JP2001102343A - Cleaning method of semiconductor wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleaning method of a semiconductor wafer that is low cost, obtains effective washing effect where the generation of irregularities or the like is suppressed, and has low load for natural environment. SOLUTION: In a method for cleaning a one-bath cleaning type semiconductor wafer, a set of cleaning process where treatment 101 by oxidation cleaning liquid, treatment 102 by rare fluoric acid, and treatment by rinsing liquid 103 are carried out is repeated at least for two times. After that, a drying process 104 is made. In the method for cleaning the one-bath cleaning type semiconductor wafer, a set of cleaning processes where the treatment by the oxidation cleaning liquid, the treatment by the rinse liquid, and the treatment by the rare fluoric acid, and the treatment by the rinsing liquid are carried out is repeated at least for two times. After that, the drying process is made. In a batch-type semiconductor wafer-cleaning method, a set of cleaning processes where the treatment by oxidation cleaning liquid, and the treatment by the rare fluoric acid are carried out is repeated at least two times. After that, the treatment by the rinsing liquid is performed, and drying process is conducted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for cleaning a semiconductor wafer. INDUSTRIAL APPLICABILITY The present invention can be widely used for cleaning a semiconductor wafer in various technical fields using the semiconductor wafer.

[0002]

2. Description of the Related Art When cleaning a semiconductor wafer in the manufacture of semiconductor devices, etc., ozone (O 2) has been conventionally used.
₃ ) A process of performing treatment with an oxidizing cleaning solution such as water, followed by treatment with dilute hydrofluoric acid, rinsing treatment with pure water or the like as appropriate, and then drying to obtain a washed semiconductor wafer is adopted. . In this case, the following conventional techniques are known.

FIG. 36 shows a conventional multi-tank type wafer cleaning technique using ozone water / hydrofluoric acid cleaning. Ozone water treatment tank 2 for cleaning semiconductor wafer 1 to be treated
a, a pure water tank 2b and a dilute hydrofluoric acid tank 2c are installed, and cleaning by ozone treatment with ozone water 3 using an ozone water treatment tank 2a is performed. Thereafter, pure water rinsing with pure water 4 using a pure water tank 2b is performed. Then, cleaning with dilute hydrofluoric acid (DHF) 5 using the dilute hydrofluoric acid tank 3c is performed.
As shown in FIG. 7, the semiconductor wafer 1 to be processed is lifted from the cleaning tank, and a drying (DRY) step is performed.

In this conventional technique, since a plurality of processing tanks are used, a cleaning apparatus becomes large and complicated. Of course,
The cleaning cost per wafer increases.

FIGS. 38 to 46 show a conventional one-bath (one-bath) hydrofluoric acid cleaning process using a wafer cleaning technique. A single cleaning bath 2 is used for cleaning the semiconductor wafer 1 to be processed. In the case shown,
The treatment liquid replacement method is an underwater replacement method. The cleaning process in this prior art is as follows.

Pure water 4 is supplied to the cleaning tank 2 (FIG. 3).
8). The semiconductor wafer 1 to be processed is put into the pure water 4 in the cleaning tank 2 (FIG. 39). The wafer 1 is immersed in pure water 4 (FIG. 40). At this time, the supply of pure water to the cleaning tank 2 is stopped. Dilute hydrofluoric acid (DHF) 5 is supplied to the cleaning tank 2 (FIG. 41). The wafer 1 is etched in the diluted hydrofluoric acid 5 (FIG. 42). Next, pure water 4 is supplied to the cleaning tank 2 to overflow (FIG. 43). The supply of the pure water 4 is stopped (FIG. 44). The semiconductor wafer 1 to be processed is lifted from the cleaning tank 2 and dried (DRY) (FIG. 45), and the process is terminated (FIG. 46).

[0007] This cleaning method is not preferable because unevenness occurs in the steps from the supply of the diluted hydrofluoric acid 5 (FIG. 41), the wafer etching (FIG. 42), and the pure water supply overflow (FIG. 43).

