JP4082157B2 - Method for manufacturing substrate for electro-optical device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a substrate cleaning method suitable for glass substrates and polysilicon substrates.
[0002]
[Prior art]
The liquid crystal device is configured by sealing liquid crystal between two substrates such as a glass substrate and a quartz substrate. The structure of the liquid crystal device includes a passive type in which pixels are arranged in a matrix on the surface of the substrate, and a non-linear such as TFT (Thin Film Transistor) or TFD (Thin Film Diode) for each pixel. There is an active type in which an element is provided and a signal electrode and a pixel electrode are connected through the nonlinear element.
[0003]
In an active liquid crystal device, active elements are arranged in a matrix on one substrate, electrodes facing the other substrate are arranged, and the optical characteristics of the liquid crystal layer sealed between the two substrates are in accordance with the image signal. It is possible to display images by changing them.
[0004]
Such a TFT substrate is configured by repeating the steps of cleaning, film formation, and pattern formation. In a liquid crystal device, there is a strong general demand for high-quality display images. For this purpose, it is necessary to reduce the pixel pitch. With such miniaturization of elements, the influence of particles and metal impurities mixed in the manufacturing process on device yield and characteristics is increasing. For example, the adhesion of particles causes non-uniform film thickness of various insulating films, and the metal impurity causes a breakdown voltage failure or a junction leak failure of the oxide film. However, since most TFT manufacturing processes are sources of particles and metal impurities, the substrate surface must be kept clean throughout the entire manufacturing process in order to improve device yield and characteristics. .
[0005]
For such TFT substrate cleaning, RCA cleaning (for example, RCA Review 31-6, pp.185-205 (1970)), which has been widely used as a method for cleaning a silicon semiconductor substrate, is employed. The RCA cleaning, which is representative of the wet cleaning method, is a cleaning method based on hydrogen peroxide and comprising alkali cleaning and acid cleaning. In general RCA cleaning, so-called SC-1 (RCA Standard Clean-1) cleaning using a solution composed of ammonia and hydrogen peroxide, so-called SC-2 (RCA) using a solution consisting of hydrochloric acid and hydrogen peroxide. Standard Clean -2) Cleaning and dilute hydrofluoric acid cleaning are adopted. SC-1 cleaning is effective for removing particles, and SC-2 (RCA Standard Clean-2) cleaning is effective for removing metal impurities. The diluted hydrofluoric acid cleaning is effective in removing the natural oxide film formed on the substrate surface by SC-1 cleaning and SC-2 cleaning and removing metal impurities.
[0006]
In recent years, a functional water cleaning method in consideration of the influence on the environment and the like has come to be adopted for such a chemical cleaning method represented by RCA cleaning. For example, in Patent Document 1, as a cleaning method for a silicon semiconductor substrate, a silicon oxide film is formed with ozone water, particles and metal impurities are taken into the oxide film, and the silicon oxide film is cleaned with a dilute hydrofluoric acid aqueous solution. A cleaning method is disclosed in which particles and metal impurities are simultaneously removed by etching.
[0007]
For example, Patent Document 2 discloses a cleaning method for removing and cleaning a Cu film by treating a silicon semiconductor substrate with a dissolved ozone aqueous solution and then treating with a dilute hydrofluoric acid aqueous solution.
[0008]
[Patent Document 1]
JP-A-6-314679
[0009]
[Patent Document 2]
JP-A-8-153698
[0010]
[Problems to be solved by the invention]
However, the functional water cleaning method proposed by Patent Document 1 and Patent Document 2 is designed to remove contamination by repeatedly using ozone water and hydrofluoric acid aqueous solution. Even in this case, there is no particular problem because these proposals aim to clean the single crystal silicon substrate. However, when the cleaning method according to these proposals is applied to the cleaning of the polysilicon film formed on the glass substrate, the polycrystal is obtained by repeatedly cleaning with ozone water and hydrofluoric acid aqueous solution in consideration of the roughness characteristics of the polysilicon. It is conceivable that the roughness of the silicon film becomes large and adversely affects the oxide film. In addition, since the surface potential is different between the single crystal silicon substrate and the polysilicon substrate and the behavior of metal adhesion and particle adhesion is different, the functional water cleaning method for the single crystal silicon substrate is simply diverted to the polysilicon substrate. I can't do it.
[0011]
The present invention has been made in view of such problems, and an object thereof is to provide a substrate cleaning method capable of obtaining a sufficient cleaning effect while suppressing an increase in roughness by only one cleaning. .
[0012]
[Means for Solving the Problems]
The substrate cleaning apparatus according to the present invention includes a mounting table on which a single substrate is mounted, and ozone water supply means for supplying ozone water having a concentration of 15 ppm or more to the substrate on the mounting table. It is characterized by.
[0013]
According to such a configuration, the organic and metal impurities existing on the substrate surface are dissolved and removed by ozone water having a sufficient concentration, and an oxide film is formed on the treated surface to take in the metal impurities, and the cleaning is performed once. Thus, reliable decontamination is possible. In addition, since the single wafer processing is performed, the processing time can be shortened.
[0014]
Further, the present invention is further characterized by further comprising dilute hydrofluoric acid aqueous solution supply means for supplying a dilute hydrofluoric acid aqueous solution having a concentration of 0.1 to 10% to the substrate on the mounting table.
[0015]
According to such a configuration, the organic and metal impurities existing on the substrate surface are dissolved and removed with a sufficient concentration of ozone water, and an oxide film is formed on the treated surface to incorporate the metal impurities. With the acid aqueous solution, the oxide film can be removed and at the same time, the metal impurity molecules (atoms) present in the oxide film and the metal impurities and particles remaining on the oxide film surface can be separated almost completely from the treated surface. .
[0016]
The ozone water supply means supplies ozone water having a concentration of 15 ppm or more to the substrate before and after the dilute hydrofluoric acid aqueous solution supply means supplies the dilute hydrofluoric acid aqueous solution to the substrate. .
[0017]
According to such a configuration, it is possible to perform passivation to remove organic substances and metal impurities with ozone water and to prevent reattachment of contamination.
[0018]
Further, the present invention is further characterized by further comprising pure water supply means for supplying pure water to the substrate on the mounting table.
[0019]
According to such a configuration, contamination remaining on the substrate can be reliably removed by rinsing with pure water.
[0020]
Further, the mounting table is characterized by rotating.
[0021]
According to such a configuration, the substrate is also rotated by the rotation of the mounting table, and ozone water, dilute hydrofluoric acid aqueous solution, pure water and the like flow vigorously on the substrate from the center toward the centrifugal direction. This reliably removes contamination on the substrate.
[0022]
Further, the ozone water supply means, the dilute hydrofluoric acid aqueous solution supply means, and the pure water supply means are configured by a nozzle that discharges liquid to the substrate surface and a cleaning liquid discharge port that discharges liquid to the back surface of the substrate. It is characterized by.
[0023]
According to such a configuration, ozone water and dilute hydrofluoric acid aqueous solution can be ejected vigorously from the nozzle onto the substrate, and the effect of removing contamination on the substrate is high.
[0024]
Further, the nozzle is capable of scanning a surface parallel to the substrate surface.
