JPH1140531A - Washing system, and washing method and apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify a liquid discharge mechanism and to effectively remove particles sticking on the surface of to-be-processed body while suppressing chapping on surface to a most, by using neutral or acid washing liquid for a washing apparatus wherein the to-be-processed body is washed while contacting to the washing liquid. SOLUTION: At a washing/drying process part 3, wafer chuck washing/drying apparatus 1 for washing and drying a wafer chuck 36 of a transportation apparatus 30, washing apparatus 12-17 for washing a wafer W using each washing liquid, a wafer chuck washing/drying apparatus 18 for washing and drying a wafer chuck 38 of a transportation apparatus 32, and a drying apparatus 19 for steam-drying the wafer W which is washed with respective washing apparatus 12-17 in, for example, isopropyl alcohol, etc., are arrayed in such order from a taking-in/taking-out part 2 side to a loading/carrying-out part 4 side. Here, the washing liquid used with the washing apparatuses 12-17 is limited to pure water or acid washing liquid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning system, a cleaning apparatus, and a cleaning method for cleaning an object to be processed by contacting the object with a cleaning liquid.

[0002]

2. Description of the Related Art For example, a cleaning process in a manufacturing process of a semiconductor device such as an LSI will be described as an example. A cleaning system is used to remove. Among them, among others, a wet type cleaning system including a cleaning device for performing a cleaning process by immersing a wafer in a cleaning liquid in a cleaning tank is widely used because particles attached to the wafer can be effectively removed.

[0003] In order to enable continuous batch processing, this cleaning system has, for example, a loading / unloading section for taking out 25 wafers from a carrier, and 50 wafers for 2 carriers taken out by the loading / unloading section. For transporting a batch of paper, and 5
A cleaning / drying processing unit for performing various cleaning processes on zero wafers, and a loading / unloading unit for storing the cleaned wafers in the carrier again are provided.

In the washing and drying section, a rinsing process,
Cleaning devices for performing various cleaning processes such as an ammonia process, a hydrofluoric acid process, a sulfuric acid process, and a hydrochloric acid process are sequentially arranged. Among them, the ammonia treatment is called SC-1 cleaning, and is performed by an APM cleaning solution obtained by diluting a chemical solution in which an aqueous ammonia solution and a hydrogen peroxide solution are mixed with pure water. The APM cleaning liquid used is usually heated to about 40 ° C. to 90 ° C.

[0005] There is also a megasonic cleaning for applying, for example, ultrasonic vibration to a cleaning liquid. In this case, a vibration force is applied to the water molecules in the cleaning liquid, so that the cleaning liquid supplied into the cleaning tank can shake off particles from the surface of the wafer by the vibration force, thus providing an effective cleaning process. It can be performed.

[0006]

The APM cleaning solution is an alkaline aqueous solution, and the other cleaning solutions used for hydrofluoric acid treatment, sulfuric acid treatment and hydrochloric acid treatment are acidic aqueous solutions. For this reason, in the conventional cleaning system, A
An alkaline drainage mechanism and an acid drainage mechanism are provided so that the PM cleaning liquid and other acidic cleaning liquids do not react with each other to generate contamination such as salts. As described above, the provision of the two drainage mechanisms in the cleaning system increases the size and complexity of the cleaning system itself and complicates drainage management.

When ultrasonic vibration is applied to the APM cleaning liquid, ammonia molecules may be dissociated in the APM cleaning liquid to generate ions or the like for etching silicon or a silicon oxide film. And this APM
If the surface of the wafer is cleaned with a cleaning solution,
The silicon surface is etched, and the so-called surface roughening (roughening) occurs on the surface of the wafer. In recent years, further integration of semiconductor devices has been desired in order to improve productivity, and the necessity of miniaturization technology in sub-quarter micron units has been increasing. Such surface roughness of the wafer has an adverse effect on the manufacture of a wafer that requires miniaturization.

Also, pure ammonia has a boiling point of -20.
It is as low as -30 ℃, and diluted with pure water to 40 ℃.
It can also be present as a liquid in the range from to 90 ° C. However, to improve cleaning efficiency,
Heated APM containing ammonia component as described above
When ultrasonic vibration is applied to the cleaning solution,
The ammonia component is vaporized and bubbles are generated in the APM cleaning liquid. In addition, the cleaning process cannot be effectively performed on the surface of the wafer to which the bubbles are attached. This is not desirable in today's world where the need for further miniaturization techniques is increasing.

Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a cleaning system that can simplify a drainage mechanism.

Another object of the present invention is to provide a cleaning apparatus and a cleaning method capable of effectively removing particles adhering to the surface of an object to be processed while minimizing surface roughness.

[0011]

According to a first aspect of the present invention, there is provided a cleaning system comprising one or more cleaning apparatuses for cleaning an object to be processed by bringing the object into contact with a cleaning liquid. The cleaning liquid used in the cleaning apparatus is neutral or acidic.

According to the cleaning system of the first aspect, since the alkaline cleaning liquid is used, there is no need to provide an alkaline drainage mechanism in the cleaning system, and the drainage mechanism can be simplified. In this way, it is possible to reduce the size of the system and facilitate the management of drainage.

According to a second aspect of the present invention, there is provided a cleaning apparatus for cleaning an object to be processed by bringing the object into contact with a cleaning liquid, wherein the cleaning tank is made of a hydrogen peroxide solution.

According to the second aspect of the present invention, since the hydrogen peroxide solution is used as the cleaning solution, oxygen molecules in the hydrogen peroxide solution oxidize the silicon surface of the object to be processed, and the surface of the object to be processed is removed. To form a silicon oxide film. Further, the surface of the object to be processed can be protected from etching by ions or the like generated in the cleaning liquid. Accordingly, particles attached to the surface of the object to be processed can be effectively removed while suppressing surface roughness as much as possible. In this way, even after the cleaning, the surface of the object to be processed is not roughened, so that it is possible to prevent an adverse effect on later production.

Further, in order to realize sufficient protection of the surface of the object, it is preferable that the concentration of the hydrogen peroxide solution is 0.15 wt% or more. In this case, as described in claim 4, a temperature adjusting means for adjusting the temperature of the cleaning liquid is provided, and as described in claim 5, the temperature of the cleaning liquid is set at 3 degrees.
The temperature is preferably 5 ° C. or higher. It is preferable that a vibration oscillating mechanism for applying vibration to the cleaning liquid be provided. In this way, while the surface of the object to be processed can be sufficiently protected, the temperature of the cleaning solution is optimally adjusted, and vibration is applied to the cleaning solution by a vibration oscillating mechanism so that the surface of the object is not roughened. Fine particles can be effectively removed from the surface.

According to a seventh aspect of the present invention, there is provided a cleaning method for cleaning an object to be processed by contacting the object with a cleaning liquid, wherein the cleaning liquid is a hydrogen peroxide solution.

Further, in the cleaning method according to the present invention, it is preferable that the concentration of the hydrogen peroxide solution is 0.15 wt% or more. Also,
It is preferable that the temperature of the cleaning liquid is adjusted as described in claim 9, and the temperature of the cleaning liquid is 35 ° C. or higher as described in claim 10. It is preferable that vibration is applied to the cleaning liquid filled in the cleaning tank.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of the present invention will be described based on a wet-type cleaning system 1 in which a wafer W as an example of an object to be processed is immersed in a cleaning liquid in a cleaning tank for cleaning. explain. FIG. 1 is a perspective view of a cleaning system 1 for explaining a preferred embodiment of the present invention.

The cleaning system 1 includes a loading / unloading unit 2 for unloading wafers W before cleaning, which have been loaded in units of carriers C, in an aligned state from the carriers C. A cleaning / drying processing unit 3 for cleaning and drying a plurality of taken out wafers W (for example, 50 wafers for two carriers C) in a batch manner;
The wafers W cleaned and dried by the cleaning / drying processing unit 3 can be roughly classified into three portions of a loading / unloading unit 4 for loading the carriers C into the carrier C and unloading the wafers in units of the carrier C.

The loading / unloading section 2 includes a loading section 5 for loading and mounting a carrier C containing, for example, 25 wafers W before cleaning, and a carrier C sent to a predetermined position of the loading section 5. , An appropriate number (e.g., 2
A transfer device 7 is provided for transferring each piece.

