JPH0536661A - Cleaning method - Google Patents

Abstract

PURPOSE:To easily clean an object to be cleaned, such as a semiconductor substrate, etc., in a short time by treating the object with a low-viscosity liquid chemical after treating the object with a high-viscosity liquid chemical, and then, washing the object with water in the manufacturing process of a semiconductor device. CONSTITUTION:In the manufacturing process of a semiconductor device, an object to be cleaned getting wet with a high-viscosity liquid chemical is treated with a low- viscosity liquid chemical after the object is treated with the high-viscosity liquid chemical and the adhering low-viscosity liquid chemical is then washed away with water. At the time of removing, for example, the nitride film of a semiconductor substrate, the substrate is first treated with hot phosphoric acid which is the high-viscosity liquid chemical in a hot phosphoric acid tank 11. As a result, the nitride film is removed from the surface of the substrate and the phosphoric acid adheres to the surface. Then the substrate is dipped in nitric acid which is the low-viscosity liquid chemical so as to replace the phosphoric acid with the nitric acid. As a result, the nitric acid adheres to the surface of the substrate. Thereafter, the substrate is dipped in pure water in a water washing tank 13. Since the adhering nitric acid easily dissolves in water, the water washing can be completed in a short time with a small amount of pure water.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a method for cleaning an object to be processed such as a semiconductor substrate processed by a highly viscous chemical in a semiconductor device manufacturing process.

In the recent semiconductor device manufacturing process, with the increase in the diameter and integration of wafers, in the cleaning process of a semiconductor substrate treated with a highly viscous chemical solution, cleaning with heated pure water and a large amount of pure water are carried out. However, a pure water heating device and a large-sized pure water producing device are required for this purpose.

Under the circumstances as described above, there is a demand for a cleaning method capable of efficiently performing the cleaning process without using heated pure water or a large amount of pure water.

[0004]

2. Description of the Related Art A conventional cleaning method for a semiconductor substrate using a plurality of tanks will be described in detail with reference to FIG.

FIG. 4 is a diagram showing a conventional cleaning method in the order of steps. First, as shown in the figure, the semiconductor substrate is dipped in the highly viscous chemical solution in the highly viscous chemical solution tank 31. The high-viscosity chemical is attached to the surface of the semiconductor substrate processed in the high-viscosity chemical bath 31, but conventionally, this semiconductor substrate is directly dipped in pure water in the washing bath 33, and the high-viscosity chemical is applied. After being dissolved and removed with heated pure water or a large amount of pure water, it is dried in the drying chamber 34.

[0006]

In the conventional method for cleaning a semiconductor substrate described above, the highly viscous chemical liquid adheres to the surface of the semiconductor substrate treated with the highly viscous chemical liquid, and this semiconductor substrate is directly washed with water. To completely remove highly viscous chemicals that are difficult to dissolve in pure water by dipping them in pure water in the tank, it will take a long time to wash water, so use heated pure water or use a large amount of pure water. Since the highly viscous chemical liquid is dissolved and removed, there is a problem that a pure water heating device and a large-sized pure water production device are required.

Under the circumstances as described above, the present invention has an object to provide a cleaning method capable of easily and quickly cleaning an object to be processed which has been treated with a highly viscous chemical solution.

[0008]

The cleaning method of the present invention is a method for cleaning an object to be processed which has been treated with a highly viscous chemical liquid, which is processed by this highly viscous chemical liquid and to which the highly viscous chemical liquid is attached. A step of treating the treated material with a low-viscosity chemical,
And a step of washing the object to which the low-viscosity chemical liquid is attached with water.

[0009]

That is, in the present invention, as shown in FIG. 1, the semiconductor substrate that has been subjected to the high-viscosity chemical solution treatment in the high-viscosity chemical solution tank 1 is dipped in the low-viscosity chemical solution in the low-viscosity chemical solution tank 2 to obtain the high-viscosity chemical solution. After the chemical solution is replaced with a low-viscosity chemical solution, the semiconductor substrate to which the low-viscosity chemical solution, which is easily dissolved in pure water, adheres is removed by dipping it in pure water in the washing tank 3. It becomes possible to wash the product with pure water in an extremely short time.

