JP2008300865A - Method of manufacturing semiconductor device, semiconductor manufacturing apparatus used for the method, and liquid-crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid-crystal display device manufactured by activating impurity ions at a relatively low temperature. <P>SOLUTION: A glass substrate 2 on which a silicon oxide film 12 is formed is directly placed on a stage 55a with the rear-side surface of the glass substrate 2 downside. A second harmonic wave of a Nd:YAG laser as a laser beam is applied to the placed glass substrate 2 from the front-side surface obliquely with respect to the surface of the glass substrate 2 by an optical system. A part of the applied laser beam passes through a polysilicon film 6a and is reflected by the rear-side surface of the glass substrate 2, and a part thereof is applied to the polysilicon film 6a. The remaining component of the laser beam passes through the glass substrate 2 and is reflected by the mirror surface of the stage 55a, and a part thereof is applied to the polysilicon film 6a. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a semiconductor device, a semiconductor manufacturing device used therefor, and a liquid crystal display device, and more particularly, a method for manufacturing a semiconductor device including a step for activating implanted impurity ions, and a method used for the method. The present invention relates to a semiconductor manufacturing apparatus and a liquid crystal display device obtained by such a method of manufacturing a semiconductor device.

  In a semiconductor device having a function of displaying an image typified by a liquid crystal display or the like, a plurality of thin film transistors are formed on an insulating substrate for pixel switching. Therefore, as an example of a conventional method for manufacturing a semiconductor device, a method for manufacturing a semiconductor device disclosed in Patent Document 1 will be described.

  First, a two-layer film of a silicon nitride film and a silicon oxide film is formed as a base film on a glass substrate as an insulating substrate, for example, by PECVD (Plasma Enhanced Chemical Vapor Deposition). Next, an amorphous silicon film is formed on the base film. By irradiating the amorphous silicon film with a predetermined laser beam, the amorphous silicon film is crystallized to become a polysilicon film.

  Next, a predetermined resist pattern is formed on the polysilicon film, and the polysilicon film is etched using the resist pattern as a mask, thereby patterning the portions of the polysilicon film that will become the source region, the channel region, and the drain region. Is done. Next, predetermined impurity ions for controlling the threshold voltage of the thin film transistor are implanted into the polysilicon film portion.

  A silicon oxide film serving as a gate insulating film is formed on the glass substrate so as to cover the portion of the polysilicon film. A gate electrode is formed on the silicon oxide film. Next, a gate insulating film is formed on the base film so as to cover the polysilicon film portion. A gate electrode is formed on the gate insulating film.

  Next, impurity ions of a predetermined conductivity type for forming a source region and a drain region having an LDD (Lightly Doped Drain) structure are implanted into the polysilicon film portion using the gate electrode and a predetermined resist pattern as a mask. Next, by irradiating laser light, the impurities implanted into the polysilicon film portion are activated. In this way, a thin film transistor including source / drain regions and a gate electrode is formed.

Next, an interlayer insulating film is formed so as to cover the thin film transistor. Contact holes are formed in the interlayer insulating film to expose the surfaces of the source region and the drain region. A predetermined wiring electrode is formed so as to fill the contact hole. Thereafter, a silicon oxide film and a silicon nitride film are formed so as to cover the wiring electrodes. In this way, the main part of the thin film transistor in the semiconductor device is formed.
JP-A-10-74952

  However, the conventional method for manufacturing a semiconductor device has the following problems. As described above, after the impurity ions of a predetermined conductivity type for forming the source region and the drain region are implanted in the polysilicon film portion, the excimer laser (XeCl) is irradiated as the laser beam to thereby remove the polysilicon. Impurity ions implanted into the film portion are activated.

  Alternatively, the impurity ions are activated by performing an annealing process at a predetermined temperature instead of irradiating the laser beam.

