JP2001334218A - Substrate cleaning method - Google Patents

Abstract

(57) [Summary] [PROBLEMS] In a cleaning method using a spin cup, mist may adhere to or damage the surface side of a substrate, thereby deteriorating the quality of a liquid crystal display panel and increasing the yield. Was getting worse. This is improved, and a method for cleaning a substrate without mist adhering to or damaging the substrate surface is provided. A substrate (35) is mounted and fixed on a rotatable spin table (18) constituting a spin cup (12).
When discharging the first solution 36 on the front surface side of the substrate 5 and discharging the second solution 37 also on the back surface side of the substrate 35, the amount of the first solution 36 is changed to the liquid amount of the second solution 37. Set more for the quantity. [Effect] On the surface side of the substrate 35, the second solution 37
As a result, it is possible to prevent the mist from adhering and causing damage, to improve the quality of the substrate 35, and to improve the quality of products using the substrate 35 and the yield.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cleaning a substrate such as a glass substrate or a semiconductor substrate used for a liquid crystal display device or a semiconductor device.

[0002]

2. Description of the Related Art Liquid crystal display devices have been required to have higher display capacity and display area and higher image quality as the performance of equipment used has improved. Internal scratches and unevenness have become a factor leading to deterioration of image quality.

[0003] Therefore, in order to minimize the occurrence of such scratches and unevenness, it is necessary to reliably remove fine dust and particles in a cleaning process performed as a pretreatment in each manufacturing process of a liquid crystal display device. In addition, it is necessary to surely remove the organic film and the like attached on the substrate surface.

[0004] Various cleaning methods are employed for this substrate cleaning method. For example, pure water or a cleaning treatment liquid used for cleaning is spread evenly over the entire surface of the substrate.
For efficient cleaning, the spot-shaped nozzle is moved parallel to the substrate surface for cleaning, a method in which a plurality of spot-shaped nozzles are arranged side by side for cleaning, or the nozzle surface is formed in a slit shape for cleaning. A method of cleaning a wide area at a time is adopted.

Further, in order to remove foreign substances adhering to the substrate surface, high-pressure jet cleaning with enhanced physical cleaning capability, ultrasonic cleaning using ultrasonic waves, or acid / chemical cleaning capability with enhanced chemical cleaning capability. Chemical cleaning using an alkali is also performed.

An example of this cleaning method will be described with reference to FIG. A substrate 51 to be cleaned is fixedly mounted on a spin table 52 rotatably provided in a spin cup (not shown) by a holding pin 53 implanted in the spin table 52 or the like.

Thereafter, the spin table 52 is rotated at a low speed of, for example, 70 rpm so that the substrate 5 is rotated.
1 is rotated from the upper side of the cleaning surface of the substrate 51 to be cleaned.
Hydrogen water 54, which is a cleaning solution to which ultrasonic energy has been added, is discharged from a nozzle 55 at a flow rate of 2 l / sec, and at the same time, pure water 56 The substrate 51 is discharged from the nozzle 57 at a flow rate of 2 l / sec, and cleans the substrate 51 for a predetermined time.

When this cleaning is completed, each nozzle 5
The supply of the hydrogen water 54 and the pure water 56 discharged from the nozzles 5 and 57 is stopped.
By rotating the substrate 51 at a high speed of 00 rpm, a draining process is performed on the substrate 51, and subsequently a drying process is performed. This drying step can be performed in a spin cup. However, for example, at the stage when the draining processing is completed, the substrate 51 may be taken out of the spin cup and transported to a hot plate to perform the drying processing. .

The cleaning of the substrate 51 is performed in this manner. The flow rate of the cleaning liquid (hydrogen water) 54 discharged on the cleaning surface side of the substrate 51 and the pure water 56 discharged on the non-cleaning surface side of the substrate 51 are determined. When the spin table 52 is rotated to clean the substrate 51 and the cleaning is performed, the centrifugal force and the substrate 51
Around the spin table 52 for holding the
The phenomenon that the pure water 56 discharged on the back surface side of the substrate 51 along the holding pins 53 implanted in the direction goes around to the cleaning surface side of the substrate 51 has occurred.

For this reason, the pure water 56 mixed with the garbage and the organic matter after the cleaning remains on the upper surface of the substrate 51, that is, on the cleaning surface side. Even in the step of performing the draining process, dirt and organic matter remain without being removed, and are continuously dried in this state, so that the dirt and organic matter remain on the substrate 51 as foreign matter, and the foreign matter is deposited on the liquid crystal display device. Display failure.

