JP2003007673A - Etching method and apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an etching method which can reduce deposition of particles on a liquid crystal display panel, in an etching apparatus to be used in a step of manufacturing the panel, and the etching apparatus. SOLUTION: In the etching method and apparatus, which immerses a substrate into a chemical to dissolve unwanted thin film and ejecting a cleaning solution from a nozzle above a liquid surface of the chemical, when the substrate is moved up to clean the substrate, prior to dried and deposition of particles on the surface of the substrate, thus reducing particle deposition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an LCD (liquid crystal display) device, and more particularly to an etching method used in the manufacturing process of an active type liquid crystal panel having a built-in TFT (thin film transistor).

[0002]

2. Description of the Related Art As is well known, in a manufacturing process of a display device such as a semiconductor integrated circuit, a plasma display panel and an LCD device, a film forming process for forming a thin film on a substrate, a photo process for masking, and a removal of an unnecessary thin film. It is formed by repeating the etching step and the cleaning step for performing a plurality of times. In these etching processes, a mass production factory uses a manufacturing apparatus for immersing a substrate in a chemical solution for etching.

FIG. 3 is a schematic view of a conventional etching apparatus and shows a sectional configuration diagram thereof. The structure of the conventional etching apparatus will be briefly described below. The chemical circulation pump 1, the filter 2 for removing dust or particles in the chemical, and the circulation piping system including the valve 3 for adjusting the flow rate and the substrate are immersed. The etching tank 4, the recovery pipe 5 for recovering the chemical liquid overflowing from the etching tank 4, and the recovery tank 6 constitute a closed loop. Further, the supply pipe system having the valve 7 for adjusting the flow rate is the chemical liquid supply pipe 8 for supplying the chemical liquid to the etching tank, and although not shown, for example, by a pressure supply with pressurized nitrogen gas from a separately installed supply tank, Is supplied to the etching tank 4. Similarly, the waste pipe system having the valve 9 for adjusting the flow rate is a chemical liquid waste pipe 1 for discarding the used chemical liquid to the outside.
The recovery tank upper limit disposal pipe 11 is a pipe for discarding excess chemical liquid when the tank liquid level rises. Although not shown, procedures such as transferring to a separately installed waste liquid tank or the like and treating as industrial waste are performed.

The substrate 12 is held by the substrate holding portion 13 and moved up and down in the etching bath 4 by the elevator 14.
Although not shown, after the etching process, a washing process and a drying process are continuously performed.

In the manufacturing process of an LCD device, the substrate size is significantly larger than that of a silicon single crystal substrate, and a substrate having a size of 300 mm square or more is adopted from the beginning, and the etching tank also becomes large.

[0006]

In the structure of the conventional example, when dust or particles are mixed in the etching tank, it is difficult to remove them by circulation filtration because the etching tank is deep. Further, there is a problem that particles once dried and fixed on the surface of the substrate cannot be easily removed even by washing. Generally, in a process of manufacturing an LCD device, after forming an amorphous silicon layer on a glass substrate, a substrate containing a chemical solution containing hydrofluoric acid as a chemical solution to remove a thin silicon oxide layer formed on the amorphous silicon layer. To remove the silicon oxide. In particular, when a glass substrate is immersed in a chemical solution containing hydrofluoric acid, the glass components eluted from the glass substrate and fluoride crystals generated from hydrofluoric acid become particles and adhere to the glass substrate surface, causing defects.

The present invention solves the above problems,
It is an object of the present invention to provide an etching method that prevents dust and particles from adhering.

[0008]

In order to achieve this object, the etching method of the present invention is such that a cleaning liquid is discharged from a nozzle located above the liquid surface of an etching tank and discharging the cleaning liquid when the substrate is lifted from the etching tank. To do.

By this method, it is possible to clean the particles and dust before they dry and adhere to the surface of the substrate when the substrate is lifted from the etching bath.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION (Embodiment 1) Hereinafter, Embodiment 1 of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic block diagram of an etching apparatus according to the first embodiment of the present invention. Here, components having substantially the same functions as those in the conventional example described in FIG. 3 are designated by the same reference numerals. In FIG. 1, 15 is a cleaning nozzle, 1
6 is a flow rate adjusting valve, 17 is a cleaning liquid filter, 18 is a cleaning liquid pressure pump, and 19 is an etching device including a cleaning liquid supply tank.

An embodiment of etching by the etching apparatus having the above structure will be described.

As described above, a solution containing hydrofluoric acid as a chemical solution for forming an amorphous silicon layer on a glass substrate and removing the silicon oxide layer formed thereon, for example, 0.1.
The substrate is immersed in a 3% aqueous solution of hydrofluoric acid to remove silicon oxide. The etching tank is W500 × L800 × H800m
m, the filter diameter is 0.2 μm, the chemical solution is 0.3% hydrofluoric acid solution, and the chemical solution circulation rate is 100 L / min.
Amorphous silicon layer 1000 Å is formed on a glass substrate of 50 × 670 mm, immersed for 60 seconds, and a 0.3% hydrofluoric acid solution is applied from a nozzle of 5 mm in diameter at the upper part of the etching tank when the ascending.
L / min was discharged, and immediately after etching, the substrate was immersed in a water washing tank to remove the chemicals, and then IPA vapor dried. The number of particles having a size of 1.5 μm or more attached to the surface of the substrate was 91 first particles. The 500th sheet is 108
It was an individual.