In this embodiment, the cleaning / drying processing unit 3 includes a cleaning / drying unit for cleaning and drying a wafer chuck 36 of a transfer unit 30 to be described later in order from the loading / unloading unit 2 to the loading / unloading unit 4. Wafer chuck cleaning / drying equipment 1
1, a cleaning apparatus 12 for cleaning a wafer W using each cleaning liquid
To 17, a wafer chuck cleaning / drying device 18 for cleaning and drying the wafer chuck 38 of the transfer device 32,
Further, a drying device 19 for vapor-drying the wafer W cleaned by each of the cleaning devices 12 to 17 with, for example, IPA (isopropyl alcohol) or the like is arranged.

Here, the cleaning liquid used in the cleaning devices 12 to 17 is limited to pure water or an acidic cleaning liquid. Therefore, as shown in FIG. Only the pure water draining mechanism 26 is provided.

The wafer chuck cleaning / drying devices 11 and 18 for cleaning and drying the wafer chuck 36 and the wafer chuck 38 and the drying device 19 for drying the wafer W are provided.
The arrangement and combination of the cleaning devices 12 to 17 except for the above can be arbitrarily combined depending on the type of cleaning for the wafer W. For example, it is possible to omit a certain cleaning device or add another cleaning device. is there. However, when a cleaning device is added, the cleaning liquid used in the cleaning device is pure water or an acidic cleaning liquid.

The loading / unloading section 4 has the loading / unloading section described above.
Unloader 2 having the same configuration as loader 6 of unloading section 2
0, an unloading unit 21 having the same configuration as the loading unit 5, and a transfer device (not shown) having the same configuration as the transfer device 7 are provided.

Then, the front side of the cleaning / drying processing section 3 (FIG. 1)
, Three transporting devices 30, 31, 32 are arranged in order from the loading / unloading unit 2 side to the loading / unloading unit 4 side, and these transporting devices 30, 31, 32 are
Each of them is configured to be slidable along the guide 33 in the longitudinal direction of the cleaning system 1. Each transport device 30,
31 and 32 are the corresponding wafer chucks 36 and
37, 38, each transport device 30, 31, 32
It is possible to collectively hold a predetermined number of wafers W (for example, 50 wafers W for two carriers C) by the wafer chucks 36, 37 and 38.

Since all of the transfer devices 30, 31, and 32 have the same configuration, for example, the transfer device 30 for transferring the wafer W between the chuck cleaning / drying device 11, the cleaning device 12, and the cleaning device 13 is provided. As shown in FIG. 3, the wafer chuck 36 of the transfer device 30 includes a plurality of wafers W for two carriers C, that is, as shown in FIG.
In this embodiment, a pair of left and right grips 40a and 40b for gripping 50 wafers W at a time is provided.

The grips 40a, 40b are symmetrical in the left-right direction, and are configured to pivot symmetrically to open and close the legs. The gripping portions 40a and 40b are supported by a support portion 41 of the transfer device 30, and are configured to be freely rotatable (θ direction) and movable in the front-rear direction (Y direction) by a driving mechanism in the support portion 41. ing. The support section 41 is moved in the vertical direction (Z direction) by a drive mechanism 42, and the drive mechanism 42 itself is mounted on an upper portion of a transport base 43 that is movable in the longitudinal direction (X direction).

On the other hand, chuck cleaning / drying devices 11 and 18
At the bottom of each of the other cleaning devices 12 to 17 except for the drying device 19, a boat unit 50 for aligning and holding the wafers W in an upright state while maintaining the wafers at predetermined equal intervals in each device is provided. Each is installed. The boat 50 has three parallel holding rods 5 for supporting the lower part of the wafer W.
1, 52 and 53 are provided as shown in FIG. On the surfaces of these holding rods, 50 holding grooves into which the peripheral portion of the wafer W is inserted are formed respectively.

Then, the 50 wafers W, which are collectively gripped by the gripping portions 40a, 40b, are held by the holding rods 51, 5 of the boat 50 as the wafer chuck 36 is lowered.
2 and 53 are respectively fitted into the holding grooves. Then, the gripping portions 40a and 40b are opened by the rotation of the support portion 41, the gripping state of the wafer W is released, and the wafer W is placed in the cleaning device 12.
To store. Thereafter, the wafer chuck 36 moves up and retreats upward from the cleaning device 12, and a predetermined cleaning process is performed on the wafer W transferred on the boat unit 50.

