JPH10106996A - Cleaning device and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable both the surfaces of a substrate to be surely cleaned at the same time by a method in which a porous material high in chemical resistance is held on both the sides of the substrate to be cleaned in non-contact manner, and cleaning solution is supplied to both surfaces of the target substrate through the intermediary of the porous materials. SOLUTION: A substrate 3 to be cleaned is placed on a lower porous material 2-2 at a prescribed position by a transfer arm 10, an opening/closing drive section 5 is closed to keep the substrate 3 in a cleaning chamber 1, chemicals 4-1 is selected by a switching feeder 4 and fed to an upper porous material 2-1 and a lower porous material 2-2 respectively. The chemicals 4-1 is made to pass through the porous materials 2-1 and 2-2, then the chemicals 4-1 is uniformly spread in the porous materials 2-1 and 2-2 by its resistance induced when it passes. The substrate 3 sandwiched in between the porous materials 2-1 and 2-2 is brought into contact with chemicals 4-1 which flows out in the direction of an arrow F passing through the porous materials 4-1 and 4-2, from a prescribed space, and a drainage gap 1-3, thereby both the surfaces of the target substrate 3 can be cleaned at the same time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning apparatus and a cleaning method used in a cleaning step for removing surface metal contamination in the manufacture of semiconductor devices and the like, and a final cleaning step in the manufacture of semiconductor wafers and the like.

For example, in the manufacture of a photomask used for manufacturing a semiconductor device or the like, in a process of cleaning a glass substrate for a mask or a substrate such as a photomask, pure water cleaning is used as a final finish cleaning.

[0003] Such cleaning means is an important step whose quality affects the mask quality, the production yield of the semiconductor device, and the reliability. With the trend toward larger size, development of a cleaning apparatus and a cleaning method that can obtain more efficient and higher cleanliness is required.

[0004]

2. Description of the Related Art Conventionally, a semiconductor substrate is cleaned by removing the fine particles and metal impurities adhering to the surface by treating the substrate with an acid or alkali solution, and then rinsing with pure water.
A method of replacing an acid or an alkali from the surface of a semiconductor substrate has been used.

As this means, there is a method in which a plurality of semiconductor substrates are immersed in a tank storing a chemical solution or pure water. More recently, attempts have been made to externally apply vibration energy such as ultrasonic vibration to the tank in order to improve the cleaning efficiency.

[0006]

However, as the diameter of the semiconductor substrate increases, the problem of the uniformity (mixing ratio, temperature, etc.) of the state of the chemical solution in the tank has become apparent. When a plurality of semiconductor substrates are immersed in a tank storing a chemical solution or pure water, there is a problem that as the number of semiconductor substrates increases, it becomes more difficult to exchange the liquid in the tank. In addition, cost and energy issues for chemicals used and discarded in large quantities are also coming to the surface. Furthermore, when supplying vibration energy such as ultrasonic waves, there is a problem that vibrations propagate non-uniformly to the semiconductor substrate.

As a means for cleaning these large-diameter semiconductor substrates, recently, a shower system has been adopted to supply a chemical solution or pure water to the semiconductor surface, thereby cleaning the semiconductor surface in a uniform state. Attempts have been made. However, also in this case, while the front surface is being cleaned, the supply of the chemical solution or the like is not performed on one of the back surface or the handling contact portion, and it is difficult to supply the vibration energy.

According to the present invention, in cleaning a large-diameter semiconductor substrate, the front and rear surfaces are simultaneously and reliably cleaned, the amount of chemical solution and pure water used is minimized, and vibration energy is reduced when necessary. It is an object of the present invention to provide a cleaning apparatus and a cleaning method that can apply a voltage uniformly over the entire surface.

[0009]

SUMMARY OF THE INVENTION The above-mentioned problems are caused by using a single-wafer cleaning method, in which a chemical-resistant porous material is held on both sides of a substrate to be cleaned in a non-contact manner for reliable cleaning. The problem can be solved by simultaneously supplying the cleaning liquid from both surfaces of the substrate to be cleaned through the porous material, and, if necessary, by bringing the porous material into close contact with both surfaces of the substrate to be cleaned and applying ultrasonic vibration through the porous material.

