interlayer film 114 from the opening 115 a formed between the adjacent reflective electrodes 115, a part of the readout light L is part of the first and second light shielding films 111. , 113 and the active element 102 provided on the first substrate 101 does not reach the active element 102, so that it is possible to suppress the occurrence of light leakage in the active element 102 due to a part of the readout light L. Measures have been applied to so that.

In the liquid crystal display device 100 of the second conventional example having the above configuration, a voltage is applied to the first light shielding film 111, and the first light shielding film 111, the third interlayer film 112, and the second light shielding film 113 are used. A capacitor (capacitor) is formed. Then, when the voltage of the reflective electrode 115 is changed with respect to the counter electrode 119, the first electrode by the reflective electrode 115, the liquid crystal composition 117, the counter electrode 119, the first light shielding film 111, the third The interlayer film 112 and the second capacitor formed by the second light shielding film 113 are used.

  Further, it is disclosed that, with the above configuration, it is possible to prevent the incidence of unnecessary light generated in the liquid crystal display element, and to realize a high-quality liquid crystal display device 100 and a liquid crystal projector using the same. .

  By the way, in the reflective liquid crystal display device 10A of Conventional Example 1 shown in FIG. 1, as described above, part of the color image readout light L 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. 3, the second light shielding film 113 is provided below the reflective electrode 115 so as to cover the opening 115a formed between the adjacent reflective electrodes 115, Furthermore, the second substrate (transparent substrate) 120 is provided by providing the second light shielding film 113 below the second light shielding film 113 so as to cover the opening 113a formed between the adjacent second light shielding films 113. Although part of the readout light L incident from the side does not reach the active element 102 formed on the first substrate 101, no light leakage occurs, but the first conductive film 109 is formed above the first substrate 101. The second interlayer film 110, the first light shielding film 111, the third interlayer film 112, the second light shielding film 113, the fourth interlayer film 114, and the reflective electrode (second conductive film). ) 115 in order, Forming a first via hole Via1 in the conductive film 109; forming a second via hole Via2 in the first light shielding film 111; and forming a third via hole Via3 in the second light shielding film 113. And the step of forming the fourth via hole Via4 with respect to the reflective electrode (second conductive film) 115. In particular, the liquid crystal display device 100 is manufactured by increasing the number of steps of forming the via hole. It takes time, and the yield tends to deteriorate, which is a problem.

  Therefore, when minimizing light leakage in the switching element due to part of the readout light L incident from the transparent substrate side, at least two or more metal light-shielding films between the semiconductor substrate and the reflective pixel electrode Even if each is provided with an insulating film interposed above and below, the step of forming a via hole can be reduced by one process compared to the conventional example 2, and the thickness of the insulating film for light shielding formed between two metal light shielding films And a reflective liquid crystal display device capable of setting a larger storage capacitance value for one switching element provided on a semiconductor substrate, and setting so that good characteristics can be obtained with respect to readout light for a color image A manufacturing method of a reflective liquid crystal display device is desired.

The present invention has been made in view of the above problems, and the first invention is a semiconductor substrate, a drive circuit portion provided on the semiconductor substrate, and a conductive first electrode provided above the drive circuit portion. a first light-shielding film, wherein the first light shielding film second light-shielding film of conductive provided above, the upward Matricaria box shape into a plurality of light reflective provided in the second light-blocking film A drive substrate having a pixel electrode;
A light transmissive substrate having a light transmissive electrode disposed opposite to the pixel electrode with a predetermined gap;
Liquid crystal sealed in the predetermined gap and driven for each pixel electrode by the drive circuit unit;
With
The plurality of pixel electrodes are electrically insulated from each other by a first opening provided between the plurality of pixel electrodes,
The first light shielding film is surrounded by a second opening provided in a range that does not face the first opening for each pixel electrode, and is electrically connected to the drive circuit portion. And a second region provided outside the second opening and electrically insulated from the first region,
It said second light-shielding film, among the second opening are electrically isolated for each of the pixel electrode and the third opening provided in a range that does not face Rutotomoni, region corresponding to the pixel electrode It is provided in
Wherein the pixel electrode and the previous SL said first region of the first light shielding film, through the electrically connected via hole in said second light-shielding film as well as through the second light shielding film, the pixel being connected thereto respectively electrical manner for every electrode is a reflective type liquid crystal display device according to claim.

According to a second aspect of the present invention, in the reflective liquid crystal display device according to the first aspect, the second light-shielding film is a titanium (Ti) film, a titanium nitride (TiN) film, or the titanium film and titanium nitride. A reflective liquid crystal display device having a laminated film in which films are laminated .

According to a third aspect of the present invention, in the reflective liquid crystal display device according to the first aspect of the present invention, a capacitance portion is provided in which a gap between the first light shielding film and the second light shielding film is filled with a dielectric material. It is a reflection type liquid crystal display device.

According to a fourth aspect of the invention, in the reflective liquid crystal display device according to the third aspect of the invention, the dielectric material contains silicon nitride (SiN) or silicon nitride oxide (SiON). It is a display device.

Further, the fifth invention is characterized in a reflective liquid crystal display device, in that said first light shielding film and the second light-shielding film and the interval is less 400 n m of the first invention described above reflected Type liquid crystal display device.

According to a sixth aspect of the present invention, an antireflection film, a first insulating film, a conductive second light shielding film, and a second light shielding film are provided on the conductive first light shielding film provided above the semiconductor substrate. A film stacking step of sequentially stacking insulating films;
After the film stacking step, a hole is formed through the second insulating film, the second light shielding film, the first insulating film, and the antireflection film to expose the first light shielding film. Hole formation process;
After the hole forming step, a hole conductive member connecting step of filling the hole with a conductive member and electrically connecting the first light shielding film and the second light shielding film with the conductive member ;
After the hole conductive member connecting step, a light reflective pixel electrode electrically connected to the conductive member is formed on the second insulating film, and the pixel electrode, the second light shielding film, A pixel electrode forming step of electrically connecting the first light-shielding film with the conductive member;
It is a manufacturing method of the reflection type liquid crystal display device characterized by having.

According to the manufacturing method of the reflection-type liquid crystal display device and a reflective liquid crystal display device according to the present invention, the step of forming a bi via holes, such as the above-described conventional example 2, were measures to suppress the occurrence of light leakage it can be reduced by one step than the liquid crystal display device.