  When the impurity ions are activated by irradiating the excimer laser light, the laser light is absorbed by the polysilicon film even after the activation, so that if the intensity of the laser light is higher than a predetermined intensity, the polysilicon is absorbed. Remelting of the film occurs. Therefore, it is necessary to set the intensity of the laser light between the intensity necessary for activation (minimum crystallization energy) and the intensity at which remelting occurs (microcrystallization start energy), and it is difficult to control the laser light. was there.

  On the other hand, when impurity ions are activated by performing annealing treatment, the substrate expands and contracts greatly, and a magnification error occurs during patterning. Therefore, it is necessary to heat treat the substrate in advance. It was a factor that hindered improvement of sex.

  The present invention has been made to solve the above problems, and one object thereof is to provide a method of manufacturing a semiconductor device in which impurity ions can be activated at a relatively low temperature. Another object is to provide a liquid crystal display device manufactured by such a method for manufacturing a semiconductor device.

  A manufacturing method of a semiconductor device according to the present invention includes the following steps. A base insulating film serving as a base is formed on the main surface of the substrate. A semiconductor film is formed in a predetermined region on the surface of the base insulating film. The semiconductor film is crystallized and subjected to predetermined patterning. An insulating film is formed on the substrate so as to cover the patterned semiconductor film. An electrode portion is formed on the portion of the insulating film located immediately above the patterned semiconductor film. Using the electrode portion and a predetermined resist pattern as a mask, impurity ions of a predetermined conductivity type are introduced into the patterned semiconductor film with a gap. By irradiating the patterned semiconductor film into which the impurity ions are introduced with laser light of the second harmonic of the Nd: YAG laser, the impurity ions are activated. The activation step of activating the impurity ions includes a step of directly placing the substrate on a predetermined stage and irradiating the patterned semiconductor film with laser light from the side where the electrode portion is formed. .

  Another semiconductor device manufacturing method according to the present invention includes the following steps. A base insulating film serving as a base is formed on the main surface of the substrate. A semiconductor film is formed in a predetermined region on the surface of the base insulating film. The semiconductor film is crystallized and subjected to predetermined patterning. An insulating film is formed on the substrate so as to cover the patterned semiconductor film. An electrode portion is formed on the portion of the insulating film located immediately above the patterned semiconductor film. Using the electrode portion and a predetermined resist pattern as a mask, impurity ions of a predetermined conductivity type are introduced into the patterned semiconductor film with a gap. By irradiating the patterned semiconductor film into which the impurity ions are introduced with laser light of the second harmonic of the Nd: YAG laser, the impurity ions are activated. The activation step of activating the impurity ions includes a step of irradiating the patterned semiconductor film with laser light from the side of the substrate opposite to the side where the electrode portion is formed.

  The semiconductor manufacturing apparatus according to the present invention includes a stage, an irradiation optical system, and a control unit. The substrate is directly placed on the stage. The irradiation optical system includes a predetermined laser light source for irradiating the substrate with laser light from at least one of the front surface side and the back surface side of the substrate held on the stage. The control unit controls the irradiation optical system.

  The liquid crystal display device according to the present invention includes a substrate having a main surface and a thin film transistor. As the substrate, a substrate that does not require heat treatment applied in advance to prevent deformation due to a thermal history during manufacture is used.

  According to the semiconductor device manufacturing method of the present invention, the second harmonic of the Nd: YAG laser is used as the laser beam to activate the impurity ions, so that the thin film transistor As a result, it is possible to significantly suppress the temperature rise of the substrate on which the impurity ions are formed, and to activate the impurity ions at a relatively low temperature. Further, compared with the case where activation is performed using an excimer laser, the absorption rate of laser light in the crystallized semiconductor film is low, the margin of the energy range necessary for activation is increased, and the process is stabilized.

