JP3194245B2 - Processing method for substrate on which amorphous silicon layer is formed - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to the, LCD (liquid crystal display) device, in particular TFT (thin film transistor) treatment of the substrate which is formed using amorphous silicon layer that is used in the manufacturing process of the liquid crystal panel of the active-type with a built-in It is about the method.

[0002]

2. Description of the Related Art As is well known, semiconductor integrated circuits, PDPs
(Plasma display panel) and a manufacturing process of a display device such as an LCD device require a plurality of etching processes and cleaning processes. In these etching processes, for example, in the process of developing a photosensitive resin at the time of photo-engraving and the process of etching various thin film layers, a chemical solution is sprayed onto a substrate in a shower or spray form, and the chemical solution is continuously applied one by one. In general, the processing is performed, and in a mass production factory, a manufacturing apparatus that continuously processes one by one by spraying pure water onto a substrate in a shower or spray form also in a cleaning process is often used.

FIG. 2 is a schematic view of such an etching apparatus, and is a sectional view of the apparatus. In the configuration as an etching apparatus, the etching chamber 2, the washing chamber 4 and the drying chamber 5 are the minimum components, and when the chemical solution processing time is long, the etching chamber 2 may be multi-staged or the etching liquid may be used. A draining chamber 3 is provided between the etching chamber 2 and the washing chamber 4 in order to reduce the amount taken out to the washing chamber 4, and the buffer chamber 1 is eaten in order to prevent diffusion of the chemical mist outside the apparatus. A design method such as installation on the upstream side of the chamber 2 is added. The configuration of the etching apparatus will be briefly described below. The chemical liquid circulation pump 6, a filter 7 for removing dust or particles in the chemical liquid, and a circulation pipe 9 system including a flow rate control valve 8, and an etching chamber There is provided a system for circulating and using the etching liquid 13 by forming a closed loop with the nozzle 10 for injecting the chemical liquid in the nozzle 2, the chemical liquid recovery pipe 11 provided at the bottom of the etching chamber 2, and the chemical liquid circulation tank 12. Further, a supply pipe 15 system having a valve 14 for adjusting a flow rate is connected to a circulation tank 12.
A new chemical is supplied to the circulation tank 12 by, for example, a pressurized nitrogen gas supply from a separately provided supply tank (not shown). Similarly, a waste pipe 17 system having a valve 16 for adjusting the flow rate is a chemical liquid waste pipe for discarding the used etching liquid 13 to the outside, and not shown, but after being transferred to a separately installed waste liquid tank or the like. Procedures such as disposal as industrial waste are performed. In order to avoid the deterioration and deterioration of the etching liquid due to the reaction of the etching liquid with the atmosphere, the etching chamber 2
A method of purging the atmosphere in the chamber with an inert gas such as nitrogen is adopted, and a nitrogen gas supply pipe 19 having a flow rate valve 18 is used.
Supplies a purge gas.

Next, in the rinsing chamber 4, since pure water of appropriate purity is generally required to wash away the chemical solution adhering to the substrate, a pure water supply pipe 21 having a valve 20 for adjusting the flow rate is required.
Is provided, and a nozzle 22 for injecting pure water is disposed at a tip of the pipe. The treated water after washing the substrate is passed through the drain pipe 23.In the early stage of the pure water washing, even though the amount is small, the drainage contains chemicals, so it is usually necessary to perform treatment for pollution control before the factory Discarded as wastewater. In addition, the washing room has a two-stage structure, and the wastewater in the first washing room is treated as described above, and the wastewater in the second washing room is recovered because of its high purity, and is again used as a pure water source for another purpose. In recent years, efforts to conserve resources, such as using it as raw water for a pure water production apparatus, have also often been adopted recently.