As another method for cleaning the substrate 51, the surface of the substrate 51 on which a wiring pattern of a semiconductor substrate or a glass substrate is arranged is cleaned, and the back surface of the substrate 51 is cleaned. Is also being applied for the treatment of.

At this time, the number of rotations of the spin table required for cleaning the substrate 51 is, for example, 200 to 300 rpm.
On the other hand, the chemical solution is applied to the back surface of the substrate 51 by discharging the chemical solution on the back surface of the substrate 51 and then rotating the spin table 52 at a high speed of, for example, about 1200 rpm to centrifuge the chemical solution. A spin coating method of extending the entire back surface of the substrate 51 using force is usually employed.

When the spinning table 52 is rotated at a high speed, the cleaning liquid and the substrate 51
In order to prevent the generation of static electricity due to friction with the substrate 51 and to prevent the surface of the substrate 51 from being damaged, cleaning is not performed at the same time.

However, if a chemical solution is applied to the back surface of the cleaned substrate 51 by a spin coating method using high-speed rotation, the high-speed rotation causes turbulence in the air flow in the spin cup, and the air flows in the spin cup. The mist of the chemical liquid is scattered and adheres to the surface side of the substrate 51 after cleaning, or the mist of the chemical liquid bounces off the wall surface of the spin cup due to high-speed rotation, and similarly falls down on the surface side of the substrate 51 and adheres as an impurity. Or

If such mist damages the surface of the substrate 51 or the mist adheres to the surface of the substrate 51,
There is a defect that quality problems occur, such as a decrease in adhesion of a film formed in the next step.

[0016]

As described above, in order to remove mist adhering to the substrate or damage to the substrate, after applying a chemical solution to the back surface of the substrate, a cleaning method or mist having a higher cleaning efficiency is applied. Re-cleaning using a cleaning solution suitable for removal of damage and damage is required, the structure of the cleaning device becomes more complicated, and the type of cleaning solution used increases, which makes the handling difficult and makes the cleaning process difficult. There is a problem that it takes a long time and it is difficult to perform efficient manufacturing.

In the case of simultaneous double-sided cleaning, as described above, cleaning water mixed with debris and organic matter after cleaning remains on the cleaning surface side of the substrate, and the substrate after cleaning is rotated at a high speed. In the draining process, the dirt and organic substances are dried without being removed, and the dirt and organic substances remain on the substrate as foreign substances, and the foreign substances cause display defects of the liquid crystal display device.

The present invention has been made in view of such a problem and can perform cleaning so that mist or the like does not remain on the cleaning surface of the substrate. An object of the present invention is to provide a method for cleaning a substrate, which can prevent mist from adhering to or damage the surface, and can improve the quality of the substrate.

[0019]

According to the present invention, a substrate is mounted and fixed on a rotatable spin table, the spin table is rotated, and a first solution is discharged onto one plane of the substrate. A method for cleaning a substrate, comprising discharging a second solution in a smaller amount than the first solution to the other plane side of the substrate.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 are structural views showing a spin cup apparatus used in the method of cleaning a substrate according to the present invention.
FIG. 1 is a partially cutaway sectional view showing the configuration of the spin cup device, and FIG. 2 is a plan view of the spin cup device as viewed from above.

The spin cup device 11 includes a spin cup 1
The spin cup 12 includes a disc-shaped bottom plate 13 and a conical partition wall 14 formed by extending the periphery of the bottom plate 13 upward. An opening 15 is provided above the partition 14.

A rotary shaft 17 of a motor 16 is mounted at the center of the bottom plate 13, and a rectangular spin table 18 is fixed to one end of the rotary shaft 17. Around the corner of the spin table 18, holding pins 19 for holding a plurality of substrates are erected, and a plurality of support columns 20 for regulating the position of the substrate are provided on the plane of the spin table 18. But have been planted as well.

A drain hole 21 for draining the solution is formed in the bottom plate 13, and a drain device 23 is attached to the drain hole 21 via a water pipe 22. A supply pipe 25 penetrating through the rotation shaft 17 of the motor 16 and connected to the back surface treatment liquid supply device 24 is provided.
2, a nozzle 26 for ejecting the back surface treatment liquid is attached.

On the other hand, a nozzle 27 for injecting hydrogen water is disposed on the opening 15 of the spin cup 12 so as to face the nozzle, and this nozzle 27 is connected to a hydrogen water supply device 28 by a supply pipe 29 and At one end, an ultrasonic oscillator 30 is attached, and an oscillator 31 is connected to the ultrasonic oscillator 30.