  According to another method of manufacturing a semiconductor device according to the present invention, by using the second harmonic of an Nd: YAG laser as laser light, impurity ions can be activated at a relatively low temperature, and the laser can be activated. By irradiating the semiconductor film with light from the side of the substrate opposite to the side where the electrode portion is formed, the entire semiconductor film is irradiated with laser light, and the impurity ions can be activated efficiently. it can. Further, compared with the case where activation is performed using an excimer laser, the absorption rate of laser light in the crystallized semiconductor film is low, the margin of the energy range necessary for activation is increased, and the process is stabilized.

  The semiconductor manufacturing apparatus according to the present invention has a stage on which the substrate is directly placed, and therefore, compared to the case where the substrate is installed with a predetermined interval between the substrate and the stage. The configuration of the apparatus can be simplified.

  In addition, when activation is performed by annealing at the time of manufacturing a liquid crystal display device, it is necessary to heat-treat the substrate in advance in order to prevent deformation of the substrate, whereas when activation is performed by laser light. In the liquid crystal display device according to the present invention, it is possible to use a substrate that does not require a heat treatment applied in advance to prevent deformation due to a thermal history during manufacture. Thereby, it is not necessary to heat-treat the substrate in advance in order to prevent deformation of the substrate, and the number of processes can be reduced.

Example 1
A method for manufacturing a semiconductor device according to Embodiment 1 of the present invention will be described.

  First, as shown in FIG. 1, a two-layer film of a silicon nitride film 3 and a silicon oxide film 4 is formed as a base film on a glass substrate 2 as a substrate, for example, by PECVD. Next, as shown in FIG. 2, an amorphous silicon film 5 is formed on the silicon oxide film 4. By irradiating the amorphous silicon film 5 with a predetermined laser beam, the amorphous silicon film 5 is crystallized into a polysilicon film 6 as shown in FIG.

  Next, as shown in FIG. 4, a predetermined resist pattern 7 is formed on the polysilicon film 6. By etching the polysilicon film 6 using the resist pattern 7 as a mask, portions of the polysilicon film 6a to be a source / drain region and a channel region are patterned as shown in FIG. Thereafter, the resist pattern 7 is removed.

  Next, as shown in FIG. 6, impurity ions of a predetermined conductivity type for forming a channel region are implanted into the polysilicon film 6a. Next, as shown in FIG. 7, a silicon oxide film 9 serving as a gate insulating film is formed on the silicon oxide film 4 so as to cover the polysilicon film 6a.

  Next, as shown in FIG. 8, a chromium film 10 serving as a gate electrode is formed on the silicon oxide film 9. Next, as shown in FIG. 9, a predetermined resist pattern 11 for patterning the gate electrode is formed on the chromium film 10. By etching the chromium film 10 using the resist pattern 11 as a mask, the gate electrode 10a is formed. At this time, the width of the gate electrode 10 a is shorter than the width of the resist pattern 11.

  By implanting impurity ions of a predetermined conductivity type into polysilicon film 6a using resist pattern 11 as a mask, a pair of impurity regions 66aa and 66ab having a relatively high impurity concentration are formed. A channel region 6ac is formed in the portion of the polysilicon film 6a sandwiched between the pair of impurity regions 66aa and 66ab. Thereafter, the resist pattern 11 is removed.

  Next, as shown in FIG. 10, a pair of impurity regions 67aa and 67ab having a relatively low impurity concentration are formed by implanting impurity ions of a predetermined conductivity type into the polysilicon film 6a using the gate electrode 10a as a mask. The

  Thus, a pair of source / drain regions 6aa and 6ab having an LDD (Lightly Doped Drain) structure is formed. Next, as shown in FIG. 11, a silicon oxide film 12 is formed on the silicon oxide film 9 so as to cover the gate electrode 10a.

  Next, activation of impurity ions in source / drain regions 6aa and 6ab is performed. Laser light is used to activate the impurity ions. First, a laser beam irradiation apparatus for activating impurity ions will be described.