[0005] Further, not only pure water is simply sprayed, but also ultrasonic energy is superimposed on the pure water to be sprayed,
Alternatively, by introducing a high-pressure jet or the like, the ability to remove foreign substances and particles attached to the substrate by physical force is enhanced, so that the introduction of these is becoming established in the latest cleaning machines. In the drying chamber 5, a dry gas supply pipe 26 system such as dry air or nitrogen gas having a pressure gauge 24 and a flow rate control valve 25 is provided to dry a wet substrate after washing with water. A nozzle 27 for injecting the drying gas into a sheet on the substrate is disposed. The water condensed by the nozzle 27 in the drying chamber 5 passes through the drain pipe 28 and is discarded. The method of spraying the dried gas onto the substrate to dry it is also called an air knife. In addition, it is more efficient and general to spray the pure water nozzle 22 and the drying nozzle 27 not only from above the substrate but also from below the substrate.
Reference numeral 29 in FIG. 2 is an imaginary line indicating a substrate transfer line, which includes a substrate transfer mechanism, an interference prevention mechanism such as a gate valve and an air curtain installed between the processing chambers, and an exhaust disposed in each processing chamber. The system mechanism is also omitted in the drawing. In addition to the above-mentioned air knife, the substrate can be dried by a spin drying method in which the substrate is rotated at a high speed to dry the substrate, or by a dry IPA (isopropyl alcohol).
There is also a PA replacement type drying method, but a detailed description is omitted here.

Further, in order to selectively form various thin films deposited on a substrate in a predetermined pattern, a photosensitive resin (resist) applied on the various thin films is exposed to an exposure machine and a photomask. In this case, a photolithography technique is used in which the photosensitive resin is selectively exposed by using a developer and the photosensitive resin is selectively left using a developing solution, but a detailed description thereof is omitted here. The step of removing the photosensitive resin used for the selective pattern formation is a stripping step. If a chemical solution is used, an organic solvent, sulfuric acid, fuming nitric acid, or the like is appropriately selected depending on the properties of the substrate and the thin film.
There is also a method of irradiating vacuum equipment such as oxygen asher using oxygen plasma or ultraviolet rays without using a chemical solution, and removing the resist by the ashing action of oxygen plasma generated simultaneously with the decomposition of the resist. Omitted.

In the manufacturing process of a liquid crystal device, a substrate having a size of 300 mm square or more is adopted from the beginning because the size of the substrate is extremely large as compared with a silicon single crystal substrate. In view of this, there has been a historical background in which positive resists mainly composed of novolak resins have been frequently used as photosensitive resins. In addition, the resist stripping solution is taken into consideration that the substrate is glass, and an organic alkali stripping solution is often used from the viewpoint of safety and cost. In this case, as the peeling apparatus, the apparatus configuration is exactly the same as that of the etching apparatus shown in FIG. 2, and the only difference is that the peeling liquid is heated to a relatively high temperature of 60 to 100 ° C. as compared with the etching liquid. Although not shown, a fire extinguishing system is provided in preparation for ignition of the stripping solution. Needless to say, in the case of a peeling device, the etching chamber 2 is called a peeling chamber.

[0008]

As a matter of course, as a measure for increasing the productivity as a production apparatus or for shortening the lead time, it is more difficult to operate the etching apparatus and the peeling apparatus separately. Desirable results are obtained when driving the vehicle directly. 370 x 4
When a TFT liquid crystal display device is to be manufactured on a glass substrate having a size of 70 mm, a storage container or jig such as a cassette or a magazine having a capacity of storing about 20 substrates is used. A portion that does not contribute to the process (processing) such as a means and space for transporting such a cassette between the devices and a loader and an unloader for placing the cassette on the entrance side and the exit side of the device are generated. In view of the above, much explanation of the significance of directly connecting the etching apparatus and the peeling apparatus is unnecessary. In fact, in recent mass production factories of liquid crystal devices, for example, a transparent conductive layer serving as a pixel electrode, Al, Ta, Mo, and Cr serving as gate wiring metals, and A serving as a source wiring metal.
l, Ti, Cr and a silicon oxide layer (Si
A device configuration in which an etching device and a stripping device are directly connected has begun to be used frequently so that the resist can be stripped immediately after the etching of O ₂ ) or a silicon nitride layer (SiN _x ).