[0025]
According to such a configuration, the ozone water and dilute hydrofluoric acid aqueous solution discharged onto the substrate are vigorously discharged onto the substrate, and the effect of removing contamination on the substrate is high.
[0026]
The substrate is a single crystal silicon substrate, a polysilicon substrate, or a glass substrate.
[0027]
According to such a configuration, contamination can be removed by a single cleaning with a sufficient concentration of ozone water, so that the roughness is increased not only in a single crystal silicon substrate but also in a polysilicon substrate or a glass substrate. Reliable cleaning is possible without causing it to occur.
[0028]
Further, the substrate is a substrate that has been subjected to film formation.
[0029]
According to such a configuration, contamination of the silicon film, polysilicon film, oxide film, etc. on the substrate can be reliably removed.
[0030]
The ozone water has a concentration of 15 to 100 ppm.
[0031]
According to such a configuration, cleaning using ozone water that can be applied to a cleaning apparatus and has sufficient cleaning capability is possible.
[0032]
The treatment with ozone water is performed only once.
[0033]
According to such a configuration, it is possible to minimize the influence of the ozone water treatment on the substrate and the film on the substrate.
[0034]
The treatment with ozone water is characterized in that the treatment time is controlled so that the thickness of the oxide film formed by the ozone water treatment is in the range of 0.5 to 2.0 nm.
[0035]
According to such a configuration, a sufficient and optimal protective oxide film can be formed by controlling the treatment time of ozone water.
[0036]
The ozone water is used at a temperature similar to room temperature.
[0037]
According to such a configuration, ozone water having a temperature similar to room temperature can be used, and the cleaning workability is excellent.
[0038]
Further, the dilute hydrofluoric acid aqueous solution contains ozone.
[0039]
According to such a configuration, the effect of decontamination is higher due to the action of ozone.
[0040]
The substrate cleaning method according to the present invention is characterized in that a treatment for supplying ozone water having a concentration of 15 ppm or more to one substrate placed on the placement table and rotating the placement table is provided.
[0041]
According to such a configuration, the organic and metal impurities existing on the substrate surface are dissolved and removed by ozone water having a sufficient concentration, and an oxide film is formed on the treated surface to take in the metal impurities, and the cleaning is performed once. Thus, reliable decontamination is possible. In addition, since the single wafer processing is performed, the processing time can be shortened.
[0042]
In addition, the method further includes a process of supplying a dilute hydrofluoric acid aqueous solution having a concentration of 0.1 to 10% to the substrate after the ozone water is supplied to the substrate.
[0043]
According to such a configuration, the oxide film is removed, and at the same time, the metal impurity molecules (atoms) present in the oxide film and the metal impurities and particles remaining on the oxide film surface are substantially completely separated from the treated surface. Is possible.
[0044]
In addition, after the dilute hydrofluoric acid aqueous solution is supplied to the substrate, the substrate further includes a process of supplying ozone water having a concentration of 15 ppm or more to the substrate.
[0045]
According to such a configuration, it is possible to perform passivation to remove organic matter and metal impurities with ozone water and to prevent reattachment of contamination.
[0046]
In addition, after the dilute hydrofluoric acid aqueous solution is supplied to the substrate, the substrate further includes a process of supplying pure water to the substrate.
[0047]
According to such a configuration, contamination remaining on the substrate can be reliably removed by rinsing with pure water.
[0048]
The cleaning device or the cleaning method of the present invention can also be applied to substrates of electro-optical devices such as liquid crystal devices, EL (electroluminescence) devices, and electrophoretic devices.
[0049]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is an explanatory view showing a substrate cleaning apparatus according to a first embodiment of the present invention. FIG. 2 is an equivalent circuit diagram of various elements and wirings in a plurality of pixels constituting a pixel region of a TFT substrate (element substrate) which is a substrate to which the present embodiment is applied. FIG. 3 is a plan view of a liquid crystal device using an element substrate to which the present embodiment is applied, and is a plan view seen from the counter substrate side together with each component formed on the element substrate. FIG. 4 is a cross-sectional view of the liquid crystal device after the assembly process in which the element substrate and the counter substrate are bonded to each other and the liquid crystal is sealed is cut along the line HH ′ in FIG. FIG. 5 is a cross-sectional view showing the liquid crystal device of FIGS. 3 and 4 in detail. 7 is a flowchart showing the substrate cleaning method of FIG. 7 and 8 are process diagrams showing the substrate process of the element substrate. 9 and 10 are explanatory diagrams for explaining the state of cleaning.
[0050]
This embodiment is applied to a single-wafer cleaning device, and is performed only once with ozone water, once with ozone water and dilute hydrofluoric acid solution, and with ozone water, dilute hydrofluoric acid solution and ozone. By adopting three cleaning patterns of cleaning with water only once for each cleaning process in the TFT substrate manufacturing process, a sufficient cleaning effect can be obtained in a short time while suppressing an increase in roughness. ing. Note that cleaning with ozone water is not used for metal cleaning, but only for silicon cleaning.
[0051]
In each cleaning pattern, as will be described later, by appropriately controlling the concentration and the cleaning time, unnecessary etching is prevented while suppressing the residue of hydrofluoric acid, thereby enabling efficient cleaning. Thereby, a yield can be improved. As will be described later, the concentration of ozone water is 30 to 100 ppm, and the concentration of dilute hydrofluoric acid aqueous solution is set to 0.25 to 1%.
[0052]
First, with reference to FIGS. 2 to 5, the structure of a liquid crystal device using an element substrate to be cleaned in this embodiment will be described.
[0053]
As shown in FIGS. 3 and 4, the liquid crystal device is configured by enclosing a liquid crystal 50 between an element substrate 10 such as a TFT substrate and a counter substrate 20. On the element substrate 10, pixel electrodes and the like constituting pixels are arranged in a matrix. FIG. 2 shows an equivalent circuit of elements on the element substrate 10 constituting the pixel.
[0054]
As shown in FIG. 2, in the pixel region, a plurality of scanning lines 3a and a plurality of data lines 6a are wired so as to cross each other, and a pixel electrode is formed in a region partitioned by the scanning lines 3a and the data lines 6a. 9a are arranged in a matrix. A TFT (thin film transistor) 30 is provided corresponding to each intersection of the scanning line 3 a and the data line 6 a, and the pixel electrode 9 a is connected to the TFT 30.
[0055]
The TFT 30 is turned on by the ON signal of the scanning line 3a, whereby the image signal supplied to the data line 6a is supplied to the pixel electrode 9a. A voltage between the pixel electrode 9 a and the counter electrode 21 provided on the counter substrate 20 is applied to the liquid crystal 50. In addition, a storage capacitor 70 is provided in parallel with the pixel electrode 9a, and the storage capacitor 70 makes it possible to hold the voltage of the pixel electrode 9a for a time that is, for example, three orders of magnitude longer than the time when the source voltage is applied. The storage capacitor 70 improves the voltage holding characteristic and enables image display with a high contrast ratio.
[0056]
FIG. 5 is a schematic cross-sectional view of a liquid crystal device focusing on one pixel.
[0057]
A groove 11 is formed in an element substrate 10 such as glass or quartz. A TFT 30 having an LDD structure is formed on the groove 11 with a light shielding film 12 and a first interlayer insulating film 13 interposed therebetween. The groove 11 flattens the boundary surface between the TFT substrate and the liquid crystal 50.