  As shown in FIG. 12, the laser beam irradiation device 51 includes a stage 55a on which the glass substrate 2 is placed, and a glass substrate from the surface side (side on which the thin film transistor is formed) of the glass substrate 2 placed on the stage 55a. 2 is provided with a light source 52 and an optical system 54 for irradiating a laser beam toward the light source 2, and a controller 53 for controlling the light source 52 and the like including an incident angle.

  As a laser beam, a second harmonic (wavelength of 532 nm) of an Nd: YAG (Neodymium: Yttrium Aluminum Garnet) laser is used. The surface of the stage 55a has a mirror finish. Here, the mirror surface means that the surface roughness (unevenness) of the stage 55a is substantially shorter than the wavelength 532 nm of the second harmonic of the Nd: YAG laser.

  Next, an impurity ion activation process using the laser beam irradiation apparatus described above will be described. As shown in FIG. 13, the glass substrate 2 on which the silicon oxide film 12 is formed is directly placed on the stage 55a with the back side of the glass substrate 2 (the side opposite to the side where the thin film transistor is formed) facing down. Is done.

  The optical system 54 irradiates the glass substrate 2 placed on the stage 55a from the front side surface with a predetermined incident angle. That is, the laser beam is irradiated obliquely with respect to the surface of the glass substrate 2.

At this time, the incident angle is preferably set to 45 ° or more as will be described later. As an example of irradiation conditions, the half-width in the minor axis direction is about 40 to 60 μm, the major axis length is about 100 nm, the scanning speed is 3 mm / sec, and the energy density is about 400 mJ / cm ² . The half-value width means a width at half the intensity of the strongest intensity.

  A part of the irradiated laser light passes through the polysilicon film 6a and the like and is reflected on the back surface of the glass substrate 2 at the same angle (reflection angle) as the incident angle. The reflected laser light is transmitted through the glass substrate 2, and a part thereof is irradiated to the polysilicon film 6a.

  On the other hand, the remaining components of the laser light are transmitted through the glass substrate 2 and reflected by the surface of the stage 55a. At this time, since the surface of the stage 55a is a mirror surface, the laser light transmitted through the glass substrate 2 in this part is reflected on the surface of the stage 55a at the same reflection angle as the incident angle. The reflected laser light is transmitted through the glass substrate 2, and a part thereof is irradiated to the polysilicon film 6a.

  In this way, the impurity ions implanted by irradiating the polysilicon film 6a with the laser light are activated. The activation in this specification means that the impurity ions are electrically activated by applying energy higher than the binding energy between the implanted impurity ion species and silicon (Si).

  Next, as shown in FIG. 14, contact holes 12 a and 12 b exposing the surfaces of the source / drain regions 6 aa and 6 ab are formed in the silicon oxide films 12 and 9. Next, as shown in FIG. 15, source / drain electrodes 13a and 13b electrically connected to the source / drain regions 6aa and 6ab are formed to fill the contact holes 12a and 12b, respectively.

  Thereafter, as shown in FIG. 16, a transparent organic interlayer insulating film 14 is formed on the silicon oxide film 12. In the organic interlayer insulating film 14, a contact hole 14a exposing the surface of the source / drain region 6ab is formed. A pixel electrode 15 made of a transparent conductive film is formed in the contact hole 14 a and on the upper surface of the organic interlayer insulating film 14. An alignment film 16 a is formed so as to cover the pixel electrode 15.

  On the other hand, a color filter 19 is formed on the surface of the glass substrate 20 disposed opposite to the glass substrate 2 on the side facing the glass substrate 2. A counter electrode 18 is formed on the color filter 19. An alignment film 16 b is formed on the counter electrode 18.

  After a predetermined rubbing process is performed so that the liquid crystal is aligned, the glass substrate 20 is disposed so as to face the glass substrate 2, and the liquid crystal is injected into the gap between the glass substrate 20 and the glass substrate 2 and sealed. Is done. As described above, the semiconductor device is completed as a liquid crystal display device.