However, in the case where the amorphous silicon layer is exposed on the substrate after the etching, an organic alkali-based stripping solution, for example, a trade name "Stripper 106" manufactured by Tokyo Ohka is used as the stripper. In such a case, the stripping solution is strongly alkalized (pH 11 to 12) due to the moisture dissolved in the stripping solution, so that the amorphous silicon layer is etched by the stripping solution. It is not uncommon for the film to be completely disappeared with a film thickness of about 0.1 μm, and this tendency is particularly large as the heating temperature of the stripping solution performed for improving the stripping property is higher. This is because the release liquid is M
Because MEA is composed of a mixture of EA (monoethanolamine) and DMSO (dimethyl sulfoxide) that dissolves the resist peeled off from the substrate, MEA has an amino group, and therefore easily ionizes in the presence of water to form an alkaline solution. Because it becomes.

Here, referring to FIGS. 3A and 3B,
The state where the amorphous silicon layer is exposed will now be described in a little more detail. One of the substrates constituting the active type liquid crystal panel needs an insulated gate transistor as a switching element, and this transistor is manufactured by, for example, a process described below. First, as shown in FIG. 3A, a gate 31 of, for example, a Cr or Mo layer having a film thickness of about 0.1 to 0.2 μm, which serves as a scanning line serving as a gate, is selectively formed on one main surface of the glass substrate 30. Form. Next, the first silicon nitride layer 32 having a thickness of, for example, 0.4-0.1-0.2 μm and containing substantially no impurities is formed on the entire surface of the glass substrate 30 by plasma discharge using silane gas as a main component using a plasma CVD apparatus.
The amorphous silicon layer 33 and the second silicon nitride layer are continuously deposited. Then, a photosensitive resin is selectively left on the second silicon nitride layer on the gate 31 by a lithography technique to form a resist pattern 35, and the resist pattern 35 is used as a mask to selectively etch the second silicon nitride layer to form a resist pattern. 2
A silicon nitride layer 34 is formed, exposing the first amorphous silicon layer 33. Then, the step of removing the resist pattern 35 of the photosensitive resin is the above-mentioned problem, and it is obvious that the exposed first amorphous silicon layer 33 is exposed to the stripper.

Thereafter, as shown in FIG. 3B, a second amorphous silicon layer containing phosphorus (P) as an impurity is deposited on the entire surface to a thickness of, for example, 0.05 μm, as shown in FIG. Then, a metal layer to be drain wirings 37 and 38 is applied to the entire surface, and a selective pattern is formed using a photosensitive resin. First, a metal layer, for example, Al having a thickness of about 0.4 μm is etched to expose the second amorphous silicon layer, and then the second non-silicon layer is formed using the photosensitive resin pattern and the source and drain wirings 37 and 38 as a mask. Etching the amorphous silicon layer and the first amorphous silicon layer 33;
The silicon nitride layer 32 and the second silicon nitride layer 34 are exposed. At this time, the second silicon nitride layer 34 has a function of protecting the first amorphous silicon layer 33 'which does not contain impurities serving as a channel portion against over-etching of the formation of the second amorphous silicon layer 36. It is often called an etching stopper. After that, if the pattern of the photosensitive resin is removed, the TFT
An element functioning as a (thin film transistor) is obtained. After the formation of the source and drain wirings 37 and 38, a passivation insulating layer, a picture element electrode, and the like are generally added, but a detailed description thereof is omitted here.

In order to prevent the exposed amorphous silicon layer from being damaged by the stripping solution, the glass substrate in which the resist remains after the etching is temporarily stored in a cassette, and the glass substrate is simply cleaned. A method of storing or leaving for an appropriate period of time (several to several tens of hours) in a relatively dust-free environment such as a clean bench has been implemented, but this would go against the reduction of lead time, and furthermore, Despite the environment, there is a problem that it is difficult to avoid particles and dust from adhering to the substrate due to excessive standby, and the yield is inevitably reduced.

The present invention is directed to solving the above-mentioned problems of the prior art, and realizes a direct connection between an etching apparatus and a peeling apparatus to promote a reduction in lead time. the processing method of a substrate formed of an amorphous silicon layer which is achieved by forming a protective layer which is resistant to peeling liquid in the amorphous silicon layer exposed after etching in a short time The purpose is to provide.

