JP3470501B2 - Semiconductor wafer centrifugal drying method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor wafer centrifugal drying method and apparatus. More specifically, the present invention relates to a method and an apparatus for efficiently drying a semiconductor wafer using a single-wafer spin cleaning machine.

[0002]

2. Description of the Related Art A conventional single-wafer spin cleaning machine for cleaning and drying semiconductor wafers transfers semiconductor wafers set in a carrier one by one to a processing chamber and keeps the semiconductor wafers horizontal by a spinner. As it is, the cleaning liquid is supplied from at least one of the upper side and the lower side of the semiconductor wafer to clean the semiconductor wafer. When the cleaning with the cleaning liquid is completed, a pure water rinse liquid or the like is supplied to clean the semiconductor wafer. When the cleaning with pure water or the like is completed, the number of rotations of the semiconductor wafer is set to a high rotation speed, and moisture and the like adhering to the surface of the semiconductor wafer are cut off to dry the semiconductor wafer. Further, dry air or nitrogen may be supplied for drying. After drying, it is taken out of the processing chamber and returned to the carrier. Depending on the case, a plurality of processing chambers may be prepared and used depending on the type of cleaning liquid and processing such as drying. Further, there are cases where treatment with a plurality of treatment liquids is continuously performed in one treatment chamber.

[0003]

However, according to the above-mentioned prior art, when a deep hole is formed in the semiconductor wafer, a pattern having a large aspect ratio is formed, or the unevenness due to the mounted element is large. ,
Water remains in that area, causing water marks.
Further, since the centrifugal force is small in the central portion of the semiconductor wafer, water also remains in that portion, which also causes a watermark. In addition, since the rotation of the semiconductor wafer during drying is high, static electricity is generated due to stress on the semiconductor wafer and friction with air, which may cause damage to the device or particles to adhere to the semiconductor wafer. Become. Furthermore, in order to improve the drying effect by supplying dry air or a gas such as nitrogen, it is necessary to supply nitrogen gas or the like to the entire processing chamber in which the drying is performed, and the amount of nitrogen gas or the like used is extremely large. Will increase.

On the other hand, as a drying apparatus for semiconductor wafers, I
PA vapor dryers are known. There are three methods of drying with this device: a method of replacing water with IPA, a method of using an IPA liquid layer formed on the water surface, and a method of utilizing the Marangoni effect.

The first replacement method is to vertically put a semiconductor wafer on which cleaning water is adhered in a vapor drying tank having a saturated vapor zone in equilibrium with boiling IPA (isopropyl alcohol). The adhering water is dissolved by the IPA condensed on the surface of the semiconductor wafer, and the surface of the semiconductor wafer is removed as a drain that flows down and dried.

The second method using the IPA liquid layer is to put a semiconductor wafer in a closed container, pass pure water from the bottom to the top for rinsing, and control the flow rate in the container after rinsing. While draining from the bottom, IPA from the top of the container at the same time
Supply steam. The IPA vapor condenses on the water surface and dissolves in the water, but the continuous supply of IPA forms a liquid layer of IPA on the water surface. When the rinse water is drained and the water surface descends and crosses the wafer surface, the IPA liquid layer at the interface replaces and removes the attached water film. IPA replacement surface continues to be IPA
It is heated and dried by steam. After drying, the IPA in the container is purged with nitrogen.

The third method utilizing the Marangoni effect is usually 1 when the wafer having a hydrophilic surface is pulled up from the water surface.
Although an adhered water film of about 0 μm is formed, when IPA vapor is supplied to the immersion interface, the IPA dissolved from the water surface creates a gradient of surface tension in the meniscus portion and Marangoni.
Flow is generated and the surface of the semiconductor wafer is hard to wet. Use this to dry. According to this method, it is known that the number of generated watermarks is 1/50 of that in the drying method using the single-wafer spin cleaning machine. The IPA used in these three methods has a function of discharging static electricity from a charged semiconductor wafer.

The present invention has been made in view of the drawbacks of the above-mentioned conventional single-wafer spin cleaning machine and the advantages of the IPA vapor drying apparatus, in which water marks are not generated and particles are not adhered, and a drying fluid is used. An object of the present invention is to provide a method for centrifugally drying a semiconductor wafer and an apparatus therefor capable of reducing the amount used.

