KR100538329B1 - Mask and Method of Fabricating Poly Silicon using the same and Liquid Crystal Display with the Poly Silicon and Method of Fabricating the Liquid Crystal Display - Google Patents

Abstract

The present invention relates to a mask for crystallization of amorphous silicon and a method for producing a polysilicon layer using the mask.

Method for producing a polysilicon layer according to the present invention comprises the steps of forming amorphous silicon on a substrate; The first and second transmissive pattern regions intersected with each other and the grain boundaries of polysilicon formed by melting and crystallization of the amorphous silicon in a width smaller than the first and second transmissive pattern regions are disposed. Aligning a mask having third transmission pattern regions on the amorphous silicon; Irradiating a laser beam onto the amorphous silicon through the first and second transmission pattern regions of the mask to induce melting and crystallization of the amorphous silicon to form polysilicon and the laser beam to the third transmission pattern region of the mask Irradiating the grain boundaries of the polysilicon through the above to induce surface oxidation of the grain boundaries.

Description

Mask and method of fabricating a polysilicon using the mask and a method of manufacturing the liquid crystal display device having the polysilicon {Mask and Method of Fabricating Poly Silicon using the same and Liquid Crystal Display with the Poly Silicon and Method of Fabricating the Liquid Crystal Display}

The present invention relates to polysilicon and a liquid crystal display device using the same, and more particularly, to a mask for crystallization of amorphous silicon and a method of manufacturing a polysilicon layer using the mask. The present invention also relates to a liquid crystal display device in which the silicon layer is formed and a method of manufacturing the same.

Silicon is roughly classified into amorphous silicon (Amorphous siliscon) and crystalline silicon (Crystaline silicon) according to the crystalline state.

Amorphous silicon can be deposited as a thin film at a low temperature of less than 350 ℃. Therefore, amorphous silicon is mainly used for thin film transistors (hereinafter referred to as "TFTs") of liquid crystal display devices.

However, it is difficult to apply amorphous silicon to a large screen liquid crystal display device requiring excellent electrical properties due to low mobility of 0.5 cm ² / Vs or less.

In comparison, polysilicon has a high mobility of several tens to hundreds of cm ² / Vs or less. By applying such polysilicon as a semiconductor layer of a TFT, studies are being actively conducted to realize a high quality, large screen liquid crystal display device. In particular, when the polysilicon TFT is applied to the liquid crystal display device, the TFT array substrate and the driving drive integrated circuit in the display area can be integrated together on the substrate.

The electrical properties of polysilicon depend on the size of the grain. In other words, the larger the grain size, the higher the mobility of the polysilicon.

Methods for forming such a polysilicon layer include a method of directly depositing polysilicon and a method of crystallizing the amorphous silicon film into polysilicon after depositing amorphous silicon.

As a method of directly depositing polysilicon on a substrate, Plasma Enhanced Chemical Vapor Deposition (hereinafter referred to as "Plasma Enhanced Chemical Vapor Deposition") is used to deposit polysilicon using a mixed gas of SiF ₄ , SiH ₄ , and H ₂ at a deposition temperature of 400 ° C. or less. "PECVD", etc., but difficult to control the crystal grains, there are many difficulties in applying to the actual liquid crystal display device.

Crystallization of amorphous silicon into polysilicon may be divided into low temperature process and high temperature process according to the process temperature. The high temperature process has the advantage of producing polysilicon with good crystallinity by crystallizing by using furnace and ion implantation at high temperature of 1000 ℃ or higher, but due to high temperature process, The disadvantage is the use of a quartz substrate. Low temperature processes include laser annealing and metal induced crystallization.

Recently, an excimer laser is irradiated to an amorphous silicon thin film to completely melt the thin film, and the sequential lateral solidification method (“SLS”) allows crystals to grow vertically from the side during cooling. This has been proposed. This SLS method is disclosed in International Patent WO0 / 45827 and Korean Laid-Open Patent Publication No. 2001-004129.

1A through 1D illustrate a step-by-step process of converting amorphous silicon to polysilicon using the SLS method.

Referring to FIG. 1A, an amorphous silicon layer 52a is deposited on the substrate 51. In addition, as shown in FIG. 1B, a mask 53 having a transmission pattern in a portion to be converted to polysilicon is aligned on the amorphous silicon layer 52a, and the laser beam 56 passes through the mask 53 to form an amorphous silicon layer ( 52a). The laser beam 56 has a wavelength band of an energy region in which the amorphous silicon layer 52a can be completely melted to an interface in contact with the substrate 51. Therefore, the amorphous silicon layer 52a irradiated with the laser beam 56 is melted as shown in FIG. 1C to change into a liquid state. Thus, the amorphous silicon portion 52b melted by the laser beam 56 is vertically determined at each of the sides from the sides of the solid-state amorphous silicon portion 52a as shown in FIGS. 1D to 1G while the temperature decreases. This is grown and converted to the solid polysilicon layer 52c. The boundary where the crystals growing from both sides meet constitutes a grain boundary 54. This grain boundary 54 lowers the field mobility.