Further, by the reflection type liquid crystal display device according to the present invention lever, it is possible to reduce the variation in the potential of the reflection pixel electrode, which is advantageous with respect to such flicker and image sticking.

Further, it is possible to absorb a portion of the reflective type liquid crystal display device by the lever, reading light entering from the opening formed between adjacent Ri fit reflective pixel electrode according to the present invention.

Further, since in B (blue) light below a wavelength 400nm of light it does not require the use of reading light L for reflective type liquid crystal display device by the lever, color image according to the present invention, the light shielding insulating film The light shielding effect can be maximized.

Moreover, improved shielding performance by the reflective liquid crystal display device by the lever, adjacent Ri fit a portion of the reading light which has entered from the formed opening between the reflective pixel electrode is lower reflectivity SiN or SiON according to the present invention In addition, the storage capacitance value of the storage capacitor portion formed by the light shielding insulating film formed between the two metal light shielding films and the two metal light shielding films can be increased by using SiN or SiON having a high dielectric constant. can do. Furthermore, the light-shielding effect can be further increased by combining a light-shielding insulating film made of SiN or SiON with a high refractive index and a metal light-shielding film having a light absorption property.

Further, by the manufacturing method of the reflection-type liquid crystal display device shown below lever, upon producing a reflection-type liquid crystal display device, the metal light-shielding film is in contact with the metal film in the opening formed in the metal film The phenomenon of short circuit is eliminated. Accordingly, the reflective pixel electrode and the COM potential are not short-circuited, and the storage capacitor portion can be normally formed between the metal light-shielding film and the metal film. Can be manufactured.

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

FIG. 4 is a cross-sectional view schematically showing one pixel in the reflective liquid crystal display device of Example 1 according to the present invention,
FIG. 5 illustrates 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. 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. 6 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.
FIG. 7 is a cross-sectional view for explaining the formation of a storage capacitor for one switching element in the reflective liquid crystal display device of Example 1 according to the present invention. FIG. 7A is a case of Conventional Example 1 as a comparative example. (B) is a diagram showing the case of the present invention,
FIG. 8 is a diagram for explaining the reflectance of the light shielding insulating film formed on the first metal light shielding film (second metal film) / antireflection film in the reflective liquid crystal display device of Example 1 according to the present invention. FIG.

  The structural form of the reflective liquid crystal display device 10B of Example 1 according to the present invention shown in FIG. 4 is different from the structural form of the reflective liquid crystal display device 10A of Conventional Example 1 described above with reference to FIG. A part of the technical idea of the light leakage prevention measure in the liquid crystal display device 100 of the conventional example 2 described above with reference to FIG. 3 is applied. At this time, at least between the semiconductor substrate and the reflection pixel electrode. Even if two or more layers of metal light-shielding films are provided with insulating films above and below each other, the step of forming a via hole is reduced by one process compared to the conventional example 2, and is formed between two layers of metal light-shielding films. The film thickness of the light-shielding insulating film can be set so that good characteristics can be obtained with respect to the readout light for color images, and the holding capacitance value for one switching element provided on the semiconductor substrate can be set larger. What was configured to be able to A.

  For convenience of explanation, the same constituent members as those of the reflection type liquid crystal display device 10A of the conventional example 1 shown above are denoted by the same reference numerals, and the same constituent members are appropriately selected as necessary. Explanation will be given, and a new reference numeral will be given to the constituent members different from the conventional example 1, and the points different from the conventional example 1 will be mainly described.

As shown in FIG. 4, in the reflective liquid crystal display device 10B according to the first embodiment of the present invention, when one pixel among a plurality of pixels for displaying an image is enlarged and described, a semiconductor serving as a base The substrate 11 is a p-type Si substrate (or an n-type Si substrate), similar to the reflective liquid crystal display device 10A of the first conventional example described with reference to FIG. (Referred to as a p-type Si substrate) 11, a single p ^- well region 12 is provided in a state of being electrically isolated pixel by pixel by left and right field oxide films 13A and 13B. A low voltage drive type MOSFET is provided as one switching element 14 in one p ^- well region 12. The switching element (hereinafter referred to as MOSFET) 14 includes a gate G in which a gate electrode 16 is formed on a gate oxide film 15, a drain D in which a drain electrode 18 is formed on a drain region 17, and a source region 19. And the source S on which the source electrode 20 is formed, and is configured to be driven at a low voltage of about 7V.

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 isolated in pixel units by the left and right field oxide films 13B and 13C.

In addition, among the plurality of functional films formed by laminating above the field oxide films 13A to 13C, the gate electrode 16, and the capacitor electrode 23, a plurality of reflective pixel electrodes 30 corresponding to the MOSFETs 14 are electrically connected to the uppermost layer. When the layers are provided separately, 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 Conventional Example 1, and aluminum. The first metal film 26 formed by the wiring is connected to one switching element 14 and the storage capacitor 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 Via1. ing. 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.

  Here, the difference from the conventional example 1 will be described. The second metal film 28 described above is an opening formed between adjacent reflection pixel electrodes 30 among the plurality of reflection pixel electrodes 30 formed above. The first metal light shielding film is formed so as to cover the opening 30a in order to shield part of the color image readout light L entering from the part 30a toward the p-type Si substrate 11 side. is there.

  Further, as shown in an enlarged view in FIG. 5A or 5B, an antireflection film 31 and a predetermined film are disposed above a second metal film (hereinafter referred to as a first metal light shielding film) 28. A second metal light shielding film 33 is formed in order through a light shielding insulating film 32 having a thickness (400 nm or less), and an opening formed between adjacent first metal light shielding films 28 by the second metal light shielding film 33. It covers the portion 28a (FIG. 4). Further, as described later, the second metal light shielding film 33 is electrically separated for each pixel similarly to the reflective pixel electrode (third metal film) 30.

  A third interlayer insulating film 29 is formed on the second metal light shielding film 33, and a reflective pixel electrode (third metal film) 30 is further formed on the third interlayer insulating film 29 via an antireflection film 34. Is formed. Note that the antireflection films 31 and 34 are not shown in FIG. 4 and are enlarged only in FIG. 5A or FIG. 5B 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 (third metal film) 30 are: The readout light L for the color image that has entered the third interlayer insulating film 29 from the opening 30a (FIG. 4) formed between the adjacent reflective pixel electrodes 30 using both conductive TiN (titanium nitride). It is provided to prevent reflection on a part.