(Comparative Example 1) In the method shown in the first embodiment, the discharge of the cleaning liquid from the nozzle above the liquid surface of the etching tank was stopped, and the 501st substrate was attached to the surface of the substrate subjected to the etching treatment. The number of foreign matters taken was 831.

As described above, according to this embodiment, the nozzles for ejecting the cleaning liquid are provided above the liquid surface of the etching tank, and the particles adhered to the surface of the substrate by ejecting the cleaning liquid when the substrate rises from the liquid surface. Can be reduced.

(Second Embodiment) A second embodiment of the present invention will be described below with reference to the drawings. FIG. 2 shows a second embodiment of the present invention. In FIG. 2, 2
Reference numeral 1 is a cleaning nozzle, 22 is a flow rate adjusting valve, 23 is a cleaning filter, and 24 is a cleaning liquid pressure-feeding pump, which has the same structure as that shown in FIG.

The difference from the configuration of FIG. 1 is that the chemical liquid tank 25 also serves as a cleaning liquid supply tank and an etching liquid recovery tank.
Is to reuse the cleaning liquid.

With respect to the etching apparatus configured as described above, the numbers of particles after the same processing as in Example 1 were 115 for the first sheet and 104 for the 500th sheet.

(Comparative Example 2) In the method shown in the second embodiment, the discharge of the cleaning liquid from the nozzle above the liquid surface of the etching tank was stopped, and the 501th substrate was adhered to the surface of the substrate which had been subjected to the etching treatment. The number of foreign matters taken was 1053.

As described above, according to this embodiment, it is possible to reduce particles adhering to the substrate surface by filtering the chemical liquid and discharging it as a cleaning liquid from the cleaning nozzle above the liquid surface of the etching tank.

In the first and second embodiments, even if the cleaning nozzle is a spray that discharges in a mist state,
A nozzle that discharges in a rod shape from a hole having a diameter of about 0 mm may be used, and is selected in consideration of the physical properties, viscosity, specific gravity, and vapor pressure of the chemical liquid. Although the cleaning liquid is pumped by pressure, the cleaning liquid supply tank may be a pressure resistant container and may be pressurized by nitrogen pressure. The cleaning liquid used has the same composition as the etching chemical liquid, but a solvent such as pure water can be used as the cleaning liquid by adding a concentration adjusting function to the recovery tank.

[0022]

As described above, according to the present invention, the nozzle for discharging the cleaning liquid is provided above the liquid surface of the etching tank, and the cleaning liquid is discharged when the substrate is lifted from the liquid surface. By washing before drying and fixing, the advantageous effect of reducing the number of particles adhering to the substrate surface can be obtained, which is of great industrial value.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an outline of an etching apparatus in a first embodiment of the present invention.

FIG. 2 is a configuration diagram showing an outline of an etching apparatus in a second embodiment of the present invention.

FIG. 3 is a schematic view for explaining a conventional etching apparatus and its sectional configuration diagram.

[Explanation of symbols]

1 chemical circulation pump 2 filters 3 Flow rate adjustment valve 4 etching tank 5 Recovery piping 6 collection tank 7 valves 8 supply piping 9 valves 10 Waste liquid piping 11 Upper limit waste piping 12 substrates 13 Substrate support 14 Elevator 15 Cleaning nozzle 16 Flow rate adjustment valve 17 Cleaning liquid filter 18 Cleaning liquid pressure pump 19 Cleaning liquid supply tank

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI Theme Coat (reference) H01L 21/304 643 H01L 21/306 J (72) Inventor Yoshihiro Kazue 1006 Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Appliances Industry Co., Ltd. (72) Inventor Hiroyoshi Takezawa 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Shinji Tokunaga 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. Reference) 2H088 FA30 HA01 MA20 2H092 JA24 KA05 MA13 MA17 3B201 AB01 BB02 BB22 BB92 BB95 CB12 CC01 5F043 BB22 DD12 DD13 EE01 EE07 EE24 EE25 EE28 EE30 GG10

Claims (3)

[Claims] 1. An etching method comprising: immersing a substrate in a chemical solution that dissolves an unnecessary thin film, and then ejecting a cleaning solution from a nozzle above the surface of the chemical solution when raising the substrate. 2. The etching method according to claim 1, wherein the chemical solution for dissolving the unnecessary thin film contains hydrofluoric acid. 3. An etching apparatus comprising a nozzle for discharging a cleaning liquid above a liquid surface of an etching tank for immersing a substrate in a chemical liquid to dissolve an unnecessary thin film.