However, as can be seen in FIG. 1G, the highly elevated portion 55 appears at the grain boundary 54. The raised portion 55 is generated due to the difference in density between the liquid material and the solid material. In detail, in the case of silicon, the density of the liquid phase (2.53 g / cm ² ) is about 10% larger than the density of the solid phase (2.30 g / cm ² ). For this reason, about 10% of volume expansion occurs when the liquid silicon melted and exposed to the laser beam 56 becomes a solid phase. Therefore, in the process of obtaining the polysilicon layer 52c by melting the amorphous silicon layer 52a by the SLS method and inducing crystallization from the side surface, when the solid phases are gradually grown along the lateral facing directions in each of the two sides. The grain boundary 54 appears in the middle part of the liquid phase where the solid phases growing in the direction meet, and the surplus portion of the volume expansion rises by mass transfer. The raised portion 55 may lower the electric field mobility and adversely affect the reliability of the device, and may cause insulation breakdown of the device. Therefore, the raised portion 55 should be lowered or removed as much as possible.

As a method for reducing or removing the ridge 55, a method of depositing a separate capping layer on the amorphous silicon layer 52a and performing laser crystallization again has been proposed. It has the disadvantage of reducing the grain size by acting as another nucleation part. In another way, a method of reducing the ridge 55 by controlling a crystallization atmosphere has been proposed, but there is a problem in that a chamber is required and laser crystallization is performed again in the chamber.

Accordingly, an object of the present invention is to provide a mask and a method for producing a polysilicon layer using the mask to lower the raised portion rising from the grain boundary in a simple process.

In addition, the present invention provides a liquid crystal display device having a silicon layer from which the ridges are removed and a method of manufacturing the same.

In order to achieve the above object, the mask according to the embodiment of the present invention are alternately disposed and the first and second transmission pattern regions for transmitting the laser beam to induce melting and crystallization of the amorphous silicon; And third transmission pattern regions disposed at positions where grain boundaries of polysilicon formed by melting and crystallization of the amorphous silicon are smaller than the first and second transmission pattern regions. The semiconductor device may further include blocking patterns disposed between the second transmission pattern regions and the third transmission pattern regions to block the laser beam. The method of manufacturing polysilicon according to the embodiment of the present invention provides amorphous silicon on a substrate. Forming; The first and second transmissive pattern regions intersected with each other and the grain boundaries of polysilicon formed by melting and crystallization of the amorphous silicon in a width smaller than the first and second transmissive pattern regions are disposed. Aligning a mask having third transmission pattern regions on the amorphous silicon; Irradiating a laser beam onto the amorphous silicon through the first and second transmission pattern regions of the mask to induce melting and crystallization of the amorphous silicon to form polysilicon and the laser beam to the third transmission pattern region of the mask And irradiating the grain boundaries of the polysilicon through the above to induce surface oxidation of the grain boundaries. The method of manufacturing the polysilicon further includes removing an oxide film formed on the surface of the grain boundaries. Method of manufacturing a liquid crystal display according to an embodiment of the present invention comprises the steps of forming a buffer layer on a substrate; Forming the amorphous silicon; Aligning a mask on the amorphous silicon, the mask having first and second transmission pattern regions and third transmission pattern regions formed to have a smaller width than the first and second transmission pattern regions; Irradiating a laser beam onto the amorphous silicon through the first and second transmission pattern regions of the mask to induce melting and crystallization of the amorphous silicon to form polysilicon and the laser beam to the third transmission pattern region of the mask Irradiating the grain boundaries of the polysilicon through the surface to induce surface oxidation of the grain boundaries; Removing the oxide film formed on the surface of the grain boundary; Patterning the polysilicon to form an active layer; And forming a semiconductor switch device including the active layer on the active layer. The forming of the semiconductor switch device may include forming a gate insulating film on the buffer layer to cover the active layer; Forming a gate metal layer on the gate insulating layer and patterning the gate metal layer to form a gate electrode pattern and a gate line overlapping a portion of the active layer; Implanting impurities into the active layer other than the portion overlapping the gate electrode pattern using the gate electrode pattern as a mask to form a source region and a drain region in the active layer; Forming an interlayer insulating film on the gate insulating film to cover the gate electrode pattern and the gate line, and forming a first contact hole through the interlayer insulating film and the gate insulating film to expose the source region and the drain region; ; Forming a source line pattern connected to the source region, a drain electrode pattern connected to the drain region, and a data line connected to the source electrode pattern; And forming a passivation layer on the interlayer insulating layer to cover the source electrode pattern, the drain electrode pattern, and the data line. The forming of the semiconductor switch device may include forming a passivation layer on the passivation layer to expose the drain electrode pattern. And forming a pixel electrode connected to the drain electrode and forming a second contact hole in the semiconductor switch device. The semiconductor switch element is formed at an intersection of the data line and the gate line and is formed through the drain electrode pattern. A data voltage on the data line is supplied to the pixel electrode in response to a scan pulse from the gate line. The semiconductor switch element is included in a data driving circuit for supplying a data voltage to the data line. The semiconductor switch device scan pulses on the gate line In the method of manufacturing a liquid crystal display device according to an embodiment of the present invention, a liquid crystal in which data lines and gate lines intersect and semiconductor switch elements for driving a liquid crystal cell are formed at an intersection thereof. In the display device, the grain boundaries of the polysilicon formed by melting and crystallization of the amorphous silicon in a width smaller than the first and second transmission pattern regions intersected with each other and the first and second transmission pattern regions are Melting and crystallization of the amorphous silicon exposed to the laser beam through the first and second transmission pattern regions by irradiating a laser beam onto the amorphous silicon using a mask having third transmission pattern regions disposed at the appearing position. Inducing and in the position where a grain boundary appears through the third transmission pattern regions. Polysilicon from which an oxide film formed on the surface of the grain boundary is removed by irradiating an irradiator beam; And a semiconductor switch element formed on the polysilicon. The semiconductor switch element is connected to a pixel electrode of the liquid crystal cell through a drain electrode pattern formed at an intersection of the data line and the gate line. The voltage on the data line is supplied to the pixel electrode of the liquid crystal cell in response to a scan pulse of the semiconductor cell. The semiconductor switch element is included in a data driving circuit for supplying a data voltage to the data line. It is included in the gate driving circuit for supplying the scan pulse to the gate line.