Further, in this type of cleaning, it is desired that the load on the environment is low, but it is not always easy to sufficiently improve this point in the prior art.

[0009]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and does not require a large and complicated apparatus, can perform a cleaning process at low cost, and suppresses the occurrence of unevenness and the like. It is an object of the present invention to provide a method for cleaning a semiconductor wafer, which can provide an improved effective cleaning effect and has a low load on an environment in consideration of a natural environment.

[0010]

A method for cleaning a semiconductor wafer according to the present invention is a method for cleaning a semiconductor wafer by a one-bath cleaning method, in which a treatment with an oxidizing cleaning liquid is performed, followed by a treatment with dilute hydrofluoric acid. Thereafter, a set of cleaning steps for performing a treatment with a rinsing liquid is repeated at least twice, and thereafter, a drying step is performed.

Another method for cleaning a semiconductor wafer according to the present invention is a method for cleaning a semiconductor wafer by a one-bath cleaning method, in which a treatment with an oxidizing cleaning liquid, a treatment with a rinsing liquid, and a treatment with dilute hydrofluoric acid are performed. A set of cleaning steps for performing a treatment and thereafter performing a treatment with a rinsing liquid is repeated at least twice, and thereafter, a drying step is performed.

Another method for cleaning a semiconductor wafer according to the present invention is a method for cleaning a semiconductor wafer by a batch-type cleaning method, in which a cleaning process is performed by performing a treatment with an oxidizing cleaning liquid and then performing a treatment with dilute hydrofluoric acid. At least 2
The process is repeated a number of times, thereafter, a treatment with a rinsing liquid is performed, and then a drying step is performed.

According to the present invention, since the semiconductor wafer is cleaned by the one-bath cleaning method or the batch-type cleaning method, it is possible to avoid an increase in the size and complexity of the apparatus and reduce the cost of cleaning the wafer. In addition, since at least the treatment with the oxidizing cleaning solution and the subsequent treatment with the dilute hydrofluoric acid are repeated twice or more, it is possible to realize effective cleaning without unevenness. Further, since the number of repetitions can be set arbitrarily, it can be freely set according to a desired degree of cleaning or the like. Further, the chemical solution used is only hydrofluoric acid, and the oxidizing cleaning liquid, for example, ozone water is decomposed, and is used to increase the cleaning and removing effect of metal by adding it to diluted hydrofluoric acid as needed. Good aqueous hydrogen peroxide is also decomposed and therefore has a low environmental impact.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be further described below, and preferred specific examples will be described with reference to the drawings. Needless to say, the present invention is not limited to the illustrated embodiment.

In each invention, it is a preferred embodiment that the treatment with the oxidizing cleaning liquid is an ozone water treatment. In a preferred embodiment, the treatment with the rinsing liquid is a rinsing treatment with pure water.

In the above treatment with dilute hydrofluoric acid, dilute hydrofluoric acid can be used alone. Further, a treatment liquid obtained by adding a hydrogen peroxide solution to dilute hydrofluoric acid can be used. For example, a 1% hydrogen peroxide solution (H ₂ O ₂ ) is added to a diluted hydrofluoric acid solution.
By adding 0.1 to 0.1%, the metal removing effect on the surface of the semiconductor wafer is enhanced.

A specific embodiment of the present invention will be described below. Prior to that, an outline of a one-bath type cleaning apparatus that can be used in each of the following examples will be described. Please refer to FIG. 4 to FIG. Each figure shows a state in which a plurality of wafers 1 to be cleaned are carried on a wafer carrier and cleaned by the cleaning apparatus. FIG.
FIG. 5 is a side sectional view of the same, and FIG. 6 is a side sectional view showing a state where the wafer 1 is pulled up from the processing liquid.

In the drawing, reference numeral 1 denotes a wafer to be cleaned, and a carrier 6 holds the wafer 1. The carrier 6 is attached to an arm 8 of a robot 7, and the arm 8 has a mechanism that moves up and down. 4 and 5, the wafer 1 and the carrier 6 are immersed in the processing liquid in the inner tank 21 of the cleaning tank 2.