Here, the light shielding insulating film 32 constitutes a part of the main part of the present invention, and the SiO ₂ (silicon oxide) is formed on the first metal light shielding film (second metal film) 28 / antireflection film 31. However, it may not be an oxide film, and other than the oxide film, SiN (silicon nitride), SiON (silicon nitride oxide), etc. having a dielectric constant larger than that of SiO ₂ may be used. Can be used.

  Further, the thickness of the light shielding insulating film 32 is preferably 400 nm or less, and preferably around 300 nm. The reason for this will be described. The reflective liquid crystal display device 10B performs color display by reflecting the readout light L for a color image having a wavelength of 400 nm to 700 nm in the visible light region by the reflective pixel electrode 30. Accordingly, it is not necessary to use B (blue) light having a wavelength of 400 nm or less among the color image readout light L, and thus it is not necessary to make light having a wavelength of 400 nm or less incident on the transparent substrate 42.

  Therefore, if the film thickness of the light shielding insulating film 32 is set to 400 nm or less corresponding to the wavelength of B (blue) light or less in the color image readout light L, the adjacent second metal light shielding film 33 is set. A part of the color image readout light L incident into the light shielding insulating film 32 through the opening 33a formed therebetween is a first metal light shielding film 28 formed below and above the light shielding insulating film 32. In addition, since the second metal light shielding film 33 is absorbed or reflected, the light shielding effect of the light shielding insulating film 32 can be maximized.

  Further, since the light shielding insulating film 32 is formed by a chemical vapor deposition method (CVD method: Chemical Vapor Deposition), it is excellent in the in-plane variation of the wafer as is well known. Accordingly, the thickness of the light shielding insulating film 32 formed between the first metal light shielding film 28 and the second metal light shielding film 33 can be set relatively uniformly to 400 nm or less. Variations in the light shielding effect of the film 32 can also be reduced.

  Next, the second metal light shielding film 33 formed on the light shielding insulating film 32 also constitutes a part of the main part of the present invention, and the second metal light shielding film 33 is adjacent to the reflective pixel electrode 30. It is important to form a film using a metal having low reflectance in order to absorb a part of the color image readout light L that has entered the third interlayer insulating film 29 from the opening 30a formed therebetween, Specifically, TiN (titanium nitride: titanium nitride), Ti (titanium), TiN / Ti laminated with TiN and Ti, or the like is used to form the second metal light shielding film 33 within a range of 50 nm to 200 nm. The film is formed with a film thickness. Thereby, when the second metal light-shielding film 33 absorbs part of the readout light L, the reflectance of the second metal light-shielding film 33 can be set low, so that the second metal light-shielding film 33 is formed between the adjacent reflection pixel electrodes 30. A part of the readout light L that has entered from the opening 30a can be absorbed.

  Further, when forming the third via hole Via3 for connecting one reflective pixel electrode (third metal film) 30 to one first metal light shielding film (second metal film) 28 formed therebelow. Since the second metal light-shielding film 33 is a light-absorbing metal film that can be etched simultaneously with the third interlayer insulating film 29, the second and first metal light-shielding films 33 are disposed below the reflective pixel electrode 30. , 28 can be reduced to one step compared to the conventional example 2, and the number of steps for forming the via hole can be reduced to three in the first to third via holes Via1 to Via3.

  At this time, although the second metal light-shielding film 33 has a higher resistance value than the first to third metal films 26, 28, and 30 using aluminum wiring, the second metal light-shielding film 33 is used for light shielding and a storage capacitor described later. Since it is intended for formation, it does not need a function as a wiring that allows current to flow, so there is no need to lower the resistance value, and this does not affect the electrical characteristics. It works well for.

  Further, as shown in FIG. 6, 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 (third metal film) 30 formed in a square shape. In addition, like the reflective pixel electrode 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 opening 30 a formed between the adjacent reflection pixel electrodes 30, the opening 33 a formed between the second metal light shielding films 33 is between the adjacent reflection pixel electrodes 30. Even if the opening position substantially coincides with the opening 30a formed at the top and bottom, no trouble occurs.

  In the first embodiment, the first metal light shielding film 28 covers the opening 30a formed between the adjacent reflection pixel electrodes 30, but one of the first and second metal light shielding films 28 and 33 is used. The opening 30a formed between the adjacent reflective pixel electrodes 30 may be covered. 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.

  As described above, by providing the first and second metal light-shielding films 28 and 33 between the p-type Si substrate 11 and the reflective pixel electrode 30, the color image readout light L incident from the transparent substrate 42 side is provided. Even if a part of the light enters the third interlayer insulating film 29 from the opening 30a formed between the adjacent reflective pixel electrodes 30, a part of the readout light L is generated as shown by the dotted line in FIG. The reflection pixel electrode 30 and the second metal light shielding film 33 provided above and below in the three-layer insulating film 29 only repeat reflection and absorption, and a part of the readout light L is provided on the p-type Si substrate 11. Therefore, the occurrence of light leakage in the MOSFET 14 due to part of the readout light L can be suppressed.

Further, as shown in FIGS. 5A and 6, one reflective pixel electrode (third metal film) 30 and one first metal light shielding film (second metal film) 28 are electrically connected. In the case of connection, the third interlayer insulating film 29 formed using SiO ₂ is etched from a position corresponding to the substantially central portion of the reflective pixel electrode 30, and further conductive TiN or Ti or TiN / Ti. A second metal light-shielding film 33 formed using, a light-shielding insulating film 32 formed using SiO _2, SiN or SiON, and an antireflection film 31 formed using conductive TiN. At the same time, the third via hole Via3 is formed by etching. Then, conductive tungsten 35 is formed and buried in the third via hole Via3 by the CVD method, so that the lower end portion of the tungsten 35 is electrically connected to one first metal light shielding film (second metal film) 28. A second metal light-shielding film 33 is electrically connected to an intermediate portion of the tungsten 35, and an antireflection film 34 is formed on the upper end of the tungsten 35 using conductive TiN. And is electrically connected to the reflective pixel electrode 30.

  At this time, an oxide film etching apparatus (not shown) is generally intended to etch only an oxide film, and therefore has a low etching rate with respect to Al (aluminum), and is intended to perform selective etching. . However, simultaneously with the etching of the third via hole Via3, TiN or Ti or TiN / Ti used for the second metal light shielding film 33 can be easily etched by the above-described oxide film etching apparatus.