When a predetermined process in the cleaning device 12 is completed as described later, the holding portions 40a and 40b are inserted into the cleaning device 12 as the wafer chuck 36 is lowered. Then, by the rotation of the support portion 41, the grip portion 40 is rotated.
a, 40b are closed. Then, the 50 wafers W held on the holding rods 51, 52, 53 of the boat unit 50 are collectively gripped. Thereafter, the wafer chuck 36 rises and retracts upward. Accordingly, 50 wafers W are collectively taken out of the cleaning device 12 and carried into the next device.

Although the transfer device 30 has been described as a representative, the other transfer devices 31, 32 and their wafer chucks 37, 38 have the same configuration as the transfer device 30 and the wafer chuck 36, respectively. Similarly, for example, 50 wafers W are collectively held and transported.

Next, since each of the cleaning devices 12 to 17 has the same configuration, the cleaning device 12 will be described with reference to FIGS.

As shown in FIG. 4, the cleaning device 12 comprises a box-shaped inner tank 6 having a size sufficient to accommodate the wafer W.
The cleaning tank 62 includes an outer tank 61 and a cleaning tank 62. The upper surface of the inner tank 60 is open, and the wafer W is inserted into the inner tank 60 through the opening on the upper surface. The outer tub 61 is mounted around the opening of the inner tub 60 so as to receive the overflowing cleaning liquid from the upper end of the inner tub 60.

As shown in FIG. 5, an outlet of a cleaning liquid supply circuit 63 for supplying a cleaning liquid to the cleaning tank 62 is opened at the bottom of the inner tank 60. Further, an inlet of the cleaning liquid supply circuit 63 is connected to a cleaning liquid supply unit 64, and a heater 65 is provided in the cleaning liquid supply unit 64.
Is provided. A hydrogen peroxide supply circuit 67 having a pump 66 and a pure water supply circuit 69 having a pump 68 are connected to a cleaning liquid supply unit 64, respectively. The heater 65 and the pumps 66 and 68 are
An operation signal from the control unit 70 is input. Before performing the cleaning process on the wafer W, an operation signal is output from the control unit 70, and the supply amount of the hydrogen peroxide solution and the supply amount of the pure water are controlled and supplied into the cleaning solution supply unit 64. . In the cleaning liquid supply unit 64, the concentration of the cleaning liquid filled in the cleaning tank 62 is adjusted so as to be 0.15% by weight or more. An operation signal from the control unit 70 is transmitted to the heater 65.
The temperature of the cleaning liquid is adjusted to 35 ° C. or higher in the cleaning liquid supply unit 64.
When the cleaning process of the wafer W is performed, the cleaning liquid (hydrogen peroxide solution) adjusted to a predetermined concentration and temperature is supplied from the cleaning liquid supply unit 64 to the cleaning tank 62 via the cleaning liquid supply circuit 63. It is configured as follows. In this embodiment, the concentration of the hydrogen peroxide solution is 0.1%.
The temperature is preferably in the range of 5 wt% or more, and similarly, the temperature of the cleaning liquid is preferably in the range of 35 ° C or more.

A circulating circuit 75 for circulating a cleaning liquid during the cleaning process of the wafer W is connected between the inner tank 60 and the outer tank 61. The inlet of the circulation circuit 75 is connected to the valve 7
6, a valve 77, a pump 78, a heater 79, and a filter 80 are arranged in this order in the circulation circuit 75, and the outlet of the circulation circuit 75 is connected to the jet nozzle 81. Have been. The heater 79 is configured to receive an operation signal from the control unit 70 so that the temperature of the cleaning liquid can be adjusted to a predetermined temperature even during the cleaning process. Then, by opening the valve 76, the cleaning liquid overflowing from the inner tank 60 to the outer tank 61 flows into the circulation circuit 75. Then, the cleaning liquid flowing into the circulation circuit 75 is caused to flow in the order of the heater 79 and the filter 80 by operating the pump 78 to control the temperature to a predetermined temperature and to clean the cleaning liquid. To be supplied. The jet nozzles 81 are arranged below the cleaning tank 62 in a pair, and are configured to spray the cleaning liquid toward the surface of the wafer W.

A drainage circuit 82 is connected to the valve 77. By switching the valve 77, the cleaning liquid in the outer tank 61 is drained, and the acid-based drainage described above is discharged through the drainage circuit 82. It is configured to flow into the liquid mechanism 25. A drainage circuit 84 is connected to the bottom surface of the inner tank 60 via a valve 83. By opening and closing the valve 83, the cleaning liquid in the inner tank 60 is drained. It is configured to flow into the acid-based drainage mechanism 25.