Further, a nozzle 32 for injecting a protective liquid is also provided in parallel with the nozzle 27, and this nozzle 32 is connected to a protective liquid supply device 33 by a supply pipe 34 so that the spin cup device 11 is It is configured.

Each of the nozzles 27 and 32 is configured to be movable, and is located at a position distant from the spin cup 12 when not in operation.
It is also possible to configure so as to face the opening 15 of the spin cup 12.

The spin cup apparatus 1 configured as described above
In order to clean the substrate by using 1, first, the substrate 35 to be cleaned is placed on the support column 20 and fixed between the holding pins 19. The substrate 35 has a state in which an insulating film has been formed in the case of an array substrate, and an ITO film has been formed in the case of a counter substrate, before the pre-processing step of the cleaning process.

The substrate 35 is placed on the spin cup 12
Support column 20 and holding pin 1
Fix by 9. Thereafter, the motor 16 is rotated to rotate the substrate 35 at a low speed of, for example, about 70 rpm.

In conjunction with this rotation, the hydrogen water supply device 2
8 to the first solution for washing, for example, 2 l / min
Is supplied to the nozzle 27 through the supply pipe 29 at the same time as the ultrasonic vibrator 30 of the nozzle 27
Starts ultrasonic vibration by the oscillation signal from the oscillator 31. Therefore, hydrogen water to which ultrasonic energy has been added is discharged from the nozzle 27 toward the surface of the substrate 35.

In accordance with the discharge of the hydrogen water, a nozzle 26 disposed on the back side of the substrate 35 is supplied with a second solution, for example, pure water having a flow rate of 1.5 l / min, Is supplied through the supply pipe 25, so that pure water is discharged from the nozzle 26 toward the back surface of the substrate 35.

In other words, the respective solutions are discharged from the nozzles 26 and 27 from both sides of the substrate 35, and the solution on the cleaning surface side of the substrate 35 to be cleaned, that is, the hydrogen water is transferred to the other surface side. It is supplied at a higher flow rate than the pure water to be injected.

As a result, when the substrate 35 is cleaned, the flow rate of the hydrogen water 36 on the upper surface, which is the cleaning surface side of the substrate 35, is discharged toward the back surface of the substrate 35 as shown in FIG. Since the amount of the pure water 37 is set to be larger than that of the pure water 37, the pure water 37 on the back side of the substrate 35
5 is to suppress the occurrence of the wraparound phenomenon, such as the centrifugal force caused by the rotation of No. 5 and the incidental accompanying centrifugal force, which reaches the surface cleaning surface side of the substrate 35 through the holding pin 19 of the spin cup 12. Can be.

After the cleaning of the substrate 35 is completed, the supply of the solution such as the hydrogen water 36 and the pure water 37 from the hydrogen water supply device 28 and the back surface treatment liquid supply device 24 is performed.
In addition, the oscillation of the oscillator 31 is stopped, and then, while each solution is stopped, the motor 16 is set to, for example, 2000 rpm.
Rotate at high speed.

Because the substrate 35 is also rotated at a high speed, the hydrogen water 36 and pure water 3 remaining on the substrate 35 are removed.
Each of the solutions 7 is scattered by centrifugal force, and the substrate 35 is drained. The substrate 3 that has been subjected to this draining process
5 is taken out of the spin cup 12 and conveyed to a hot plate which is the next drying step.

As a result of examining the residual ratio of the mist on the cleaning surface side of the substrate 35 which has been subjected to such a cleaning process, a comparison between the conventional cleaning method and the case of this embodiment shows that The mist remaining rate was 90%,
In the case of the present example, the residual rate could be reduced to 70%, and a high improvement rate of about 20% could be obtained.

Next, another embodiment of the present invention will be described with reference to FIGS. As the substrate 35, an array substrate used for each liquid crystal display device, or a square glass substrate having a plurality of single substrates of a counter substrate and having a size capable of being divided and chamfered is used. In order to easily confirm the influence of damage due to adhesion or corrosion, a substrate obtained by sputtering a metal film on the surface of the substrate 35 is used.

The substrate 35 constructed as described above is placed and fixed on the spin table 18 of the spin cup 12, and the spin table 18 is moved by the motor 16 to 200 to 200, for example.
It is rotated at a rotation speed of about 300 rpm. In conjunction with this rotation, the cleaning liquid is discharged from the cleaning nozzle 27 onto the surface of the substrate 35 to clean the cleaning surface of the substrate 35.