Pure water 4, dilute hydrofluoric acid solution 5, and ozone water 3 are supplied to the cleaning tank inner tank 21 through supply valves. The supply procedure will be described in the following embodiments and specific process examples.

Reference numeral 22 denotes a washing tank outer tank, which is
This tank receives pure water 4, diluted hydrofluoric acid solution 5, ozone water 3, etc., which are overflowed and drained from the washing tank inner tank 21. These waste liquids are discharged through a drain valve 9.

Reference numeral 10 denotes a pure water supply valve for down flow instead of overflow. In order to improve the cleaning removal efficiency when cleaning the wafer 1, the high-frequency vibration plate 11 is replaced with a high-frequency vibration plate (megasonic) 23 so that the high-frequency vibration plate 11 can be used. It is attached to the tank. Pure water is supplied to the mega tank 23 from the pure water supply valve 12.

FIG. 6 shows that in the repeated cleaning process,
This shows the state at the time of waiting for wafer lifting. Dilute hydrofluoric acid solution 5
Is supplied from a DHF (dilute hydrofluoric acid) mixing tank indicated by reference numeral 13. The liquid in the DHF mixing tank 13 is basically a mixed aqueous solution of pure water and hydrofluoric acid. In the DHF mixing tank 13, a hydrogen peroxide solution 14 is supplied by opening a hydrogen peroxide solution supply valve. , A fixed amount can be supplied.
The ozone water 3 is supplied from an ozone water production device indicated by reference numeral 16.

In each figure, reference numeral 17 denotes a dispersion plate, and 18 denotes a mounting screw. Next, an example of an embodiment of the present invention will be described with reference to FIGS.

Embodiment 1 Referring to FIG. In this example, ozone water treatment 101 is performed, then dilute hydrofluoric acid treatment 102 is performed, and then pure water rinse 1 is performed.
03, and ozone water treatment 10
1 'is performed, then a dilute hydrofluoric acid treatment 102' is performed, and then a pure water rinse 103 'is performed. That is, here, a series of cleaning processes including the ozone water treatment 101, the diluted hydrofluoric acid treatment 102, and the pure water rinse 103 are repeated twice as indicated by reference numerals I and II. Thereafter, drying 104 is performed.

In this embodiment, an overflow replacement system is used, and the apparatus shown in FIGS. 4 and 5 is used.

In this example, the repetition was performed twice,
Further, it can be performed as many times as necessary.

Embodiment 2 Referring to FIG. In this example, ozone water treatment 201 is performed, then pure water rinse 202 is performed, and then dilute hydrofluoric acid treatment 2 is performed.
03, then a pure water rinse 204, and in the same procedure, perform an ozone water treatment 201 ', then perform a pure water rinse 202', and then perform a diluted hydrofluoric acid treatment 203 ',
Next, pure water rinsing 204 'is performed. That is, here, ozone water treatment 201, pure water rinse 202, dilute hydrofluoric acid treatment 2
03, a series of cleaning processes including the pure water rinse 204 is repeated twice as indicated by reference numerals I and II. afterwards,
Drying 205 is performed.

In this embodiment, the overflow replacement system is used, and the apparatus shown in FIGS. 4 and 5 is used.

In this example, the repetition was performed twice,
Further, it can be performed as many times as necessary.

Third Embodiment Referring to FIG. In this example, an ozone water treatment 301 is performed, then a dilute hydrofluoric acid treatment 302 is performed, and further, an ozone water treatment 301 ′ is performed in the same procedure, and then a dilute hydrofluoric acid treatment 3 is performed.
Perform 02 '. That is, here, the ozone water treatment 10
1. A series of cleaning processes including dilute hydrofluoric acid treatment 102 are repeated twice as indicated by reference numerals I and II. Thereafter, pure water rinsing 303 is performed, and then drying 30
Perform 4.