[0058]
The TFT 30 includes a scanning line 3a that forms a gate electrode through a lower layer and upper insulating films 2a and 2b in a semiconductor layer in which a channel region 1a, a source region 1d, and a drain region 1e are formed. The light shielding film 12 is formed in a region corresponding to the formation region of the TFT 30, a formation region such as a data line 6a and a scanning line 3a described later, that is, a region corresponding to a non-display region of each pixel. The light shielding film 12 prevents reflected light from entering the channel region 1 a, the source region 1 d, and the drain region 1 e of the TFT 30.
[0059]
A second interlayer insulating film 14 is laminated on the TFT 30, and an intermediate conductive layer 15 is formed on the second interlayer insulating film 14. On the intermediate conductive layer 15, the capacitor line 18 is disposed opposite to the dielectric film 17. The capacitance line 18 includes a capacitance layer and a light shielding layer, and forms a storage capacitor with the intermediate conductive layer 15 and has a light shielding function for preventing internal reflection of light. The intermediate conductive layer 15 is formed at a position relatively close to the semiconductor layer, so that irregular reflection of light can be efficiently prevented.
[0060]
A third interlayer insulating film 19 is disposed on the capacitor line 18, and a data line 6 a is stacked on the third interlayer insulating film 19. The data line 6a is electrically connected to the source region 1d through contact holes 24a and 24b penetrating the third and second interlayer insulating films 19 and 14. A pixel electrode 9a is stacked on the data line 6a with a fourth interlayer insulating film 25 interposed therebetween. The pixel electrode 9a is electrically connected to the drain region 1e through the capacitor line 18 through contact holes 26a and 26b that penetrate the fourth to second interlayer insulating films 25, 19, and 14. On the pixel electrode 9a, an alignment film 16 made of polyimide polymer resin is laminated and rubbed in a predetermined direction.
[0061]
When the ON signal is supplied to the scanning line 3a (gate electrode), the channel region 1a becomes conductive, the source region 1d and the drain region 1e are connected, and the image signal supplied to the data line 6a becomes the pixel electrode. 9a.
[0062]
On the other hand, the counter substrate 20 is provided with a first light-shielding film 23 in a region facing the data line 6a, scanning line 3a, and TFT 30 formation region of the TFT array substrate, that is, in a non-display region of each pixel. The first light shielding film 23 prevents incident light from the counter substrate 20 side from entering the channel region 1 a, the source region 1 d, and the drain region 1 e of the TFT 30. A counter electrode (common electrode) 21 is formed over the entire surface of the substrate 20 on the first light shielding film 23. An alignment film 22 made of a polyimide-based polymer resin is laminated on the counter electrode 21 and rubbed in a predetermined direction.
[0063]
A liquid crystal 50 is sealed between the element substrate 10 and the counter substrate 20. Thereby, the TFT 30 writes the image signal supplied from the data line 6a to the pixel electrode 9a at a predetermined timing. Depending on the potential difference between the written pixel electrode 9a and the counter electrode 21, the orientation and order of the molecular assembly of the liquid crystal 50 change, and light is modulated to enable gradation display.
[0064]
As shown in FIGS. 3 and 4, the counter substrate 20 is provided with a light shielding film 42 as a frame for partitioning the display area. The light shielding film 42 is formed of, for example, the same or different light shielding material as the light shielding film 23.
[0065]
A sealing material 41 that encloses liquid crystal in a region outside the light shielding film 42 is formed between the element substrate 10 and the counter substrate 20. The sealing material 41 is disposed so as to substantially match the contour shape of the counter substrate 20, and fixes the element substrate 10 and the counter substrate 20 to each other. The sealing material 41 is missing in a part of one side of the element substrate 10, and a liquid crystal injection port 78 for injecting the liquid crystal 50 is formed in the gap between the bonded element substrate 10 and the counter substrate 20. The After the liquid crystal is injected from the liquid crystal injection port 78, the liquid crystal injection port 78 is sealed with a sealing material 79.
[0066]
A data line driving circuit 61 and a mounting terminal 62 are provided along one side of the element substrate 10 in a region outside the sealing material 41 of the element substrate 10, and scanning lines are provided along two sides adjacent to the one side. A drive circuit 63 is provided. On the remaining side of the element substrate 10, a plurality of wirings 64 are provided for connecting between the scanning line driving circuits 63 provided on both sides of the screen display area. In addition, a conductive material 65 for electrically connecting the element substrate 10 and the counter substrate 20 is provided in at least one corner of the counter substrate 20.
[0067]
In FIG. 1, a substrate cleaning device 70 is a cup-type cleaning device. The substrate cleaning device 70 is rotatably provided with a spin chuck 71 as a mounting table that is rotated by a driving device (not shown). A substrate 72 is placed on the spin chuck 71 while holding the end face while keeping its surface horizontal. A bottomed cylindrical cup 73 (not shown in FIG. 1) is disposed so as to surround the spin chuck 71 and the substrate 72 and constitutes a cleaning chamber for cleaning the substrate 72 above the spin chuck 71. ) Is provided.
[0068]
In the present embodiment, the cup 73 has two cleaning chambers 74 and 75 that are separated into two layers. A portion near the center of rotation at the top of the cup 73 is opened, and an annular lid 76 is attached to the opening. The annular lid 76 rotates with the substrate 72.
[0069]
Further, above the cup 73 and the lid 76 and in the center of the spin chuck 71, nozzles 77 to 79 for supplying a cleaning liquid for cleaning the substrate 72 to the cleaning chambers 74 and 75, and a cleaning liquid discharge port 82 are provided. It is arranged. The nozzles 77 to 79 are arranged so that the discharge outlets at the tips are arranged in the vicinity of the surface of the substrate 72 in the cleaning chambers 75 and 74. Thus, the nozzles 77 to 79 can discharge the cleaning liquid and spray it directly onto the substrate 72. Further, the nozzles 77 to 79 can discharge the cleaning liquid while horizontally scanning a surface parallel to the surface of the substrate 72.
[0070]
In the present embodiment, the nozzles 77 to 79 are for ozone water discharge, hydrofluoric acid aqueous solution discharge, or pure water discharge, respectively. From the cleaning liquid discharge port 82, ozone water discharge, hydrofluoric acid aqueous solution discharge, pure water discharge, N₂(Nitrogen) can be discharged. The nozzles 77 to 79 and the cleaning liquid discharge port 82 are used as cleaning liquids such as ozone water, hydrofluoric acid aqueous solution, pure water, or N₂Can be selectively sprayed onto the substrate 72 for an appropriate time. The cup 73 has a pair of discharge ports 80 and 81 so that waste liquid from the cleaning chambers 75 and 74 flows out from the corresponding discharge ports 80 and 81 to the outside.
[0071]
Due to the centrifugal force generated by the rotation of the substrate 72, the cleaning liquid in the cleaning chambers 74 and 75 flows at a sufficient speed in the centrifugal direction from the center of rotation to the upper and lower portions of the substrate 72, and further flows out from the discharge ports 80 and 81 to the outside. It has become.