After cleaning the surface of the substrate 35, the spin table 18 is rotated at a high speed to perform a draining process. Next, the back surface treatment liquid is discharged from the nozzle 26 to the center of rotation of the substrate 35, for example, at a rate of 0.5 l / min. For example, the high-speed rotation is performed at 1200 rpm for 3 seconds. As a result, the back surface treatment liquid is applied to the entire back surface of the substrate 35 by the centrifugal force accompanying the rotation of the substrate 35.

At the time of this high-speed spin coating, for example, a protective liquid such as pure water or a cleaning treatment liquid is supplied from a protective liquid supply device 33 through a supply pipe 34 to a protective liquid supply nozzle 32 through a substrate 3.
5 With respect to the center of rotation of the substrate 35 on the front side, for example, 3 l
/ Min. Thus, even when the back surface treatment liquid is spin-coated at a high speed, the surface of the substrate 35 is protected by the protective liquid, so that even if mist is generated, the surface of the substrate 35 is protected from damage by the mist.

Incidentally, when there is no protective liquid, and when the flow rate of the protective liquid is 1 l / min, 1.5 l / min, 2 l / min,
The flow rates were changed to 2.5 l / min and 3 l / min, respectively, and further, the protective liquid was discharged to the center of rotation of the substrate 35 and to a position shifted by 100 mm from the center of rotation. The effect was compared between the case and the case.

As a result, when there is no protective liquid, the substrate 3
5 When the surface damage was confirmed and the protective liquid was discharged at a position shifted by 100 mm from the center of rotation of the substrate 35, the flow rates of the protective liquid were 1 l / min and 1.5 l / mi.
In the case of n, although slight damage was observed, and in the case of a flow rate of 2 l / min or more, no damage was found.

Further, when the protective liquid was discharged to the center of rotation of the substrate 35, no damage was confirmed in any case regardless of the flow rate of the protective liquid.

Therefore, in the case where the precision of the discharge position of the protective liquid is not required, setting the flow rate of the protective liquid to a predetermined amount or more has an advantage that the discharge position does not have to be affected to the left.

If the discharge position of the protective liquid is set at the center of rotation of the substrate 35, the surface of the substrate 35 can be protected from damage irrespective of the flow rate of the protective liquid. It can be seen that it can be effectively protected from damage.

An example of a manufacturing process for manufacturing a liquid crystal display device using the above-described method of cleaning the substrate 35 will be described with reference to FIG.

First, a glass substrate constituting a substrate 35 of a predetermined size is prepared (a), and then washed in a washing step (b). In the case of an array substrate, a thin film forming step (c) is performed thereafter. , A pattern etching step (d) and an insulating film forming step (e).

The steps (c) to (e) will be described in detail. A gate metal film is formed on the surface of the cleaned substrate, and then a gate wiring pattern is formed. Further, a film for a gate insulating film is formed, an amorphous silicon film is formed, and a channel protective film pattern is formed. This amorphous silicon film is etched to form an amorphous island pattern, and then ITO is formed to form a pixel electrode pattern.

Next, after forming a via hole pattern, a metal film for signal lines is formed to form a signal wiring pattern, and finally, an insulating film for signal wiring is formed to form a protective film pattern.

On the other hand, when the glass substrate is a counter substrate having a color filter, a black matrix (BM) is formed (c ') on the washed glass substrate, and then an RGB color layer is formed (d'). . Next, an overcoat layer is formed (e ′), and a step (e ^″ ) of forming a transparent electrode film made of an ITO film is performed.

The glass substrate that has undergone the insulating film forming step (e) or the transparent electrode film forming step (e ^″ ) is
By brush cleaning (f) using hydrogen water, relatively large dust is first washed away. Then, the substrate having been brush-cleaned is subjected to a rinsing step (g), and then cleaned using the cleaning method using the spin cup device shown in FIGS. 1 and 2.

That is, the process enters an ultrasonic cleaning step (h) using hydrogen water, where fine particles and the like adhering to the substrate are cleaned. The rinsed substrate is rinsed and subjected to a draining process in the draining step (i), and then dried (j).

An alignment film is applied to the dried substrate (k)
Then, the alignment film is baked (l) and rubbed (m). Thereafter, the ultrasonic cleaning process (n) using hydrogen water is performed again using the spin cup device, and the rinsing and draining processes (o) and the drying process (p) are performed.