In the present embodiment, an underwater replacement system is used. In particular, for cleaning with ozone water, an underwater replacement system is made possible to achieve effective cleaning. A more specific process of this example will be described later with a specific process example.

Although the present embodiment is also performed twice, it can be repeated any number of times.

Specific Process Example 1 Hereinafter, a specific process will be described by way of example. First
The process example uses the apparatus shown in FIG. 4 to FIG.
The wafer was cleaned by the processes shown in FIGS. In this specific process, ozone / hydrofluoric acid cleaning was performed by an underwater replacement method.

The ozone water 3 is supplied to the cleaning tank 2 (FIG. 7). The semiconductor wafer 1 to be processed is put into the ozone water 3 in the cleaning tank 2 (FIG. 8). The ozone water 3 overflows, and the wafer 1 is immersed in the ozone water 3 (FIG. 9). Next, pure water 4 is supplied to the cleaning tank 2 (FIG. 1).
0). Dilute hydrofluoric acid (DHF) 5 is supplied to the cleaning tank 2,
The wafer 1 is etched in the diluted hydrofluoric acid 5 (FIG. 11). Next, the pure water 4 is supplied to the cleaning tank 2 to overflow (FIG. 12). By supplying the pure water 4, the inside of the cleaning tank 2 is replaced with the pure water 4 (FIG. 13).

Further, ozone water 3 is supplied to cause overflow (FIG. 14). Next, dilute hydrofluoric acid (DHF) 5 is supplied to the cleaning tank 2, and the wafer 1 is diluted with the dilute hydrofluoric acid 5.
Is etched (FIG. 15). Next, pure water 4 is supplied to the cleaning tank 2 to cause overflow (FIG. 16). By supplying the pure water 4, the pure water is rinsed in the cleaning tank 2, and the wafer is pulled up and dried as shown in FIG. When the drying is completed, the process ends (FIG. 18).

Specific Process Example 2 In a second process example, wafer cleaning was performed by the process shown in FIGS. 19 to 35 using the apparatus shown in FIGS. In this specific process, ozone / hydrofluoric acid cleaning was performed in a repeated cleaning process.

An apparatus and a wafer to be cleaned are prepared (FIG. 1).
9) In the overflow state of the ozone water 3, the wafer 1 is put into the cleaning tank 2 (FIG. 20). The wafer 1 is immersed in ozone water 3 (FIG. 21). The wafer 1 is pulled up, pulled up and made to stand by (see FIG. 6), and the ozone water 3 is drained (FIG. 22). In a standby state above the wafer 1, dilute hydrofluoric acid (DHF) 5 is supplied to the cleaning tank 2 (FIG. 23). The wafer 1 is put into the diluted hydrofluoric acid (DHF) 5 (FIG. 24). The diluted hydrofluoric acid 5 is circulated. In the circulation state of the diluted hydrofluoric acid 5, the wafer 1 is immersed in the diluted hydrofluoric acid 5 (FIG. 25). Thereby, etching cleaning of the wafer 1 is performed. In dilute hydrofluoric acid cleaning,
About 1-0.1%, add hydrogen peroxide solution to diluted hydrofluoric acid,
The metal cleaning effect may be enhanced. Alternatively, megasonic vibration may be applied to enhance the cleaning effect. After that, the wafer 1 is pulled up, pulled up and put on standby, and the diluted hydrofluoric acid 5 is drained (FIG. 26).

Further, the above processing is repeated.
That is, in a standby state above the wafer 1, the ozone water 3 is supplied to the cleaning tank 2 and replaced (FIG. 2).
7). In the overflow state of the ozone water 3, the wafer 1 is put into the cleaning tank 2 (FIG. 28). The wafer 1 is immersed in ozone water 3 (FIG. 29). The wafer 1 is pulled up, pulled up and put on standby, and the ozone water 3 is drained (FIG. 30). In a standby state above the wafer 1, dilute hydrofluoric acid (DHF) 5 is supplied to the cleaning tank 2 (FIG. 3).
1). The wafer 1 is put into the circulating dilute hydrofluoric acid (DHF) 5 (FIG. 32). The replacement with the pure water 4 is performed, and the wafer 1 is washed (FIG. 33). Thereafter, the wafer 1 is pulled up (FIG. 34). The cleaning is completed, the drying is completed, and the process ends (FIG. 35).