As shown in FIG. 4, a megasonic device 90 having a built-in ultrasonic vibrator is mounted below the cleaning tank 62. The ultrasonic wave oscillated from the megasonic device 90 has a function of vibrating the cleaning liquid filled in the cleaning tank 62 and removing particles attached to the surface of the wafer W. Further, a water tank 91 is provided between the cleaning tank 62 and the megasonic device 90, and the ultrasonic wave from the megasonic device 90 is transmitted to the cleaning liquid in the cleaning tank 62 via the water in the water tank 91. It is configured.

The other cleaning devices 13 to 17 have the same configuration as the cleaning device 12, and each of the cleaning devices 13 to 17 has the same configuration.
The cleaning processing is performed on the wafer W with various cleaning liquids within the range of ~ 17.

Now, the processing steps of the wafer W in the cleaning system 1 of FIG. 1 configured as described above will be described. First, a transfer robot (not shown) loads a carrier C containing, for example, 25 wafers W that have not been cleaned yet.
It is placed on the carry-in section 5 of the take-out section 2. And this loading section 5
Is transferred to the adjacent loader 6 by the transfer device 7. In the loader 6, for example, the carrier C
50 wafers W for two wafers are taken out of the carrier C,
Further, with the orientation flat aligned, 50 wafers W are aligned and waited.

Subsequently, the transfer device 30 already cleaned and dried in the wafer chuck cleaning / drying device 11.
The wafer chuck 36 moves above the wafers W in a standby state aligned with the loader 6, and the aligned wafers W are collectively gripped by the wafer chuck 36 in units of 50 wafers. Then, the wafers W are transferred to the transfer devices 31, 32.
While being attracted by the wafer chucks 37 and 38 of FIG. Thus, cleaning is performed to remove impurities such as particles and organic contaminants attached to the surface of the wafer W.

Here, the cleaning process in the cleaning device 12 will be described. First, before the wafer W is loaded into the cleaning tank 62 of the cleaning device 12 by the wafer chuck 36 of the transfer device 30, The inner tank 60 is filled with the cleaning liquid. That is, as described above with reference to FIG.
Before performing the cleaning process, the control unit 70 outputs an operation signal to the pumps 66 and 68. Then, a predetermined supply amount from the hydrogen peroxide water supply circuit 67 is supplied so that the concentration of the cleaning liquid filled in the cleaning tank 62 becomes 0.15 wt% or more.
The hydrogen peroxide solution is supplied to the cleaning liquid supply unit 64, and similarly, pure water is supplied to the cleaning liquid supply unit 64 from the pure water supply circuit 68 by a predetermined supply amount. The control unit 70
Is output to the heater 65, and the heater 65 is operated so that the cleaning liquid has a predetermined temperature. Thus, the cleaning liquid (hydrogen peroxide solution) adjusted to a predetermined concentration and temperature in the cleaning liquid supply unit 64 is supplied into the cleaning tank 62.

After the cleaning liquid is filled in the inner tank 60 of the cleaning tank 62, the 50 wafers W held by the wafer chuck 36 of the transfer device 30 described with reference to FIG.
The wafer W is carried into the inner tank 60 of the cleaning tank 62. 50
After the wafers W are delivered in a state of being aligned on the boat unit 50 in the inner tank 60, the wafer chuck 36 releases the gripping state of the wafer W, and the wafer chuck 36 is retracted above the cleaning tank 62. .

At this time, the megasonic device 90 mounted below the cleaning tank 62 operates to enhance the effect of removing particles attached to the wafer W. Specifically, ultrasonic vibration from the megasonic device 90 is transmitted to the immersed wafer W to apply a vibration force to water molecules around the wafer W, and particles are shaken off from the surface of the wafer W. The vibration applied to the cleaning tank 62 is from 400 kHz to 2
Since the ultrasonic waves are in the frequency band of MHz, no cavitation occurs in the liquid, and sub-quarter micron particles can be removed without damaging the wafer W.