Thereafter, in the case of an array substrate, a transfer material is applied (q) and spacers are scattered (r). In the case of a counter substrate, a sealing material is applied (r '). Thereafter, the array substrate and the opposing substrate are bonded to each other so as to oppose each other (s), and the sealing material is cured (t), thereby fixing both substrates.

Usually, a large-sized substrate having a substrate area of a plurality of single-substrates forming individual panels is collectively processed in the steps up to this point to create a plurality of panels at a time. Since a large substrate, which is an aggregate of single-unit substrates, is being manufactured, a chamfering process is performed to divide the large substrate into single-unit substrates corresponding to a plurality of individual panels. (U)
Is made.

A liquid crystal is injected (v) into the gaps of the individual panels subjected to the dividing process (u). After the liquid crystal is injected, the injection port is sealed (w), and the panel is washed (x). . Next, a polarizing plate is attached (y) to the outer surface side of the array substrate and the counter substrate, and the liquid crystal display panel is completed (z).

In this way, a liquid crystal display panel is manufactured. The method of cleaning a substrate according to the present invention is as follows.
For example, it is used in the above-described ultrasonic cleaning step, but is not limited to this cleaning step, and any cleaning step using a spin cup device can be used.

Although the case where the hydrogen water supply device 28 and the protection liquid supply device 33 are separately provided has been described, when the cleaning treatment liquid such as hydrogen water is used as the protection liquid, the protection liquid supply device 33 and the protection liquid supply device 33 are used. It is also possible to omit the nozzle 32 and the like, and the configuration of the spin cup 12 itself is not limited thereto, and various modifications and applications can be made without departing from the gist of the present invention. Needless to say,

[0059]

As described above, according to the method for cleaning a substrate of the present invention, a solution such as a cleaning liquid supplied to the front surface of the substrate to be cleaned is replaced with a solution such as a back processing liquid supplied to the other surface of the substrate. By setting the flow rate higher than that, the centrifugal force accompanying the rotation of the substrate, and the solution such as the back surface treatment liquid generated by transmitting the holding pins of the substrate along with the centrifugal force onto the substrate surface. Since wraparound can be prevented, mist can be prevented from adhering to the substrate surface, and as a result, the cleaning quality of the substrate can be improved.

Even when a solution such as a chemical solution is applied to the back surface of the substrate, since a solution such as a protective solution is discharged to the front surface side of the substrate, a mist such as a mist of the back surface treatment solution is applied to the surface of the substrate. It is possible to protect against the attachment of impurities and the damage to the substrate surface.

From these facts, by using the substrate cleaning method of the present invention, as a result, the quality of the manufactured liquid crystal display device and the yield of the substrate can be greatly improved. A method can be provided.

[Brief description of the drawings]

FIG. 1 is a partially cutaway sectional view showing a spin cup device used in a method for cleaning a substrate according to the present invention.

FIG. 2 is a plan view showing the same spin cup device.

FIG. 3 is a schematic explanatory view schematically showing a substrate surface cleaning state when the substrate cleaning method according to the present invention is used.

FIG. 4 is a process explanatory view showing a manufacturing process of a liquid crystal display panel using the substrate cleaning method according to the present invention.

FIG. 5 is a schematic explanatory view schematically showing a substrate surface cleaning state using a conventional substrate cleaning method.

[Explanation of symbols]

 18: Spin table 35: Substrate 36: First solution 37: Second solution

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 21/304 647 H01L 21/304 647Z (72) Inventor Noriko Kannai 7th Nisshincho, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture 1 F-term in Toshiba Electronic Engineering Corporation (reference) 2H088 FA21 FA30 MA20 2H090 JB02 JC01 JC19 3B201 AA02 AB01 AB34 AB42 BA02 BB22 BB85 BB92 BB93 BB96 CB12 CC01 CC11 CC21

Claims (7)

[Claims] 1. A substrate is mounted and fixed on a rotatable spin table, the spin table is rotated, and a first solution is discharged on one plane side of the substrate, and the first solution is discharged on another plane side of the substrate. A method for cleaning a substrate, comprising discharging a second solution in a smaller amount than the first solution. 2. The method for cleaning a substrate according to claim 1, wherein said one plane side is a surface to be cleaned. 3. The method according to claim 2, wherein the second solution is pure water. 4. The method according to claim 1, wherein the second solution is an antistatic chemical. 5. The method according to claim 4, wherein the first solution is pure water. 6. The method for cleaning a substrate according to claim 1, wherein a thin film element is formed on one plane side of the substrate. 7. The method according to claim 1, wherein the substrate has a rectangular shape.