  When the third via hole Via3 is formed, the tungsten 35 does not have to be embedded in the third via hole Via3. In this case, as shown in FIG. The third interlayer insulating film 29 is etched from the position corresponding to the part, and the second metal light shielding film 33, the light shielding insulating film 32, and the antireflection film 31 are simultaneously etched to form the third via hole Via3. Thereafter, if the antireflection film 34 made of TiN and the reflection pixel electrode 30 made of aluminum wiring are formed in the third via hole Via 3 by a normal sputtering process, the reflection pixel electrode 30, the second metal light shielding film 33, and the second One metal light shielding film 28 is electrically connected.

  Accordingly, the third via hole Via3 serves to electrically connect the reflective pixel electrode (third metal film) 30, the second metal light shielding film 33, and the first metal light shielding film (second metal film) 28. Have. As a result, the second metal light shielding film 33 does not need to be provided with a dedicated via hole, so that processes such as lithography and etching can be simplified.

  Next, the formation of the storage capacitor for one MOSFET 14 will be described with reference to FIGS. 7A and 7B in the case of the conventional example 1 as a comparative example and the case of the present invention.

  As shown in FIG. 7A, in the case of the conventional example 1 as a comparative example, the diffusion capacitance electrode 21 and the insulating film are formed on the p-type Si substrate 11 with respect to the MOSFET 14 provided on the p-type Si substrate 11. 22, only one storage capacitor portion C including the capacitor electrode 23 and the capacitor electrode contact 24 is formed.

  As opposed to the above, in the present invention, as shown in FIG. 7B, the storage capacitor C1 including the diffusion capacitor electrode 21, the insulating film 22, the capacitor electrode 23, and the capacitor electrode contact 24 on the p-type Si substrate 11. In addition, a second metal light-shielding film 33 is formed on the first metal light-shielding film (second metal film) 28 / antireflection film 31 (FIG. 5) with a light-shielding insulating film 32 interposed therebetween. 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 divided between the left and right sides of the third via hole Via3. Is formed. The reflective pixel electrode (third metal film) 30, the second metal light shielding film 33, and the first metal light shielding film (second metal film) 28 are electrically connected to one MOSFET 14 and the storage capacitor portions C1 to C3. Has been.

At this time, if SiN or SiON having a high dielectric constant is used as the light-shielding insulating film 32, the storage capacitance values of the storage capacitor portions C2 and C3 can be further increased. For example, in the case of using SiN as the light shielding insulating film 32 is the dielectric constant of the SiN 9, on the other hand, in the case of using SiO ₂ as a light-shielding insulating film 32 is a dielectric constant of SiO ₂ is 4.2 it is therefore, 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.

  Accordingly, in the present invention, the total storage capacitance value of the three locations can be set larger than that of the conventional example 1 by the storage capacitance portions C1 to C3 in total of three locations, and the reflection pixel electrode 30 due to a leak current due to light or the like. Therefore, 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, as shown in FIG. 8, each of the cases where SiN or SiO ₂ is formed as the light shielding insulating film 32 on the first metal light shielding film (second metal film) 28 / antireflection film 31 (FIG. 5). As a reference example, the reflectance of only the first metal light-shielding film (second metal film) 28 made of aluminum wiring is also shown. In the figure, when SiN is used as the light shielding insulating film 32, the reflectance can be suppressed lower than when SiO ₂ is used. Therefore, the light shielding insulating film 32 is not SiO ₂ but SiN or SiON. By using, the light shielding effect can be increased. In addition, the refractive index of SiO ₂ is 1.45, whereas the refractive index of SiN is about 2.0, and the refractive index of SiON is about 1.8, which is higher than that of SiO ₂ . By combining such a high-refractive-index light-shielding insulating film 32 with the above-described second metal light-shielding film 33 having light absorption, the light-shielding effect can be further increased.

  The operation of the reflective liquid crystal display device 10B according to the first embodiment of the present invention configured as described above is the same as that of the conventional reflective liquid crystal display according to the first embodiment described with reference to FIGS. 2 (a) and 2 (b). Since the operation is substantially the same as the operation of the device 10A, detailed description thereof will be omitted. However, in the present invention, three storage capacitor portions C1 to C3 are provided on the source electrode 20 (or the drain electrode 18) of the MOSFET (switching element) 14. In order to be connected, the total storage capacitance value obtained by adding the storage capacitance values of the three storage capacitor portions C1 to C3 is different between the source electrode 20 (or the drain electrode 18) and the COM potential. .

  Next, a manufacturing method of the reflective liquid crystal display device 10B according to the first embodiment of the present invention configured as described above will be described with reference to FIGS. 9 (a) to 9 (d) and FIGS. 10 (a) to 10 (c). It demonstrates in order of a process.

9A to 9D are cross-sectional views sequentially showing a first step to a fourth step in the method of manufacturing a reflective liquid crystal display device of Example 1 according to the present invention,
10A to 10C are cross-sectional views sequentially showing the fifth to seventh steps in the method of manufacturing the reflective liquid crystal display device according to the first embodiment of the present invention.

First, in the first step shown in FIG. 9A, a MOSFET (switching element) 14, a storage capacitor C1, field oxide films 13A to 13C are formed on a p-type Si substrate (semiconductor substrate) 11 by a known method. A first interlayer insulating film 25, a first metal film 26, a second interlayer insulating film 27, a first metal light-shielding film (second metal film) 28 / an antireflection film 31 (shown only in FIG. 5). ) In order. At this time, the first metal film 26 is electrically connected to the MOSFET 14 and the storage capacitor C1 by the aluminum wiring in the first via hole Via1, and the first metal light shielding film (second metal film) 28 is in the second via hole Via2. It is electrically connected to the first metal film 26 by aluminum wiring. Further, an opening 28a is formed between the adjacent first metal light shielding film (second metal film) 28 / antireflection film 31 (FIG. 5) by predetermined patterning and etching by lithography, and one first metal is formed. The light shielding film (second metal film) 28 is electrically separated from the adjacent.

Next, in the second step shown in FIG. 9B, the light-shielding insulating film 32 is formed on the first metal light-shielding film (second metal film) 28 / antireflection film 31 (FIG. 5) by SiO ₂ or SiN or A film is formed by SiON with a thickness of, for example, 300 nm using SiON.