A first aspect of the present invention provides a cleaning housing comprising an upper lid and a lower lid, having a space for drainage at a joint between the upper lid and the lower lid, and having a space therein, a lower surface of the upper lid, and a lower lid. A pair of porous members fixed to each of the upper surfaces of the first and second members, and a switching supply unit for selectively supplying one of a chemical solution, pure water, or a pressurized gas to each of the pair of porous members through the upper lid and the lower lid. And an opening and closing drive unit for vertically moving at least one of the upper lid and the lower lid,
The substrate to be cleaned is cleaned between the pair of porous materials.

With this configuration, the liquid supplied through the porous material can be simultaneously supplied to both surfaces of the non-cleaning substrate at the same concentration, so that cleaning and rinsing can be effectively performed with a minimum amount of liquid. There is an effect that the process can be efficiently performed up to the drying step by switching to the pressurized gas.

In a second aspect of the present invention, the ultrasonic vibration section for applying vibration energy to the pair of porous members and a porous member for driving the pair of porous members so as to be capable of pressing the pair of porous members against both surfaces of the substrate to be cleaned are further provided. And a material pressing portion.

According to this structure, the pair of porous members are cleaned while maintaining a predetermined gap between both surfaces of the substrate to be cleaned and the opposite surfaces of the substrate to be cleaned, respectively. It is possible to implement a method of cleaning by applying vibration energy by pressing against the surface.

Accordingly, when the degree of contamination on both sides of the substrate to be cleaned cannot be eliminated by merely cleaning with a chemical solution or the like, a porous material is pressed against both surfaces of the substrate to be cleaned and ultrasonic vibrations are simultaneously and uniformly applied from both sides. Shaking has an effect that a cleaning effect can be easily expected.

[0015]

Embodiments of the present invention will be specifically described below. To facilitate understanding of the description of the configuration and operation, the same portions are denoted by the same reference numerals throughout the drawings, and redundant description will be omitted.

FIG. 1 is an external perspective view of a first embodiment of the present invention.
FIG. 2 is a sectional view of a main part of the first embodiment of the present invention.
(A) shows the principal part sectional drawing in a washing | cleaning housing | casing. In both figures, reference numeral 1 denotes a cleaning housing, which is formed of, for example, a chemical-resistant plastic material and has at least one of an upper lid 1-1 and a lower lid 1-2 having a space for forming a cleaning chamber therein. It is constructed so as to be able to move up and down by the action of an opening / closing drive section 5 described later, and is provided with a drainage gap 1-3 at the joint thereof.

Reference numeral 2 denotes a porous material, for example, a sponge member having a soft chemical resistance or a nonwoven fabric similar to the sponge member (a member formed by solidifying a fine thread such as felt or Teflon / polyvinyl chloride). .

The porous material 2 comprises a pair of an upper porous material 2-1 and a lower porous material 2-2, and the lower surface of the upper cover 1-1 and the lower cover 1-2, respectively.
The upper porous material 2-1 and the lower porous material 2-2 are housed so as to face each other, and a peripheral edge of a substrate 3 to be cleaned, which will be described later, is sandwiched between the facing surfaces. It is arranged as follows.

Reference numeral 3 denotes a substrate to be cleaned, which is held by a transfer arm 10 or the like by an external control device (not shown) and placed at a predetermined position on the lower porous material 2-2. The peripheral edge of the mounted substrate 3 to be cleaned is sandwiched between the upper porous material 2-1 and the lower porous material 2-2. 1 and each opposing surface of the lower porous material 2-2,
It is sandwiched so as to secure a predetermined gap (about 10 to 30 mm).

Reference numeral 4 denotes a switching supply unit, which has a built-in valve for selecting one of a chemical solution 4-1 or pure water 4-2 or a pressurized gas 4-3 supplied from the outside. The gas penetrates the upper lid 1-1 and the lower lid 1-2 through the flexible pipe 6 composed of the upper flexible pipe 6-1 and the lower flexible pipe 6-2, and the corresponding upper porous material 2-1, It is configured so that it can be supplied to the lower porous material 2-2.

The outer ends of the upper flexible pipe 6-1 and the lower flexible pipe 6-2 in FIG. 2A are bent in a direction perpendicular to the paper surface and connected to the switching supply unit 4. The state is shown.