On the other hand, during the cleaning of the wafer W, the circulation of the cleaning liquid by the circulation circuit 75 is started. The washing liquid overflowing from above the inner tank 60 is received in the outer tank 61 and the valve 76 is
Is opened and the valve 77 is operated to switch the cleaning liquid to the pump 7.
The cleaning liquid is circulated and supplied again to the inner tank 60 of the cleaning tank 62 through the jet nozzle 81 after the temperature is adjusted to a predetermined temperature and the cleaning is performed by flowing the heater 8, the heater 79, and the filter 80 in this order.
Then, as described earlier with reference to FIG.
A uniform cleaning is performed by forming a rising flow of the cleaning liquid in the inner tank 60 with the cleaning liquid sprayed from the above, and supplying the cleaning liquid evenly to the surface of the wafer W held on the boat unit 50.

During the cleaning, oxygen molecules (O ₂ ) in the hydrogen peroxide solution react with the silicon surface of the wafer W to form a silicon oxide film (SiO ₂ ) on the surface of the wafer W. On the other hand, dissociation occurs in the cleaning liquid due to vibration, and ions and the like for etching silicon (Si) and silicon oxide films are generated. However, since the concentration of the hydrogen peroxide solution is sufficiently adjusted and the rate at which oxygen molecules react with the silicon surface of the wafer W is faster than the etching rate by ions or the like, a silicon oxide film is always formed on the surface of the wafer W. It is formed and is protected from etching by ions or the like.
Also, even if vibration is given to the cleaning liquid, ammonia (NH ₄ O
H) Compared with the APM cleaning liquid in which the components are mixed, the generation of bubbles is smaller, the adhesion of bubbles to the wafer W is suppressed, and the entire wafer W is uniformly cleaned.

After a lapse of a predetermined time, the cleaning with the cleaning liquid is completed. The valve 83 is opened, and the cleaning liquid in the inner tank 60 is drained from the drainage circuit 84 to the acid-based drainage mechanism 25.
Similarly, with the valve 76 opened, the valve 77 is switched,
The cleaning liquid in the outer tank 61 is drained from the drainage circuit 82 to the acid-based drainage mechanism 25.

When the cleaning process in the cleaning device 12 is completed, the wafer chuck 36 of the transfer device 30 is lowered into the inner bath 60 of the cleaning bath 62, and the 50 wafers W held on the boat unit 50 are collectively transferred. Hold and rise.
In this way, 50 wafers W are collectively taken out of the inner tank 60 of the cleaning tank 62 and transported to the next cleaning device 13. Thereafter, the same cleaning process is sequentially performed in each of the cleaning devices 13 to 17. Finally, the wafer W is dried in the drying device 19 and is carried out of the device via the loading / unloading unit 4 in units of the carrier C.

The cleaning liquid used in the subsequent cleaning devices 13 to 17 is pure water or an acidic cleaning liquid. Therefore, as described above with reference to FIG. 2, the drainage mechanism provided in the cleaning system 1 only needs to be the acid-based drainage mechanism 25 and the pure water drainage mechanism 26.

Thus, according to the cleaning system 1 of this embodiment, there is no need to provide an alkaline drainage mechanism, and the drainage mechanism can be simplified. Therefore, it is possible to reduce the size of the system and to facilitate the management of drainage. Further, according to the cleaning apparatus 12 of this embodiment, the concentration of the cleaning liquid filled in the cleaning tank 62 is 0.1.
By using a hydrogen peroxide solution of 5 wt% or more, the surface of the wafer W is protected from etching caused by ions or the like generated in the cleaning liquid, and thereby, the surface of the wafer W is prevented from being roughened. Particles attached to the surface can be effectively removed. Therefore, even after the cleaning, the surface of the wafer W is not roughened, so that it is possible to prevent an adverse effect on later manufacturing. As a result, semiconductor devices can be manufactured smoothly, and productivity can be improved.

Although the cleaning system 1 and the cleaning apparatus 12 for processing a wafer W have been mainly described as an example, the present invention is applicable to a cleaning system and a cleaning apparatus for handling another object to be processed such as an LCD substrate. It is also possible to make it. Further, the present invention may be applied to a so-called single wafer type cleaning apparatus for cleaning wafers one by one.