  Next, in the third step shown in FIG. 9C, the second metal light-shielding film 33 is formed on the light-shielding insulating film 32 by sputtering with TiN or Ti or TiN / Ti to a thickness of, for example, 70 nm. In addition, an opening 33a is formed between the adjacent first metal light shielding films 33 by predetermined patterning and etching by lithography, and one second metal light shielding film 33 is electrically separated from the adjacent pixels.

Next, in the fourth step shown in FIG. 9D, a third interlayer insulating film 29 is formed on the second metal light-shielding film 33 with a thickness of, for example, 700 nm using SiO ₂ , and this third interlayer insulating film is formed. The upper surface of 29 is flattened by a chemical mechanical polishing method (CMP method: Chemical Mechanical Polishing).

  Next, in the fifth step shown in FIG. 10A, the third interlayer insulating film 29 is subjected to predetermined patterning by lithography, and the third via hole Via3 is formed by etching. At this time, the second metal light-shielding film 33 and the light-shielding insulating film 32 are simultaneously etched and are etched until the first metal light-shielding film (second metal film) 28 is reached. As described above, since the second metal light-shielding film 33 is formed using TiN, Ti, or TiN / Ti, it can be easily etched even in an oxide film etching apparatus (not shown).

  Next, in a sixth step shown in FIG. 10B, tungsten 35 is formed in the third via hole Via3 from above the third interlayer insulating film 29 by the CVD method, and then tungsten is etched by etch back or CMP method. 35 is embedded. Note that aluminum may be sputtered into the third via hole Via3 and etched back to embed the aluminum. Thereby, one second metal light shielding film 33 and one first metal light shielding film (second metal film) 28 are electrically connected to tungsten 35 or aluminum.

  Next, in the sixth step shown in FIG. 10C, an antireflection film 34 (shown only in FIG. 5) / reflection pixel electrode (third metal film) is formed on the third interlayer insulating film 29 by a known method. 30 is formed by sputtering aluminum, and an opening 30a is formed between the adjacent reflective pixel electrodes 30 by predetermined patterning using lithography and etched to form one reflective pixel electrode 30. Electrical isolation from adjacent pixels. At this time, tungsten 35 or aluminum in the third via hole Via 3 is electrically connected to one antireflection film 34 (FIG. 5) / reflection pixel electrode (third metal film) 30. Then, the formation of various functional films on the p-type Si substrate 11 is completed.

  As described above, compared with the structure of the conventional example 1, the pixel 14 can be miniaturized because it is more resistant to light leakage in the MOSFET 14, and, for example, more pixels are packed in the same screen area than in the conventional example 1. And high definition can be realized.

  Compared with the structure of the conventional example 2, the first and second metal light-shielding films 28 and 33 are interposed between the p-type Si substrate 11 and the reflection pixel electrode 30 above and below the insulating films 27, 32, and 29, respectively. Even if provided, the via hole forming process can be reduced by one process compared to the conventional example 2, and the first and second metal films 26 and 28 having the second metal light-shielding film 33 formed above and below when forming the via hole. Can be connected to one MOSFET 14 and the storage capacitors C1 to C3 and one reflection pixel electrode 30, and the storage capacitance value for one MOSFET 14 can be set large.

  FIG. 11 is a cross-sectional view schematically showing one pixel enlarged in the reflective liquid crystal display device according to the second embodiment of the present invention.

  The reflective liquid crystal display device 10C according to the second embodiment of the present invention shown in FIG. 11 is the position of the first and second metal light shielding films in the reflective liquid crystal display device 10B according to the first embodiment of the present invention described above. Here, only the differences from the first embodiment will be briefly described.

  In the second embodiment, a metal light shielding film is not formed above the first metal light shielding film (second metal film) 28, but the second metal light shielding is provided on the first metal film 26 via the light shielding insulating film 36. A film 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 opening 30a 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 corresponding to the same positions as in the first embodiment.

  In Example 2, since the metal light-shielding film is not formed above the first metal light-shielding film (second metal film) 28, the storage capacitor portion C has been described with reference to FIG. As in Example 1, there is only one place provided on the p-type Si substrate 11.

At this time, the light shielding insulating film 36 is formed with a film thickness of 400 nm or less using SiO _2, SiN or SiON. The second metal light-shielding film 37 is formed with a film thickness in the range of 50 nm to 200 nm using TiN or Ti or TiN / Ti having a low reflectance.

  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 in the second via hole Via2 is used. The first metal light-shielding film 28, the second metal light-shielding film 37, and the first metal film 26 are electrically connected. Therefore, in the second embodiment, the step of forming the via hole can be reduced by one step compared to the conventional example 2, and can be accommodated in the three steps of the first to third via holes Via1 to Via3.

  When the reflective liquid crystal display device 10C of Example 2 is configured as described above, a part of the color image readout light L incident from the transparent substrate 42 side is formed between adjacent reflective pixel electrodes 30. Intrusion into the third interlayer insulating film 29 from the opened opening 30a, and between the lower surface of the reflective pixel electrode 30 made of aluminum wiring and the upper surface of the first metal light shielding film 28 made of aluminum wiring in the third interlayer insulating film 29 After that, a part of the readout light L penetrates into the second interlayer insulating film 27 through the opening 28a formed between the adjacent first metal light shielding films 28. Thereafter, the readout light L As shown by a dotted line in FIG. 11, only part of the first metal light-shielding film 28 and the second metal light-shielding film 37 provided above and below in the second interlayer insulating film 27 are repeatedly reflected and absorbed, and the readout light L Is partially on the p-type Si substrate 11 In order not to reach the MOSFET14 side provided, it is possible to suppress the generation of light leakage in the MOSFET14 by part of the read light L.

  FIG. 12 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 device 10D according to the third embodiment of the present invention shown in FIG. 12 is a combination of the metal light-shielding films in the reflective liquid crystal display devices 10B and 10C according to the first and second embodiments of the present invention described above. Only the differences from the first and second embodiments will be described briefly.

  In the third embodiment, a second metal light shielding film 37 is formed on the first metal film 26 via a light shielding insulating film 36 as in the second embodiment, and the first metal is formed in the same manner as in the first embodiment. A third metal light shielding film 39 is formed on the light shielding film (second metal film) 28 via a light shielding insulating film 38, and the third metal light shielding film 39 is formed between adjacent first metal light shielding films 28. The opened opening 28a is covered.

  The first, second, and third metal light shielding films 28, 37, and 39 are not named in the order of film formation, but are the same as the first and second metal light shielding films corresponding to the same positions as in the first and second embodiments. A different number is assigned to the third metal light-shielding film corresponding to the same position as in the first embodiment.