  In the semiconductor device manufacturing method described above, in particular, laser light is used to activate impurity ions in the source / drain regions 6aa and 6ab. At this time, the second harmonic (wavelength 532 nm) of the Nd: YAG laser is used as the laser light, and the laser light is irradiated onto the glass substrate 2 from the front side with a predetermined incident angle. In addition, the laser light is irradiated in a state where the glass substrate 2 is directly placed on the stage 55a finished to a mirror surface in the laser irradiation apparatus.

  Thereby, the direction of the laser beam incident on the glass substrate 2, the component of the laser beam reflected on the back surface of the glass substrate 2, and the component of the laser beam transmitted through the glass substrate 2 and reflected on the surface of the stage, respectively. Unlike the traveling direction, the interference between the incident component of the laser beam and the reflected component is suppressed. As a result, the incident laser beam and the reflected laser beam are irradiated to the source / drain regions 6aa and 6ab without interference, and the impurity ions can be activated efficiently.

  Further, since the second harmonic of the Nd: YAG laser is used as the laser light, the ratio of the laser light absorbed by the polysilicon film 6a is lower than that of the excimer laser, and the laser light can be easily controlled. become.

  Furthermore, since the glass substrate 2 is placed directly on the stage, the configuration of the laser light irradiation device is simpler than when the glass substrate is installed with a predetermined gap between the glass substrate and the stage. Can be.

In the above-described embodiment, the energy density value of the irradiated laser beam is about 400 mJ / cm ² , but the energy density value is not limited to this. This will be described using the relationship between energy density and sheet resistance. FIG. 17 shows the energy density of the laser light of the sheet resistance when a silicon film formed on a predetermined substrate and doped with phosphorus ions at 2 × 10 ¹⁵ / cm ² is irradiated with laser light from the back side of the substrate. It is a graph which shows dependence.

As shown in FIG. 17, in the energy density range P2 (about 350 to 550 mJ / cm ² ), the sheet resistance is relatively low and activation is optimally performed. On the other hand, in the energy density range P1 (about ˜350 mJ / cm ² ), as the energy density decreases from 350 mJ / cm ² , the energy required for activation gradually becomes insufficient. At the energy density P3 (about 550 mJ / cm ² ), activation is performed, but the sheet resistance is relatively high due to scattering of the silicon film due to overpower.

Therefore, the energy density of the laser beam for activation is most preferably about 350 to 550 mJ / cm ^2, and considering the structure including the ion implantation amount and each film thickness in the semiconductor device, the energy of the laser beam is considered. A density of about 100 to 1500 mJ / cm ² is considered desirable.

  In the above-described embodiment, it has been described that the incident angle of the laser beam is preferably set to 45 ° or more. This will be described using the relationship between the implanted ion region and the optical path of the laser beam.

  FIG. 18 shows a scattering region 61 of ions implanted from the vicinity of the side wall of the gate electrode 10a and an optical path 62 of laser light incident at an incident angle θ. The incident angle θ of the laser beam may be any angle that can irradiate the ion scattering region 61 located in the polysilicon film 6a immediately below the gate electrode 10a.

Particularly in this case, by setting the incident angle θ to 45 ° or more from the structure of the gate electrode 10a, the silicon oxide film (gate insulating film) 9 and the polysilicon film 6a, the polysilicon film immediately below the gate electrode 10a is formed. It can be seen that the ion scattering region located in 6a can be irradiated. Note that the scattering region 61 is a result of simulation.
(Example 2)
Here, a case where impurity ions are activated using a laser beam irradiation apparatus including a stage on which a surface on which a glass substrate is placed is a scattering surface will be described as an example.

  First, after performing the same steps as those shown in FIGS. 1 to 12, the impurity ions in the source / drain regions are activated. Here, a laser beam irradiation apparatus for activating impurity ions will be described.