[0009]

SUMMARY OF THE INVENTION The present invention is a semiconductor wafer.
Rotate the spinner holding the
Wipe off the water adhering to the surface of the semiconductor wafer.
The semiconductor wafer is dried and the semiconductor wafer
Drying to cover the surface of the semiconductor wafer with a drying fluid.
Semi-conductor using a semiconductor wafer centrifugal dryer equipped with a guide
Conductor wafer centrifugal drying method, rotating semiconductor wafer
While supplying the pure water from the drying guide,
Pure water is filled between the conductor wafer and the drying guide.
Then, supply IPA vapor from the drying guide and push
IPA aggregated at the interface between the deionized water and the IPA vapor
An IPA liquid layer is formed, and the semiconducting force is generated by centrifugal force of this liquid layer.
Water on the surface of the semiconductor wafer due to movement on the surface of the body wafer
After replacing the content with IPA to remove water, the drying gas is removed.
A drying gas is supplied from the id to attach to the surface of the semiconductor wafer.
The attached IPA is evaporated to dry the semiconductor wafer.
It is something.

The present invention also holds a semiconductor wafer horizontally.
The spinner is rotated and the centrifugal force is applied to the semiconductor.
A semiconductor wafer that removes moisture adhering to the surface of the wafer
For drying and covering the semiconductor wafer
A drying guide is provided to guide the fluid to the surface of the semiconductor wafer.
Semiconductor wafer centrifuge
This is a method of drying the core, which is performed while rotating the semiconductor wafer.
Pure water is supplied from the drying guide to the semiconductor wafer and
After being filled with pure water between the drying guide,
The IPA vapor is supplied from the drying guide to push it away.
IP using Marangoni effect at the interface between water and IPA vapor
A surface tension gradient of A is formed, and a gas-liquid interface having this gradient is formed.
The semiconductor is moved by the movement on the surface of the semiconductor wafer by the centrifugal force of
The water on the surface of the body wafer is replaced with IPA to remove the water.
After that, supply the drying gas from the drying guide and
Semiconductive by evaporating the IPA adhering to the surface of the body wafer
The body wafer is dried.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a semiconductor wafer is horizontally
Rotate the held spinner and use centrifugal force to
The semiconductor wafer is wiped off by removing the moisture adhering to the surface of the conductor wafer.
Dry the roof and cover the semiconductor wafer to dry it.
A drying guide for guiding a drying fluid to the surface of the semiconductor wafer
Semiconductor wafer using a semiconductor wafer centrifugal drying device
The present invention relates to a centrifugal drying method.

That is, the present invention rotates a semiconductor wafer.
While supplying the pure water from the drying guide,
Pure water is filled between the conductor wafer and the drying guide.
Then, supply IPA vapor from the drying guide and push
IPA aggregated at the interface between the deionized water and the IPA vapor
An IPA liquid layer is formed, and the semiconducting force is generated by centrifugal force of this liquid layer
Water on the surface of the semiconductor wafer due to movement on the surface of the body wafer
After replacing the content with IPA to remove water, the drying gas is removed.
A drying gas is supplied from the id to attach to the surface of the semiconductor wafer.
The attached IPA is evaporated to dry the semiconductor wafer.
It is characterized by that.

The present invention also does not rotate the semiconductor wafer.
The pure water is supplied from the drying guide, and
After the pure water is filled between the roof and the drying guide,
Supply IPA vapor from the drying guide to push
Utilizing the Marangoni effect at the interface between pure water and IPA vapor
Forming a surface tension gradient of the IPA and
By the movement on the surface of the semiconductor wafer by the centrifugal force of the liquid interface,
Replacing water on the surface of semiconductor wafers with IPA
After removing it, supply the drying gas from the drying guide.
To evaporate the IPA adhering to the surface of the semiconductor wafer
The semiconductor wafer is dried by
It

[0014]

[0015]

[0016]

EXAMPLES The present invention mainly enables an excellent drying method utilizing IPA vapor in a single-wafer spin cleaning machine.

FIG. 1 is a basic constitutional view showing an essential part of an example of a semiconductor wafer centrifugal drying apparatus according to the present invention, (A) showing its plan view and (B) showing its sectional view. The semiconductor wafer 1 is formed in a disk shape having an orientation flat (not shown), and is horizontally held by a holder 20 above the peripheral edge of a bottomed cylindrical spinner 4. The rotating shaft 4a provided at the center of the bottom of the spinner 4 is formed in a cylindrical shape having a small diameter. The upper and lower surfaces of the semiconductor wafer 1 are covered with disk-shaped drying guides 2 and 5 that guide the drying fluid to the surface of the semiconductor wafer 1. The upper drying guide 2 is provided with a small-diameter cylindrical drying fluid supply port 2a projecting upward at the center thereof. The lower drying guide 5 is provided with a small-diameter cylindrical drying fluid supply port 5a protruding downward at the center thereof, and the drying fluid supply port 5a penetrates the hollow portion of the rotation shaft 4a of the spinner 4. To do. In this example, both of the drying guides 2 and 5 are configured to rotate in the same direction as the spinner 4 with the center of the supply ports 2a and 5a as the center of rotation. Further, IPA vapor and nitrogen gas were used as the drying fluid supplied from the supply ports 2a and 5a. Pure water for rinsing was also supplied from the supply ports 2a and 5a.