According to the above-described embodiments and specific process examples, one-bus processing can be performed by batch processing, so that the apparatus is prevented from becoming large and complicated, and the wafer cleaning cost is reduced. . The number of times of oxidizing treatment liquid such as ozone water / hydrofluoric acid treatment can be freely set, and uniform and effective cleaning can be realized. The oxidizing treatment liquid is easily decomposed, and the load on the environment is small. Addition of hydrogen peroxide to hydrofluoric acid, combined use of high-frequency vibration, and the like can further enhance a cleaning effect such as a metal removing effect. Further, in the above specific process example 1, after the cleaning with hydrofluoric acid, the underwater replacement with ozone water is possible.

[0040]

As described above, according to the present invention, a large-sized and complicated apparatus is not required, cleaning can be performed at low cost, and an effective cleaning effect in which the occurrence of unevenness or the like is suppressed can be obtained. In addition, a method for cleaning a semiconductor wafer which has a low load on an environment in consideration of the natural environment can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a first embodiment of the present invention.

FIG. 2 is a diagram for explaining a second embodiment of the present invention.

FIG. 3 is a diagram for explaining a third embodiment of the present invention.

FIG. 4 is a diagram showing a configuration of a cleaning device that can be used in the embodiment of the present invention.

FIG. 5 is a diagram showing a configuration of a cleaning device that can be used in the embodiment of the present invention.

FIG. 6 is a diagram showing a configuration of a cleaning apparatus that can be used in the embodiment of the present invention.

FIG. 7 is a view showing a first specific process example in the order of steps (1).

FIG. 8 is a view showing a first specific process example in the order of steps (2).

FIG. 9 is a view showing a first specific process example in the order of steps (3).

FIG. 10 is a view showing a first specific process example in the order of steps (4).

FIG. 11 is a view showing a first specific process example in the order of steps (5).

FIG. 12 is a view showing a first specific process example in the order of steps (6).

FIG. 13 is a view showing a first specific process example in the order of steps (7).

FIG. 14 is a view showing a first specific process example in the order of steps (8).

FIG. 15 is a view showing a first specific process example in the order of steps (9).

FIG. 16 is a view showing a first specific process example in the order of steps (10).

FIG. 17 is a view showing a first specific process example in the order of steps (11).

FIG. 18 is a view showing a first specific process example in the order of steps (12).

FIG. 19 is a view showing a second specific process example in the order of steps (1).

FIG. 20 is a view showing a second specific process example in the order of steps (2).

FIG. 21 is a view showing a second specific process example in the order of steps (3).

FIG. 22 is a view showing a second specific process example in the order of steps (4).

FIG. 23 is a view showing a second specific process example in the order of steps (5).

FIG. 24 is a view showing a second specific process example in the order of steps (6).

FIG. 25 is a view showing a second specific process example in the order of steps (7).

FIG. 26 is a view showing a second specific process example in the order of steps (8).

FIG. 27 is a view showing a second specific process example in the order of steps (9).

FIG. 28 is a view showing a second specific process example in the order of steps (10).

FIG. 29 is a view showing a second specific process example in the order of steps (11).

FIG. 30 is a view showing a second specific process example in the order of steps (12).

FIG. 31 is a view showing a second specific process example in the order of steps (13).

FIG. 32 is a view showing a second specific process example in the order of steps (14).

FIG. 33 is a view showing a second specific process example in the order of steps (15).

FIG. 34 is a diagram showing a second specific process example in the order of steps (16).

FIG. 35 is a view showing a second specific process example in the order of steps (17).

FIG. 36 is a diagram showing a conventional technique.

FIG. 37 is a diagram showing a conventional technique.

FIG. 38 is a diagram showing a conventional technique.