[0072]
Next, an element substrate manufacturing process and a substrate cleaning method configured as described above will be described with reference to the flowchart of FIG. 6, the process diagrams of FIGS. 7 and 8, and the explanatory diagrams of FIGS. 9 and 10.
[0073]
First, a TFT array substrate 10 such as a quartz substrate, hard glass, or silicon substrate is prepared. In the present embodiment, the substrate 10 is arranged as the substrate 72 in FIG. 1, and the cleaning process in step S21 is performed on the substrate 10. That is, first, the substrate 10 is placed on the spin chuck 71, and the spin chuck 71 and the cup 73 are moved in the vertical direction so that the upper surface of the spin chuck 71 is positioned substantially at the bottom surface of the cleaning chamber 75.
[0074]
In step S21, ozone water O having a concentration of 30 to 100 ppm and a temperature of 23 to 40 ° C. is supplied from the nozzle 77 and the cleaning liquid discharge port 82 to the substrate 10 of FIG._ThreeTo discharge. This ozone water is discharged from the nozzle 77 and the cleaning liquid discharge port 82 and sprayed on the front and back surfaces of the substrate 72, and cleaning is performed for 30 seconds to 3 minutes. This removes organic substances and metals on the front and back surfaces of the substrate 10 and forms a protective film with ozone water (passivation).
[0075]
FIG. 9A shows the cleaning effect by ozone water. As shown in FIG. 9A, an oxide film as a passivation is formed by ozone water, and contaminants are surrounded by the oxide film. The above cleaning method is referred to as [O_Three(Ozone) water (concentration 30-100ppm / temperature 23-40 ° C / 30s-3min) Organic substance removal / metal removal / passivation].
[0076]
Next, in step S21, rinsing with pure water is performed. That is, the spin chuck 71 and the cup 73 are moved in the vertical direction so that the upper surface of the spin chuck 71 is positioned substantially at the bottom surface of the cleaning chamber 74. Then, instead of the nozzle 77, the nozzle 79 is disposed opposite to the substrate 10, and pure water is discharged from the nozzle 79 and the cleaning liquid discharge port 82. Then, rinsing with pure water is performed for 10 seconds. As a result, the ozone water on the front and back surfaces of the substrate 10 is rinsed and removed. This cleaning method is hereinafter referred to as [ultra pure water (spin rinse, 10s) substitution].
[0077]
Next, in step S21, instead of the nozzle 79, the nozzle 78 is disposed opposite to the substrate 10, and a dilute hydrofluoric acid aqueous solution having a temperature of 23 to 25 ° C. mixed with hydrofluoric acid and pure water at a ratio of 1:50 to 200 is used. It is discharged from the nozzle 78 and the cleaning liquid discharge port 82. And it wash | cleans for 5 to 60 second using dilute hydrofluoric acid aqueous solution. Thus, the metal on the front and back surfaces of the substrate 10 is removed, and the chemical and natural oxide films are removed by etching. FIG. 9B shows this state, and the contaminants are lifted off by the dilute hydrofluoric acid aqueous solution. This cleaning method is hereinafter referred to as [DHF (HF: H₂O = 1: 50 to 200/23 to 25 ° C./5 to 60 s) Metal removal, chemical and natural oxide film etching].
[0078]
Next, in step S21, rinse with pure water [replacement with ultrapure water (spin rinse, 1 min)] is performed again for 1 minute. That is, the spin chuck 71 and the cup 73 are moved in the vertical direction so that the upper surface of the spin chuck 71 is positioned substantially at the bottom surface of the cleaning chamber 74. Then, pure water is discharged from the nozzle 79 and the cleaning liquid discharge port 82 and sprayed on the front and back surfaces of the substrate 72.
[0079]
FIG. 10 shows this state. Due to the centrifugal force generated by the rotation of the spin chuck 71, the pure water discharged from the nozzle 79 and the cleaning liquid discharge port 82 flows out from the center of the substrate 10 in the centrifugal direction. Due to the flow of pure water, particles (contaminants) lifted off from the substrate 10 are swept away around the substrate 10 and removed from the substrate 10.
[0080]
Next, the spin chuck 71 and the cup 73 are moved again in the vertical direction, and are arranged so that the upper surface of the spin chuck 71 is positioned substantially at the bottom surface of the cleaning chamber 75. Then, ozone water is discharged from the nozzle 77 and the cleaning liquid discharge port 82 and sprayed on the front and back surfaces of the substrate 72. That is, ozone water O having a concentration of 30 to 100 ppm and a temperature of 23 to 40 ° C. is formed in order to remove organic substances and metals, form passivation, and prevent the reattachment of contaminants._ThreeAnd is washed for 30 seconds to 3 minutes. This cleaning method [O_Three(Ozone) water (concentration 30-100 ppm / temperature 23-40 ° C / 30s-3min) Organic substance removal / metal removal / passivation / prevention of contamination / reattachment].
[0081]
Next, in step S21, cleaning with [ultra pure water (spin rinse, 10s) replacement] is performed again. That is, the spin chuck 71 and the cup 73 are moved in the vertical direction so that the upper surface of the spin chuck 71 is positioned substantially at the bottom surface of the cleaning chamber 74. Then, instead of the nozzle 77, the nozzle 79 is disposed opposite to the substrate 10, and pure water is discharged from the nozzle 79 and the cleaning liquid discharge port 82. Then, rinsing with pure water is performed for 10 seconds. As a result, the ozone water on the front and back surfaces of the substrate 10 is rinsed and removed.
[0082]
Finally, the lid body 76 is lowered to a substantially upper surface of the cleaning chamber 75, and the cleaning chamber 75 is substantially closed in the vertical direction.₂Is dried while discharging from the center of the lid 76 and the cleaning liquid discharge port 82 ([Dry (N₂Purge type spin drying)]]. Even during the drying step, the substrate 10 can be drained in a short time by rotating the spin chuck 71 and the lid 76.
[0083]
The nozzles 77 to 79 can be scanned in the horizontal direction. By causing the nozzles 77 to 79 to scan in the horizontal direction, the liquid to be ejected can be sprayed onto the surface of the substrate 10 more vigorously, and the effect of removing contaminants from the substrate 10 can be improved.
[0084]
That is, the substrate cleaning in step S21 is summarized as follows.
[0085]
[O_Three(Ozone) Water (Concentration: 30-100 ppm / Temperature: 23-40 ° C / 30 s-3 min) Organic removal, metal removal, passivation formation]
[Super pure water (spin rinse, 10s) replacement]
[DHF (HF: H₂O = 1: 50 ~ 200/23 ~ 25 ℃ / 5 ~ 60s) Metal removal, chemical and natural oxide film etching]
[Super pure water (spin rinse, 1 min) replacement]
[O_Three(Ozone) Water (Concentration: 30-100 ppm / Temperature: 23-40 ° C / 30 s-3 min) Organic removal, metal removal, passivation, contamination re-adhesion prevention]
[Super pure water (spin rinse, 10s) replacement]
[Dry (N₂Purge type spin drying)]
In order to increase the reactivity of ozone, it is effective to control the temperature of the ozone water so that the temperature is in the range of 23 to 40 ° C. In addition, the temperature around 35 ° C. is the most reactive than ozone deterioration, and the cleaning ability is about 8 times higher than normal temperature. Moreover, in this Embodiment, ozone water is used by the density | concentration of 30 ppm or more, and the high cleaning capability is acquired. In addition, since the deterioration of ozone occurs even when the temperature is controlled, it is desirable that the original ozone concentration is high.