[0014]

In order to achieve this object, a substrate having an amorphous silicon layer according to the present invention is provided .
Treatment method, etching means the step of immersing the treated injection or the substrate to the substrate while circulating the etching solution like a shower or spray-like containing at least hydrogen fluoride at etching chamber,
Industrial washing the etching liquid adhering to the substrate in the first washing chamber
Degree, and drying the substrate after cleaning in the first drying chamber
Wherein the heating means comprises a heating to the extent that the photosensitive resin pattern substrate after drying at a plurality of hot plate does not become difficult to remove by stripping solution to thermal changes, the stripping means
Is a process of spraying or dipping the substrate in a shower or spray form on the substrate while circulating an organic alkali-based release liquid in the release chamber, and cleaning the release liquid adhering to the substrate in the second washing chamber. in that process, and the second substrate after washing with drying chamber comprising the step of drying the substrate processing method
Substrate by the heating process using a hot plate
Atmosphere containing oxygen in the amorphous silicon layer exposed above
To form a thinner silicon oxide layer .

In the present invention, the above - mentioned amorphous silicon layer is formed.
And a plurality of hot-presses for heating the substrate with the etched resist adhered between the etching means and the peeling means by using the processing method of the processed substrate and using the apparatus of the processing method. A plate is arranged, and a heating means for forming a protective layer against a stripping solution in a short time is applied to the exposed amorphous silicon layer after etching, so that the substrate on which the amorphous silicon layer is exposed is exposed to oxygen. By heating in an atmosphere containing, a thin silicon oxide layer of about 100 mm is formed on the surface of the amorphous silicon layer. The situation where the layer is reduced in film thickness can be avoided.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a substrate on which an amorphous silicon layer is formed according to an embodiment of the present invention.
FIG. 1 is a schematic configuration diagram of an etching peeling apparatus that performs the processing method of FIG. Here, components having substantially the same functions as the components described in FIG. 3 showing the conventional example and having substantially the same functions are denoted by the same reference numerals. In FIG. 1, 2 is an etching room, 4 'is a first washing room, 4 "is a second washing room, 5' is a first washing room.
A drying chamber, 5 ″ is a second drying chamber, 40 is a loader, 41 is an unloader, 42 is a heating chamber which is a means for heating a substrate, specifically composed of several hot plates, and 43 is a peeling chamber. This device has at least the loader 40, the etching room 2, the first
An etching device portion which is an etching means provided with a rinsing room 4 'and a first drying room 5', and a peeling device provided with at least a peeling chamber 43, a second washing room 4 ", a second drying room 5" and an unloader 41. An etching peeling device is directly connected to a peeling device portion as a means via a heating chamber 42 of a heating device.

[0017] The etching peeling apparatus constructed as described above is used.
A method for processing a substrate on which an amorphous silicon layer is formed will be described below. Glass having an amorphous silicon layer formed thereon as described above and a photosensitive resin pattern formed on the silicon nitride layer to selectively remove the silicon nitride layer formed on the amorphous silicon layer Substrate 30 (FIG. 3)
(See (a) and (b)) from the loader 40 to the etching chamber 2 one by one. In the etching chamber 2, a solution containing hydrogen fluoride as an etching solution, for example, a buffered hydrofluoric acid solution of HF: NH ₄ F = 1: 6 (volume ratio) is sprayed onto the substrate in a shower shape, and an unnecessary silicon nitride layer is formed. The amorphous silicon layer is exposed by being dissolved and removed. After the etching is completed, buffer hydrofluoric acid as an etching liquid is washed away with pure water in the first washing chamber 4 ', and the substrate wet with pure water is dried in the first drying chamber 5'.

Next, in the heating chamber 42, the dried substrate is left on several hot plates for 1 to 2 minutes, so that
After a heat treatment for about 10 minutes, a thin silicon oxide layer is formed on the exposed amorphous silicon layer. The heating conditions are desirably heating so that the general pattern of the photosensitive resin does not thermally change to make removal with a stripping solution difficult, that is, the temperature is 150 ° C. or less, and the time is 15 minutes or less. Oxygen is required to form a silicon oxide film, but it is not necessary to cover the periphery of the hot plate with an oxygen atmosphere, and a clean atmosphere or a dry air purge is sufficient.