FIG. 39 is a diagram showing a conventional technique.

FIG. 40 is a diagram showing a conventional technique.

FIG. 41 is a diagram showing a conventional technique.

FIG. 42 is a diagram showing a conventional technique.

FIG. 43 is a diagram showing a conventional technique.

FIG. 44 is a diagram showing a conventional technique.

FIG. 45 is a diagram showing a conventional technique.

FIG. 46 is a diagram showing a conventional technique.

[Explanation of symbols]

101, 101 ', 201, 201', 301, 30
1 ': Treatment with oxidizing treatment liquid (ozone water) 10
2,102 ', 203,203' ... dilute hydrofluoric acid treatment,
103, 103 ', 202, 202', 204, 20
4 '... pure water rinse, 104, 205, 304 ...
Drying.

Claims (15)

[Claims] 1. A method for cleaning a semiconductor wafer by a one-bath cleaning method, wherein a set of cleaning steps of performing a process using an oxidizing cleaning solution, performing a process using a diluted hydrofluoric acid, and then performing a process using a rinse solution includes at least two processes. A semiconductor wafer cleaning method using a one-bath cleaning method, wherein the method is repeated twice and then a drying step is performed. 2. The method for cleaning a semiconductor wafer by a one-bath cleaning method according to claim 1, wherein a replacement method of a processing liquid used for each processing in the set of cleaning steps is an overflow replacement method. 3. The method according to claim 1, wherein the treatment with the oxidizing cleaning liquid is an ozone water treatment. 4. The method according to claim 1, wherein the rinsing treatment is a rinsing treatment with pure water. 5. The semiconductor according to claim 1, wherein the treatment with dilute hydrofluoric acid uses a dilute hydrofluoric acid alone or a treatment liquid obtained by adding hydrogen peroxide to dilute hydrofluoric acid. Wafer cleaning method. 6. A method for cleaning a semiconductor wafer by a one-bath cleaning method, wherein a treatment with an oxidizing cleaning liquid, a treatment with a rinsing liquid, a treatment with a diluted hydrofluoric acid, and a treatment with a rinsing liquid are performed. A method of cleaning a semiconductor wafer by a one-bath cleaning method, comprising repeating a set of cleaning steps at least twice, and thereafter performing a drying step. 7. The method for cleaning a semiconductor wafer by a one-bath cleaning method according to claim 6, wherein a replacement method of a processing solution used for each processing in the set of cleaning steps is an overflow replacement method. 8. The method according to claim 6, wherein the treatment with the oxidizing cleaning liquid is an ozone water treatment. 9. The method according to claim 6, wherein the treatment with the rinsing liquid is a rinsing treatment with pure water. 10. The method for cleaning a semiconductor wafer by a one-bath cleaning method according to claim 6, wherein a treatment liquid obtained by adding hydrogen peroxide to dilute hydrofluoric acid is used in the treatment with dilute hydrofluoric acid. 11. A method for cleaning a semiconductor wafer by a batch cleaning method, wherein a set of cleaning steps of performing a treatment with an oxidizing cleaning liquid and thereafter performing a treatment with dilute hydrofluoric acid is performed at least twice, and thereafter, A method for cleaning a semiconductor wafer by a batch-type cleaning method, comprising performing a treatment with a rinsing liquid and then performing a drying step. 12. The method for cleaning a semiconductor wafer by a batch cleaning method according to claim 11, wherein the replacement method of the processing liquid used in each of the processes is an underwater replacement method. 13. The semiconductor wafer cleaning method according to claim 11, wherein the treatment with the oxidizing cleaning liquid is an ozone water treatment. 14. The method for cleaning a semiconductor wafer by a batch cleaning method according to claim 11, wherein the treatment with the rinsing liquid is a rinsing treatment with pure water. 15. The method for cleaning a semiconductor wafer by a one-bath cleaning method according to claim 11, wherein a treatment liquid obtained by adding hydrogen peroxide to dilute hydrofluoric acid is used in the treatment with dilute hydrofluoric acid.