[0086]
In single wafer cleaning, fluorine tends to remain at the Si-SiO cleaning interface. HF in dangling bonds₂ ⁻, HF⁻Since it tends to remain as a residue, complete hydrogen termination is hindered. Rinse after DHF cleaning is recommended to improve substitution characteristics and to optimize hydrogen termination.
[0087]
Next, for the cleaned substrate 10, preferably N₂Annealing is performed in an inert gas atmosphere such as (nitrogen) and at a high temperature of about 900 to 1300 ° C., and pretreatment is performed so as to reduce distortion generated in the TFT array substrate 10 in a high-temperature process to be performed later.
[0088]
Next, in step S1 of FIG. 6, a groove 11 (see FIG. 5) is formed on the TFT array substrate 10 by etching or the like. Next, in step S2 of FIG. 6, a metal such as Ti, Cr, W, Ta, Mo and Pd or a metal alloy film such as metal silicide is sputtered to a thickness of about 100 to 500 nm, preferably about 200 nm. Deposit to film thickness. Then, the lower light-shielding film 12 whose planar shape is a lattice is formed by photolithography and etching.
[0089]
Next, in step S22, a cleaning process before the formation of the first interlayer insulating film 13 (FIG. 7B) is performed. The cleaning in step S22 is indicated as follows using the same notation as the above [] writing.
[0090]
[O_Three(Ozone) Water (Concentration: 30-100 ppm / Temperature: 23-40 ° C / 30s-3min) Organic removal, metal removal, passivation]
[Super pure water (spin rinse, 10s) replacement]
[DHF (HF: H₂O = 1: 50-200 / 23-25 ° C / 5-60s)) Metal removal, chemical and natural oxide film etching, particle removal]
[Super pure water (spin rinse, 1 min) replacement]
[O_Three(Ozone) Water (Concentration: 30-100 ppm / Temperature: 23-40 ° C / 30 s-3 min) Organic removal, metal removal, passivation, contamination re-adhesion prevention]
[Super pure water (spin rinse, 10s) replacement]
[Dry (N₂Purge type spin drying)]
Although WSi constituting the lower light-shielding film 12 is easily oxidized, in this embodiment, it can be quickly passivated by the strong oxidizing power of ozone. In addition, the lift-off function using hydrofluoric acid makes it possible to obtain a high particle removal capability after sputter deposition without using megasonic cleaning (MS) at room temperature. If residual particles remain, the abnormal growth in the correlation insulating film is promoted, and the uniform film formation of the upper film is hindered, resulting in a film residue after disconnection or subsequent dry etching, causing a device failure. End up. However, in the present embodiment, high particle removal performance is obtained by cleaning with a hydrofluoric acid aqueous solution, and the occurrence of device defects can be prevented.
[0091]
Next, in step S3, TEOS (tetraethyl orthosilicate) gas, TEB (tetraethyl boatrate) gas, TMOP (TMOP) is formed on the lower light shielding film 12 by, for example, atmospheric pressure or low pressure CVD. An interlayer insulating film 13 made of a silicate glass film such as NSG, PSG, BSG, or BPSG, a silicon nitride film, a silicon oxide film, or the like is formed using a gas such as (tetra-methyl-oxy-phosphate). The film thickness of the interlayer insulating film 13 is, for example, about 500 to 2000 nm.
[0092]
Next, in step S23, a cleaning process before the formation of the semiconductor layer 1a (FIG. 7C) is performed. The cleaning in step S23 is expressed as follows using the same notation as the above [] writing.
[0093]
[O_Three(Ozone) Water (Concentration: 30-100 ppm / Temperature: 23-40 ° C / 30s-3min) Organic removal, metal removal, passivation]
[Super pure water (spin rinse, 10s) replacement]
[DHF (HF: H₂O = 1: 50 ~ 200/23 ~ 25 ℃ / 5 ~ 60s) Metal removal, chemical and natural oxide film etching]
[Super pure water (spin rinse, 1 min) replacement]
[O_Three(Ozone) Water (Concentration: 30-100 ppm / Temperature: 23-40 ° C / 30 s-3 min) Organic removal, metal removal, passivation, contamination re-adhesion prevention]
[Super pure water (spin rinse, 10s) replacement]
[Dry (N₂Purge type spin drying)]
Next, in step S4, low pressure CVD using monosilane gas, disilane gas or the like at a flow rate of about 400 to 600 cc / min on the interlayer insulating film 13 in a relatively low temperature environment of about 760 to 550 ° C., preferably about 500 ° C. An amorphous silicon film is formed by (for example, CVD at a pressure of about 20 to 40 Pa). Thereafter, annealing is performed in a nitrogen atmosphere at about 600 to 700 ° C. for about 1 to 10 hours, preferably 4 to 6 hours, so that the polysilicon film has a grain size of about 50 to 200 nm, preferably Solid phase growth is performed until the particle size becomes about 100 nm. As a method for solid phase growth, annealing using RTA (Rapid Thermal Anneal) may be used, or laser annealing using an excimer laser or the like may be used. At this time, depending on whether the TFT 30 for pixel switching is an n-channel type or a p-channel type, a dopant of a group V element or a group III element may be slightly doped by ion implantation or the like. Then, a semiconductor layer 1a having a predetermined pattern is formed by photolithography and etching.
[0094]
Next, in step S24, a cleaning process before the formation of the gate insulating film 2a (FIG. 7D) is performed. The cleaning in step S24 is expressed as follows with the same notation as [] above.
[0095]
[O_Three(Ozone) Water (Concentration: 30-100 ppm / Temperature: 23-40 ° C / 30s-3min) Organic removal, metal removal, passivation]
[Super pure water (spin rinse 10s) replacement]
[DHF (HF: H₂O = 1: 50-200 / 23-25 ° C / 5-60s) Metal removal, chemical and natural oxide film etching]
[Super pure water (spin rinse 1 min) replacement]
[O_Three(Ozone) Water (Concentration: 30-100 ppm / Temperature: 23-40 ° C / 30 s-3 min) Organic removal, metal removal, passivation, contamination re-adhesion prevention]
[Super pure water (spin rinse 10s) replacement]
[Dry (N₂Purge type spin drying)]
From light element impurity inspection of SIMS (secondary ion mass spectrometry), O_Three-DHF cleaning tends to leave fluorine at the Si-SiO cleaning interface. HF in dangling bonds₂ ⁻, HF⁻Since it tends to remain as a residue, complete hydrogen termination is hindered. Rinse after DHF cleaning is recommended to improve substitution characteristics and to optimize hydrogen termination.
[0096]
Further, when contamination in the air or in the apparatus adheres to dangling bonds of Si, it is difficult to remove with only hydrofluoric acid. So once ozone (O_Three) Oxidation passivation is formed with water and lifted off with hydrofluoric acid.