On the substrate heated on several hot plates in the heating chamber 42, a thin silicon oxide layer of 100 ° or less is formed on the exposed amorphous silicon layer.
If the peeling conditions are not severe even when the film is continuously exposed to a high-temperature peeling liquid in the peeling chamber 43, specifically, the processing temperature is 100 ° C. or less,
If the processing time is 10 minutes or less and the water content of the stripping solution is 1% or less, the thin silicon oxide layer is removed, and as a result, the situation where the amorphous silicon layer is reduced in thickness or disappears can be avoided.

After the photosensitive resin pattern is peeled and removed in the peeling chamber 43, the peeling solution is removed with pure water in the second washing chamber 4 "and wet with pure water in the second drying chamber 5". The substrates are dried, and finally, the unloader 41 stores the substrates one by one in a cassette.

[0021]

As described above, according to the present invention,
The processing method of the substrate with the amorphous silicon layer formed is a continuous etching and stripping process, which not only significantly reduces the production lead time, but also reduces the chance of dust and particle adhesion. This contributes not only to improving yields, but also to reducing the area occupied by production equipment, reducing the cost of production equipment, and improving the efficiency of clean room operation. The effect is obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram schematically showing an etching peeling apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic view of a conventional etching apparatus and is a configuration diagram showing a cross section thereof.

FIGS. 3A and 3B are manufacturing steps 1 and 2B of a TFT gate using amorphous silicon as a channel constituting a liquid crystal panel;
FIG. 4 is a sectional view showing a source / drain manufacturing process 2 of the TFT.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Buffer room, 2 ... Etching room, 3 ... Draining room, 4 ... Washing room, 4 '... First washing room, 4 "... Second washing room, 5
... drying room, 5 '... first drying room, 5 "... second drying room,
6: Circulation pump, 7: Filter, 8, 14, 16, 1
8, 20, 25 ... valve, 9 ... circulation pipe, 10, 22 ... nozzle, 11 ... recovery pipe, 12 ... circulation tank, 13 ... etching liquid,
15 ... supply pipe, 17 ... waste pipe, 19 ... nitrogen gas supply pipe, 21 ... pure water supply pipe, 23, 28 ... drain pipe, 24 ...
Pressure gauge, 26 ... dry gas supply pipe, 27 ... dry nozzle,
29… Transfer line, 30… Glass substrate, 31… Gate,
32 ... first silicon nitride layer, 33,33 '... first amorphous silicon layer, 34,34' ... second silicon nitride layer, 35 ... resist pattern, 36,36 '... second amorphous silicon layer,
37 ... source wiring, 38 ... drain wiring, 40 ... loader, 41 ... unloader, 42 ... heating chamber, 43 ... peeling chamber.

Continuation of the front page (51) Int.Cl. ⁷ identification code FI H01L 29/786 (58) Investigation field (Int.Cl. ⁷ , DB name) H01L 21 / 304,21 / 306,21 / 308 H01L 21 / 336,29 / 786 G03F 7/42

Claims (1)

(57) [Claims] An etching means performs processing by spraying or dipping the substrate in a shower or spray shape on a substrate while circulating an etching solution containing at least hydrogen fluoride in an etching chamber.
Step includes the step of drying the substrate after the cleaning step, and in the first drying chamber to wash the etching solution adhering to the substrate at a first washing chamber, the heating means includes a plurality of hot plate
Engineering of the substrate after dried preparative photosensitive resin pattern is heated to the extent that removal is not difficult in a stripping solution to thermal changes
Includes a degree, step stripping means for processing by immersing the injection or the substrate in the form of a shower or spray form to said substrate while circulating the stripping solution of an organic alkaline by peeling chamber, the
(2) Cleaning the stripping solution adhering to the substrate in the washing room
Step, and the second the substrate after washing with drying chamber method for processing a substrate comprising the step of drying, the substrate by a process of heating by the hot plate
Atmosphere containing oxygen in the amorphous silicon layer exposed above
A method for treating a substrate on which an amorphous silicon layer has been formed, wherein a thinner silicon oxide layer is formed by the method .