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Other objects and advantages of the present invention in addition to the above object will become apparent from the description of the preferred embodiment of the present invention with reference to the accompanying drawings.

Hereinafter, exemplary embodiments of the present invention will be described with reference to FIGS. 2 to 13G.

2 and 3, the mask according to the first embodiment of the present invention is a crystallization region having a width of 2/3 W and a crystal grain having a width of 1/3 W when the width of the laser beam is W; It has a boundary oxidation region.

The crystallization region includes a first shot region STD1 and a second shot region STD2 in which the transmission patterns 2a and 3a and the blocking patterns 2b and 3b are alternately disposed. The transmission patterns 2a of the first shot region STD1 and the transmission patterns 3a of the second shot region STD2 are alternately arranged in the horizontal direction. Each of these transmission patterns 2a and 3a transmits a laser beam toward the amorphous silicon, thereby causing the amorphous silicon to melt. In addition, the blocking patterns 2b of the first shot region STD1 and the blocking patterns 3b of the second shot region STD2 are alternately arranged. These blocking patterns 2b and 3b block the laser beam. The width SW1 of the transmission patterns 2a and 3a formed in each of the first shot region STD1 and the second shot region STD2 is equal to or less than twice the lateral growth length of the crystal grains.

The grain boundary oxide region (Domain of oxidizing Grain boundary) is the third shot region (STD3) is a transmission slit patterns 4a disposed along the imaginary line (5a to 5i) where the grain boundary can appear, and the transmission And blocking patterns 4b disposed between the slit patterns 4a. The width SW2 of the transmission slit patterns 4a is equal to or greater than the width of the grain boundary and the width SW1 of the transmission patterns 2a and 3a formed in each of the first shot region STD1 and the second shot region STD2. It is set smaller. Each of the transmission slit patterns 4a transmits the laser beam toward the grain boundary so that only the grain boundary melts again to induce oxidation of the grain boundary. The blocking patterns 4b block the laser beam.

A method of manufacturing polysilicon using the mask 1 will be described with reference to FIGS. 4A to 9.

4A and 5A, a method of manufacturing polysilicon according to an exemplary embodiment of the present invention may be performed by first depositing an insulating material such as SiO ₂ , SiN _x, or the like on a substrate 10 using a known deposition method such as PECVD. A buffer film 11 is formed on the substrate 10, and the amorphous silicon layer 12 is entirely deposited on the buffer film 11. Subsequently, the method of manufacturing polysilicon according to the embodiment of the present invention removes hydrogen entrained in the amorphous silicon layer 12 through a dehydrogenation process of heating the amorphous silicon layer at a temperature of approximately 400 ° C. After the dehydrogenation process, the polysilicon manufacturing method according to the embodiment of the present invention converts the amorphous silicon layer 12 into the polysilicon layer 13 by laser annealing the amorphous silicon layer 12 by the SLS method.

If the laser crystallization process is described assuming the SLS method, the mask 1 is aligned on the amorphous silicon layer 12. The laser beam 14 is irradiated onto the amorphous silicon layer 12 through the mask 1 at an initial position, so that the amorphous silicon layer of the regions corresponding to the transmission patterns 2a and 3a and the transmission slit patterns 4a ( 13) is melted. The amorphous silicon layer 12 irradiated with the laser beam 14 is almost melted to an interface in contact with the buffer film 11. The molten amorphous silicon layer 12 is crystallized while the temperature is lowered. At this time, crystallization is induced from seeds present in the side contacting the adjacent amorphous silicon layer 12 which maintains the solid state, and the amorphous silicon layer 12 exposed to the laser beam 14 is almost perpendicular to the side. It grows and turns into the polysilicon layer 13. In the center of the polysilicon layer 13, a grain boundary 15 is formed along a transverse direction perpendicular to the growth direction of the crystal, and the grain boundary 15 is separated from the grain boundary 15 due to the density difference between the liquid phase and the solid phase and the mass transfer. Soaring as high as the duck will appear bulge (16). On the other hand, the surface of the polysilicon layer 13 exposed to the laser beam 14 is thinly oxidized.