[0097]
In the single wafer process, since there is no re-deposition phenomenon of metal impurities or foreign matters, the Si-SiO interface state is easily cleaned. This is proved by electrical property evaluation including TDDB (Time Dependent Dielectric Breakdown) property. It can also be seen from the electronic behavior when the neutralization conditions near the SIMS interface are changed that there is little electrical leakage due to impurities.
[0098]
Next, in step S5, the semiconductor layer 1a constituting the TFT 30 is thermally oxidized at a temperature of about 900 to 1300 [deg.] C., preferably about 1000 [deg.] C., followed by low pressure CVD or the like. Thus, lower and upper gate insulating films 2a and 2b (including a gate insulating film) made of a multilayer high-temperature silicon oxide film (HTO film) or a silicon nitride film are formed.
[0099]
As a result, the semiconductor layer 1a has a thickness of about 30 to 150 nm, preferably about 35 to 50 nm, and the insulating films 2a and 2b have a thickness of about 20 to 150 nm, preferably about 30 to The thickness is 100 nm.
[0100]
Next, in order to control the threshold voltage Vth of the TFT 30 for pixel switching, the N channel region or the P channel region of the semiconductor layer 1a is doped with a predetermined amount of a dopant such as boron by ion implantation or the like. To do.
[0101]
Next, in step S25, a cleaning process before forming the scanning line 3a (FIG. 7E) is performed. The cleaning in step S25 is indicated as follows with the same notation as the above [] writing.
[0102]
[O_Three(Ozone) Water (Concentration: 30-100 ppm / Temperature: 23-40 ° C / 30s-3min) Organic removal, metal removal, passivation]
[Super pure water (spin rinse 10s) replacement]
[Dry (N₂(Purge type spin drying)
In step S25, the following cleaning method can be employed.
[0103]
[O_Three(Ozone) Water (Concentration: 30-100 ppm / Temperature: 23-40 ° C / 30s-3min) Organic removal, metal removal, passivation]
[Super pure water (spin rinse, 10s) replacement]
[DHF (HF: H₂O = 1: 50 ~ 200/23 ~ 25 ℃ / 5 ~ 60s) Metal removal, chemical and natural oxide film etching]
[Super pure water (spin rinse, 1 min) replacement]
[O_Three(Ozone) Water (Concentration: 30-100 ppm / Temperature: 23-40 ° C / 30 s-3 min) Organic removal, metal removal, passivation, contamination re-adhesion prevention]
[Super pure water (spin rinse, 10s) replacement]
[Dry (N₂Purge type spin drying)]
Next, in step S6, a polysilicon film is deposited by a low pressure CVD method or the like, and phosphorus (P) is further thermally diffused to make this polysilicon film conductive. Alternatively, a doped silicon film into which P ions are introduced simultaneously with the formation of the polysilicon film may be used. The thickness of this polysilicon film is about 100 to 500 nm, preferably about 350 nm. Then, a scanning line 3a having a predetermined pattern including the gate electrode portion of the TFT 30 is formed by photolithography and etching.
[0104]
For example, when the TFT 30 is an n-channel TFT having an LDD structure, the scanning line 3a (gate electrode) is used as a mask in order to form a low concentration source region and a low concentration drain region in the semiconductor layer 1a. , P and other group V element dopants at low concentrations (eg, 1 to 3 × 10 P ions)¹³/ Cm²(Step S7). As a result, the semiconductor layer 1a under the scanning line 3a becomes a channel region 1a ′.
[0105]
Further, in order to form the high concentration source region 1d and the high concentration drain region 1e constituting the pixel switching TFT 30, a resist layer having a planar pattern wider than the scanning line 3a is formed on the scanning line 3a. Thereafter, a dopant of a group V element such as P is used at a high concentration (for example, P ions are added to 1 to 3 × 10¹⁵/ Cm²(Step S8).
[0106]
Thus, an LDD structure element having a low concentration source / drain region and a high concentration source / drain region is formed. For example, a TFT having an offset structure may be used without doping at a low concentration, or a self-aligned TFT may be formed by an ion implantation technique using P ions, B ions, or the like using the scanning line 3a as a mask. The scanning line 3a is further reduced in resistance by doping of the impurities.
[0107]
Next, in step S26, a cleaning process before the formation of the second interlayer insulating film 14 (FIG. 7F) is performed. The cleaning in step S26 is expressed as follows with the same notation as the above [] writing.
[0108]
[O_Three(Ozone) Water (Concentration: 30-100 ppm / Temperature: 23-40 ° C / 30s-3min) Organic removal, metal removal, passivation]
[Super pure water (spin rinse, 10s) replacement]
[Dry (N₂(Purge type spin drying)
In step S26, the following cleaning method can be employed.
[0109]
[O_Three(Ozone) Water (Concentration: 30-100 ppm / Temperature: 23-40 ° C / 30s-3min) Organic removal, metal removal, passivation]
[Super pure water (spin rinse, 10s) replacement]
[DHF (HF: H₂O = 1: 50 ~ 200/23 ~ 25 ℃ / 5 ~ 60s) Metal removal, chemical and natural oxide film etching]
[Super pure water (spin rinse, 1 min) replacement]
[O_Three(Ozone) Water (Concentration: 30-100 ppm / Temperature: 23-40 ° C / 30 s-3 min) Organic removal, metal removal, passivation, contamination re-adhesion prevention]
[Super pure water (spin rinse, 10s) replacement]
[Dry (N₂Purge type spin drying)]
Next, in step S9, a silicate glass film such as NSG, PSG, BSG, BPSG, or the like is nitrided on the scanning line 3a using, for example, TEOS gas, TEB gas, TMOP gas or the like by atmospheric pressure or reduced pressure CVD method. A second interlayer insulating film 14 made of a silicon film, a silicon oxide film or the like is formed. The film thickness of the second interlayer insulating film 14 is about 500 to 2000 nm, for example. Here, preferably, annealing is performed at a high temperature of about 800 ° C. to improve the film quality of the interlayer insulating film 14.
[0110]
Next, in step S10, the contact holes 24a and 26a are simultaneously opened by dry etching such as reactive ion etching and reactive ion beam etching for the second interlayer insulating film.
[0111]
Next, in step S27, a cleaning process is performed before the formation of the first intermediate conductive layer 15 (FIG. 7G) constituting the lower electrode of the storage capacitor. The cleaning in step S27 is shown as follows with the same notation as the above [] writing.
[0112]
[O_Three(Ozone) Water (Concentration: 30-100 ppm / Temperature: 23-40 ° C / 30s-3min) Organic removal, metal removal, passivation]
[Super pure water (spin rinse, 10s) substitution]
[DHF (HF: H₂O = 1: 50 ~ 200/23 ~ 25 ℃ / 5 ~ 60s) Metal removal, chemical and natural oxide film etching]
[Super pure water (spin rinse, 1 min) replacement]
[Dry (N₂(Purge type spin drying)
Next, in the present embodiment, in step S11, the first intermediate conductive layer 15 that becomes the lower capacitor electrode of the storage capacitor is formed. That is, a polysilicon film is deposited on the second interlayer insulating film 14 by a low pressure CVD method or the like, and phosphorus (P) is further thermally diffused to make the polysilicon film conductive. Alternatively, a doped silicon film into which P ions are introduced simultaneously with the formation of the polysilicon film may be used. The thickness of the polysilicon film is about 100 to 500 nm, preferably about 150 nm. Then, patterning is performed by photolithography and etching to form the first intermediate conductive layer 15.