At this time, the light shielding insulating film 36 and the light shielding insulating film 38 are formed to a thickness of 400 nm or less using SiO _2, SiN, or SiON. The second metal light-shielding film 37 and the third metal light-shielding film 39 are formed with a film thickness in the range of 50 nm to 200 nm using TiN or Ti or TiN / Ti having a low reflectance.

  In the third 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 in the second via hole Via2 is used. The first metal light-shielding film 28, the second metal light-shielding film 37, and the first metal film 26 are electrically connected, and the reflection pixel electrode (third metal film) 30 is replaced with the first metal light-shielding film (second metal film). When the third via hole Via3 for connection is formed, the reflective pixel electrode 30, the third metal light shielding film 39, and the first metal light shielding film 28 are electrically connected by tungsten or aluminum in the third via hole Via3. Connected to. Therefore, in the third embodiment, the step of forming the via hole can be reduced by one step compared to the conventional example 2, and can be accommodated in the three steps of the first to third via holes Via1 to Via3.

  By the above, generation | occurrence | production of the light leak in MOSFET14 by a part of read-out light L for color images can be suppressed further than Example 1,2. Of course, in the third embodiment, as in the first embodiment, in addition to the storage capacitor portion C1 formed on the p-type Si substrate 11, the first metal light shielding film (second metal film) 28 and the third metal light shielding film. 39 also functions as a storage capacitor, so that storage capacitor portions C2 and C3 are formed between the left and right sides of the third via hole Via3. As a result, the total storage capacitance value at the three locations can be set larger than that in the conventional example 1 by the storage capacitance portions C1 to C3 at the total of three locations, so that the fluctuation of the potential of the reflective pixel electrode 30 is reduced. This is advantageous for flicker and burn-in.

  Even if a metal light-shielding film of at least two layers or more is provided between the p-type Si substrate 11 and the reflective pixel electrode 30 from the first to third embodiments described above with an insulating film interposed between the upper and lower sides, The number of formation steps can be reduced by one step compared to the conventional example 2, and one MOSFET 14 and the storage capacitor portions C1 to C3 (or C1) and one can be formed through the metal film in which the metal light shielding film is formed above and below when forming the via hole. It can be connected to the reflection pixel electrode 30 and the holding capacitance value for one MOSFET 14 can be set large.

  Here, in the first embodiment described above with reference to FIGS. 4 and 5A and 5B, the first metal light-shielding film (second metal film) 28 is provided above the first metal light-shielding film 32 via the light-shielding insulating film 32. When the two-metal light-shielding film 33 is formed, or in the second embodiment described above with reference to FIG. 11, the second metal light-shielding film 37 is formed above the first metal film 26 via the light-shielding insulating film 36. In the third embodiment described above with reference to FIG. 12, the second metal light shielding film 37 is formed above the first metal film 26 via the light shielding insulating film 36 and the first metal light shielding is performed. When the third metal light shielding film 39 is formed above the film (second metal film) 28 via the light shielding insulating film 38, the second metal light shielding film 33, the second metal light shielding film 37, or the third metal light shielding film 37 described above. The metal light-shielding film 39 may cause a film formation failure. It is found that the phenomenon shown in FIG. 13 below has occurred, and by taking measures as shown in FIG. 14 or FIG. 33, the formation failure of the second metal light shielding film 37 or the third metal light shielding film 39 could be solved.

FIG. 13 is a diagram schematically showing a case where a metal light-shielding film causes film formation failure when a metal light-shielding film is formed over the metal film via a light-shielding insulating film.
FIG. 14 is a diagram schematically showing one embodiment in which a metal light-shielding film formed over a metal film via a light-shielding insulating film is improved.
FIG. 15 is a view schematically showing another embodiment in which a metal light shielding film formed over a metal film via a light shielding insulating film is improved.

  For example, in the first embodiment, the first metal light shielding film (second metal film) 28 and the first metal film 26 positioned below the reflective pixel electrode (third metal film) 30 described with reference to FIG. In forming the openings 28a and 26a for electrical separation corresponding to one reflective pixel electrode 30 in each of the films 28 and 26, the resolution at the time of exposure in photolithography is set as described later. In order to improve, an antireflection film for lowering the surface reflectance is formed using TiN (titanium nitride).

  More specifically, as described above with reference to FIGS. 5A and 5B, the reflective pixel electrode 30 is formed above the first metal light shielding film (second metal film) 28. A second metal light shielding film 33 for shielding part of the color image readout light L that has entered the third interlayer insulating film 29 from the opening 30a (FIG. 4) is formed through the light shielding insulating film 32. At this time, an antireflection film 31 is formed on the first metal light-shielding film (second metal film) 28 with a film thickness of about 30 nm using TiN (titanium nitride).

  Here, as shown in FIG. 13, the reason why the antireflection film 31 is formed on the first metal light-shielding film (second metal film) 28 will be described. The antireflection film 31 is formed by the photolithography method. This is necessary for forming the opening 28a in the metal light shielding film 28 with high dimensional accuracy.

  In a normal case, a photoresist (not shown) is applied on the first metal light shielding film 28 without forming the antireflection film 31 on the first metal light shielding film (second metal film) 28, and this photo A photomask is placed on the resist, and exposure / development is performed from above the photomask using a photolithography method to form a photoresist pattern (opening) on the photoresist. Thereafter, when dry etching is performed from the first metal light shielding film 28 exposed from the photoresist pattern (opening) to the second interlayer insulating film 27, an opening 28a is formed in the first metal light shielding film 28. . At this time, the exposure light is transmitted in the thickness direction of the photoresist pattern and reaches the first metal light-shielding film 28, causing irregular reflection in the first metal light-shielding film 28 and expanding the exposure area. For this reason, a photoresist pattern with good dimensional accuracy cannot be formed. Accordingly, the opening 28a in the first metal light shielding film 28 has poor dimensional accuracy.

  Therefore, as a measure against the above, the opening 28a in the first metal light shielding film (second metal film) 28 was formed as follows.

  First, a photoresist is applied on the antireflection film 31 formed on the first metal light shielding film 28.

  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 28 to the second interlayer insulating film 27, it is reflected in the first metal light-shielding film 28. An opening 28 a wider than the opening 31 a in the prevention film 31 is formed concentrically.