Reference numeral 5 denotes at least one of the upper cover 1-1 and the lower cover 1-2, and the substrate 3 to be cleaned held externally by the transfer arm 10 or the like.
The opening / closing drive unit is configured to open and close to the extent that it can be inserted. For example, the lifting / lowering mechanism is configured by a combination of a step motor, a worm gear, a worm wheel, and a pinion gear and a rack gear.

Although the opening / closing operation has been described by the lifting mechanism, the invention is not limited to this, and a method of pivotally supporting one end of the upper lid 1-1 and the lower lid 1-2 may be used. It is also possible to use it.

FIG. 2B is an enlarged cross-sectional view of a portion C shown in FIG. 2A, in which the peripheral edge of the substrate 3 to be cleaned is divided into an upper porous material 2-1 and a lower porous material 2-2. Is a predetermined gap (about 10 ~
30mm) is shown.

In the above configuration, the substrate 3 to be cleaned is placed at a predetermined position on the lower porous material 2-2 by the transfer arm 10,
The opening / closing drive unit 5 is closed to hold the substrate 3 to be cleaned in the cleaning housing 1. For example, a chemical solution 4-1 is selected by the switching supply unit 4, and the upper porous material 2-1 and the lower porous material 2-2 are respectively selected. To supply.

As a result, the chemical solution 4-1 penetrates through the upper porous material 2-1 and the lower porous material 2-2, and spreads uniformly in the porous material due to resistance at the time of transmission. The substrate to be cleaned 3 sandwiched between the porous materials penetrates the porous material and passes through a predetermined gap (about
10 to 30 mm), and by contacting the chemical solution 4-1 flowing out in the direction of arrow F through the drainage gap 1-3, both surfaces can be washed at the same time.

By using this means, it is easy to maintain a predetermined concentration of the chemical solution, and even when the chemical solution 4-1 or pure water 4-2 is supplied or replaced, the porous material 2 and the substrate to be cleaned are replaced. Since a predetermined gap (approximately 10 to 30 mm) is held between both sides of the liquid crystal 3, the liquid flows through this gap at an appropriate flow rate without waste, so that replacement and washing is easy, and the required amount of liquid Can also be controlled to the minimum. Further, by switching to a pressurized gas, it is possible to carry out the drying process efficiently.

FIG. 1 does not show a mechanism relating to the drainage processing means, but it goes without saying that a required enclosure and a drainage recovery channel are formed. FIG. 3 is a cross-sectional view of a main part of a second embodiment of the present invention. FIG. 3 (a) is a cross-sectional view of a main part inside a cleaning housing, and FIG. FIG. 3C is an enlarged sectional view of the portion D shown in FIG. 3A when the ultrasonic vibration is not applied.

In the figure, reference numeral 7 denotes an ultrasonic vibrator,
It comprises an upper vibration transmitting member 7-1 and a lower vibration transmitting member 7-2, and an upper ultrasonic vibrator 7-3 and a lower ultrasonic vibrator 7-4.
The upper vibration transmitting section 7-1 inserts a plurality of plates of a hard material having chemical resistance between the upper porous material 2-1 and the upper lid 1-1 to cover almost the entire surface of the upper porous material 2-1. The plates or rods erected on the respective plates are slidably penetrated and exposed to the upper lid 1-1 while maintaining airtightness, and the respective exposed portions are connected by a plate or the like. The structure is such that the upper ultrasonic vibrator 7-3 is attached to the connecting portion.

The lower vibration transmitting section 7-2 is also the upper vibration transmitting member 7.
-1 and a plate or rod that stands upright on a plate that can abut almost the entire surface of the lower porous material 2-2. And the lower ultrasonic vibrator 7-4 is attached to the connecting portion.

Reference numeral 8 denotes a porous material pressing portion, which comprises an upper porous material pressing portion 8-1 and a lower porous material pressing portion 8-2, and the upper porous material pressing portion 8-1 is fixed to the upper lid 1-1. The connecting portion to which the upper ultrasonic vibrator 7-3 is attached is extended and pulled in, and a pressing force is applied to the extended end to form the upper porous material 2-1.
To the surface of the substrate 3 to be cleaned.