After the primary laser irradiation, the mask 1 moves to the right by 1/3 W width or the substrate 10 moves to the left by 1/3 W width. To this end, the substrate 10 is installed on an X-Y stage (not shown) so that the substrate 10 can be transported in two directions of the X axis and the Y axis, or the mask 1 is installed on an X-Y robot (not shown). Subsequently, the laser beam 14 has a grain boundary 15 of the polysilicon layer 13 crystallized by the amorphous silicon layer 12 and the primary laser irradiation through the mask 1 at the moving position as shown in FIGS. 4B and 5B. ) Is irradiated again to melt the silicon in the regions corresponding to the transmission patterns 2a and 3a and the transmission slit patterns 4a. Silicon irradiated with the laser beam 14 is almost melted to an interface in contact with the buffer film 11. The molten silicon is crystallized at a lower temperature. At this time, crystallization is induced from the seeds present on the side in contact with the solid silicon, so that the amorphous silicon layer 12 exposed to the laser beam 14 is grown almost vertically with respect to the side to become the polysilicon layer 13. do. The region, which is exposed to the laser beam 14 through the transmission patterns 3a of the second shot region STD2 by the secondary laser irradiation and is converted into the polysilicon layer 13, is the first during the first laser irradiation. Located between the regions exposed to the laser beam 14 through the transmission patterns 2a of the shot region STD1 and converted into the polysilicon layer 13, the upper and lower sides overlap the neighboring polysilicon layer 13. do. Therefore, the regions switched to the polysilicon layer 13 at the time of the first laser irradiation and the regions switched to the polysilicon layer 13 at the time of the second laser irradiation are alternately arranged above and below, so that the continuous laser irradiation is performed. In the region where the first shot region STD1 and the second shot region STD2 overlap, all of the amorphous silicon layers 12 are changed to the polysilicon layer 13.

On the grain boundary 15 formed in the polysilicon layer 13 during the primary laser irradiation, the laser beam 14 is transmitted through the transmission slit patterns 4a of the third shot region STD3 during the secondary laser irradiation. Is investigated. At this time, the grain boundary 15 is melted again and undergoes a recrystallization process. As shown in FIG. 7 through the recrystallization process, the silicon of the ridge 16 of the grain boundary 15 flows to both sides, and the oxide layer 17 is formed thicker. The oxidation rate of silicon proceeds faster at the grain boundaries than in the grains, as shown by well-known studies, for example, in the article Poly Crystalline Si for IC Processing p 137 figure 4.4 published by Kamins. Therefore, when the laser beam 14 is irradiated secondly to the raised portion 16 of the grain boundary 15, the oxide layer 17 is formed thicker than the grains in the polysilicon layer 13. In addition, when the laser beam 14 is irradiated to the ridge 16 of the grain boundary 15 secondly, mass transfer of non-oxidized silicon occurs in the ridge 16 of the grain boundary 15. 16) the height of the non-oxidized silicon layer in the lower.

After the secondary laser irradiation, the mask 1 further moves to the right by 1/3 W width or the substrate 10 further moves to the left by 1/3 W width. Subsequently, the laser beam 14 is a grain boundary 15 of the polysilicon layer 13 crystallized by the amorphous silicon layer 12 and the primary laser irradiation through the mask 1 at the moving position as shown in FIGS. 4C and 5C. ) Is irradiated again to melt the silicon in the regions corresponding to the transmission patterns 2a and 3a and the transmission slit patterns 4a. Silicon irradiated with the laser beam 14 is almost melted to an interface in contact with the buffer film 11. The molten silicon is crystallized at a lower temperature. At this time, crystallization is induced from the seeds present on the side in contact with the solid silicon, so that the amorphous silicon layer 12 exposed to the laser beam 14 is grown almost vertically with respect to the side to become the polysilicon layer 13. do. The region exposed to the laser beam 14 through the transmission patterns 3a of the second shot region STD2 by the third laser irradiation and converted into the polysilicon layer 13 is the first during the second laser irradiation. Located between the regions exposed to the laser beam 14 through the transmission patterns 2a of the shot region STD1 and converted into the polysilicon layer 13, the upper and lower sides overlap the neighboring polysilicon layer 13. do. Therefore, since the region switched to the polysilicon layer 13 at the time of the secondary laser irradiation and the region switched to the polysilicon layer 13 at the time of the third laser irradiation are alternately arranged above and below, the continuous laser irradiation is performed. In the region where the first shot region STD1 and the second shot region STD2 overlap, all of the amorphous silicon layers 12 are changed to the polysilicon layer 13.

On the grain boundary 15 formed in the polysilicon layer 13 at the time of the secondary laser irradiation, the laser beam 14 passes through the transmission slit patterns 4a of the third shot region STD3 at the time of the third laser irradiation. Is investigated. At this time, the grain boundary 15 is melted again and undergoes a recrystallization process. Through this recrystallization process, the silicon of the ridge 16 of the grain boundary 15 flows to both sides as shown in FIG. 7, and the oxide layer 17 is thicker.

If the polysilicon layer 13 is formed on the substrate 10 by the desired region due to the repetition of the laser crystallization process, the polysilicon manufacturing method according to the embodiment of the present invention is hydrofluoric acid (HF) or buffered oxide etchant (BOE). As described above, the oxide layer 17 is removed from the grain boundary 15 by etching the oxide layer 17 existing on the grain boundary 15 with an etchant having an etching selectivity between silicon and oxide. When the oxide layer 17 is removed, as shown in FIG. 8, the height of the grain boundary 15 is melted again, and the height is significantly lowered due to the removal of the oxide layer 17, or as shown in FIG. 9. It will have the same height. Therefore, the surface roughness of the polysilicon layer 13 is improved.