  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, the antireflection film 31 using TiN (titanium nitride) and the first metal light-shielding film (second metal film) 28 using aluminum are different from each other in the etching gas. The cross-sectional shape of the opening 28a formed in the first metal light-shielding film 28 after the etching is as shown in the figure, that is, the antireflection film 31 is at an upper portion in the opening 28a 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 32 is formed with a thickness of 400 nm or less on the antireflection film 31 using SiO ₂ , and TiN (titanium nitride) and / or Ti (titanium) is further formed on the light shielding insulating film 32. ) Is used to form the second metal light-shielding film 33 substantially along the opening 28a formed in the first metal light-shielding film 28 via the light-shielding insulating film 32. At this time, since the “lower part of the eaves” of the antireflection film 31 projecting in the “eave shape” at the upper portion in the opening 28a becomes a shadow, the light shielding insulation is formed in the opening 28a. Since the film 32 and the second metal light-shielding film 33 are not normally formed, the second metal light-shielding film 33 comes into contact with the first metal light-shielding film 28 in the opening 28a and is short-circuited. As a result, defects such as adjacent reflection pixel electrodes 30 (FIG. 4) are short-circuited or formation of the storage capacitor portions C2 and C3 described earlier with reference to FIG. 7B becomes difficult. It has been found that this may occur.

  Therefore, as shown in FIG. 14, a photoresist is applied on the antireflection film 31 'formed on the first metal light-shielding film (second metal film) 28, and the photolithography method is used to apply the photoresist onto the photoresist. When dry etching is performed from the antireflection film 31 ′ to the second interlayer insulating film 27 through the first metal light-shielding film 28 after forming the photoresist pattern (opening), the above-described case of FIG. Similarly to the above, after the dry etching, the antireflection film 31 ′ protrudes in an “eave shape” at the upper portion in the opening 28 a formed in the first metal light shielding film (second metal film) 28. After completion of the etching, all of the antireflection film 31 ′ formed on the first metal light shielding film 28 is removed. At this time, even if all of the antireflection film 31 ′ is removed, part of the intrusion light of the readout light L can be shielded by the second metal light shielding film 33 formed thereon via the light shielding insulating film 32. It will not cause any trouble.

Here, when the antireflection film 31 ′ using TiN (titanium nitride) is removed by dry etching, CF ₄ and O ₂ gases are introduced in a vacuum atmosphere to generate RF plasma. At this time, the film thickness of the antireflection film 31 ′ is approximately 30 nm as described above, and faces the opening 28 a formed below the first metal light shielding film 28 and formed in the first metal light shielding film 28. The thickness of the second interlayer insulating film 27 is about 1000 nm, and the etching rates of the antireflection film 31 ′ and the second interlayer insulating film 27 are substantially the same, so that the antireflection film 31 ′ is about 30 nm. When the second interlayer insulating film 27 facing the opening 28a is etched by about 30 nm, the thickness is only about 970 nm when the etching is performed.

Thereafter, on the first metal light-shielding film 28 from which all of the antireflection film 31 ′ has been removed, a light-shielding insulating film 32 is formed with a film thickness of 400 nm or less using SiO ₂ , and further on the light-shielding insulating film 32. If the second metal light-shielding film 33 is formed using TiN (titanium nitride) and / or Ti (titanium), the second metal light-shielding film 33 is in the first metal light-shielding film 28 via the light-shielding insulating film 32. The film is normally formed substantially along the opening 28a formed in the step. Thereafter, the second metal light shielding film 33 is electrically separated into a plurality corresponding to the plurality of reflective pixel electrodes (third metal film) 30, and one separated second metal light shielding film 33 is first shown in FIG. As described with reference to FIG. 5 (a) or FIG. 5 (b), the via hole Via3 formed in one reflective pixel electrode 30 is electrically separated above and through the third interlayer insulating film 29. Connected.

  As a result, the second metal light-shielding film 33 is free from the phenomenon of being short-circuited by contacting the first metal light-shielding film 28 in the opening 28a formed in the first metal light-shielding film (second metal film) 28. As a result, the reflective pixel electrode 30 (FIG. 4) and the COM voltage are not short-circuited, and the second metal light-shielding film 33 and the first metal light-shielding film as described above with reference to FIG. 7B. The storage capacitor portions C2 and C3 can also be formed normally between the film (second metal film) 28.

  In Example 1, as shown in FIG. 4, no metal light-shielding film is formed above the first metal film 26. Therefore, the first metal film 26 is formed to reduce the surface reflectance during exposure. The formed antireflection film (not shown) may not be removed.

  In accordance with the above, when the second metal light-shielding film 37 is formed above the first metal film 26 via the light-shielding insulating film 36 in the second embodiment described above with reference to FIG. The second metal light shielding film 37 is formed above the first metal film 26 via the light shielding insulating film 36 and above the first metal light shielding film (second metal film) 28 in the third embodiment described using FIG. In the case where the third metal light-shielding film 39 is formed through the light-shielding insulating film 38, the same operation as in the first embodiment may be performed.

  When the antireflection film 31 ″ formed on the first metal light shielding film (second metal film) 28 is desired to remain, it is formed in the first metal light shielding film 28 as shown in FIG. If the antireflection film 31 '' of the opening peripheral portion 31b located around the opening 28a is patterned with a photoresist and only the opening peripheral portion 31b of the antireflection film 31 '' is removed by the dry etching, the second portion is obtained. The metal light shielding film 33 is normally formed substantially along the opening 28 a formed in the first metal light shielding film 28 via the light shielding insulating film 32. Thereafter, the second metal light shielding film 33 is electrically separated into a plurality corresponding to the plurality of reflective pixel electrodes (third metal film) 30, and one separated second metal light shielding film 33 is first shown in FIG. As described with reference to FIG. 5 (a) or FIG. 5 (b), the via hole Via3 formed in one reflective pixel electrode 30 is electrically separated above and through the third interlayer insulating film 29. Connected.

  As a result, the second metal light-shielding film 33 is free from the phenomenon of short-circuiting the first metal light-shielding film 28 in contact with the first metal light-shielding film 28 in the opening 28a formed in the first metal light-shielding film (second metal film) 28. As a result, the reflective pixel electrode 30 (FIG. 4) and the COM voltage are not short-circuited, and the second metal light-shielding film 33 and the first metal light-shielding film as described above with reference to FIG. 7B. The holding capacitor portions C2 and C3 can be normally formed between the film (second metal film) 28, and in this case, a masking step for the antireflection film 31 ″ is added to the case shown in FIG. However, the antireflection film 31 ″ other than the removed part can maintain the antireflection function for part of the intrusion light of the readout light L.