[0051]

EXAMPLE Next, an example of the present invention was performed. The cleaning apparatus described with reference to FIGS. 4 and 5 was actually manufactured, and the effect of removing particles and the influence of wafer surface roughness due to changes in the concentration and temperature of the cleaning liquid were examined. Three types of cleaning liquid were used: pure water, hydrogen peroxide diluted with pure water, and a mixed solution of aqueous ammonia, hydrogen peroxide and pure water (APM cleaning liquid). The temperature of the washing liquid was changed in two cases, 50 ° C. and 80 ° C. In each of the embodiments, the cleaning liquid was subjected to ultrasonic vibration from a megasonic device, and the cleaning time was 1 min, 3 min, and 10 m as a common condition.
in and the number of wafers to one, 25
The cleaning process was performed in three stages of 50 sheets. Before the cleaning process, particles were artificially attached to the surface of the wafer, and then the cleaning process was performed. The particle removal rate was determined as follows.

Particle removal rate = (B−C) /
(B−A) × 100% A: Particle initial value of wafer before artificially attaching particles B: Particle value of wafer after artificially attaching particles C: Particle value of wafer after cleaning process

The removal rate of the particles on the wafer was 1
A value exceeding 00% indicates that the particle value (C) of the wafer after the cleaning process is further smaller than the particle initial value (A) of the wafer.

Hereinafter, the results are shown in Tables 1 to 8.

[0055]

[Table 1]

[Table 2]

[Table 3]

[Table 4]

[Table 5]

[Table 6]

[Table 7]

[Table 8]

Tables 1 to 4 all show that the temperature of the cleaning solution was 50
° C. When the cleaning treatment was performed with pure water at 50 ° C., as can be understood from Table 1, although the particle removal rate was good, slight surface roughness was observed. In addition, when the cleaning treatment was performed with 50 ° C. and 0.33 wt% hydrogen peroxide solution, as can be understood from Table 2,
Although the particle removal rate was slightly lower than in Table 1, no surface roughness was observed. Here, it is estimated that the reaction rate required for oxygen molecules in the hydrogen peroxide solution to oxidize the silicon surface of the wafer to form a silicon oxide film and the etching rate due to ions generated in the cleaning solution are almost balanced. Is done. In addition, 3.00 wt.
When the cleaning process is performed with a hydrogen peroxide solution of
As can be understood from Table 3, the particle removal rate was higher than that in Table 2, and no surface roughness was observed. Here, since the concentration of the hydrogen peroxide solution is high, the reaction rate of oxidation by oxygen molecules becomes faster than the etching rate by ions and the like generated in the cleaning solution, and a silicon oxide film is always formed on the surface of the wafer. It is estimated that it is protected from etching by ions and the like. Also, at 50 ° C,
As can be understood from Table 4, when the cleaning process was performed using an APM cleaning solution in which a 0.46 wt% aqueous ammonia solution, 2.95 wt% hydrogen peroxide solution and pure water were mixed, the particle removal rate was as shown in Table 3. There is almost no change compared to the time.

Tables 5 to 8 show that the temperature of the cleaning solution was 80
° C. When the cleaning treatment was performed with pure water at 80 ° C., as can be understood from Table 5, the surface was roughened to a point where measurement was impossible. Further, when the cleaning treatment was performed at 80 ° C. with a 0.33 wt% aqueous hydrogen peroxide, as can be understood from Table 6, no surface roughness was observed. Here, as in the case of Table 2, the reaction rate required for oxygen molecules in the hydrogen peroxide solution to oxidize the silicon surface of the wafer to form a silicon oxide film, the etching rate due to ions generated in the cleaning solution, and the like. Are estimated to be almost balanced. Further, when the cleaning treatment was carried out with 80 ° C. and 3.00 wt% of hydrogen peroxide solution, as can be understood from Table 7, the particle removal rate was improved as compared with those in Tables 3 and 6. No surface roughness was observed. Here, since the temperature is as high as 80 ° C. as compared with Table 3, it is estimated that the particle removal rate has been improved. As in the case of Table 3, since the concentration of the hydrogen peroxide solution is high, the oxidation reaction rate by oxygen molecules becomes faster than the etching rate by ions and the like generated in the cleaning solution, and the silicon oxide film is always formed on the wafer surface. It is presumed that it is formed and protected from etching by ions and the like. Thus, the cleaning solution in Table 7
The concentration of the hydrogen peroxide solution was as high as 3.00 wt% and the temperature was as high as 80 ° C.
Particle removal was most effectively performed among the examples up to Table 8. In addition, when the cleaning process was performed using an APM cleaning solution obtained by mixing an aqueous ammonia solution of 0.46 wt%, a hydrogen peroxide solution of 2.95 wt%, and pure water at 80 ° C., as can be understood from Table 8, the particles were removed. The ratio was lower than in Tables 4 and 7, and surface roughness was also observed. Here, the aqueous ammonia solution is mixed,
Further, since the temperature is as high as 80 ° C., it is estimated that the etching rate by ions and the like generated in the cleaning solution becomes faster than the reaction rate of oxidation by oxygen molecules. As a result, it is presumed that the protection by the silicon oxide film is inferior, the etching by ions or the like is performed on the silicon surface of the wafer, and the wafer is roughened.