FIG. 2 shows an example of the centrifugal drying method for semiconductor wafers according to the present invention, which is a combination of the single-wafer spin cleaning machine having the structure shown in FIG. 1 and the IPA vapor drying method using the IPA liquid layer formed on the water surface. It is a process explanatory view shown. In this example, there are no restrictions on the method of processing the cleaning chemical liquid before the drying processing and the configuration of the cleaning device. In addition, the method of holding the holder 20 and the semiconductor wafer 1
There is no restriction on the shape and number of contacting parts with.

In this drying method, first, the spinner 4 rotates the semiconductor wafer 1 while keeping it horizontal, and further the upper and lower drying guides 2 and 5 also rotate. Pure water 6 for rinsing is supplied to the upper surface and the lower surface of the semiconductor wafer 1 through the supply ports 2a and 5a of both the drying guides 2 and 5 (see FIG. 2).
(A)). Here, the supply amount of pure water, the number of revolutions of the semiconductor wafer 1, and the distance between the drying guides 2 and 5 and the semiconductor wafer 1 are determined by the pure water 6 between the semiconductor wafer 1 and the drying guides 2 and 5.
Is set in advance so that

When pure water is filled between the semiconductor wafer 1 and the drying guides 2 and 5, the IPA vapor 7 is supplied from the supply ports 2a and 5a of the upper and lower drying guides 2 and 5, respectively. IPA
When the vapor 7 is supplied, the pure water is pushed away, and IPA aggregates at the interface between the pure water 6 and the IPA vapor 7 to form the IPA liquid layer 8
Are formed (FIG. 2 (B)). In this case, the IP to supply
A may be pure IPA vapor, a mixed gas of water vapor, or a mixed gas of IPA vapor and nitrogen gas. Further, the supply amount, temperature, and concentration of the IPA gas or the like are adjusted according to the size, surface state, and rotation speed of the semiconductor wafer 1.
The water supplied with IPA or the like and pushed away is discharged from the outer periphery of the semiconductor wafer 1 and shaken off. Furthermore, IP
When the vapor A continues to be supplied, the interface between the IPA vapor 7 and the pure water 6 reaches the surface of the semiconductor wafer 1 and the semiconductor wafer 1 is rotating. Therefore, the centrifugal force causes a concentric circle around the center of the semiconductor wafer 1. An interface between the IPA vapor 7 and the pure water 6 is formed on the to form an IPA liquid layer 8 (FIG. 2 (C)). This I
When the PA liquid layer 8 passes over the surface of the semiconductor wafer 1, that is, the upper surface and the lower surface, the water content of the semiconductor wafer 1 becomes IPA.
Is replaced with water to remove water. The interface between the IPA vapor 7 and the pure water 6 spreads concentrically, and when it reaches the peripheral edge of the semiconductor wafer 1, it is shaken off by the centrifugal force.

Next, the supply ports 2a of the drying guides 2 and 5,
When the nitrogen gas 9 is supplied from 5a, the IPA adhering to the semiconductor wafer 1 evaporates and the drying is completed (FIG. 2).
(D)). The rotation direction and the rotation speed of the drying guides 2 and 5 may be different from or the same as the rotation direction and the rotation speed of the semiconductor wafer 1, or may be stopped.

FIG. 3 is a process explanatory view showing another example of the semiconductor wafer centrifugal drying method of the present invention in which the single-wafer spin cleaning machine having the configuration of FIG. 1 and the IPA vapor drying method utilizing the Marangoni effect are combined. Is. Also in this drying method, first, as shown in FIG.
Similarly, the semiconductor wafer 1 and the upper and lower drying guides 2, 5
Rotation, and supply ports 2a, 5a of both drying guides 2, 5
The pure water 6 for rinsing is supplied from above to the upper surface and the lower surface of the semiconductor wafer 1, and the pure water 6 is filled between the semiconductor wafer 1 and the drying guides 2 and 5 (FIG. 3A).