  The manufacturing process in the case shown in FIG. 14 or FIG. 15 will be briefly described. The antireflection film 31 is provided for each layer on the plurality of metal films 28 (26) located below the plurality of pixel electrodes 30 for reflection. After depositing '(31 ″), a step of applying a photoresist on the antireflection film 31 ′ (31 ″); and after forming an opening in the photoresist using a photolithography method, antireflection Etching is performed from the film 31 ′ (31 ″) until reaching the interlayer insulating film 27 (25), so that the metal film 28 (26) is wider than the opening 31 a in the antireflection film 31 ′ (31 ″). The step of forming the opening 28a (26a) concentrically and the antireflection film 31 ′ formed on the metal film 28 (26) of at least one layer are all removed, or the metal film 28 (26 ) Opening 28 (26a) The step of removing the antireflection film 31 ″ in the peripheral portion 31b around the opening, the upper portion of the metal film 28 (26) of at least one layer and the opening 28 (26a) of the metal film 28 (26). The reflective liquid crystal display device 10B (10C, 10D) can be satisfactorily manufactured by the step of forming the metal light shielding film 33 (37, 39) through the insulating film 32 (36, 38).

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 drive 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. 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. 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 inside of a 3rd via hole is formed with tungsten, (b) is the figure which showed the case where the inside of a 3rd via hole was formed with aluminum wiring. . 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. 4 in a plane. In the reflective liquid crystal display device of Example 1 according to the present invention, it is a cross-sectional view for explaining the formation of a storage capacitor for one switching element, (a) shows the case of Conventional Example 1 as a comparative example, (B) is the figure which showed the case of this invention. In the reflective liquid crystal display device of Example 1 according to the present invention, it is a diagram for explaining the reflectance of the light shielding insulating film formed on the first metal light shielding film (second metal film) / antireflection film. . (A)-(d) is sectional drawing which showed the 1st process-the 4th process in order in the manufacturing method of the reflection type liquid crystal display device of Example 1 which concerns on this invention. (A)-(c) is sectional drawing which showed the 5th process-the 7th process in order in the manufacturing method of the reflection type liquid crystal display device of Example 1 which concerns on this invention. 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. It is the figure which showed typically the case where a metal light shielding film raise | generates the film-forming defect, when forming a metal light shielding film above the metal film through the light shielding insulating film. It is the figure which showed typically one form which improved the film-forming defect of the metal light shielding film formed into a film through the insulating film for light shielding above a metal film. It is the figure which showed typically the other form which improved the film-forming defect of the metal light shielding film formed into a film through the insulating film for light shielding above a metal film.

Explanation of symbols

10B: Reflective liquid crystal display device of Example 1 according to the present invention,
10C: Reflective liquid crystal display device of Example 2 according to the present invention,
10D: Reflective type 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 ... 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),
31 ... Antireflection film, 31a ... Opening, 31b ... Opening peripheral part,
32. Insulating film for light shielding,
33, 33 ', 33''... the second metal light-shielding film of Example 1,
34 ... Antireflection film, 35 ... Tungsten,
36 ... light-shielding insulating film, 37 ... second metal light-shielding film of the second and third embodiments,
38 ... insulating film for light shielding, 39 ... third metal light shielding film of Example 3,
41 ... Liquid crystal, 42 ... Transparent counter electrode, 43 ... Transparent substrate (glass substrate),
70: Active matrix drive 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,
Via 1 to Via 3... First to third via holes.

Claims (6)

A semiconductor substrate; a drive circuit portion provided on the semiconductor substrate; a conductive first light shielding film provided above the drive circuit portion; and a conductivity provided above the first light shielding film. a second light-shielding film, and a driving substrate having a plurality of pixel electrodes of the light reflective provided Matricaria box-shaped above the second light shielding film,
A light transmissive substrate having a light transmissive electrode disposed opposite to the pixel electrode with a predetermined gap;
Liquid crystal sealed in the predetermined gap and driven for each pixel electrode by the drive circuit unit;
With
The plurality of pixel electrodes are electrically insulated from each other by a first opening provided between the plurality of pixel electrodes,
The first light shielding film is surrounded by a second opening provided in a range that does not face the first opening for each pixel electrode, and is electrically connected to the drive circuit portion. And a second region provided outside the second opening and electrically insulated from the first region,
It said second light-shielding film, among the second opening are electrically isolated for each of the pixel electrode and the third opening provided in a range that does not face Rutotomoni, region corresponding to the pixel electrode It is provided in
Wherein the pixel electrode and the previous SL said first region of the first light shielding film, through the electrically connected via hole in said second light-shielding film as well as through the second light shielding film, the pixel reflection type liquid crystal display device characterized by being connected thereto respectively electrical manner for each electrode.   2. The reflective liquid crystal according to claim 1, wherein the second light shielding film includes a titanium (Ti) film, a titanium nitride (TiN) film, or a laminated film in which the titanium film and the titanium nitride film are laminated. Display device.   2. The reflective liquid crystal display device according to claim 1, further comprising a capacitor portion in which a gap between the first light shielding film and the second light shielding film is filled with a dielectric material.   4. The reflective liquid crystal display device according to claim 3, wherein the dielectric material includes silicon nitride (SiN) or silicon nitride oxide (SiON). Reflection type liquid crystal display device according to claim 1, characterized in that said first light shielding film and the second light-shielding film and spacing than 400 n m. A film stack in which an antireflection film, a first insulating film, a conductive second light-shielding film, and a second insulating film are sequentially stacked on a conductive first light-shielding film provided above the semiconductor substrate. Process,
After the film stacking step, a hole is formed through the second insulating film, the second light shielding film, the first insulating film, and the antireflection film to expose the first light shielding film. Hole formation process;
After the hole forming step, a hole conductive member connecting step of filling the hole with a conductive member and electrically connecting the first light shielding film and the second light shielding film with the conductive member ;
After the hole conductive member connecting step, a light reflective pixel electrode electrically connected to the conductive member is formed on the second insulating film, and the pixel electrode, the second light shielding film, A pixel electrode forming step of electrically connecting the first light-shielding film with the conductive member;
A method for producing a reflective liquid crystal display device, comprising:

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