10 and 11 show a mask according to a second embodiment of the present invention.

10 and 11, when the mask 100 according to the second embodiment of the present invention has a width of W, (Where N is a positive integer greater than 2) a crystallization region having a width of W, A grain boundary oxide region having a width of W is provided.

The crystallization region includes first to Nth shot regions STD1 to STDN in which transmission patterns 6a and blocking patterns 6b are alternately disposed. The transmission patterns 6a of the first to Nth shot regions STD1 to STDN are alternately arranged in the horizontal direction. Each of these transmission patterns 6a induces crystallization by allowing the amorphous silicon to melt by transmitting the laser beam toward the amorphous silicon. In addition, the blocking patterns 6b of the first to Nth shot regions STD1 to STDN are alternately arranged in the horizontal direction. These blocking patterns 6b block the laser beam. The width SW3 of the transmission patterns 6a formed in each of the first to Nth shot regions STD1 to STDN is equal to or less than twice the lateral growth length of the crystal grains.

The grain boundary oxide region is an N + 1 shot region STDN + 1, and is formed between the transmission slit patterns 7a disposed along an imaginary line where the grain boundaries can appear, and the transmission slit patterns 7a. The blocking patterns 7b are disposed. The width SW4 of the transmission slit patterns 7a is smaller than or equal to the width of the grain boundary and smaller than the width SW3 of the transmission patterns 6a formed in each of the first to Nth shot regions STD1 to STDN. Each of the transmission slit patterns 7a transmits the laser beam toward the grain boundary so that only the grain boundary is melted again to induce oxidation of the grain boundary. The blocking patterns 6b block the laser beam.

In the method of manufacturing polysilicon according to the exemplary embodiment of the present invention, the transmission patterns 6a and 7a of the crystallization region and the grain boundary oxide region are shot every shot using the mask 100 illustrated in FIGS. 10 and 11. Through melting the amorphous silicon to induce crystallization, the amorphous silicon is converted to polysilicon and the grain boundary is melted again to induce oxidation of the ridge. And the method of manufacturing polysilicon according to the embodiment of the present invention between the shot and the shot The polysilicon area is enlarged by moving the substrate from left to right by W or by moving the mask 100 from right to left.

On the other hand, when the grain boundary oxide regions of the masks 1 and 100 are formed at the left end in the above-described embodiments, the moving directions of the masks 1 and 100 or the substrate 10 become opposite to the above-described embodiments. .

When polysilicon is obtained in this manner, a liquid crystal display device can be manufactured using the polysilicon layer. Since the polysilicon layer has a high electric field mobility, not only a semiconductor layer of a thin film transistor (hereinafter referred to as "TFT") for driving a liquid crystal cell in a display region, but also a semiconductor layer of a switch element included in a driving circuit. It can be used as.

12 schematically shows a display area and driving circuits formed on a lower substrate of a liquid crystal display device.

Referring to FIG. 12, in the liquid crystal display according to the exemplary embodiment of the present invention, the data lines 124 and the gate lines 125 intersect with each other, a TFT is formed at an intersection thereof, and the liquid crystal cells Clc form a matrix. A display area 122 disposed in the first region, a data driving circuit 121 for supplying data to the data lines 124, and a gate driving circuit 123 for supplying scan pulses to the gate lines 125. Equipped.

The TFTs in the display area 122 are generally implemented as N-type TFTs and supply data on the data lines 124 to the liquid crystal cell Clc in response to a scan pulse from the gate lines 125. The gate electrode of this TFT is connected to the gate line 125 and the source electrode is connected to the data line 124. The drain electrode of the TFT is connected to the pixel electrode of the liquid crystal cell Clc.

The display area 122 includes a storage capacitor Cst for maintaining a constant voltage of the liquid crystal cell Clc. The storage capacitor Cst is formed between the front gate line and the pixel electrode of the liquid crystal cell Clc or between a separate common line and the pixel electrode of the liquid crystal cell Clc.

The data driving circuit 121 stores a shift line for sampling a clock, a register for temporarily storing data, a line for storing data in response to a clock signal from the shift register, and simultaneously outputs the stored one line of data. Latch, a digital-to-analog converter for selecting a positive / negative gamma voltage corresponding to the digital data value from the latch, and data lines 124 to which analog data voltages converted by the positive / negative gamma voltage are supplied. ), And a multiplexer for selecting) and an output buffer connected between the multiplexer and the data line. The data driving circuit 121 converts digital video data into an analog voltage under the control of a timing controller (not shown) and controls the polarity of the analog voltage according to a polarity inversion scheme such as dot inversion, column inversion, and line inversion. do.

The gate driving circuit 123 includes a shift register for sequentially generating scan pulses, and a level shifter for shifting the voltage of the scan pulses to a level suitable for driving the liquid crystal cell Clc. The gate driving circuit 123 sequentially supplies scan pulses to the gate lines 125 under the control of a timing controller (not shown).