  As shown in FIG. 19, the laser beam irradiation device 51 includes a stage 55b on which the glass substrate 2 is placed, and a glass substrate from the surface side (side on which the thin film transistor is formed) of the glass substrate 2 placed on the stage 55b. 2, a light source 52 for irradiating laser light toward the optical system 54, an optical system 54, a control unit 53 for controlling the light source 52 and the like are provided.

  The surface of the stage 55b is a scattering surface. The scattering surface means that the surface roughness (unevenness) of the stage 55b is substantially larger than the wavelength 532 nm of the second harmonic of the Nd: YAG laser.

  Next, an impurity ion activation process using the laser beam irradiation apparatus described above will be described. As shown in FIG. 20, the glass substrate 2 on which the silicon oxide film 12 is formed is directly placed on the stage 55b with the back side of the glass substrate 2 (the side opposite to the side where the thin film transistor is formed) facing down. Is done.

  The optical system 54 irradiates the surface of the glass substrate 2 obliquely with respect to the glass substrate 2 placed on the stage 55b from the front surface. As in the case described above, the incident angle is desirably set to 45 ° or more. However, since the incident angle is scattered by the stage 55b, the incident angle is not particularly limited, and is substantially perpendicular to the glass substrate 2. Laser light may be irradiated.

  A part of the irradiated laser light passes through the polysilicon film 6a and the like and is reflected on the back surface of the glass substrate 2 at the same angle (reflection angle) as the incident angle. The reflected laser light is transmitted through the glass substrate 2, and a part thereof is irradiated to the polysilicon film 6a.

  On the other hand, the remaining components of the laser light are transmitted through the glass substrate 2 and reflected by the surface of the stage 55b. At this time, since the surface of the stage 55b is a scattering surface, the laser light transmitted through the glass substrate 2 is reflected in all directions on the glass substrate 2 side. The reflected laser light is transmitted through the glass substrate 2, and a part thereof is irradiated to the polysilicon film 6a.

  In this way, the impurity ions implanted by irradiating the polysilicon film 6a with the laser light are activated. Thereafter, the semiconductor device is completed as a liquid crystal display device through steps similar to those shown in FIGS.

  In the semiconductor device manufacturing method described above, as in the case described above, when activating impurity ions in the source / drain regions 6aa and 6ab, laser light is irradiated from the front side with a predetermined incident angle. Thereby, the direction in which the laser light entering the glass substrate 2 travels is different from the direction in which the component of the laser light reflected on the back surface of the glass substrate 2 travels, and interference between the component incident to the laser light and the reflected component Is suppressed, and control of the laser beam is facilitated.

  In addition, when the glass substrate 2 is directly placed on the stage 55b having a scattering surface, the laser light component transmitted through the glass substrate 2 is irradiated on the surface of the stage by being irradiated with laser light. The light is reflected in all directions on the substrate 2 side.

  As a result, the reflected laser light is uniformly irradiated by the source / drain regions 6aa and 6ab, and the impurity ions can be activated more efficiently.

  Further, since the glass substrate 2 is directly placed on the stage 55b, the configuration of the laser irradiation apparatus is simpler than the case where the glass substrate is placed with a predetermined gap between the glass substrate and the stage. Can be.

  In the above-described embodiment, the stage 55b having a scattering surface as an example has been described. However, as shown in FIG. 21, a scattering plate 55bb having a scattering surface formed on a mirror stage 55a is mounted. The stage may be used. In particular, in this case, since the height of the stage becomes higher by mounting the scattering plate 55bb, it is necessary to adjust the focus of the laser beam.

  In each of the above-described embodiments, the laser beam irradiation apparatus configured to irradiate the laser beam with a predetermined incident angle when activating the impurity ions has been described as an example. In addition, as shown in FIG. 22, a laser beam irradiation device 51 in which a scattering plate 56 is disposed between the optical system 54 and the glass substrate 2 placed on the stage 55a may be used.