The structure of the lower porous material pressing portion 8-2 is also completely symmetric with the structure of the upper porous material pressing portion 8-1, and the connecting portion to which the lower ultrasonic vibrator 7-4 is attached is extended. The lower end of the lower porous material 2 by applying a pressing force to the extended end.
-2 is pressed against the surface of the substrate 3 to be cleaned.

The internal mechanism of the upper porous material pressing portion 8-1 and the lower porous material pressing portion 8-2 may have the same configuration as that of the opening / closing drive portion 5, or the upper cover 1-1 may be attached to the opening / closing drive portion 5. And lower lid 1-2
Of the fixed side, the connecting portion is connected to the opening / closing drive portion 5
It is also possible to extend the drive function and extend it.

As described above, by adding the function of the second embodiment to the function of the first embodiment,
The pair of porous members 2 are respectively pressed against both surfaces of the substrate 3 to be cleaned only when vibration energy is applied. In other cases, the porous members 2 are pressed against the both surfaces of the substrate 3 by a predetermined gap ( (Approximately 20 to 30 mm) to carry out the method of cleaning.

Accordingly, when the degree of contamination on both surfaces of the substrate 3 to be cleaned cannot be eliminated only by cleaning with a chemical solution or the like, the porous material 2
Is pressed against both sides of the substrate 3 to be cleaned and the ultrasonic vibration is simultaneously and evenly applied from both sides, whereby a cleaning effect that can easily remove contamination can be expected.

Using this apparatus, a silicon wafer having a diameter of 20 mm was cleaned. After introducing the wafer into the cleaning equipment, 50 ℃
Ammonia / hydrogen peroxide / water solution (deposition ratio 1: 1.5: 5)
Was supplied at a flow rate of 100 ml / s for 1 minute through the inlet of the cleaning housing, the porous material was pressed against the substrate to be cleaned, and 1 GHz ultrasonic waves were applied. After that, the ultrasonic wave is stopped, the pressure contact of the porous material is released, and the porous material is switched to pure water and rinsed at the same flow rate for 2 minutes.

A 5% aqueous solution of hydrogen fluoride is again supplied for 30 seconds. Further, switching to pure water is performed to rinse the aqueous solution of hydrogen fluoride. The resulting cleanliness of the silicon wafer on both front and back surfaces is such that the total concentration of metal impurities is ≦ 10 ¹⁰ atoms.
A level of / cm ² was obtained. The surface natural oxide film had an optical evaluation of ≦ 0.1 nm.

[0038]

As described above, according to the present invention,
The cleaning of the front and back surfaces of the semiconductor substrate can be performed at the same time, and the time required for the cleaning step can be reduced to half the time required by the conventional method. In addition, the amount of chemicals and pure water used can be reduced to 80% of the conventional level.

[Brief description of the drawings]

FIG. 1 is an external perspective view of a first embodiment of the present invention.

FIG. 2 is a sectional view of a main part of the first embodiment of the present invention.

FIG. 3 is a sectional view of a main part of a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cleaning housing 1-1 Upper lid 1-2 Lower lid 1-3 Drainage gap 2 Porous material 3 Substrate to be cleaned 4 Switching supply part 5 Opening / closing drive part 7 Ultrasonic vibration part 8 Porous material pressing part

Claims (3)

[Claims] 1. A cleaning housing comprising an upper lid and a lower lid, having a drainage gap at a joint between the upper lid and the lower lid, and having a space inside, a lower surface of the upper lid and the lower lid. A pair of porous materials fixed to each of the upper surfaces of the pair, and selectively supplying one of a chemical solution, pure water, or a pressurized gas to each of the pair of porous materials through the upper lid and the lower lid. A cleaning apparatus, comprising: a supply unit; and an opening / closing drive unit for vertically moving at least one of the upper lid and the lower lid, and cleaning a substrate to be cleaned between the pair of porous materials. 2. An ultrasonic vibrating unit for applying vibration energy to the pair of porous materials, and a porous material pressing unit for driving the pair of porous materials so as to be able to press against the both surfaces of the substrate to be cleaned, respectively. The cleaning device according to claim 1, wherein: 3. The cleaning is performed by holding each of the pair of porous materials with a gap between both surfaces of the substrate to be cleaned, or by pressing each of the pair of porous materials against both surfaces of the substrate to be cleaned, A cleaning method, wherein the cleaning is performed by applying the vibration energy.