The driving circuits 123 include a plurality of CMOS devices in which an N-type TFT and a P-type TFT are combined.

13A to 13G illustrate a method of manufacturing a liquid crystal display device according to an exemplary embodiment of the present invention step by step.

Referring to FIG. 13A, in the method of manufacturing a liquid crystal display device according to an exemplary embodiment, the active layer 13a of the N-type TFT included in the display area 122 is patterned by patterning the polysilicon layer 13 by a photolithography process. The active layers 13d and 13g of the N-type TFT and the P-type TFT included in the driving circuits 121 and 123 are formed.

Subsequently, in the method of manufacturing the liquid crystal display according to the exemplary embodiment of the present invention, an insulating material such as SiO ₂ , SiN _X, or the like is covered on the buffer layer 11 so as to cover the active layers 13a, 13d, and 13g as shown in FIG. By depositing, the gate insulating film 21 is formed on the buffer layer 11. On the gate insulating film 21, a gate metal layer such as aluminum or aluminum / neodium is deposited on the entire surface. This gate metal layer is patterned into gay electrodes 23a, 23b, 23c, gate lines and gate pads (not shown).

When the gate electrodes 23a, 23b and 23c are formed as described above, impurities are injected into the active layer 114 using the gate electrodes 23a, 23b and 23c as masks. At this time, n-ion is implanted into the N-type TFT 131 included in the display area 122 and the N-type TFT 132 included in the driving circuits 121 and 123. n-ions are impurities such as phosphorus (P) and arsenic (As), and their concentration is relatively small at about 10 ¹² to 10 ¹³ / cm ² . In contrast, p-ion is implanted into the P-type TFT 133 included in the driving circuits 121 and 123. P-ion is an impurity such as boron (B) and its concentration is relatively small, such as 10 ¹² to 10 ¹³ / cm ² . This impurity implantation process forms lightly doped drain (hereinafter referred to as " LDD ") regions 14a to 14f having relatively small impurity concentrations on both sides of the active layers 13a, 13d, and 13g. LDD regions 14a to 14f serve to reduce off current.

Referring to FIG. 13C, a method of manufacturing a liquid crystal display device according to an exemplary embodiment of the present invention may apply a photoresist on the gate insulating film 21 and drain the source regions 13b, 13e, and 13h on the photoresist. Align the mask for defining the regions 13c, 13f, 13i. In the method of manufacturing a liquid crystal display device according to an exemplary embodiment of the present invention, a photoresist pattern for exposing the source regions 13b, 13e and 13h and the drain regions 13c, 13f and 13i through an exposure process and a development process is performed. Form them. Impurities are implanted again into the source regions 13b, 13e and 13h and the drain regions 13c, 13f and 13i through the photoresist patterns. In this impurity implantation process, source regions 13b and 13e and drain regions of the N-type TFT 131 included in the display region 122 and the N-type TFT 132 included in the driving circuits 121 and 123. The concentration of n + ions in (13c, 13f) is about 1 to 2 x 10 ¹⁵ / cm 2. In contrast, p + ions are implanted into the source regions 13h and the drain regions 13i of the P-type TFT 133 included in the driving circuits 121 and 123, and their concentrations are 1 to 2 × 10 ^15. / Cm 2 or so.

Referring to FIG. 13D, a method of manufacturing a liquid crystal display device according to an exemplary embodiment of the present invention may include an insulating material such as SiO ₂ , SiN _X, or the like to cover gate metal patterns including gate electrodes 23a, 23b, and 23c. The interlayer insulating film 22 is formed on the gate insulating film 21 by full-deposition on 21. On the interlayer insulating film 22, a photoresist (not shown) is entirely coated. In the method of manufacturing a liquid crystal display device according to an embodiment of the present invention, a mask for defining source contact holes 134a, 134c and 134e and drain contact holes 134b, 134d and 134f is arranged on a photoresist. The photoresist patterns exposing the regions of the source contact holes 134a, 134c and 134e and the drain contact holes 134b, 134d and 134f are formed on the interlayer insulating layer 22 by performing an exposure process and a developing process. . In the method of manufacturing a liquid crystal display device according to an exemplary embodiment of the present invention through the photoresist patterns, the interlayer insulating film 22 and the gate insulating film 21 are etched to form source regions 13b, 13e, and 13h and drain regions 13c and 13f. Source contact holes 134a, 134c, and 134e and drain contact holes 134b, 134d, and 134f exposing 13i are formed in the interlayer insulating film 22 and the gate insulating film 21.

Referring to FIG. 13E, a method of manufacturing a liquid crystal display device according to an exemplary embodiment of the present invention may include an interlayer insulating layer having metal having source contact holes 134a, 134c and 134e and drain contact holes 134b, 134d and 134f formed therein. 22) deposition on the front. Subsequently, in the method of manufacturing a liquid crystal display device according to an exemplary embodiment of the present invention, a photoresist is entirely coated on a metal layer, and a mask for defining the source electrode 108 and the drain electrode 110 is arranged on the photoresist. . Photoresist patterns are formed on the metal layer through an exposure process and a development process. In the method of manufacturing a liquid crystal display device according to an exemplary embodiment of the present invention through the photoresist patterns, the metal layer is etched and the photoresist patterns are removed. As a result, the source electrodes 24a, 24c and 24e and the drain electrodes 24b, 24d and 24f are formed and the data lines 124 and the data pads (not shown) are formed. The source electrodes 24a, 24c and 24e are connected to the source regions 13b, 13e and 13h of the active layer through the source contact holes 134a, 134c and 134e. The drain electrodes 24b, 24d and 24f are connected to the drain regions 13c, 13f and 13i of the active layer through the drain contact holes 134b, 134d and 134e.