In this case, the laser light is irradiated and reflected by the scattering plate 56 at many different incident angles with respect to the glass substrate 2. As a result, the reflected laser light is uniformly irradiated by the source / drain regions 6aa and 6ab, and the impurity ions can be activated efficiently.
(Example 3)
Here, a case where laser light is irradiated from the back side of the glass substrate will be described as an example.

  First, after performing the same steps as those shown in FIGS. 1 to 12, the impurity ions in the source / drain regions are activated. Here, a laser beam irradiation apparatus for activating impurity ions will be described.

  As shown in FIG. 23, the laser beam irradiation device 51 includes a stage 55c on which the glass substrate 2 is placed, and the back side of the glass substrate 2 placed on the stage 55c (the side opposite to the side on which the thin film transistor is formed). ) To the glass substrate 2 is provided with a light source 52, an optical system 54, a control unit 53 for controlling the light source 52 and the like.

  Next, an impurity ion activation process using the laser beam irradiation apparatus described above will be described. As shown in FIG. 24, the glass substrate 2 on which the silicon oxide film 12 is formed is placed on the stage 55c with the back side of the glass substrate 2 (the side opposite to the side where the thin film transistor is formed) facing down. The

The optical system 54 irradiates the surface of the glass substrate 2 with a laser beam from the back surface with respect to the glass substrate 2 placed on the stage 55c. At this time, the laser light may be incident on the glass substrate 2 obliquely or vertically. In addition, as an example of irradiation conditions, as in the case described above, the half-width in the short axis direction is about 40 to 60 μm, the long axis length is about 100 nm, the scan speed is 3 mm / sec, and the energy density is about 400 mJ / cm ^2. It is.

  The laser light transmitted through the glass substrate 2 is irradiated to the entire polysilicon film 6a including the channel region 6ac and the source / drain regions 6aa and 6ab.

  In this manner, the impurity ions implanted by the irradiation of the laser beam to the entire polysilicon film 6a are sufficiently activated. Thereafter, the semiconductor device is completed as a liquid crystal display device through steps similar to those shown in FIGS.

  In the semiconductor device manufacturing method described above, laser light is irradiated from the back side of the glass substrate when the impurity ions are activated. Thereby, the entire polysilicon film 6a including the channel region 6ac and the source / drain regions 6aa and 6ab is irradiated with the laser light, and the impurity ions can be activated efficiently.

  In addition, since the glass substrate 2 is directly placed on the stage 55c, the configuration of the laser irradiation apparatus is simpler than when the glass substrate is installed with a predetermined gap between the glass substrate and the stage. It can also be.

  In each of the above-described embodiments, in order to activate impurity ions when forming a thin film transistor of a semiconductor device (liquid crystal display device), the second harmonic (wavelength 532 nm) of an Nd: YAG laser is irradiated as a laser beam. Predetermined activation is performed. By using laser light, the temperature of the glass substrate 2 rises only to about 100 ° C. even if the temperature of the glass substrate 2 is high, compared with the case where activation is performed by annealing treatment, and the temperature rise is greatly suppressed.

  Thereby, a low heat-resistant glass substrate (non-annealed glass substrate) that is not annealed can be used as the substrate. In addition to such a glass substrate, for example, a resin substrate can also be applied. As a result, it is not necessary to heat-treat the substrate in advance, and the productivity can be improved by reducing the number of processes.

  In each of the above-described embodiments, for example, phosphorus can be applied as the impurity ions of the predetermined conductivity type, and boron can be applied as the p-type. For example, boron can be efficiently activated.

  Further, in each of the above-described embodiments, a pair of impurity regions 66aa and 66ab having a relatively high impurity concentration are formed by implanting impurity ions using the resist pattern 11 as a mask in order to form source / drain regions having an LDD structure. Then, the case where a pair of impurity regions 67aa and 67ab having a relatively low impurity concentration is formed by implanting impurity ions using the gate electrode 10a as a mask has been described as an example.