[0010]

EXAMPLE In the case of a semiconductor substrate using a plurality of tanks, a first embodiment of the present invention for removing a nitride film will be described with reference to FIG. 2 and a second embodiment of the present invention for removing a resist film according to FIG. Will be described in detail in the order of steps.

FIG. 2 is a diagram showing the cleaning method of the first embodiment according to the present invention in process order, and FIG. 3 is a diagram showing the cleaning method of the second embodiment according to the present invention in process order. When removing the nitride film, first, the semiconductor substrate is treated with high temperature phosphoric acid, which is a highly viscous chemical, in the high temperature phosphoric acid tank 11 as shown in FIG. 2, and the nitride film on the surface of the semiconductor substrate is removed to remove the high temperature phosphoric acid. Adhere to.

Next, when the semiconductor substrate is dipped into nitric acid, which is a low-viscosity chemical in the nitric acid tank 12, and high temperature phosphoric acid is replaced with nitric acid, nitric acid adheres to the surface of the semiconductor substrate. Then, dip the semiconductor substrate with nitric acid adhering to the surface in pure water in the washing tank 13, because nitric acid, which is a low-viscosity chemical, is easily dissolved in pure water, so that it is washed with a small amount of pure water within a short time. It becomes possible.

When the resist film is peeled off, first, as shown in FIG.
When a semiconductor substrate is treated with high-temperature sulfuric acid / H ₂ O ₂ which is a highly viscous chemical in a high-temperature sulfuric acid / hydrogen peroxide tank 21 (hereinafter abbreviated as high-temperature sulfuric acid / H ₂ O ₂ tank 21) as shown in Fig. The resist film on the surface of the substrate is peeled off and high temperature sulfuric acid / H ₂ O ₂ is attached.

Next, when the semiconductor substrate is dipped in nitric acid, which is a low-viscosity chemical in the nitric acid tank 22, and high temperature sulfuric acid / H ₂ O ₂ is replaced with nitric acid, nitric acid adheres to the surface of the semiconductor substrate.
Next, wash the semiconductor substrate with nitric acid on the surface with a water bath 23
When dipping in pure water, nitric acid, which is a low-viscosity chemical, is easily dissolved in pure water, so that it is possible to wash with a small amount of pure water within a short time.

Since the treatment with nitric acid is performed in this manner, if the resist stripping / cleaning is performed before the diffusion step or the CVD step, the semiconductor substrate can be put into the diffusion or the CVD step without the pretreatment, and the throughput is improved. It is possible to contribute to.

Although nitric acid was used as the low-viscosity chemical in the first and second embodiments of the present invention, even if a mixed solution of hydrochloric acid and hydrogen peroxide is used, a small amount of pure water can be obtained within a short time. It is possible to wash with water.

Although the present embodiment is a multi-tank cleaning method using a plurality of tanks, a single-tank cleaning method in which the treatment chemicals are sequentially exchanged using only one tank is also possible.

[0018]

As is clear from the above description, according to the present invention, the highly viscous chemical liquid adhered to the object to be treated treated with the highly viscous chemical liquid is replaced with the low viscous chemical liquid by adding an extremely simple process. However, there is an advantage that this low-viscosity chemical solution can be easily dissolved in pure water, and it is possible to provide a cleaning method that can be expected to be significantly economical and to improve reliability.

[Brief description of drawings]

FIG. 1 is a principle diagram of the present invention,

FIG. 2 is a diagram showing a cleaning method according to a first embodiment of the present invention in process order,

FIG. 3 is a diagram showing a cleaning method according to a second embodiment of the present invention in process order,

FIG. 4 is a diagram showing a conventional cleaning method in order of steps,

[Explanation of symbols]

1 is a high-viscosity chemical solution tank, 2 is a low-viscosity chemical solution tank, 3 is a water washing tank, 11
Is a high temperature phosphoric acid tank, 12 is a nitric acid tank, 13 is a water washing tank, 14 is a drying room,
21 is a high temperature sulfuric acid / H ₂ O ₂ tank, 22 is a nitric acid tank, 23 is a water washing tank, 24
Is a drying room,

Claims (1)

Claim: What is claimed is: 1. A method of cleaning an object to be processed, which has been treated with a highly viscous chemical liquid, comprising: A cleaning method comprising: a step of treating with a low-viscosity chemical solution; and a step of washing the object to which the low-viscosity chemical solution adheres with water.