[0113]
Next, in step S28, a cleaning process is performed before the formation of the dielectric film 17 (FIG. 7G) constituting the capacitive insulating film. The cleaning in step S28 is shown as follows with the same notation as the above [] writing.
[0114]
[O_Three(Ozone) Water (Concentration 30-60ppm / Temperature 23-40 ° C / 30s-3min) Organic removal, metal removal, and passivation]
[Super pure water (spin rinse 10s) replacement]
[DHF (HF: H₂O = 1: 50 ~ 200/23 ~ 25 ℃ / 5 ~ 30s) Metal removal, chemical and natural oxide film etching]
[Super pure water (spin rinse 1 min) replacement]
[O_Three(Ozone) Water (Concentration: 30-100 ppm / Temperature: 23-40 ° C / 30 s-3 min) Organic removal, metal removal, passivation, contamination re-adhesion prevention]
[Super pure water (spin rinse 10s) replacement]
[Dry (N₂Purge type spin drying)]
In step S28, the following cleaning method can be employed.
[0115]
[O_Three(Ozone) Water (Concentration: 30-100 ppm / Temperature: 23-40 ° C / 30s-3min) Organic removal, metal removal, passivation]
[Super pure water (spin rinse 10s) replacement]
[DHF (HF: H₂O = 1: 50 ~ 200/23 ~ 25 ℃ / 5 ~ 30s) Metal removal, chemical and natural oxide film etching]
[Super pure water (spin rinse 1 min) replacement]
[Dry (N₂Purge type spin drying)]
In the next step S12, a dielectric film 17 which is an insulating film of a storage capacitor is formed. That is, a dielectric made of a high-temperature silicon oxide film (HTO film) or a silicon nitride film on the first intermediate conductive layer 15 and the second interlayer insulating film 14 also serving as the pixel potential side capacitor electrode by a low pressure CVD method, a plasma CVD method or the like. The film 17 is deposited to a relatively thin thickness of about 50 nm.
[0116]
The dielectric film 17 may be composed of either a single layer film or a multilayer film as in the case of the insulating films 2a and 2b, and various known types generally used for forming a gate insulating film of a TFT. It can be formed by technology. As the dielectric film 17 is made thinner, the storage capacity becomes larger. Consequently, the dielectric film 17 is formed so as to be an extremely thin insulating film having a film thickness of 50 nm or less on the condition that defects such as film breakage do not occur. It is advantageous to form
[0117]
Next, in step S29, a cleaning process is performed before the formation of the capacitor line 18 (FIG. 8 (i)) constituting the upper electrode of the storage capacitor. The cleaning in step S29 is indicated as follows with the same notation as the above [] writing.
[0118]
[O_Three(Ozone) Water (Concentration: 30-100 ppm / Temperature: 23-40 ° C / 30s-3min) Organic removal, metal removal, passivation]
[Super pure water (spin rinse 10s) replacement]
[Dry (N₂(Purge type spin drying)
Next, in step S13, the capacitor line 18 is formed on the dielectric film 17. The film thickness of the capacitor line 18 is set to 150 nm, for example.
[0119]
Next, in step S30, a cleaning process before the formation of the third interlayer insulating film 19 (FIG. 8J) is performed. The cleaning in step S30 is indicated as follows using the same notation as the above [] writing.
[0120]
[O_Three(Ozone) Water (Concentration: 30-100 ppm / Temperature: 23-40 ° C / 30s-3min) Organic removal, metal removal, passivation]
[Super pure water (spin rinse, 10s) replacement]
[DHF (HF: H₂O = 1: 50 ~ 200/23 ~ 25 ℃ / 5 ~ 60s) Metal removal, chemical and natural oxide film etching]
[Super pure water (spin rinse, 1 min) replacement]
[O_Three(Ozone) Water (Concentration: 30-100 ppm / Temperature: 23-40 ° C / 30 s-3 min) Organic removal, metal removal, passivation, contamination re-adhesion prevention]
[Super pure water (spin rinse, 10s) replacement]
[Dry (N₂(Purge type spin drying)
Next, in step S14, a third interlayer insulating film made of a silicate glass film such as NSG, PSG, BSG, or BPSG, a silicon nitride film, a silicon oxide film, or the like using, for example, atmospheric pressure or reduced pressure CVD method or TEOS gas. A film 19 is formed. The film thickness of the third interlayer insulating film 19 is, for example, about 500 to 1500 nm.
[0121]
Next, in step S15, a low-resistance metal such as light-shielding Al (aluminum), metal silicide, or the like is formed on the entire surface of the third interlayer insulating film 19 so as to fill the contact holes 24a and 24b by sputtering or the like. As about 100-500 nm thick, preferably about 300 nm. Then, the data line 6a having a predetermined pattern is formed by photolithography and etching (step S16).
[0122]
Next, in step S17, a silicate glass film such as NSG, PSG, BSG, or BPSG, a silicon nitride film or an oxide film is used to cover the data line 6a using, for example, atmospheric pressure or reduced pressure CVD or TEOS gas. A fourth interlayer insulating film 25 made of a silicon film or the like is formed. The film thickness of the fourth interlayer insulating film 25 is, for example, about 500 to 1500 nm.
[0123]
Next, in step S18, the contact hole 26b is opened by dry etching such as reactive ion etching or reactive ion beam etching for the fourth interlayer insulating film 25 and the third interlayer insulating film 19.
[0124]
Next, in step S19, a transparent conductive film such as an ITO film is deposited to a thickness of about 50 to 200 nm on the inner peripheral surface of the contact hole 26b and the fourth interlayer insulating film 25 by sputtering or the like. . Then, the pixel electrode 9a is formed by photolithography and etching. Note that when the liquid crystal device is used for a reflective liquid crystal device, the pixel electrode 9a may be formed from an opaque material having a high reflectance such as Al. The contact hole 26b connects the first intermediate conductive layer 15 and the pixel electrode 9a.
[0125]
As described above, in the present embodiment, single wafer processing is adopted, and cleaning is performed only once with ozone water, cleaning is performed only once with ozone water and dilute hydrofluoric acid solution, and ozone water, dilute hydrofluoric acid solution and By adopting three cleaning patterns of cleaning with ozone water only once in each cleaning process during the manufacturing process of the TFT substrate, a sufficient cleaning effect is obtained while suppressing an increase in roughness.
[0126]
That is, the glass substrate / or film surface on which organic impurities, particle foreign matter, or metal impurities taken into the surface on the production line or in the apparatus are present is first present on the outermost surface by washing with about 30 ppm ozone water. Organic and metal impurities to be removed from the surface are dissolved and removed in an aqueous solution. If it is on the surface of the polysilicon film, the surface can be uniformly oxidized by 0.5 to 2.0 nm with high-concentration ozone water, and the polar interface region having a depth of 0.5 to 2.0 nm from the outermost surface of the polysilicon film Therefore, metal impurities that are likely to exist as minute residues can be taken into the oxide film.