In the method of manufacturing the liquid crystal display device according to the exemplary embodiment of the present invention, the inorganic or organic insulation layer is formed on the interlayer insulating layer 22 to cover the source electrodes 24a, 24c, and 24e and the drain electrodes 24b, 24d, and 24f. By forming the entire surface, a protective film 25 as shown in FIG. 13F is formed on the interlayer insulating film 22.

In the method of manufacturing a liquid crystal display device according to an exemplary embodiment of the present invention, a photoresist (not shown) is coated on the protective film 25, and a mask for defining the pixel contact hole 134 is aligned on the photoresist. In the method of manufacturing a liquid crystal display device according to an exemplary embodiment of the present invention, photoresist patterns are formed on the passivation layer 25 to expose regions of the pixel contact holes 135 by performing exposure and development processes. The protective layer 25 is etched through the patterns, and then the photoresist patterns are removed. As a result, as shown in FIG. 13F, a pixel contact hole 135 penetrating through the passivation layer 25 is formed, and a portion of the drain electrodes 24b, 24d, and 24f are exposed through the pixel contact hole 135.

Finally, the method of manufacturing the liquid crystal display device according to the embodiment of the present invention deposits a transparent conductive material such as ITO on the protective film 25 having the pixel contact hole 135 formed thereon, and shows the transparent conductive material layer on the transparent conductive material layer. A photoresist not applied is applied all over. In the method of manufacturing a liquid crystal display according to an embodiment of the present invention, the transparent conductive material is formed by arranging a mask for defining the pixel electrodes 122 as shown in FIG. 13G on a photoresist and then performing an exposure process and a developing process. Etch the layer. As a result, pixel electrodes 122 connected to the drain electrodes 24b through the pixel contact holes 135 are formed in the display area 122.

As described above, according to the present invention, a mask and a method of manufacturing polysilicon using the mask dissolve amorphous silicon by using a mask having a transmissive pattern for crystallization of silicon and a transmissive slit pattern for oxidizing a grain boundary. By inducing crystallization, polysilicon is formed, and the grain boundary of polysilicon is melted again to induce oxidation, and then the oxide film is removed by etching. Therefore, the mask according to the present invention and the silicon layer to be crystallized using the mask and a method of manufacturing the same can be obtained a high quality polysilicon by minimizing the raised portion appearing at the grain boundary without a separate capping layer or chamber and atmosphere control, The defect of the device formed on the polysilicon can be minimized. In addition, the liquid crystal display device and the method of manufacturing the same according to the present invention can simultaneously form the display area and the driving circuit on the substrate by forming the switch elements of the display area and the driving circuit using the polysilicon. Driving reliability can be secured by improving electrical characteristics such as the degree.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

1A-1G are cross-sectional views that illustrate step by step conventional methods for forming polysilicon.

2 is a plan view illustrating a mask according to a first embodiment of the present invention.

FIG. 3 is a cross-sectional view of the mask cut along the line 'I-I' in FIG. 2.

4A to 4C are plan views illustrating step by step methods of manufacturing polysilicon according to an exemplary embodiment of the present invention.

5A through 5C are cross-sectional views illustrating a method of manufacturing polysilicon according to an exemplary embodiment of the present invention by cutting lines 'III-III' and 'IV-IV' in FIGS. 4A through 4C.

6 is a cross-sectional view showing a raised portion on the grain boundary shown in the crystallization process.

FIG. 7 is a cross-sectional view illustrating an oxide film of a raised portion generated by a laser beam irradiated through the transmission slit patterns shown in FIGS. 2 and 3.

8 is a cross-sectional view illustrating a state in which the height of the ridge is reduced by removing the oxide film shown in FIG. 7.

FIG. 9 is a cross-sectional view illustrating a state in which the ridge is removed by removing the oxide film shown in FIG. 7.

10 is a plan view illustrating a mask according to a second embodiment of the present invention.

FIG. 11 is a cross-sectional view of the mask cut along the line 'II-II' in FIG. 10.

12 is a plan view illustrating a liquid crystal display device according to an exemplary embodiment of the present invention.

13A to 13G are cross-sectional views illustrating a method of manufacturing a semiconductor switch device included in the display area and the driving circuits shown in FIG. 12.