Next, the supply ports 2 of the two drying guides 2 and 5
The IPA vapor 7 is supplied from a and 5a. In this example, the supply amount and the concentration of the IPA vapor 7 are the same as those of the pure water 6 and the IPA.
The supply amount and concentration are set so that IPA does not aggregate on the interface of the vapor 7 of the above and an IPA liquid layer is not formed (FIG. 3).
(B)). In such a state, when the IPA vapor 7 is continuously supplied, the interface between the pure water 6 and the IPA vapor 7 reaches the surface of the semiconductor wafer 1 and forms a gas-liquid interface in a concentric pattern from the center of rotation (see FIG. 3). (C)), the semiconductor wafer 1 is dried by the Marangoni effect due to the surface tension gradient (based on the IPA concentration gradient) formed at the interface. When the nitrogen gas 9 is supplied after the gas-liquid interface reaches the peripheral edge of the semiconductor wafer 1, the IPA adhering to the semiconductor wafer 1 evaporates and the drying is completed (FIG. 3D).

FIG. 4 is a process explanatory view showing an example of the semiconductor wafer centrifugal drying method of the present invention in which the single-wafer spin cleaning machine having the structure of FIG. 1 and the IPA vapor drying method in which IPA replaces water are combined. is there. In this drying method, the semiconductor wafer 1 and the upper and lower drying guides 2, 5 are rotated in advance, and pure water 6 for rinsing is supplied from the supply ports 2a, 5a of the both drying guides 2, 5 to the upper and lower surfaces of the semiconductor wafer 1. To clean the semiconductor wafer. Semiconductor wafer 1 after cleaning
Water locally remains (FIG. 4 (A)), and in the case of hydrophilicity, a water film remains. In this example, first, while rotating the semiconductor wafer 1, the IPA vapor 7 is continuously supplied from the supply ports 2a and 5a of the drying guides 2 and 5 (FIG. 4 (B)). The IPA vapor 7 is condensed on the surface of the semiconductor wafer 1 and the moisture 1 on the upper and lower surfaces of the semiconductor wafer 1 is condensed.
Mix with 0. The IPA 11 mixed with water is shaken off from the outer peripheral edge of the semiconductor wafer 1 by the centrifugal force generated by the rotation of the semiconductor wafer 1 (FIG. 4C). The supply of IPA vapor is continued until the water content on the semiconductor wafer 1 is exhausted. Next, the nitrogen gas 9 is supplied to the supply ports 2 of the drying guides 2 and 5.
When supplied from a and 5a, the IPA adhering to the upper and lower surfaces of the semiconductor wafer 1 is evaporated and the drying is completed (FIG. 4).
(D)).

In the drying method shown in FIGS. 2 to 4, the cleaning chemical solution, pure water for rinsing, and IPA are supplied from the supply port of the drying guide.
If the vapors are supplied in this order, the semiconductor wafer can be cleaned and dried without being exposed to the atmosphere, and contamination from the atmosphere and oxidation of the surface of the semiconductor wafer can be prevented.

In the above embodiment, each of the upper and lower drying guides has one supply port, but the supply port for the drying gas and the supply port for the pure water for rinsing may be provided separately.

In the drying method shown in FIG. 4, the supply of IPA vapor is omitted, the water on the surface of the semiconductor wafer is washed off with pure water after being washed with pure water, and then dry nitrogen or dry air is immediately supplied to supply the semiconductor. The wafer 1 may be dried.

Although the drying guides are provided above and below the semiconductor wafer in the above embodiment, they may be provided on only one of them depending on the application.

In addition, the IPA is used for the drying guide of the above embodiment.
A heating device may be added to adjust the temperature of the steam or nitrogen gas so as not to drop.

In the above examples, IPA vapor was used, but instead of this, vapor of a compound having a high affinity (compatibility) with water and high volatility, such as perfluoroheptane and trifluoroethanol, is used. You may use the mixed solvent of these.

In the above-mentioned embodiment, the drying guide has a flat disk shape, but the drying guide need not be flat as long as the drying fluid can be supplied to the semiconductor wafer.