  In addition, after forming a pair of impurity regions 67aa and 67ab having a relatively low impurity concentration by implanting impurity ions using the gate electrode 10a as a mask, a sidewall film formed on the side surface of the gate electrode 10a is formed. A pair of impurity regions 66aa and 66ab having a relatively high impurity concentration may be formed by implanting impurity ions as a mask.

It is sectional drawing which shows 1 process of the manufacturing method of the semiconductor device which concerns on Example 1 of this invention. FIG. 2 is a cross-sectional view showing a step performed after the step shown in FIG. 1 in the same example. FIG. 3 is a cross-sectional view showing a step performed after the step shown in FIG. 2 in the same example. FIG. 4 is a cross-sectional view showing a step performed after the step shown in FIG. 3 in the same example. FIG. 5 is a cross-sectional view showing a step performed after the step shown in FIG. 4 in the same example. FIG. 6 is a cross-sectional view showing a step performed after the step shown in FIG. 5 in the same example. FIG. 7 is a cross-sectional view showing a step performed after the step shown in FIG. 6 in the same example. FIG. 8 is a cross-sectional view showing a step performed after the step shown in FIG. 7 in the same example. FIG. 9 is a cross-sectional view showing a process performed after the process shown in FIG. 8 in the same Example. FIG. 10 is a cross-sectional view showing a step performed after the step shown in FIG. 9 in the same example. FIG. 11 is a cross-sectional view showing a step performed after the step shown in FIG. 10 in the same example. In the Example, it is the schematic which shows the structure of a laser beam irradiation apparatus. FIG. 12 is a cross-sectional view showing a step performed after the step shown in FIG. 11 in the same example. FIG. 14 is a cross-sectional view showing a step performed after the step shown in FIG. 13 in the same example. FIG. 15 is a cross-sectional view showing a step performed after the step shown in FIG. 14 in the same Example. FIG. 16 is a cross-sectional view showing a process performed after the process shown in FIG. 15 in the same Example. In the same Example, it is a graph which shows the relationship between sheet resistance and laser power. In the Example, it is a figure which shows the ion ion scattering area | region and the optical path of a laser beam. It is the schematic which shows the structure of the laser beam irradiation apparatus used for the manufacturing method of the semiconductor device which concerns on Example 2 of this invention. FIG. 4 is a cross-sectional view showing a step of the method of manufacturing a semiconductor device in the example. In the Example, it is the schematic which shows the structure of the laser beam irradiation apparatus which concerns on a modification. In the Example, it is the schematic which shows the structure of the laser beam irradiation apparatus which concerns on another modification. It is the schematic which shows the structure of the laser beam irradiation apparatus used for the manufacturing method of the semiconductor device which concerns on Example 3 of this invention. FIG. 4 is a cross-sectional view showing a step of the method of manufacturing a semiconductor device in the example.

Explanation of symbols

  2,20 glass substrate, 3 silicon nitride film, 4,9,12 silicon oxide film, 5 amorphous silicon film, 6,6a polysilicon film, 7,11 resist pattern, 6aa, 6ab source / drain region, 66aa, 66ab, 67aa, 67ab impurity region, 6ac channel region, 10 chromium film, 10a gate electrode, 12a, 12b, 14a contact hole, 13a, 13b source / drain electrode, 14 organic interlayer insulating film, 15 pixel electrode, 16a, 16b alignment film, 17 liquid crystal, 18 counter electrode, 19 color filter, 51 laser light irradiation device, 52 light source, 53 control unit, 54 optical system, 55a-55c stage, 55bb, 56 scattering plate.

Claims (2)

A substrate having a main surface;
A thin film transistor formed on the main surface of the substrate,
A liquid crystal display device in which a substrate that does not require a heat treatment applied in advance to prevent deformation due to a thermal history during manufacture is used as the substrate.   The liquid crystal display device according to claim 1, wherein the substrate is made of a resin.

Images