From the above results, in a cleaning solution containing pure water alone or a conventional APM cleaning solution, as the temperature rises, the particle removal rate decreases and the wafer tends to be roughened. On the other hand, when the cleaning solution is a hydrogen peroxide solution having a concentration of 3.00 wt%, the silicon surface of the wafer is sufficiently protected, and the particle removal rate is improved when ultrasonic vibration is applied. Furthermore, the higher the temperature of the cleaning liquid, the more the particle removal rate tends to be improved. Therefore, as shown in Table 7, it is considered that the cleaning liquid having a high concentration of the hydrogen peroxide solution and the high temperature removes the particles most effectively.

[0059]

According to the present invention, there is no need to provide an alkaline drainage mechanism, so that the drainage mechanism can be simplified. Therefore, it is possible to reduce the size of the system and to facilitate the management of drainage.

Further, according to the present invention, by using a hydrogen peroxide solution as the cleaning liquid filled in the cleaning tank, the surface of the object to be processed is prevented from being etched by ions or the like generated in the cleaning liquid by ultrasonic vibration. Thus, particles adhered to the surface of the object to be processed can be effectively removed while suppressing surface roughness as much as possible. Therefore, even after the cleaning, the surface of the object to be processed is not roughened, so that it is possible to prevent adverse effects on the later manufacturing. As a result, for example, further technical innovation of miniaturization technology in the manufacture of semiconductor devices can be promoted, and productivity can be improved.

[Brief description of the drawings]

FIG. 1 is a perspective view of a cleaning system including a cleaning device according to an embodiment of the present invention.

FIG. 2 is a circuit diagram of a drainage mechanism of the cleaning system.

FIG. 3 is an enlarged perspective view showing a transport device.

FIG. 4 is a schematic diagram of a circuit system of the cleaning device according to the embodiment of the present invention.

FIG. 5 is a sectional view of a cleaning device.

[Explanation of symbols]

 C Carrier W Wafer 1 Cleaning system 2 Loading / Unloading unit 3 Cleaning / drying processing unit 4 Loading / Unloading unit 12 Cleaning device 25 Acid-based drainage mechanism 26 Pure water drainage mechanism 62 Cleaning tank 64 Cleaning liquid supply unit 65, 79 Heater 90 Megasonic device

Claims (11)

[Claims] 1. A cleaning system comprising one or more cleaning devices for cleaning an object to be processed by contacting the object with the cleaning liquid, wherein the cleaning liquid used in the cleaning device is neutral or acidic. Cleaning system. 2. A cleaning apparatus for cleaning by bringing a cleaning liquid into contact with an object to be processed, wherein the cleaning liquid is a hydrogen peroxide solution. 3. The concentration of the hydrogen peroxide solution is 0.15 wt.
%. 4. The cleaning apparatus according to claim 2, further comprising a temperature adjusting unit for adjusting a temperature of the cleaning liquid. 5. The cleaning apparatus according to claim 4, wherein the temperature of the cleaning liquid is 35 ° C. or higher. 6. The cleaning apparatus according to claim 2, further comprising a vibration oscillating mechanism for applying vibration to the cleaning liquid. 7. A cleaning method for cleaning by bringing a cleaning liquid into contact with an object to be processed, wherein the cleaning liquid is an aqueous solution of hydrogen peroxide. 8. The concentration of the hydrogen peroxide solution is 0.15 wt.
The cleaning method according to claim 7, wherein the cleaning rate is not less than%. 9. The cleaning method according to claim 7, wherein the temperature of the cleaning liquid is adjusted. 10. The cleaning method according to claim 9, wherein the temperature of the cleaning liquid is 35 ° C. or higher. 11. The cleaning method according to claim 7, wherein vibration is applied to the cleaning liquid.