[0127]
Further, by using dilute hydrofluoric acid together, the oxide film is removed, and at the same time, metal impurity molecules (atoms) present in the oxide film and metal impurities and particles remaining on the oxide film surface are removed from the polysilicon film and the insulating film surface. Can be separated almost completely.
[0128]
By using this method, the surface of the polysilicon film having large lattice defects or roughness compared to single crystal silicon or the impurity diffused polysilicon film can be cleaned without excessive damage. The formed oxide film or interlayer insulating film promotes better quality film growth, and the device formed thereby can stabilize characteristics and yield.
[0129]
As described above, in the present embodiment, the surface of the polysilicon film, the surface of the impurity diffusion polysilicon film, the silicide film that are easily damaged by the hydrofluoric acid aqueous solution, the ammonia aqueous solution, compared to the single crystal silicon substrate. It is possible to clean the surface while suppressing micro-damage on the surface. In addition, organic contamination, metal contamination, and particle contamination can be removed in a short time and satisfactorily. In addition, cleaning of a liquid crystal substrate, particularly cleaning of a polysilicon surface with many lattice defects and impurity doping, may cause surface roughness due to selective oxidation and etching as compared with a single crystal silicon surface. In the configuration, surface roughness is suppressed by uniform oxidation with concentrated ozone-dissolved water and etching with a combination of dilute hydrofluoric acid aqueous solution or high-concentration ozone water containing dilute hydrofluoric acid, and the pressure resistance life of the oxide film formed on polysilicon is reduced. The yield can be improved and the yield can be further stabilized. In order to improve the uniform oxidation rate and to reduce the diluted hydrofluoric acid concentration as much as possible in consideration of the influence of the etching on the polysilicon surface and other insulating films, the dissolved concentration of ozone water is 15 ppm as described above. Set to above. As a result, the time for forming an oxide film on the polysilicon that takes in the impurities existing at a depth of 0.5 to 2.0 nm from the polysilicon surface is shortened, and contamination with one treatment with ozone water and dilute hydrofluoric acid. Allows removal.
[0130]
In the present embodiment, single-wafer spin cleaning is performed. Thereby, recontamination can be remarkably reduced as compared with batch cleaning, and back-contamination from the back surface of the substrate can be remarkably reduced. Moreover, it is possible to easily switch to cleaning with ozone water, dilute hydrofluoric acid aqueous solution or pure water only by changing the nozzle, and the workability is excellent.
[0131]
Moreover, since cleaning can be performed while the nozzle is scanned in the horizontal direction, the effect of removing contamination is extremely high.
[0132]
The substrate of the present invention is not limited to a liquid crystal device, but can be applied to a display panel such as an EL (electroluminescence) device or an electrophoresis device.
[Brief description of the drawings]
FIG. 1 is a flowchart showing a substrate cleaning method according to a first embodiment of the present invention.
FIG. 2 is an equivalent circuit diagram of various elements and wirings in a plurality of pixels constituting a pixel region of a TFT substrate (element substrate) which is a semiconductor device to which the present embodiment is applied.
FIG. 3 is a plan view of a liquid crystal device using an element substrate to which the present embodiment is applied, and is a plan view seen from the counter substrate side together with each component formed on the element substrate.
4 is a cross-sectional view of the liquid crystal device after the assembly process in which the element substrate and the counter substrate are bonded to each other and the liquid crystal is sealed is cut along the line HH ′ in FIG. 3;
5 is a cross-sectional view showing in detail the liquid crystal device of FIGS. 3 and 4. FIG.
FIG. 6 is a flowchart showing a substrate cleaning method.
FIG. 7 is a process chart showing a substrate cleaning method in the order of processes.
FIG. 8 is a process diagram illustrating a substrate cleaning method in the order of processes.
FIG. 9 is an explanatory diagram for explaining a state of cleaning.
FIG. 10 is an explanatory diagram for explaining a state of cleaning.
[Explanation of symbols]
71 ... Spin chuck, 72 ... Substrate, 73 ... Cup, 74, 75 ... Storage chamber, 76 ... Lid, 77-79 ... Nozzle.

Claims (3)

A method for manufacturing a substrate for an electro-optical device comprising scanning lines and data lines intersecting each other, and a thin film transistor for pixel switching,
Forming a lower light-shielding film made of WSi on the substrate;
Cleaning the substrate on which the lower light-shielding film is formed;
Forming an interlayer insulating film on the lower light-shielding film;
Forming a polysilicon film on the interlayer insulating film;
Patterning the polysilicon film by photolithography and etching to form a semiconductor layer of the thin film transistor;
Cleaning the substrate on which the semiconductor layer is formed;
Forming a gate insulating film on the semiconductor layer after cleaning the substrate;
Forming a gate electrode portion on the semiconductor layer via the gate insulating film and forming a scanning line;
Forming a source region and a drain region by doping impurities into the semiconductor layer;
Forming a data line electrically connected to the source region;
With
The step of cleaning the substrate on which the lower light-shielding film is formed and the step of cleaning the substrate on which the semiconductor layer is formed are performed using a single-wafer type substrate cleaning apparatus, in ozone water cleaning, pure water rinsing cleaning, dilute fluorine cleaning. It is performed in the order of acid cleaning, pure water rinse cleaning, ozone water cleaning, pure water rinse cleaning, and drying with nitrogen .
The concentration of the dilute hydrofluoric acid aqueous solution used in the dilute hydrofluoric acid cleaning is 0.1 to 10%, the dilute hydrofluoric acid aqueous solution contains ozone, and the ozone water concentration used in the ozone water cleaning is 15 ppm or more. A method for manufacturing a substrate for an electro-optical device. The substrate cleaning apparatus includes a spin chuck that holds the substrate, a cup that accommodates the substrate and the spin chuck to form a cleaning chamber, a nozzle that discharges dilute hydrofluoric acid onto the surface of the substrate, A nozzle that discharges ozone water onto the surface of the substrate; a nozzle that discharges pure water onto the surface of the substrate; and a center of the spin chuck, the dilute hydrofluoric acid, the dilute hydrofluoric acid, and the pure water; A cleaning liquid discharge port that selectively discharges the nitrogen to the back side of the substrate for a predetermined time, and a lid that discharges the nitrogen from the center, which can close the cleaning chamber, are provided,
When performing the ozone water cleaning, the pure water rinsing cleaning, and the dilute hydrofluoric acid cleaning, the dilute hydrofluoric acid or the ozone from the nozzles while the nozzles scan the surface parallel to the surface of the substrate. Water or pure water is discharged onto the surface of the substrate, and the diluted hydrofluoric acid, ozone water, or pure water is discharged from the cleaning liquid discharge port onto the back surface of the substrate.
Wherein by the time of drying is nitrogen, the method of manufacturing the electro-optical device substrate according to claim 1, characterized in that nitrogen is discharged from the center of the cleaning liquid discharge port and said lid. The cleaning chamber comprises two cleaning chambers, a cleaning chamber for performing the ozone water cleaning and the dilute hydrofluoric acid cleaning, and a cleaning chamber for performing the pure water rinse cleaning,
3. The method for manufacturing a substrate for an electro-optical device according to claim 2 , wherein the waste liquid from each of the cleaning chambers is caused to flow out from a corresponding discharge port.

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