<Description of Main Parts of Drawing>

1: mask 2a, 3a, 6a: transmission pattern

2b, 3b, 4b, 6b, 7b: blocking pattern 4a, 7a: transmission slit pattern

10, 51: substrate 11: buffer layer

12, 52a, 52b: amorphous silicon layer 13, 52c: polysilicon layer

14: laser beam 15, 54: grain boundaries of the polysilicon layer

16, 55: raised part of the grain boundary 17: oxide film

121: data driving circuit 122: display area

123: gate driving circuit 13a, 13d, 13g: active layer

13b, 13e, 13h: source region of the active layer

13c, 13f, 13i: drain region of active layer

14a to 14f: LED area of the active layer

21 gate insulating film 22 interlayer insulating film

23a, 23b, 23c: gate electrode 24a, 24c, 24e: source electrode

24b, 24d, 24f: drain electrode 25: protective film

26 pixel electrode 131 N-type thin film transistor of display area

134a, 134c, 134e: source contact hole 134b, 134d, 134f: drain contact hole

132: N type thin film transistor of driving circuit

133: P type thin film transistor of driving circuit

135: pixel contact hole

Claims (17)

First and second transmission pattern regions intersected with each other and transmitting laser beams to induce melting and crystallization of amorphous silicon; And third transmission pattern regions disposed at positions where grain boundaries of polysilicon formed by melting and crystallization of the amorphous silicon appear in a width smaller than the first and second transmission pattern regions. delete delete The method of claim 1, And a blocking pattern disposed between the first and second transmission pattern regions and the third transmission pattern regions to block the laser beam. Forming amorphous silicon on the substrate; The first and second transmissive pattern regions intersected with each other and the grain boundaries of polysilicon formed by melting and crystallization of the amorphous silicon in a width smaller than the first and second transmissive pattern regions are disposed. Aligning a mask having third transmission pattern regions on the amorphous silicon; Irradiating a laser beam onto the amorphous silicon through the first and second transmission pattern regions of the mask to induce melting and crystallization of the amorphous silicon to form polysilicon and the laser beam to the third transmission pattern region of the mask Irradiating the grain boundaries of the polysilicon through the induction of surface oxidation of the grain boundaries. delete The method of claim 6, And removing an oxide film formed on a surface of the grain boundary. Forming a buffer layer on the substrate; Forming the amorphous silicon; Aligning a mask on the amorphous silicon, the mask having first and second transmission pattern regions and third transmission pattern regions formed to have a smaller width than the first and second transmission pattern regions; Irradiating a laser beam onto the amorphous silicon through the first and second transmission pattern regions of the mask to induce melting and crystallization of the amorphous silicon to form polysilicon and the laser beam to the third transmission pattern region of the mask Irradiating the grain boundaries of the polysilicon through the surface to induce surface oxidation of the grain boundaries; Removing the oxide film formed on the surface of the grain boundary; Patterning the polysilicon to form an active layer; And forming a semiconductor switch device including the active layer on the active layer. The method of claim 8, Forming the semiconductor switch device, Forming a gate insulating film on the buffer layer to cover the active layer; Forming a gate metal layer on the gate insulating layer and patterning the gate metal layer to form a gate electrode pattern and a gate line overlapping a portion of the active layer; Implanting impurities into the active layer other than the portion overlapping the gate electrode pattern using the gate electrode pattern as a mask to form a source region and a drain region in the active layer; Forming an interlayer insulating film on the gate insulating film to cover the gate electrode pattern and the gate line, and forming a first contact hole through the interlayer insulating film and the gate insulating film to expose the source region and the drain region; ; Forming a source line pattern connected to the source region, a drain electrode pattern connected to the drain region, and a data line connected to the source electrode pattern; And forming a passivation layer on the interlayer insulating layer to cover the source electrode pattern, the drain electrode pattern and the data line. The method of claim 9, Forming the semiconductor switch device, And forming a second contact hole on the passivation layer so as to expose the drain electrode pattern and forming a pixel electrode connected to the drain electrode. The method of claim 10, The semiconductor switch element is formed at an intersection of the data line and the gate line and is connected to the pixel electrode through the drain electrode pattern to respond to a scan pulse from the gate line, thereby providing a data voltage on the data line to the pixel electrode. Method of manufacturing a liquid crystal display device characterized in that the supply. The method of claim 11, And the semiconductor switch element is included in a data driving circuit for supplying a data voltage to the data line. The method of claim 11, And the semiconductor switch device is included in a gate driving circuit for supplying a scan pulse to the gate line. In a liquid crystal display device in which data lines and gate lines intersect and semiconductor switch elements for driving a liquid crystal cell are formed at an intersection thereof. The first and second transmissive pattern regions intersected with each other and a smaller width than the first and second transmissive pattern regions are disposed at positions where grain boundaries of polysilicon formed by melting and crystallization of the amorphous silicon appear. Irradiating a laser beam onto amorphous silicon using a mask having third transmission pattern regions to induce melting and crystallization of the amorphous silicon exposed to the laser beam through the first and second transmission pattern regions and Polysilicon from which an oxide film formed on the surface of the grain boundary is removed by irradiating the laser beam to a position where the grain boundary appears through the transmission pattern regions; And a semiconductor switch element formed on said polysilicon. The method of claim 14, The semiconductor switch device is connected to a pixel electrode of the liquid crystal cell through a drain electrode pattern formed at an intersection of the data line and the gate line, and is connected to the pixel electrode of the liquid crystal cell in response to a scan pulse from the gate line. And a voltage on the data line. The method of claim 14, And the semiconductor switch element is included in a data driving circuit for supplying a data voltage to the data line. The method of claim 14, And the semiconductor switch element is included in a gate driving circuit for supplying a scan pulse to the gate line.