[0032]

As described above, according to the present invention, the drying guide which covers the semiconductor wafer and guides the drying fluid to the surface of the semiconductor wafer is provided. It is possible to clean and dry the wafer, and it is possible to dry by supplying the drying fluid to the small space between the semiconductor wafer and the drying guide. The amount of nitrogen gas or the like used can be extremely reduced as compared with the conventional technique in which the nitrogen gas must be supplied and dried. Further, if the cleaning chemical solution, the rinsing pure water and the drying fluid are sequentially supplied to the semiconductor wafer from the supply port of the drying guide, the semiconductor wafer can be cleaned and dried without being contaminated with the air. Further, by combining the single-wafer spin cleaning machine and the IPA vapor drying method to dry the semiconductor wafer, it is possible to eliminate the watermark which cannot be eliminated only by the single-wafer spin cleaning machine, and thus the high quality is achieved. You can get the product. In addition, since it is possible to dry the semiconductor wafer without rotating it at a high speed as in a normal single-wafer spin cleaning machine, it is possible to prevent the generation of static electricity, and the IPA itself has a static elimination effect. No damage will occur.

[Brief description of drawings]

FIG. 1 is a basic configuration diagram showing a main part of an example of a semiconductor wafer centrifugal drying apparatus according to the present invention.

2 is a process explanation showing an example of a semiconductor wafer centrifugal drying method of the present invention in which a single-wafer spin cleaning machine having the configuration of FIG. 1 and an IPA vapor drying method using an IPA liquid layer formed on a water surface are combined. It is a figure.

FIG. 3 is a process explanatory view showing another example of the semiconductor wafer centrifugal drying method of the present invention in which the single-wafer spin cleaning machine having the configuration of FIG. 1 and the IPA vapor drying method utilizing the Marangoni effect are combined.

FIG. 4 is a single-wafer spin cleaning machine having the configuration of FIG. 1 and IPA.
FIG. 4 is a process explanatory view showing an example of the semiconductor wafer centrifugal drying method of the present invention in combination with the IPA vapor drying method in which the water is replaced with water.

[Explanation of symbols]

1: semiconductor wafer, 2: upper drying guide, 2a: drying fluid supply port, 4: spinner, 4a: rotating shaft, 5: lower drying guide, 5a: drying fluid supply port, 6: pure water,
7: IPA vapor, 8: IPA liquid layer, 9: nitrogen gas, 1
0: residual water, 11: mixture of IPA and water, 20: holder

─────────────────────────────────────────────────── --- Continuation of the front page (56) References JP-A-5-243205 (JP, A) JP-A-8-78368 (JP, A) JP-A-8-86992 (JP, A) JP-A-8- 236497 (JP, A) JP 9-38595 (JP, A) JP 60-64436 (JP, A) JP 63-73626 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21/304

Claims (2)

(57) [Claims] 1. A spinner holding a semiconductor wafer horizontally.
Rotate the surface of the semiconductor wafer using centrifugal force
The semiconductor wafer is dried by shaking off the moisture adhering to the
At the same time, the semi-conductor wafer is covered with a drying fluid.
A semiconductor wafer provided with a drying guide for guiding the surface of the conductor wafer.
With the centrifugal drying method for semiconductor wafers using the centrifugal dryer
There are, pure water is supplied from the drying guides while rotating the semiconductor wafer, after the pure water is filled between the drying guides and the semiconductor wafer, IPA from said drying guide
By supplying vapor, IPA liquid layer in which IPA is condensed is formed at the interface between the pure water and IPA vapor to be displaced, and the centrifugal force of this liquid layer moves on the surface of the semiconductor wafer to move the moisture on the surface of the semiconductor wafer to IPA. A method for centrifuge drying a semiconductor wafer, characterized in that after the water is removed by replacement, a drying gas is supplied from the drying guide to evaporate IPA adhering to the surface of the semiconductor wafer to dry the semiconductor wafer. . 2. A spinner holding a semiconductor wafer horizontally.
Rotate the surface of the semiconductor wafer using centrifugal force
The semiconductor wafer is dried by shaking off the moisture adhering to the
At the same time, the semi-conductor wafer is covered with a drying fluid.
A semiconductor wafer provided with a drying guide for guiding the surface of the conductor wafer.
With the centrifugal drying method for semiconductor wafers using the centrifugal dryer
There are, pure water is supplied from the drying guides while rotating the semiconductor wafer, after the pure water is filled between the drying guides and the semiconductor wafer, IPA from said drying guide
A surface tension gradient of IPA that utilizes the Marangoni effect is formed at the interface between pure water and IPA vapor that is displaced by supplying steam, and the semiconductor wafer is moved by the centrifugal force of the gas-liquid interface having this gradient on the surface of the semiconductor wafer. The surface of the semiconductor wafer is replaced with IPA to remove the water, and then a drying gas is supplied from the drying guide to evaporate the IPA adhering to the surface of the semiconductor wafer to dry the semiconductor wafer. A method for centrifugally drying a semiconductor wafer.